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tom!
11-28-2017, 02:05 PM
Hi.

As promised I add my Japanese Armoured Fighting Vehicles manual. As the original post seems to be lost I will rebuild it during the next weeks, maybe months. So I have to ask for your patience.

Content::

1. Introduction
2. Japanese Designations and a short Dictionary
3. Armament: Machine Guns
4. Armament: Guns
5. Foreign AFV
6. Early japanese Projects
7. Armored Cars
8. Tankettes
9. Light Tanks
10. Medium Tanks
11. Heavy Tanks
12. Gun Tanks
13. Gun Carriers
14. Army Amphibious Tanks
15. Engineer AFV
16. Railroad AFV
17. Remote Operated AFV
18. Other Special Purpose AFV
19. Experimental Engineer AFV
20. Other Experimental AFV
21. Infantry AFV


I´m quite shure you´ll find a some vehicles unknown to you. I did during the search.

Due to the forum restriction of 10000 characters per post I´ll have to split most of the posts into two or more parts.

Yours

tom! ;)

tom!
11-28-2017, 02:14 PM
Hi.

1. Introduction part 1:

The japanese Army (IJA) had a lot of military observers on the European battlefields during WW1 which gathered many informations about modern war material and its use in a battle. This included chemical agents, light machine guns, aircraft, submarines, armored cars, tractors and also tanks. With the upcoming end of the war IJA decided in late 1918 to purchase examples of british and french tanks. As France and Great Britain had built several thousand tanks which weren´t needed any more it was no problem to receive them. A british Mark IV was delivered in late 1918 as technology transfer and propaganda vehicle. In 1919 a few FT 17s and Medium Mark A Whippets were also transferred to Japan. These were used to build up a tank company for test and training purposes at the IJA Infantry School.

During the Siberian Intervention 1918 - 1922 Japan sent several domestically made armored cars to support their troops. During the disarmament operation several white russian Austin armored cars were taken over. These vehicles were more modern and showed their value very soon.


http://www.ww2technik.de/Bilderchen/jappanzer/ausland/Jap%20mk%20IV%20female.jpg
Mark IV unloaded in Japan

In 1921 IJA decided to build up a domestic tank production. After the examinations and tests it became clear that the japanese industry was too weak to support a production at this time. So the tanks were sent on exhibitions throughout Japan to advertise for the necessary expenses in modern technology until 1928. The Kanto earthquake in 1923 delayed several projects. Nevertheless in 1925 the Japanese Army Technical Bureau was sure to be able to develop a domestic tank within 2 years. IJA high command was not convinced but nevertheless technical specifications for a heavy multi-turret tank were given. The design was quite difficult as most details had to be developed from zero. Most surprising the resulting tank, built in 1927, met almost all requirements and showed good characteristics and speed. Only the armor strength was rated too low. So after 1928 the tank was redesigned.

In addition requirements for a fast medium tank were given in 1927. This development was supported by trials to order new tank models for tests. This was quite problematic as most countries had stopped military development after 1918 to recover from the expenses of the war. So the few new designs were all rated top secret making it almost impossible to receive samples. Only rejected designs like the Vickers Medium Mark C were available. These were most useful for the development of the medium tank. Nevertheless there were some design failures making a complete restart in 1928 necessary. The new design used many features from the Vickers Mark C pre-series vehicles including the bow armor. Most important was an accident with the Mark C with the gasoline engine catching fire during an uphill drive. As a result IJA decided to use Diesel engines which used a less valuable fuel and were less vulnerable to fire. The resulting vehicle was fast enough to follow contemporary trucks, well-armed and sufficiently armored. But there were still problems to start a mass production in 1930. Especially the development of a Diesel engine took time and wasn´t finished until 1933. So some 50% of the built vehicles were equipped with gasoline engines.

In addition several foreign tractors and armored vehicles were tested during the 1920th leading to a large mechanisation wave in the early 1930th. This included the development of armored vehicles, special railway vehicles, amphibious AFV, tankettes and special purpose tanks. But due to the restricted available budgets only few projects were finally introduced and built in numbers larger than 10. This problem was solved with the start of the 2nd Sino-Japanese War or “China Incident” as it was called in Japan. Nevertheless tanks and AFV were still rated low priority compared to weapons, trucks, aircraft and ships.

The standard IJA tank tactic was infantry support based on the british and french tactics in WW1. Therefore tanks mainly had to fight field fortifications and bunkers. Enemy tanks should be fought by infantry anti-tank weapons and artillery. So IJA tanks had to be armored against infantry AP ammunition and to be armed with short, larger caliber guns. Speed was not that necessary.

In the mid-1930th IJA introduced a light tank rated as “cavalry tank”. It should be used for fast breakthroughs and had to fight enemy AFV, too. Therefore the tank had to be light. This was reached by using angled armor and finally even reducing armor to a minimum. Armament was a long barreled gun, 37 mm caliber. In 1935 a new medium tank was developed with higher speed and more armor. After this a complete development stop happened as the army high command thought they had all they need and refused any warnings that Japan would be unable to keep pace with the international tank development especially forced by Germany and the Soviet Union. There were several proposals of the Army Technical Bureau but all were rejected. These tanks had modern design features like coaxial MGs, protected suspension, more angled armor, welded armor and a 47 mm gun.

During the 1939 Nomonhan Incident against the Soviet Union a japanese tank regiment participated in the fightings. When they met T-26 and BT-5 tanks they were easily knocked out by the 45 mm long tank guns even on longer ranges. The japanese tanks had to get in closer ranges to penetrate the armor with the short 57 mm tank guns. So they were easy targets. This disaster was deemphasized by IJA High Command by focusing the war reports on the “strength and courage of the fighting forces”. Results were the development of a longer 47 mm tank gun and the necessary turret for the medium tank plus development of a long 57 mm tank and anti-tank gun. Most problematic was the decision to develop a superheavy multi-turret tank with an estimated weight of 120 t. But new, more modern designs were still rejected.

1941 the IJA tank doctrine was finally slowly redeveloped based on the experiences of the german tanks in France and during the early stages of the Operation Barbarossa. This lead to the organization of tank divisions in 1942 and development of tactics different from pure infantry support.
In addition the 1941 US embargo made a war against the allies more likely, if not necessary. First step was to speed up the development of the 47 mm, turret and 57 mm tank guns which only had low priority before. In addition proposals for an uparmored version of the medium tank and a new light tank for the airborne regiments were accepted. In early 1942 the first medium tanks with long barreled 47 mm tank gun were ready for action. They were sent to the Philippines immediately but came too late to participate in the main fightings. Test firings against a US Light M3 showed that the gun easily penetrated even the thickest armor of this tank on 500 m.


http://www.ww2technik.de/Bilderchen/jappanzer/jap%20beschusstest%20typ%201%2047%20mm%20gun%20geg en%20us%20light%20m3.jpg
Light M3 nach Beschusstests

Part 2 below.

Yours

tom! ;)

tom!
11-28-2017, 02:21 PM
Hi.

Introduction part 2

In addition the development of two new tank models able to fight KV-1 tanks were ordered in mid-1942, a medium with the planned 57 mm gun and a heavy with a long 75 mm gun. Before design reached the prototype stage intensive examinations of the contemporary german tanks were started. In early 1943 even the new Tiger and Panther tanks were examined and a sample of each bought. At this time the low stocks of raw materials became problematic and as result all developments were slowed down. Another major drawback was the decision to terminate the development of the long 57 mm tank gun due to a too low firepower.


https://static-ptl-eu.gcdn.co/dcont/fb/image/japan_tiger_1.jpg
japanese military personel examining a Tiger tank in Germany

In late 1943 the new tanks were still on the drawing boards. The US Medium M3 and Light M3 and the british Mathilda tanks were superior to anything Japan could field. So the production of the uparmored version of the medium tank was speed up as much as possible. In addition a 75 mm field gun should be converted into a tank gun able to defeat the contemporary enemy tanks as stopgap solution. This made also a new turret necessary which was finished in 1944. During all this time the completely outdated 1935 light tank and 1937 medium tank were still mass produced. All upgraded tanks were held in Japan to counter the expected invasion. In addition most transport routes were under siege by allied submarines and carrier task forces making sea transport very dangerous.

The new medium tank model was not finished before summer 1945 due to problems with the newly developed long 75 mm tank gun based on an aa-gun. The new heavy tank was still in development in August 1945. Both were not serial produced. With them an allied invasion would have been very costly. All developments could be held secret so US intelligence officers were quite surprised after surrender to find such large and quite modern tanks in Japan.

With the development of the long barreled 47 mm gun the tanks lost significant HE-power. So from 1939 on several gun tanks armed with 75 mm, 105 mm and even 150 mm artillery guns were developed and produced. These AFV should be used in special gun tank companies in the tank regiments and used for close support. These vehicles were self-propelled artillery.

The infantry received gun carriers (tanks were only allowed for tank units…..) which used long barreled AT-guns. These vehicles were tank hunters.


http://www.ww2technik.de/Bilderchen/jappak/fahrzeuge/jap%20typ%205%2075%20mm%20panzerjaeger%20na-to%20rechts%20vorn.jpg
Type 5 7 cm Gun Carrier Na-To

A lot of special purpose vehicles based on tankette and medium tank chassis were developed and produced, most of them only in smaller numbers. There were a number of special vehicles for railway units, engineers and communication units, also several armored transport vehicles.

IJA tried to develop amphibious tanks during the mid-1930th but only prototypes were produced. Only the japanese navy used amphibious tank and vehicles operational. They also had several IJA tank models and even special close-support tanks for the Special Naval Landing Forces.

Yours

tom! ;)

Rising Sun*
11-29-2017, 09:37 AM
Thanks, tom! for this interesting material.

I wonder whether the IJA gave sufficient consideration to the terrain in which their tanks would be used as part of national military strategy and local tactics, as distinct from just building tank forces based on the use and terrain of other armies?


1941 the IJA tank doctrine was finally slowly redeveloped based on the experiences of the german tanks in France and during the early stages of the Operation Barbarossa. This lead to the organization of tank divisions in 1942 and development of tactics different from pure infantry support.


While terrain in China might have been better suited to tanks, as far as the southward thrust into Malaya, NEI, Burma, Papua New Guinea, Solomon Islands etc was concerned, much of the terrain wasn't suited to IJA tanks in any seriously useful capacity apart from, occasionally, clearing lightly fortified Allied positions. The terrain certainly didn't support the sort of tank warfare which occurred in Western and Eastern Europe, whether tank to tank or tank as infantry support in advance.

Apart from the Philippines where IIRC there were about equal numbers of US and IJA tanks, the IJA tanks tended to outnumber the Allied tanks if any Allied tanks were actually present but it wasn't the relatively few IJA tanks but the superiority of IJA infantry training, battle hardening, tactics, aggression and determination which generally carried the battles in the IJA's (and IJN land forces in places) favour over Allied forces.

In particular, IJA tanks weren't suited to or even able to participate in the very effective IJA infantry tactics in close country and jungle of envelopment and infiltration of Allied positions, which were purely infantry operations, and which in Malaya in particular were primarily responsible for Japan's victory and, separately, Japan's successful advance in Papua New Guinea in 1942.

Conversely, in close country IJA tanks were largely forced to stay on the roads where they were vulnerable to British Commonwealth artillery, as at Bakri where the Australian anti-tank artillery destroyed most of the advancing IJA tanks. https://www.awm.gov.au/index.php/collection/C31281 Nonetheless, as the IJA had tanks in Malaya and the British Commonwealth didn't, this gave the IJA a significant advantage.

Separate issue, but the wheel bottom left in the linked picture looks like it has the bearing and stub axle attached (which doesn't augur well for re-attaching the wheel) and the item to the right rear of the wheel to the right of the gun looks a bit like a gun spade or perhaps the towing attachment, which in the latter case also doesn't augur well for getting the gun out of there. Anyone know what these parts are and how they worked on reassembling the gun?

Churchill
11-29-2017, 04:01 PM
Nice read Tom!, I look forward to the rest!

RS*, I presume you're talking about the Na-To. I don't know what you mean about the first part with the stub axle, but as for the gun parts, I'm not inclined to believe that the gun was meant to be removed from the vehicle during or after fire. The WarThunder model of the vehicle does not have any provisions for removing the gun from the vehicle, as it is mounted to the chassis directly after the cab with what appears to be a purpose-built mount. While I'm sure they used the best possible sources they could, they may have certain inconsistencies.

Rising Sun*
11-30-2017, 03:48 AM
RS*, I presume you're talking about the Na-To. I don't know what you mean about the first part with the stub axle, but as for the gun parts, I'm not inclined to believe that the gun was meant to be removed from the vehicle during or after fire. The WarThunder model of the vehicle does not have any provisions for removing the gun from the vehicle, as it is mounted to the chassis directly after the cab with what appears to be a purpose-built mount. While I'm sure they used the best possible sources they could, they may have certain inconsistencies.

Sorry for any confusion. I was referring to the linked picture of the Australian anti-tank gun n my last post, shown below.



https://s3-ap-southeast-2.amazonaws.com/awm-media/collection/011302/screen/4160541.JPG

navyson
11-30-2017, 07:15 AM
Thanks for posting!

Churchill
11-30-2017, 02:01 PM
This makes a lot more sense, though I misread the beginning of your last paragraph.

tom!
01-02-2018, 11:12 AM
Hi.

The original thread has been recovered by the forum owner. Many thanks.




2. Japanese designations and a short dictionary part 1

The Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN) used several designation systems which differed only marginal for land-based weapons (compared to the airforce and naval designation systems). Most designations had the same basic appearance:

Yeartype - sort of equipment - (not always) short designation - (not always) additions

A) Yeartype

The Yeartype consisted mainly of a number indicating the year of introduction or design begin and the syllable "shiki" for "Type" or "Model" (which is still not finally clarified among experts, most tend to "Type"

Until 1940 the year was used in which the weapon system was officially introduced (e.g. Type 95 Light Tank) or finally refused (e.g. Type 95 heavy tank). From 1941 on this system was not longer used that strictly, mainly to hamper enemy intellicgence (e.g. the Type 3 medium tank was introduced in 1944, design was started in 1943)

If there are different weapon systems of the same type introduced in the same year the supplement "model" and a number was added. (e.g Type 94 Model 1 - 4 for four different sized radio sets). Changes in the design of a particular "model" was indicated by the further addition "mark" and number (eg. Type 94 Model 2 Mark 3 bomb fuze).

For the year of introduction two different calendar systems were used:

a) Imperial Calendar:
With this system the additional syllable "nen" = "regency) year" was added between year and "shiki". The year is given as "Year of regency" of a particular emperor:

- Meiji regency: Emperor Mutsuhito (1852 - 1912) , regency 1867 - 1912 (death)
1867 was Year 0 , 1912 was Year 45 of Meiji era. So any weapon introduced in this era received the year- designation Meiji (e. g. the famous Arisaka rifle introduced in 1905 was designated Type Meiji 38 rifle, the 24 cm howitzer introduced in 1912 was designated Type Meiji 45 howitzer....)

- Taisho-regency: Emperor Yashihito (1879 - 1927), regency 1912 - 1927 (death)
1912 was Year 0, 1927 was year 15 of Taisho-era. Any weapon introduced in ths era after the death of Mutsuhito received the year-designation Taisho (e. g. the light 37 mm infantry gun introduced in 1923 received the designation Type Taisho 11 infantry gun...)

-Showa-regency: Emperor Hirohito (1901 - 1989), regency 1925 (from 1923 inofficially, from 1925 officially as co-emperor to aid the very ill Emperor Yashihito) - 07.01.1989 (death)
1925 was Year 0, 1989 Year 64 of Showa-era.

To simplify the designation system and to reduce irritations if the Regency addition wasn´t added completely (e. g. if only "juichi nenshiki" = "Type (regency) year 11" is mentioned it could mean a 1923 = Taisho 11 or 1936 = Showa 11 introduced weapon system) IJA and IJN changed from regency year to Jimmu-calendar year in 1928.

But many navy and airforce design orders were designated after the Showa-calendar (e. g. The design of the A6M "Zero" started as "Navy experimental 12-Shi Carrier Fighter" in year 12 of Showa regency = 1937..)

b) Jimmu-Calendar
The Jimmu-Calendar is based on the more or less mythical beginn of the japanese empire. In 660 BC (in 1872 the 11. February was declared as "correct date"a local leader defeated the last larger local enemy and founded the japanese imperial dynasty. He later received the honor name Jimmu. So the standard japanese calender which is still in use began in 660 BC.

From 1928 on IJA and IJN designated their weapon systems using the Jimmu-Calendar-year. 1928 was year 2588. To simplify this system only the last 1 or 2 ciphers were used (2588 = 88, 2604 = 4). For 1940 the possible year designations 0 and 100 were both taken (IJA used 100, IJN 0).


B) sort of equipment

In general the same designations as in western armys were used, translated into japanese language (e. g. light tank, rifle, handgrenade, radio set, gas mask etc.). Sometimes designations were somewhat different but more or less self-explanatory (e. g. "Ju-Sokosha" = "heavily armoured vehicle" for the small Type 92 recon tank used by cavalry units; "recoilless rifle/gun"for rocket-propelled at-weapons and artillery rocket launchers, "kikanho" = "automatic cannon" for light aa-guns)


C) short designation

Several japanese vehicles and some other weapon systems received short designations. Some of these designations were part of a system (e. g. light and medium tanks, gun tanks etc.), others had to do with the intended tasks (e. g. special tractor, gun carrier, armoured vehicle etc.) or were added during development and officially adopted later (e. g. "Ha-Go" or "Ka-Mi") Some meanings were lost during the years but most are still known. I will cover this topic in a later post here.



Continued in Part 2....

tom!
01-02-2018, 11:35 AM
Hi.

2. Japanese designations and a short dictionary part 2


D) additions:

Several pieces of equipment received additions to clear the identity of the piece of equipment. Often used were the following:

- KAI
short for "Kaizo"= "modified"
This was added if major modifications were made without changing the complete system (e. g. Type 97 Medium Tank Chi-Ha KAI for the Type 97 armed with the Type 1 47 mm tank gun in a new turret, major upgades on aircraft models etc.)

- alphabetic characters
Another system to mark major changes without changing the complete system (similar to the german system, e. g. Panzer III F, G, H etc.). IJA used the first letters of the traditional (chinese) alphabet:
Kou = A
Otsu = B
Hei = C
Tei = D
Bo = E
Ki = F
Kou = G (same pronunciation as Kou(A) but different character)
....
These additions were mainly used for vehicles (e. g. Kou(A) for the gasoline engined version, Otsu for the Diesel engined versions)

-nicknames
Several weapon systems received nicknames officially, mainly aircraft. Other nicknames were adopted officially after beeing used for some time inofficially by the soldiers (e. g. "Reisen" for "Rei Sentoki" = [Type] 0 fighter)

- numerations:
several vehicles received numerations meaning "first of this kind of weapon".The numerations were basically alphabetic or numeric characters followed by "gata" = "of this Kind" or "go" = "Version"(e. g. "Kou(A)-gata" = first of this kind ",here light tank, for the Renault FT-17 tanks, "Otsu-gata" = "second of this kind"for the Renault NC-27 light tanks, "I-go" = "first Version" for the Type 98 mini-engineer vehicle). This was even used as designation of the Army guided air-to ground missile development (I-Go-1)

- others:
Sometimes additions were used only inofficially but taken over by allied forces and used in literature as ´official`(e.g. "Shinhoto" = "new turret" as nickname for the modified Type 97 medium tank with the 47 mm gun in a newly designed turret)


E) Special IJA Tank designation systems

a) early years (1925 - 1934)

IJA started domestic tank developments in 1925. At this time tanks were ratet in three categorys:

- light: weight up to 10 (metric) t
- medium: weight 10,01 t to 20 t
- heavy: larger than 20,01 t

Following this system the european tanks purchased until 1930 were rated as follows:

- light: Renault FT 17 (13 bought 1919/20), St. Chamond M21 wheelcumtrack (1 bought 1923), Renault NC 27 (10 bought 1927)
- medium: Medium Mk A "Whippet" (4 - 6 bought 1919), Vickers Mk C (3 bought 1926)
- heavy: Mk IV female (1 bought 1919)

Only the FT 17 and the NC 27 were used operationally. As these were the first light tanks the FT-17 received the designation "Kou(A)-Gata" = "1st (light tank)" and the NC 27 "Otsu-Gata" = "2nd (light tank)".

The first domestic tank which was finished in 1926 was rated experimental only and so it received the designation "Experimental Tank No. 1". In 1927 a new design for a light tank was started and received the designation "Experimental Tank No. 2".

The prototype production domestic tanks received the standard designation consisting of Yeartype and sort of equipment. In addition short designations were added indicating the numer of design:

"Yi-Go" or "I-Go" = "first (domestic tank)" for Type 89 Medium Tank
"Ro-Go" = "second (domestic tank)" for the Type 95 Heavy Tank
"Ha-Go" = "third (domestic tank)" for the Type 95 Light Tank


b) mid-years (1935 - 1941)

In 1935 a new short designation system was introduced. It consisted of a syllable for the size and a numbering syllable for the design number connected by a dash.

Light tanks received the size syllable "Ke" = short for "Kei" = "light"
Medium tanks received the size syllable "Chi" = short for "Chiuu" = "medium"
Heavy tanks should receive the size syllable "Ju" = "heavy" (there was no "heavy" tank adopted in this periode)
Superheavy tanks received the syllable "O"

The nummeric syllable indicated which design of this size the vehicle was. The standart japanese numbering system was used:
Yi or I = first
Ro = second
Ha = third
Ni = fourth
Ho = fifth
He = sixth
To = seventh
Chi = eighth
Ri = ninth
Nu = tenth
Ru = eleventh
......

So "Chi-Ha" means "third medium tank design", "Ke-Ni" = "fourth light tank design" etc.

It seems that older tank models should not receive this new short designation. "Chi-Ro" = "second medium tank design&", which is sometimes used for the Type 89 Medium Tank in western literature, does not seem to be used by IJA.


Continued in part 3...

tom!
01-02-2018, 11:52 AM
Hi.

2. Japanese designations and a short dictionary part 3


c) late years (1942 - 45)

From 1942 on the mid-years system was enlarged and softened. The weight limit between medium and heavy tanks was discontinued and the syllable "Ju" was dropped. But the heavier tanks were not designated "Medium Tank" but only "Tank" (e. g. Type 5 Tank Chi-Ri). The size syllable "Chi" was still used for counter intelligence purposes.

And some new short designation systems were added:
- Close-support tanks (IJA called all AT- and CS-tanks to be used by tank units "hosensha" = "Gun Tanks") received the purpose syllable "Ho" = "Gun" instead of the size syllable

- SPGs (AT- and CS- tanks to be used by infantry units were called "Jisoho"; = "Motorised Gun") became a short designation consisting of a syllable for the gun caliber followed by the purpose syllable "to" = "(gun) carrier" (e. g. "Na-To" = "7 (cm) (gun) carrier" for the Type 5 tank hunter with it´s modified Type 5 7,5 cm Tank Gun)


F)IJA armored vehicle and gun tractor designations

a) Armoured vehicles

Early armoured cars were named by their builders (e. g. Wolseley armoured car, Chiyoda armoured car, Sumida armoured car etc.). From 1931 on the standard designation system replaced this early system.

The in Europe and USA well known designations "Aikoku" and "Hokoku" for two japanese armoured car models are wrong. The designation comes from the writings on the vehicles. But these particular vehicles were donated by the japanese public organisations "Aikoku" (for IJA) and "Hokoku" (for IJN) which collected money to support the armed forces. The official designations of these vehicles were Sumida Type P Armoured Car (Aikoku) and Typ 93 Armoured Car (Hokoku)

In IJA nomenclature "sensha"= "fighting vehicles" were armoured vehicles used by tank units. Infantry and cavalry units were only allowed to have "Sokosha" = "armoured vehicles" in their arsenals. Therefore the tank short designation system was not used for infantry AFVs. Instead a designation system based on the vehicle´s purpose was developed:

Some examples:
- The type 91 armoured railroad car was designated "So-Ki" = short for "Soko Kidosha" = "Armoured Railway (support) car"
- The Type 92 light recon tank used by cavalry recon units was designated "Ju Sokosha" = "heavy armoured vehicle"
- The Type 94 light AFV was designated "tk" = short for "Tokusyu keninsha" = "special tractor" because he was originally designed as towing vehicle for several trailers
- The Type 97 tankette was designated "Te-Ke". The meaning of this short designation is still discussed in literature but it main interpretation is that it is short for "Tokusyu keninsha - Kei Sokosha&" = "Special tractor - light armoured vehicle"
- The engineer tank received the designation "SS" = short for "Soko Sagyosha" = "Armoured Working Vehicle" without a yeartype


b) artillery tractors

Gun tractors ("keninsha") were designated with their weight and a short designation. The meaning of the short designations is not clear to me.


G) Some japanese vocabulary regarding vehicles:

Sha = vehicle
Sensha = short for sento sha = fighting vehicle or tank
Sokosha = armoured vehcle
Hosensha = gun tank
Jisoho = motorised gun or SPG
Jidosha = motorised vehicle (in general)
Jitensha = bycicle
Sokusha = motorcycle with sidecar
Kijusha = "machine gun vehicle", motorcycle with machine gun in sidecar
Joyosha = passenger car
shikisha = command car
Jidokasha = truck
Shuri Jidosha = Maintenance vehicle
Rikisakusha = generator vehicle
Keninsha = tractor/prime mover
Kamotsusha = earthmover
Sokikasha = bulldozer
heisha = troop carrier
Jidoteisha = scout car
Sokisha = halftrack vehicle
uchibitei= motor launch, used by IJN for their amphibious tanks (Tokusyu uchibitei = special motor launch)

Yours

tom! ;)

tom!
01-03-2018, 01:38 PM
Hi.

3) Armament: Machine Guns

IJA and IJN had several different MGs and machine cannons in their arsenals:

a) french 8 mm Hotchkiss MG

7893

IJA used Hotchkiss-type MGs from 1904 on, rechambered to the domestic 6,5 mm X 50,5 mm Arisaka ammunition. With the Renault FT-17 tanks at least 6 original french 8 mm Hotchkiss MGs were bought in 1919 and several more with the Medium Mk A Whippets. These were standard french army issue Hotchkiss Modellé 1909. The main difference to the infantry version was the use of belted ammunition with 250 shots instead of 24 shot ammo strips.
It´s quite possible that these MGs were replaced by the rechambered japanese version.

Caliber: 8 mm X 50 mm rimmed Type Lebel (6,5 mm X 50,5 mm semi-rimmed Type Arisaka)
Length: 1310 mm
Barrel length: 770 mm
Grooves: 4
Weight: 23,7 kg
Rate of Fire theoretical: 600 shots/min
practical: up to 500 shots/min
Muzzle velocity: 710 m/sec


b) Vickers 7,7 mm MG:

7894

In 1926 IJA bought 3 Vickers Mk C Medium Tanks, armed with these MGs. The water cooling was usefull but made the gun vulnerable to damages inflicted by bullets and splinters. Therefore this MGs were not used by IJA. The tanks were just tested and finally scrapped. IJN used this MG for boarding parties and armament of small ships.

Data:
Caliber: 7,7 X 56 mm rimmed
Length: 1100 mm
Barrel length: 720 mm
Grooves: 4
Weight: 13 kg
Maximum range: 4100 m
Effective range: 800 m
Rate of Fire theoretical: 600 shots/min
practical: 450 shots/min
Muzzle velocity: 740 m/sec

c) Type Taisho 3 6,5 mm MG

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20renault%20nc27%204.jpg

This weapon was a modification of the Type Meiji 38 Hotchkiss-type heavy MG made by Army Technical Bureau under command of NAMBU Kijiro from 1914 on. The Hotchkiss ejection mechanism was replaced by the Lewis-type ejection increasing firing speed and reliability. Other changes were done to increase barrel cooling and handling. The result was adopted officially in 1915.

For IJA tank troops the Hotchkiss-type MGs were replaced by this MG in the mid-1920th and all new tanks were armed with it.

Data:
Caliber: 6,5 X 50,5 mm semi-rimmed Type Arisaka
Length: 1204 mm
Barrel length: 742 mm
Grooves: 4
Weight: 27,9 kg
Maximum range: 2000 m
Effective range: 600 m
Rate of Fire theoretical: 600 shots/min
practical: 120 shots/min (continuos fire 480 shots/min)
Muzzle velocity: 740 m/sec


d) Type 91 6,5 mm Tank MG

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/panzermg%20typ%2091.jpg

This MG was a modified version of the Type Taisho 11 6,5 mm lMG used by ground forces. It was air-cooled and hopper-fed with oiled 5-shot-clips. The ammunition was the standard Type Meiji 38 6,5 mm rifle ammunition but with reduced propellant charge. This was necessary to reduce failures due to ripped cartridges inside the chamber. It was introduced in 1931 as the designation indicates.

The forward telescope bracket was attached to the vehicle MG-port. The weapon was then fixed inside a quick-release mount.

In the mid-1930s a removable barrel armour was added to reduce damages by bullets and splinters. A bipod could be attached to use the MG outside the vehicle. If the crew had to bail out without immediate danger e. g. due to internal fire or enemy AT-weapons the MG should be taken with the gunners.

This weapon was used in allmost all IJN and IJA vehicles until it was replaced by its successor in the late 1930th.

Data:
Caliber: 6,5 X 50,5 mm semi-rimmed Type Arisaka
Length: 838 mm
Barrel length: 488 mm
Grooves: 4
Weight: 10,15 kg
Maximum range: 2000 m
Effective range: 600 m
Rate of Fire theoretical: 500 shots/min
practical: 80 - 120 shots/min
Muzzle velocity: 700 m/sec


e) Type 97 7,7 mm Tank MG

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%2091%20tank%20mg%20mount.jpg

Successor of the Type 91 Tank MG. It was based on the czech MG ZB 26/ZB 30s captured in larger numbers during the 1935/1936 northern China operations. This weapons were tested and modified by Nambu Weapons Factory. Main modification was rechambering to the Type 92 MG ammunition developed for the Type 92 7,7 mm Heavy MG (the well known "Woodpecker"). The MG was fed by a box-type 20 shot magazine similar to the ZB-series instead of the 30 shot curved magazine used with the Type 96 6,5 mm lMG, a parallel Nambu development.

This MG was used in allmost all armoured vehicles until 1945 replacing the Type 91 Tank MGs.

Data:
Caliber: 7,7 X 56 mm semi-rimmed
Length: 1180 mm
Barrel length: 712 mm
Grooves: 4
Weight: 11,14 kg
Maximum range: 2000 m
Effective range: 600 m
Rate of Fire theoretical: 500 shots/min
practical: 80 - 120 shots/min
Muzzle velocity: 730 m/sec


g) Type 4 experimental 7,7 mm Machine gun

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20exp%20typ%204%20Panzer%20MG.jpg

Late war development of a successor to the type 97 MG. There is not much known on this weapon as most data were destroyed at surrender. It is somewhat similar to the Ho-103 12,7 mm aircraft MG but chambered for the Type 99 7,7 mm round. The gun was belt fed from the left side.

no data found


g) Type 92 13,2 mm Tank Machine Cannon

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/Typ%2092/jap%20typ%2092%20light%20late.jpg

This MG was an IJA developed from the french Hotchkiss 13,2 mm AA-MG and should not be mixed up with the IJN Type 93 13,2 mm Machine Cannon which was an only slightly modification.

The Type 92 Machine Cannon received a shorter barrel to reduce recoil. A butt stock was added to fire it from the gunner´s shoulder. It fired the Typ 93 Machine Cannon ammunition from a 20 shot clip.

This weapon was used by the Type 92 Heavily armoured vehicle exclusively. It was mounted in a modified standard MG-mount in the oriel in the right. With this mount even aa-fire was possible but to do so the gunner had to lay on the floor looking upwards. This only allowed barrage firing.

no data found


h) Type 96 25 mm Machine Cannon

http://www.ww2technik.de/Bilderchen/japflak/leicht/jap%20typ%2096%2025%20mm%20flak%204.jpg

In 1944 IJN decided to develop a version of this aa-gun for the use in their new development of an amphibious tank model. It was planned to equip the turret with this gun. So several changes were made including a new muzzle brake, a shorter barrel and a smaller recoil mechanism. The gun was never adopted officially as the tank development was ceased in spring 1945.

no data found


Yours

tom! ;)

tom!
01-04-2018, 08:41 AM
4. Armament: Tank Guns

IJA and IJN mainly used the same guns. From 1942 on IJN modified few smaller guns from their arsenal to provide more close-support power.

Until 1942 IJA developed tank guns parallel to at-guns and so the tank guns suffered from the strict weight limitations of infantry at-guns. IJA tactics prefered fast strikes using light support weapons. Therefore until 1940 guns for infantry support should not have a weight higher than 500 kgs and should be able to be moved by 2 - 4 men in the field.
To reduce weight the recoil mechanism and the lower lafette of the at-gun had to be as light as possible. Among other problems this lead to a decrease of the maximum possible recoil force. But to reach a better armour penetration the muzzle velocity had to be as high as possible, increasing the recoil force. Therefore a balance between these opposing requirements had to be found. As IJA set the weight top priority the results were almost every time a decrease of the possible penetration power. And for the tank guns the same barrels and breeches had to be used to ensure that both guns could use the same ammuntion.

After the Nomonhan-incident 1939 IJA ordered two new at-/tank guns using the calibers 47 mm and 57 mm. The 47 mm version was introduced in 1941. The 57 mm version was at a dead-end in 1942 as the result was a gun with twice the weight of the 47 mm version but only marginal higher armour penetration. As the engineers saw no chance to improve the gun with the original specifications IJA decided to cease the program. This left the IJA tank forces without a potent gun able to fight the allied medium tanks even at medium ranges from 1943 on. The gap could not be filled until mid-1945.


Part 1: Guns developed until 1940

note:
- The data for elevation and traverse are given for the guns in their standard mounts.

a) Puteaux SA18 37 mm tank gun

7895

Standard french 37 mm tank gun of the Renault FT-17 and Renault NC 27 tanks. The gun was originally built as light infantry gun. IJA modified this gun and used it as Type Taisho 11 37 mm Rapid-fire Infantry Gun.

Data:
Caliber: 37 mm
Barrel length: 777 mm
Caliber length: L/21
Traverse:
Elevation: - 20° - + 35°
muzzle velocity: AP 600 m/sec
Rate of fire: 10 shots per minute
penetration: 27 mm on 100 m/90°


b) Hotchkiss QF 6 pdr tank gun:

7897

British tank gun of World War I, still in use with a modified mount in the 1926 Vickers Medium Mk C tanks.

Data:
Caliber: 57 mm
Barrel length: 2280 mm
Caliber length: 40
Traverse:
Elevation:
muzzle velocity: AP 553 m/sec
Rate of fire:
penetration:


c)modified 37 mm infantry gun "Sogekiho" :

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20Sogekiho%2037%20mm%20tank%20gun.jpg

Before the 1931/32 northern China operations the Puteaux SA18 tank guns were replaced by obsolete 37 mm infantry guns designated "Sogekiho" (= "sniper gun"), the predecessor of the Type Taisho 11 37 mm flat-trajectory infantry gun. These guns were developed from french M1916 37 mm trench guns. The guns had to be modified slightly to allow the use in the french gun mounts.

Data:
Caliber: 37 mm
Barrel length: 1036 mm
Caliber length: 28
Traverse : +- 10°
elevation : -21° to +15°
Muzzle Velocity : 530 m/sec
Penetration:


d) Type 90 57 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%2090%2057%20mm%20tank%20gun.jpg

After the decision was made to develop a domestic tank in 1927 the development of a 57 mm tank gun was started. Main specifications were
- caliber 57 mm
- maximum ammunition weight 2,5 kg
- muzzle velocity 350 m/s
- Elevation -8° bis +30°
- traverse -10° bis + 10°
- barrel weight 90 kg
- maximum total weight 180 kg
- maximum range 4000 m
- able to penetrate 20 mm armour plates on 100 m
- operated by one man
- simple loading mechanism
- easy to handle

So a short 57 mm barrel was placed on a mount similar to the 37 mm Puteaux gun. A vertical sliding wedge breech was attached. A metal buttstock and a deflector plate was attached which allowed the operator to aim the gun safely like a rifle. The gun was fired by a trigger operated with the left hand. The right hand was used to operate the manual turret traverse mechanism and to reload. The empty cartridges were ejected automatically and then fell into a long small bag at the rear of the gun. To minimise the recoil a strong spring inside an oil tank was used to mount the gun.

The gun was introduced officially in 1930 and used in the Type 89 Medium Tanks until it was replaced by the successor

Data:
Caliber: 57 mm
Barrel length: 850 mm
Caliber length: 14,9
Weight: 147 kg
Traverse: -10 ° to + 10 °
Elevation: -15 ° to + 20 °
muzzle velocity: HE 380 m/sec
penetration: 20 mm on 100 m/90°


e)Type 94 37 mm tank gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%2094%2037%20mm%20kwk.jpg

The Type 94 37 mm Tank Gun was developed as main gun for future light tanks parallel to the Type 94 37 mm Rapid-fire Infantry Gun from 1933 on. At this time the Type Taisho 11 Rapid-fire Infantry Gun was outdated regarding armour penetration due to the increase of armour strength of contemporary tanks. Therefore a new gun with longer barrel and higher chamber volume was planned. The resulting increase of weight made a new lafette with wheels necessary. The result was a modern weapon with high mobility. But IJA technicians had large problems developing a better AP grenade. Therefore the gun was not introduced before 1936 when finally a grenade able to penetrate 40 mm @ 300 m/90° became avaliable.

The tank gun suffered from the grenade problems as well but nevertheless early prototypes of the gun were used for the Type 95 Light Tank Ha-Go from the beginning of the prototype production 1934. At this time the gun fired the old grenades of the Type Taisho 11 Infantry gun with a penetration of 30 mm @ 100 m/90°. Later the new AP grenades replaced these.

Inside the tank the gun was operated like the Type 90 57 mm Tank Gun. It was replaced by its successor from 1940 on and then used on army ships and for crew training.

Data:
Caliber: 37 mm
Barrel length: 1358,5 mm
Caliber length: 36,7
Traverse: 20 °
Elevation: -15 °to + 20 °
muzzle velocity: AP 600 m/sec
penetration: finally 40 mm on 300 m/90°


f) Type 94 70 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%2094%2070%20mm%20tank%20gun%20Schiessbet t.jpg

This gun was specially developed for the Type 95 heavy tank project as the use of a 57 mm tank gun in a heavy tank was a not acceptable waste of ressources for IJA officials. The gun was developed from the low velocity Type 92 70 mm Battalion Gun using the same breech and a slightly longer barrel. Handling followed the same system as with the other contemporary tank guns. The history of this gun ended when IJA decided to cease the heavy tank project in 1935.

Data:
Caliber: 70 mm
Barrel length: 790 mm
Caliber length: 11,3
Traverse: 20 °
Elevation: -15 °to + 20 °
muzzle velocity: HE 220 m/sec
penetration:


g) Type 97 57 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%2097%2057%20mm%20tank%20gun%20rechts.jpg

In 1936 the Type 90 57 mm Tank Gun was redesignd to increase the penetration power. Therefore a 200 mm longer barrel was used. In addition the chamber volume was increased. The higher recoil force led to a heavier recoil mechanism. The result was an increase of penetration to 30 mm @ 100 m/90° which was found acceptable even if this would not be enough even against contemporary tanks.

The gun was reliable and accurate making it a good choice against soft targets and field fortifications. From 1937 it replaced the Type 90 57 mm Tank guns of the Type 89 Medium Tanks and it became main armament of the Type 97 Medium Tank Chi-Ha.

Data:
Caliber: 57 mm
Barrel length: 1050 mm
Caliber length: 18,4
Traverse: 20 °
Elevation: -15 °to + 20 °
muzzle velocity: HE 420 m/sec
Penetration: 30 mm on 100 m/90 °


h)Type 98 37 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%2098%2037%20mm%20tank%20gun%20Schiessbet t.jpg

From 1937 on IJA forces captured several german and russian 3,7 cm Pak Rheinmetall in China. The guns were tested intensively and later introduced as Type 97 (or Type Ra with Ra for Rheinmetall) 37 mm Anti-tank Gun. Additionally the Type 94 37 mm Rapid-fire Infantry Gun was remodelled. Especially the chamber volume was increased which made a heavier recoil mechanism necessary. The resulting gun was found too heavy for an infantry gun and rejected but the parallel designed tank gun was accepted and introduced in 1938. It was planned to replace the Type 94 37 mm Tank Guns with these but the possible production capacities were just able to deliver the necessary guns for the ongoing production of the Type 95 Light Tanks Ha-Go and the Type 97 Tankettes Te-Ke.

Data:
Caliber: 37 mm
Barrel length: 1358,5 mm
Caliber length: 36,7
Traverse: 20 °
Elevation: -15 °to + 20 °
muzzle velocity: AP 700 m/sec


to be continued in part 2....
penetration: 25mm on 500 m/90°

tom!
01-04-2018, 09:11 AM
4) Armament: Tank Guns part 2


h) Type 99 75 mm tank gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%2099%2075%20mm%20kanone.jpg

During the innitial stages of the 2nd Sino-Japanese War 1937 fightings in Shanghai showed the need for a close-support tank with a gun larger than the 57 mm gun of the medium tanks. Therefore the concept of special gun tanks was introduced. First project was to equip the newly introduced Chi-Ha with a shot 75 mm gun based on the Type Meiji 41 Mountain Gun. Later the gun breech was changed to the Type 94 75 mm mointain gun breech which was larger for a higher muzzle velocity. The recoil mechanism was placed above the barrel. The result was satisfying but due to low priority only few of this guns were built, exact numbers are unknown (30 of the CS-tanks were finished in 1944).

Data:
Caliber: 75 mm
Barrel length: 1792,5 mm
Caliber length: 23,9
Traverse:
Elevation:
muzzle velocity: 450 km/h
penetration: 40 mm @ 100 m/90° with AP, 100 mm on 100 m with HEAT


i) Type 100 37 mm Tank gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%20100%2037%20mm%20tank%20gun%20schiessbe tt.jpg

With the decision to introduce the Type 98 Light Tank Ke-Ni as airborne tank the decision was made to develop a gun with larger penetration power as it had to face enemy tanks without support of the standard amount of heavy infantry at-guns. Therefore the chamber volume of the Type 98 37 mm Tank Gun was again increased. But the results were not much better with the disadvantage to need another ammunition type. This was found acceptable but only few guns were produced before the successor became avaliable only one year later.

One of the main development design features was the use of a coaxial Type 97 7,7 mm MG.

Data:
Caliber: 37 mm
Barrel length: 1358,5 mm
Caliber length: 36,7
Traverse: 20 °
Elevation: -15 °to + 20 °
muzzle velocity: AP 780 m/sec
Penetration: 27 mm on 500 m/90 °


Part 2: Guns developed after 1940

a) Type 1 37 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%201%2037%20mm%20tank%20gun.jpg

This gun was result of a major upgrading program for the Type 94 37 mm Rapid-fire Infantry Gun initiated after the disastrous 1939 Nomonhan-Incident. Basis was the Type 100 tank gun with its enlarged chamber volume. A longer barrel was attached for additional muzzle velocity. This made a heavier recoil mechanism necessary which meant additional weight. This was accepted as the additional power was badly needed.

In 1941 both tank and anti-tank gun were adopted. The tank gun should replace all earlier 37 mm tank guns but this goal could not be reached as the production numbers were not able to deliver the necessary numbers because the production of light tanks was increased at the same time. So the Type 94 37 mm Tank Guns should be replaced primarily with surplus guns which was not done until surrender 1945.

In 1943 the caliber 37 mm was found outdated and the new light tank model should be armed with a short 47 mm tank gun.

Data:
Caliber: 37 mm
Barrel length: 1699 mm
Caliber length: 45,9
Traverse: 20 °
Elevation: -15 °to + 20 °
muzzle velocity: HE 800 m/sec
penetration: 25 mm on 1000 m/90°


b)Type 1 47 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%201%2047%20mm%20panzerkanone.jpg

During the 1939 Nomonhan Incident the short 57 mm tank guns and the long 37 mm tank guns were only able to penetrate the soviet T-26, BT 5 and BT 7 tanks on short ranges while the soviet long 45 mm tank guns penetrated the IJA tanks on medium ranges. The result was the destruction of or severe damage on 80 % of the japanese tanks of 3rd and 4th tank regiment within 8 days of combat. So the decision was made to develop a medium AT- and tank gun of 47 mm caliber and a heavy AT- and tank gun of 57 mm caliber. For the 47 mm gun the results of an experimental 47 mm AT-gun developed and tested in 1937 were taken as basis.

The AT-gun was refused several times due to too much weight. In 1941 finally IJA decided to accept a higher weight as the gun was badly needed for the upcomming conflict with the US and its allies. The tank gun was finished in late 1940 but as both guns should use the same ammunition the tank gun could not be introduced until the AT-gun was accepted.

The tank gun made a larger turret necessary as it should be operated by 2 men and as the ammunition was longer. Therefore a new turret with hemispherical front and a box-shaped rear was introduced, too. The new gun was able to penetrate contemporary light and medium tanks on medium ranges. US ordnance tests even showed that this gun was able to penetrate the front armour of an early M4 Sherman on ranges up to 250 yards.

As the 57 mm gun project was cancelled in 1942 the Type 1 47 mm Tank Gun was the standard weapon of the IJA tank forces until surrender. Due to raw material shortages the production numbers of this gun never reached the necessary height even to equip all newly built Type 97 Medium Tanks Chi-Ha with this gun.

Data:
Caliber: 47 mm
Barrel length: 2250 mm
Caliber length: 48
Traverse: 20 °
Elevation: -15 °to + 20 °
muzzle velocity: AP 800 m/sec
Penetration: 60 mm on 100m / 90 °

c) Type 1 75 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%201/jap%20typ%201%20ho-ni%201%203.jpg

With the introduction of the long 47 mm tank gun in 1941 IJA decided to introduce special close-support tanks. The very potent Type 90 75 mm Field Gun was chosen as armament for such a vehicle. Therefore a special tank mount had to be developed. As a tank has less problems to cope with recoil forces the muzzle break was removed.
In 1942 the modifications were finished and the resulting weapon was introduced as Type 1 75 mm tank gun for the use in the Type 1 Gun Tank Ho-Ni I. Less than 100 field guns were modified this way until 1945 due to the low priority of gun tanks and due to the massive need of standard artillery pieces.
The gun was mainly intended for indirect fire but during the Philippine campaign 1944/45 the Ho-Ni I were also used as mobile AT-gun but with limited success as there was no sight for direct fire.

Data:
Caliber: 75 mm
Barrel length: 2883 mm
Caliber length: 38,4
Traverse:
Elevation:
muzzle velocity: HE 680 m/sec
Penetration: 80 mm on 100 m/90 °


d) Type 3 75 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%203%2075%20mm%20kanone%20links.jpg

In 1942 new tank designs was started which should receive new heavy tank guns. As these projects were assumed to be done not before 1945 and as a better tank gun was badly needed the desision was made to develop a stopgap solution from the Type 90 75 mm Field Gun. For the use inside a tank turret the recoil length had to be limited. Therefore the muzzlebreak was still used. In addition a pair of coil springs was attached below the breech inside the tank to support the original recoil system. Several minor changes were done until mid-1943. The result was a quite good gun with acceptable power.

Due to a higher priority in comparison to the earlier tank guns Osaka Army Arsenal was able to produce around 200 guns from mid-1944 (production start of Ho-Ni III) until surrender which were used in the Type 3 Medium Tanks and the Type 3 Gun Tanks Ho-Ni III.

Data:
Caliber: 75 mm
Barrel length: 2883 mm
Caliber length: 38,4
Traverse:
Elevation:
muzzle velocity: HE 680 m/sec
Penetration: 80 mm on 100 m/90 °


e) Type 5 75 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20typ%205%2075%20mm%20tank%20gun%20schiessbett %20links.jpg

With the decision to develop a new 25 t tank in 1943 the order was given to develop a high power 75 mm tank gun for this vehicle. As in other countries an AA-gun was chosen as basis, here the new Type 4 75 mm AA-Gun (a modified copy of the swedish Bofors M29 75 mm AA-Gun). The development of the tank gun started in early 1944 after the basic design for the turret was done. It was planned to put an aa-gun barrel in a modified gun mount of the Type 3 75 mm Tank Gun. The result was not satisfying as the recoil mechanism was overburdoned. Several modifications were made until fall 1944 but with only small success.

So the decision was made to restart the development. Now the barrel and the recoil mechanism of the aa-gun were taken. The turret design made it necessary to place the recoil cylinders above the barrel. Trials started on March 9th 1945 and after only few modifications the gun was introduced at the end of May. Until surrender preparations were made for a serial production which should start in September 1945. Just 2 pre-series guns were built in June on for prototype tests of the Type 4 Tank Chi-To. Improved ammunition was about to be produced, too

Postwar US ordnance tests showed that this gun was able to penetrate most allied medium tanks of 1945 on longer ranges even with the grenades used with the Type 3 75 mm Tank Gun. The penetration table below shows the results.

Data:
Caliber: 75 mm
Barrel length: 4230 mm
Caliber length: 56,4
Traverse:
Elevation: -6,5° - 20°
muzzle velocity: HE 852 m/sec
Penetration: 90 mm on 100 m/90 °


to be contionued in part 3....

tom!
01-04-2018, 09:13 AM
4) Armament :Tank Guns Part 3


f)Type 5 88 mm Tank Gun:

no Picture, sorry

After inspecting the german Tiger I IJA bought in summer 1943 the idea was Born to equip the new 45 t tank ordered in 1943 with a domestic 88 mm tank gun. The designers choose the Type 99 88 mm AA-Gun (a modified version of a german naval aa-gun captured in China) as basis. Development started in 1944. But the design of the 88 mm gun was slowed down because the 75 mm gun had top priority binding most of the avaliable ressources. In addition the development of the Type 5 Tank Chi-Ri suffered from massive raw material shortages. So the development of the gun was not finished until summer 1945. It is most likely that the design was cancelled but no official papers survived the war.

Data:
Caliber: 88 mm
Barrel length:
Caliber length:
Traverse:
Elevation:
muzzle velocity:
Penetration:


g) Type 5 105 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20exp%20typ%205%20105%20mm%20kanone%20links.jp g

This gun was originally intended as main armament for the super-heavy multi-turret tank project started in 1939. Originally the Type 92 105 mm Cannon should be taken as basis. But due to the very low priority of the project only few design studies were done until 1942. Then the development benefited much from the cancelling of the development of a successor for the Type 92 Cannon. The prototype gun was then used to develop the 105 mm tank gun which was done in summer 1944. After a short trial series in fall 1944 the gun was combat-ready in late 1944. At this time no vehicle was able to carry this gun as the tank project was delayed due to massive raw material shortages and suspension problems. New projects for this gun were not started before spring 1945 and none reached the prototype stage until surrender.

Data:
Caliber: 105 mm
Barrel length: 4720 mm
Caliber length: 44,9
Traverse:
Elevation:
muzzle velocity: HE 900 m/sec
penetration: 150 mm @ 100 m/90 °


h) Experimental Short 47 mm Tank Gun:

http://www.ww2technik.de/Bilderchen/jappanzer/waffen/jap%20exp%20short%2047%20mm%20tank%20gun%20links.j pg

For smaller turrets e.g. of light tanks a special version of the Type 1 47 mm Tank Gun was developed from 1943. Main focus was reducing the necessary space to operate the gun. Therefore the barrel was shortened by 590 mm reducing the recoil length to 200 mm. In addition the recoil mechanism was replaced to the sides of the barrel for a lower necessary turret height. There was no traverse mechanism used to simplify production.

Ammunition was the same as for the Type 1 gun. Prototype tests started in summer 1945 but were not finished until surrender.

Data:
Caliber: 47 mm
Barrel length: 1658 mm
Caliber length: L/35
Traverse: 0 °
Elevation: -15 ° to +20 °
muzzle velocity: 740 m/sec
penetration:

Yours

tom! ;)

tom!
01-05-2018, 12:51 PM
Hi.

5) Foreign Armour part 1:


In World War 1 IJA participated in several campaigns against german colonies and settlements in China and in the Pacific. In addition many IJA observers were attached to french and british troops in France. So Japan was aware of the possibilities of early armour. So in 1918 and 1919 IJA bought few british and french tanks. They were delivered to Japan until late 1920. During the following years these vehicles were tested intensively at infantry and cavalry school. With these tests IJA developed specifications for future tank designs.

From 1925 on IJA began to form tank units. Besides the old Renault FT17 tanks some Renault NC 27 tanks were issued to these unit and tested during operations in Manchuria 1931 and during the 1932 Shanghai Incident. In addition some new tank designs were bought from the mid-1920th to 1930 to get samples of contemporary state-of-the-art technologies.

During the battles of 1937 - 1942 IJA and IJN captured many chinese and allied tanks and armoured vehicles. Most of these were used by the unit which captured it until they broke down or until fuel or ammunition ran out. Only the US Light M3s captured in the Philippines and in Burma were taken over officially and supplied from captured stocks and local productions.


a) British Mk IV Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/Jap%20mk%20IV%20female%202.jpg

In mid-1918 IJA bought a Mk IV female Tank and transported it to Japan with a british crew and some military advisors. This was done to show the japanese people and industry the european superiority regarding military technology and to get the necessary political support to start a massive military modernisation campaign. After arrival IJA presented it to the people on the 1918 Tokyo Tank Week.

The vehicle made several shows and test trials in 1919. After finishing the tests it used as exhibit for a travelling exibition through Japan and Manchuria. Later it was displayed at the Yasukuni Shrine in Tokyo until it was scrapped between 1940 and 1944.

Data
vehicles bought: 1
battle weight: 27 (metric) t
crew: 8 men
armor strength: 6 - 12 mm
length: 8060 mm
width: 3200 mm
height: 2460 mm
engine: Daimler, 6-cylinder in-line
power: 105 HP at 1000 rpm
maximum speed: 6 km/h /3,7 mph
range: 56 km
fuel capacity: 318 l
transmission primary: 2 Forward, 1 Reverse
Power/weight ratio: 3,88 HP/t
armament: originally 6 X 7,7 mm Vickers MG, no armament installed in Japan


b) British Medium Mark A Whippet:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20Whippet.jpg

In mid-1919 IJA bought 6 british Medium Mk A tanks. After arrival these tanks were tested intensively by IJA infantry and cavalry school.

The cavalry disliked the tanks as they were found too clumsy and too heavy. But the infantry officers were very impressed by this tank as it was quite fast for a vehicle with a weight of 14 t and it could turn on the spot. Several basic tank tactics were tested,too, and the decision was made to develop or buy a number of tanks within 10 years. This was the beginning of the IJA tank doctrine to use tanks as infantry support which was not dropped before 1942. And it was also the birth of the IJA tank force as part of the infantry.

After the trials the tanks were used to establish a tank school from 1920 on. The Whippets were replaced by Renault FT 17 tanks after 1922 and scrapped.

vehicles bought: 6
battle weight: 14 (metric) t
crew: 3 men
armor strength: up to 14 mm
length: 6100 mm
width: 2620 mm
height: 2740 mm
engine: 2 × Tylor Twin 4 cylinder side-valve JB4 petrol engine
power: 2 X 45 HP
maximum speed: 13 km/h
range: 129 km
transmission: 4 Forward, 1 Reverse
Power/weight ratio: 6,4 HP/t
armament: 4 X 8 mm Hotchkiss MG


c) French Renault FT17:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/Jap%20Renault%20FT17%20typ%2079%20ko-gata%202.jpg

In late 1919 IJA bought 13 MG or gun (exact number of each version is unknown) eqipped Renault FT 17 tanks from the french army as cavalry tanks. They received the designation "Renault Kou(A) Gata Sensha" = "First Tank (Model)". IJA cavalry school was very impressed by these tanks due to the thick armourand good mobility even in rough terrain. Only the low maximum speed was critisised. Until 1922 several tests and exercises were done leading to the decision to equip at least cavalry recon units with armoured vehicles within 10 years.
In 1922 IJA decided to refuse this demand and also that only infantry units should be allowed to have tanks, mainly because they realised that the japanese industry would not be able to built the necessary numbers of tanks within 10 - 15 years. Therefore the Kou Gata were removed from cavalry school and handed over to infantry school where they were issued to the small tank school unit.

Around 1925 the Renault tanks were rearmed with Type Taisho 3 MGs or "Sogekiho" 37 mm infantry guns but the gun made problems as the turret was too small to operate it properly. Until 1929 all tanks were rearmed with the MG. During the 1929 Mukden Incident a small tank unit (around 10 FT-17 and NC1/NC27 tanks) were sent to Manchuria. While the NC1/NC27 tanks had massive suspension problems the FT 17 operated with good success. In 1931 a provisional tank unit was formed which used FT 17 tanks, NC1/NC 27 tanks with modified suspension and the first domestic Type 89 Medium Tanks. During several incidents in northern China and Manchuria and during the 1932 Shanghai Incident the Kou Gatas again showed their value but it became also clear that they were outdated. So they were withdrawn from active service in late 1932 and issued to the enstrengthened IJA tank school where they were used for drivers training until they were worn out. Until 1937 all FT17 had been scrapped.

Data
vehicles bought: 13
battle weight: 6,8 (metric) t
crew: 2 men
armor strength: up to 22 mm
length: 4880 mm
width: 1740 mm
height: 2140 mm
engine: Renault 4-cyl petrol engine
power: 39 HP
maximum speed: 8 km/h
range: 65 km
Power/weight ratio: 5,7 HP/t
armament: 1 X 8 mm Hotchkiss MG, later 1 X Type Taisho 3 6,5 mm MG or
1 X 37 mm Puteaux SA18 Tank Gun, later 1 X Sogekiho 37 mm low-trajectory Infantry Gun, later 1 X Type Taisho 3 6,5 mm MG


d) French St Chamond M21 Wheelcumtrack:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20stchamond%20m21%20wheelcumtrack%202.jpg

In 1923 IJA lent the prototype of the St Chamond Modellé 1921 Wheelcumtrack Tank from France to test the new wheelcumtrack technology. The results wer not satisfying. The change from wheels to tracks was quite simple and could be done within 10 minutes by raising the wheels. But he change from tracks to wheels was complicated. As the wheel suspension was not able to raise the tanks during lowering the tank had to move on a ramp first. Then the wheels were lowered in traveling position without ground contact. Now the tanks drove back until the wheels touched ground. As the ramp had to be as small as the track gauge it took a lot of time to built a suitabel ramp with the necessary enstrengthened side walls. In addition the raised wheels limited the drivers view to the sides. So the design idea was rated poorly conceived and the vehicle returned to France.

Data
vehicles bought: 1
battle weight: 3,5 (metric) t
crew: 2 men
armor strength: up to 6 mm
length: 3610 mm on wheels
width: 2080 mm
height: 1930 mm
engine: 6-cyl petrol engine
power: 15 HP
maximum speed: 28 km/h on wheels, 6 km/h on tracks
armament: 1 X 8 mm Hotchkiss MG


e) Italian Fiat 3000 Model 1921:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20fiat%203000%20M1921.jpg

In the mid-1920th IJA bought one Fiat 3000 tank for test purposes. The tank was an improved version of the Renault FT 17 tank with a stronger engine and a larger turret. The test results are unknown. But at the same time IJA was cooperating directly with Renault which designed a new suspension and so the italian model seemed to be rated outdated.

Several Fiat 3000 were taken over from the armed forces of the local warlord Chang Tso-lin, ruler of the northeast regions of China. He was killed by a terrorist bomb attack on his train (most likely done by the japanese military intelligence). The vehicles were used by the japanese Kwantung Army to built up a temporary Armoured Car Company during the Mukden Incident 1929. After the birth of Manchukuo 1931 the tanks were handed over to the manchurian army.

Data
vehicles bought: 1
battle weight: 5,5 (metric) t
crew: 2 men
armor strength: 6 - 16 mm
length: 4330 mm with ditching tail
width: 1660 mm
height: 2200 mm
engine: Fiat 4-cylinder gasoline engine
power: 50 hp
maximum speed: 21 km/h
Power/weight ratio: 9,1 HP/t
armament: originally 2 X 8 mm Breda MG, armament was not installed in Japan; 2 X 7,7 mm Lewis MG on the captured tanks


to be continued in part 2...

tom!
01-05-2018, 12:53 PM
Hi.

5)Foreign Armour part 2:


f) British Vickers Medium Mark C:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20vickers%20mk%20c.jpg

In 1926 IJA bought 3 Vickers Medium Mk. C tanks as samples of contemporary modern armour technology to gather design ideas for their domestic development program. The tanks arrived in March 1927 together with engineers and crews from Vickers. During the tests in one vehicle gasoline vapours infiltrated the fighting compartment and exploded when the tank climbs up a hill, wounding two Vickers engineers. This incident led to the decision to develop Diesel engines for domestic tanks to minimise the risk of such explosions.

IJA wanted to develop a domestic tank and Vickers didn´t want to built up a production line for spare parts for only 3 vehicles So the tanks became exibits after finishing the tests and were finally scrapped. Several details of the Mk. C were taken over for the Experimental Tank No. 2 which was introduced in 1929 as Type 89 Medium Tank.

Data
vehicles bought: 3
battle weight: 12 (metric) t
crew: 6 men
armor strength: up to 6,5 mm
length: 5330 mm
width: 2540 mm
height: 2400 mm
engine: Vickers gasoline engine
power: 110 hp
maximum speed: 30 km/h
fuel capacity: 320 l
range: 220 km
transmisson: 4 forward, 1 reverse
Power/weight ratio: 9,2 HP/t
armament: 1 X 6 pdr QF gun, 4 X 7,7 mm Vickers MG


h) Renault NC1/NC27:

[http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20renault%20nc%2027%20kanone.jpg

During the mid-1920th Renault tested several new types of suspensions for the FT17/18 tank. IJA was very interested in these developoments and even supported Renault by buying 10 vehicles (5 armed with MG, 5 armed with a gun) tanks from the pre-series production of the NC1 Modellé 1927 and allowing Renault engineers to lead the trials at Kurume in late 1929/early 1930. The results were rather unsatisfying as the suspension made several problems during duration tests.

Nevertheless IJA used a provisional tank unit during the early 1932 Manchurian Incident when chinese warlord troops entered the japanese controlled area around Harbin/Manchuria from northern China but retreated after recognising the tanks. During these operations several NC1 tanks, which were now armed with "Sogekiho" 37 mm infantry guns, broke down due to suspension failures. Renault immediately modified several suspension parts after tests with this new configuration in France 1931 were successful. In Europe these vehicles are known as "Renault NC1Modellé 1931" or "NC31". IJA designated both versions "Renault Otsu Gata" = "second (tank) model". During the 1932 Shanghai Incident IJA used some of the modified vehicles. But the suspension still had many problems reducing the operational time. So IJA finally decided to retire the NC1 tanks in late 1932.

Data
vehicles bought: 10
battle weight: 8,5 (metric) t
crew: 2 men
armor strength: 18 - 34 mm
length: 4410mm
width: 1710 mm
height: 2140 mm
engine: watercooled Renault 4 cylinder gasoline
power: 60 hp
maximum speed: 35 km/h
fuel capacity: 240 l
range: 120 km
transmisson: 6 forward, 1 reverse
Power/weight ratio: 7,6 HP/t
armament: 1 X Sogekiho 37 mm Gun or 1 X Type Taisho 3 6,5 mm MG


h) Carden-Loyd Tankette

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Jap%20carden-lloyd%20tankette%20mk%20IV.jpg

In mid 1930 IJA bought 2 britsh Carden-Loyd Tankettes Mk VI to test them as support vehicles for cavalry units. The vehicle was found generaly useful but the cross-country abilities of the suspension were found too weak, a revolving turret was found necessary and the open fighting compartment with armoured caps for driver and gunner was found inacceptable. So the decision was made to develop a domestic lightly armoured, tracked vehicle with a turret as armoured support vehicle.

In 1931 the two tankettes were tested at IJA infantry school. There the vehicle concept was found useful for armoured transport, especially due to the tracked trailer with its loading capacity of 400 kg. This allowed protected transport of men, mail, supply and ammuniton. The vehicles themselfs were rated underpowered, weakly armoured and with low self defence capacities due to the missing turret. So the decision was made to develop a similar vehicle with a larger transport compartment, a turret and a 0,75 t trailer.

The two Carden-Loyd tankettes were handed over to IJN in late 1931. At this time the tensions in China raised and the decision was made to sent armoured vehicles to Shanghai to support the naval troops stationed in the japanese settlement. Therefore four more Carden Loyd tankettes were bought in late 1931/early 1932. These vehicles were modified by replacing the small straight armour plates on the sides by higher trapeziod armour plates which were arranged sloped. In addition the two armoured caps were replaced by a single cap which closed the fighting compartment completely. During the 1932 Shanghai incidents the vehicles were used during the fightings as transport vehicles and for infantry support designated "Type Ka (for Carden-Loyd) MG vehicle" .The further fate of these vehicles is unknown.

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Jap%20carden-loyd%20tankette%20type%20Ka%20mg%20car.jpg

Sometimes these tankettes are also designated "Type 88 Tankette" in literature but this is not correct.

Data
vehicles bought: 2 + 4
battle weight: 1,5 (metric) t
crew: 2 men
armor strength: 6 - 9 mm
length: 2460 mm
width: 1700 mm
height: 1220 mm without armored caps
engine: Ford Model T 4-cylinder gasoline
power: 22,5 hp
maximum speed: 45 km/h
fuel capacity: 38 l
range: 140 km
transmisson: Ford planetary transmission
Power/weight ratio: 15 HP/t
armament: 1 X 7,7 mm Vickers MG


i) Vickers Mark E 6-ton Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20vickers%206ton.jpg

In 1930 IJA also bought two Vickers Mark E Version A tanks and tested them. During competitive tests with the new Type 89 Medium Tank the british susupension was rated slightly superiour and the stronger engine made the british tank more agile. On the other hand the use of two MG-turrets with traverse angles of only 265 ° was found a waste of ressources on such a heavy vehicle. So IJA refused to introduce this tanks.

From 1937 on IJA was able to capture several Vickers Mark E Versions B and F Tanks tanks with its single turrets armed with a 47 mm gun in China. Competitive tests with the Type 95 Light Tank Ha-Go showed a superiority of the japanese model regarding suspension and engine but also a slight inferiourity regarding armament.

Data (Version A)
vehicles bought: 2
battle weight: 7 (metric) t
crew: 3 men
armor strength: up to 13 mm
length: 4880 mm
width: 2410 mm
height: 2080 mm
engine: Armstrong-Siddeley 4-cylinder gasoline
power: 80 hp
maximum speed: 35 km/h
fuel capacity: 182 l
range: 160 km
transmisson: 4 X forward, 1 X reverse
Power/weight ratio: 12 HP/t
armament: 2 X 7,7 mm Vickers MG


j) US Light M3:

http://www.ww2technik.de/Bilderchen/jappanzer/ausland/jap%20light%20m3.jpg

During the 1941/42 Philippines campaign IJA first met the US Light M3 tanks of the US-Army 192nd and 194th Tank Battlions. The M5 37 mm Tank Gun was able to defeat any japanese tank even on long ranges while the japanese Type 95 Light Tanks could only penetrate the frontal armour of the M3 on short ranges, the Type 89 and 97 Medium tanks even had to attack from the sides on very short ranges. Due to the IJA infantry tactics and the terrain plus a bad tactical use the M3s were not the threat they could be during this campaign. As result IJA speeded up the production of the Type 97 Medium Tank KAI and the training of crews for this tanks in January 1942. But before the first tank company equipped with this tanks reached Luzon the fightings were over. Only corregidor remained as US strongpoint. IJA tankers took over several operational Light M3 tanks after surrender of the US tank battalions. During the amphibious attack of Corregidor in May 1942 a Type 97 Medium Tank KAI and two US Light M3 landed on the island. Shortly after that the US defenders surrendered.
The captured Light M3 were taken over officially by IJA as medium tanks due to their weight of 12,7 t. All tanks and all captured stocks of supply for these vehicles were handed over to IJA 7th Tank Regiment which formed at least one tank company with these vehicles. One platoon from this unit was shipped to Java to support the attack on the vital cities of this island.

During the 1942/43 Burma campaigns IJA captured some british Light M3 Stuart tanks and formed at least one company for the 14th Tank Regiment. These tanks fought quite hard during the 1944 Imphal campaign where a Light M3 became the first japanese tank who destroyed a Medium M3 Grant. The 14th tank regiment was almost annihilated during this campaign and only few Light M3s remained operational. Due to the low stocks of replacement parts the remaining tanks were finally used as pillboxes during the 1945 retreats.

The 7th Tank Regiments Light M3s fought hard during the 1944/45 Phillipines campaign but were finally destroyed due to the massive superiority of the attacking US troops.

Data
vehicles captured: between 50 and 80
battle weight: 12,7 (metric) t
crew: 4 men
armor strength: up to 44 mm
length: 4531 mm
width: 2240 mm
height: 2500 mm
engine: Continental W-670-9A 7-cylinder radial gasoline
power: 262 hp
maximum speed: 58 km/h
fuel capacity: 204 l
range: 110 km
transmisson: 5 X forward, 1 X reverse
Power/weight ratio: 21 HP/t
armament: 1 X 37 mm M5 Tank Gun, 2 - 4 X .30 cal Browning M1919A4 MG

Yours

tom! ;)

tom!
01-06-2018, 06:20 AM
Hi.

6) Early japanese Projects part 1:

After World War I IJA was quite impressed by the new tank technolgy. But the low speed and the short duration of these vehicles were also seen. So IJA decided only to buy several contemporary tank models for basic tactics development and to get modern technology samples.

With the Vickers Mark I light tank and Mark I medium tank developed from 1922 on the first tanks with quite high speed (more than 20 km/h) and a good duration became avaliable. IJA sent several observers to watch test trials at Vickers. After the reports were evaluated in 1923 IJA decided to equip their forces with such modern vehicles. At this time the japanese heavy industry wasn´t able to develop or to produce such tanks within the next years. So several military missions were sent to USA, Great Britain and France to negotiate about buying tanks. Great Britain refused to give the necessary permmissions as their own troops were not fully equipped with the planned vehicles. The armies of France and USA hadn´t ordered new tank models and so IJA talked directly with Christie and Renault but both developers did only have few designs of new tanks without plans to built prototypes.

So IJA had to realise that a quick success was impossible. So in early 1925 the decision was made to delay the purchase for several years as they saw no chance for the japanese industry to develop a domestic tank within 5 to 10 years. At this point the Army Technical Headquaters contradicted and offered to develop a domestic tank in cooperation with the industry within 2 years. IJA headquaters was sceptic but decided to give it a try.


a) Experimental Tank No. 1:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20experimentalpanzer%20nr.%201%202.jpg

In early 1925 IJA decided to give design orders for a lightweight tank for tank school training (similar to the Renault FT 17) and for a medium tank with a weight of not more than 20 (metric) t (similar to the Medium Mark A Whippet) with a tinme frame of 2 years. At best the whole project should boost the dometic heavy industry to a level that it could be able to develop own tanks within 5 years. Army Technical Bureau was not satisfied with these limitations but they took the chance. The official orders were used as cover to design a full-scale battle tank able to compete with european tanks. The Operational Chief of Staff knew this but he gave the engineers a carte blanche to do as they wanted.

Until mid 1925 the Army Technical Bureau developed the specifications for a 15 t tank:
- weight around 15 t
- suited for attacking heavy field fortifications while having good road mobility
- maximum concentration of firepower around the tank to enhance independent combat capabilities within enemy field fortifications
- therefore a 57 mm main gun in a central rotating turret
- and two separate MG turrets with one mounted in the front and one in the rear behind the engine as armament
- armour strength to defeat contemporary 37 mm at-guns even on short ranges
- road speed of 25 km/h
- suspension for maximum off-road capabilities with an easy and precise one-man steering
- trench crossing capability 2,5 m, maximum climbing gradient 43°
- crew of 5 men
- width and height fitted for railway transport even on the mountain railroads
- operational time at least 10 h

IJA expected that the development and testing of the multiple components would have been done separately before fitting to the prototype. This would have led to a massive time delay and so the developers decided to test the components on the prototype. Several components were designed and built from the domestic industries, especially Mitsubishi and Kawasaki, and delivered to Osaka Army Arsenal where the prototype was built in secrecy. A parallelogram-type suspension with 8 pairs of roadwheels on the ground and three single roadwheels (two at the front and one on the rear) for additional climbing capabilities was chosen which delivered the necessary stability. In addition five return rollers with the first raised, a forward idle wheel and a rear driving sprocket were used. This gave the tracks a distinctive buckling after roughly 1/4 of the return travel. A 6 mm armour plate protected the central suspension components.
A new 8 cylinder gasoline engine was placed behind the main turret. The engine compartment could be reached through an access hatch from the main fighting compartment. The necessary gasoline and oil tanks were placed in separate compartments on the left and right of the main fighting compartment which made them quite vulnerable for enemy fire. The exhaust gases were discharged by an exhaust pipe on the right and lead to a muffler on the rear of the vehicle.

The MG-turrets were built cylindrical with sloped upper side parts. A Type Tasho 3 6,5 mm MG was mounted in each turret. In and around the turrets ammunition boxes for a total of 500 10-shot ammuniton frames were placed. Both turrets were placed offset to the left (in driving direction) of the central axis. The driver sat in the right front next to the bow gunner.

The main turret was conical with a high rotating cylindrical comanders cupola on the rear right. A 57 mm tank gun of unknown origin was mounted in the 2-men turret. The commander was also used as loader. The gun shield was placed inside the turret which lead to a small hole in the armour below the gun at high elevation. The ammunition stowages inside and around the turret allowed a maximum load of 110 grenades.

The armour plates should be riveted on a massive frame. Due to the lack of experience several components had to be modified several times and the production of the face-hardened armour plates was problematic as the japanese industry had only experience in making thicker plates for the naval projects. The prototype was finished in February 1927 but it only had mild steel plates. Fortunately the initial trials showed only limited problems which were quickly solved.

In June 1927 the Army Technical Bureau presented the vehicle designated "Experimental Tank No. 1& officially to IJA High command during several field trials at Mount Fuji Training Ground. The army officialy were very impressed by the vehicle which was able to drive with high speed even through rough terrain. All specifications were at least met with one exception: the weight. The resulting vehicle had a battle weight of 20 t which was found too high for most railroad and road bridges. Nevertheless the results exceeded the expectations of IJA High Command by far and so in fall 1927 the decision was made to allow the development of a 10 t light tank. This was the birth of the domesic japanese tanks.

Data
vehicles built: 1
battle weight: around 18 (metric) t empty, 20 t fully loaded
crew: 5 men
armou strength: up to 17 mm
length: 6030 mm
width: 2400 mm
height: 2430 mm without commanders cupola, 2780 mm with cupola
ground clearance: 400 mm
track width: 350 mm
trench crossing capability: 2500 mm
climbing capability: 43°
maximum vertical obstacle: 1000 mm
engine: 8-cylinder V-type gasoline
power: 140 hp
maximum speed: 20 km/h on roads
fuel capacity: for an operational time of 10 h cross-country
range: n. a.
transmisson: 6 forward, 1 reverse
Power/weight ratio: 7,78 HP/t
armament: 1 X 57 mm tank gun, 2 X Type Taisho 3 6,5 mm MG


b)Experimental Tank No. 2:

no pic, sorry

In mid 1927 IJA developed specifications for the 10 t tank:
- maximum speed 25 km/h (which was the maximum speed of the contemporary trucks used by mechanised infantry units)
- trench crossing capability 2000 mm
- maximum gradient: 43°
- maximum length 4300 mm
- width and height fitted for railway transport even on the mountain railroads
- main armament one 37 mm tank gun
- one or two MGs
- armor strength to defeat contemporary 37 mm at-guns on medium ranges
- steering components similar to the Experimental Tanks No. 1

Design started in fall 1927 based on the Experimental Tank No. 1. Several design features of the Vickers Mark C tank were also copied and/or modified. But in early 1928 it became obvious that the design would result in a weight higher than 12 t. In addition the french 37 mm tank gun and the japanese "Sogekiho" 37 mm Gun were rated unsatisfying regarding HE-power. Therefore the development was stoped to modify the design.


to be continued in part 2....

tom!
01-06-2018, 06:24 AM
6) Early japanese Projects part 2:

c) Type 89 Medium Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%2089/jap%20typ%2089%20prototyp%20strassentest.jpg
Type 89 Medium Tank prototype during early trials

In mid 1928 the design of the Experimental tank No. 2 continued. Now more design features of the Vickers Mark C were used to reduce further weight and the development of a domestic 57 mm tank gun based on the Vickers 6cwt tank gun was started.

Especially the suspension was remodelled and simplified. It now consisted of four pairs of slightly larger road wheels connected by bogies and semi-elliptical springs and a ninth road wheel mounted vertically in front of the forward horizontal road wheel for better climbing and trench crossing. Five return rollers, a forward idle wheel and a rear driving sprocket completed the suspension. Bogies and springs were protected by a 6 mm armour plate.

In the bow a driver sat in the left (in driving direction) behind a simple hinged visor port. A MG gunner/technician sat in the right operating a Type Taisho 3 6,5 mm MG mounted in a fork behind an elevateable and traversable armour shield. Several ammunition boxes were placed on the right of the bow gunner.

The frontal armour was split with the upper 1/4 mounted vertical and the lower 3/4 sloped. In the lower part a large access door was implemented on the right. Due to problems producing the necessary armour plates the first prototype was built with parts of the frontal armour disassembled from one of the Vickers Mark C´s.

The main turret was slightly conical wit an extension for the main gun. A MG-port was placed in the turret rear at 180° to the gun. A small hatch for the commander was placed in the rear right of the turret. The main gun was operated by a gunner and the commander as loader, the MG by the gunner. Several grenades could be stored left and right of the gun upright with the fuse facing down. MG ammunition was also stored next to the turret MG. Additional diagonal stowages were placed on the left and right of the turret in the hull. Several further stowages were placed below the floor plates left and right of the central shaft for the steering and clutch cables allowing a total payload of 110 57 mm grenades and 2745 MG shots.

A licence-built 6 cylinder Daimler gasoline aircraft engine limited to 100 hp was placed offset to the right in the rear. A small hatch allowed limited access to the engine from the fighting compartment. Large access cover plates in the upper rear armour easily allowed the exchange of the engine. A 180 Ah battery placed in the rear of the engine delivered the necessary electrical power to start the tank. Gasoline tanks were mounted in the sides of the tank above the tracks. The upper side armour over the gasoline tanks was mounted sloped. An oil tank was placed on the left of the engine. For ventilation most of the necessary combustion air was sucked off the fighting compartment.

All armor plates were face-hardened and riveted to a frame. Besides the 17 mm frontal bow armour all other armour plates were available in early 1929 and so the prototype was finished in April 1929 at Osaka Army Arsenal armed with a Vickers 6cwt tank gun. Mechanical and performance tests were finished fast and almost all specifications were met but the weight limit could only be reached without ammunition and sparse fuel in the tanks (empty weight 9,8 metric t). The battle weight was 11,5 t. At this time IJA badly needed a successor for the outdated Ko Gata tanks, especially as the Otsu Gata tanks were disappointing. And so the vehicle was officially adopted as "Type 89 Medium Tank" in late 1929. Nevertheless several modifications were demanded:
- use of a Diesel engine as gasoline engines were rated dangerous after an accident during the tests with the Vickers Mark C tanks
- use of a domestic tank gun
- a commanders cupola should be added

Mitsubishi Heavy Industries (which was largely involved in the development of the tank) was ordered to built up a production line within one year and they built a complete new tank factory until late 1930. And they also started the development of a light, compact Diesel engine.

The tank gun was finished at Osaka Army Arsenal in late 1930 and implemented in the tank with only few necessary changes, but the production was delayed. So some of the first tanks were equipped with 37 mm "Sogekiho" infantry guns. A small, high cupola with horizontal slits was added on the hatch on the turret roof. Serial production could start in mid 1931 but only 10 vehicles were delivered in that year due to much handwork. The vehicles were issued to IJA Tank School where the crews were trained. In spring 1932 the 2nd Independent Tank Company was formed and equipped with 5 Type 89 Medium and 10 modified Otsu Gata (Renault NC27 modified) Tanks. During the 1932 Shanghai Incident the vehicles were used under naval command during the street fightings with different success. While the Otsu Gata often broke down with suspension failures the Type 89 Medium Tanks were very successful.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%2089/jap%20Typ%2089%20sogekiho%20shanghai.jpg]
A Type 89 in Shanghai 1932 with 37 mm "Sogekiho" gun

After the end of the fightings the crews were interviewed. The general performance was found good but they also demanded several changes. Main problem was the internal gun shield which opened a gap in the armour at high elevation. So the shape of the frontal turret armour was changed to close this gap. Another problem was the vertical upper bow armour which was often hit by bullets bouncing off the sloped lower bow armour. So a new fully sloped bow armour was developed which made an extension for the drivers visor port and a different shape of the MG mount necessary. A ditching tail was also added. The changes were implemented in the ongoing production leading to several intermediate versions but also slowing down the production. Until 1933 the 2nd Independent Tank Company was completely equipped with this tank and another company, the 1st Special Tank Company changed from Kou Gata to Type 89 Tanks which were rearmed to Type 90 57 mm guns. This unit participated in the early 1933 Jehol operation in northern China where it was able to move 320 km in just three days against enemy opposition. This was remarkable at this time especially as they suffered no losses by mechanical failures.

The crews participating in this operation demanded further changes. This includes modification of the suspension to increase self-cleaning from mud, a change of the rear turret MG position and a lager commanders cupola. The necessary changes were made until 1934. The upper part of the suspension was remodelled by removing one return roller to increase the space between the remaining rollers where the mud could fell off. The suspension armour plates received a sloped upper part to let the mud slide off easier. The turret was remodelled, too. A large cylindrical commanders cupola was installed and the turret MG was moved from 180° position to 210°position in an armour extension. Several minor changes were also done.

The changes were also implemented in the serial production leading to more intermediate versions. In late 1933 Mitsubishi was able to finish the development of a 120 hp 6 cylinder Diesel engine. This engine was implemented in the Type 89 Medium Tank until 1934 which made several changes regarding cooling air intakes and transmission necessary. In addition IJA decided to standardise the crew positions in their tanks. So the drivers and bow gunners position in the Type 89 Tanks had to be exchanged which was also done in 1934.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%2089/jap%20typ%2089%20chi-ro%20otsu%203.jpg

With the beginning of the production of the Diesel-equipped tanks the gasoline version received the additional designation "Kou(A)", the Diesel-engined "Otsu" But the Diesel engine production never reached the same numbers as the tank production, gasoline engines still had to be used until the end of the production in 1936. A total of 278 Type 89 Medium Tanks Kou and 126 Type 89 Medium Tanks Otsu were built.

Type 89 Medium Tanks were involved in almost all IJA and IJN tank unit operations until 1940. They did a good job in their intended task, infantry support. From 1939 on they were replaced by the successor, the Type 97 Medium Tank Chi-Ha. The Nomonhan Incident in 1939 showed that the Type 89 Medium Tanks were outdated regarding armour and armament but they were used until 1945, finally as mobile pillboxes in the Philippines and Burma.

to be continued in part 3...

tom!
01-06-2018, 06:27 AM
6) Early japanese Projects part 3:


Type 89 Medium Tank part 2:

After the war the Type 89 Tanks were still used by local chinese forces, the indonesian liberation forces and french forces in Indochina.

http://www3.plala.or.jp/takihome/newfolder/Char3.jpg
french Type 89 Medium Tank in Indochina

Data (version Ko / version Otsu)
vehicles built: 278 / 126
battle weight: 12 (metric) t early version, 14 (metric) t late version
crew: 4 men
length: 4300mm, 5750 mm with ditching tail
width: 2180 mm
height: 2560 mm
ground clearance: 480 mm
track width: 305 mm
trench crossing capability: 2000 mm, 2500 mm with ditching tail
climbing capability: 34°
maximum vertical obstacle: 840 mm
engine: 6-cylinder Daimler gasoline / 6-cylinder Mitsubishi Diesel
power: 118 hp at 1400 rpm / 120 hp at 1800 rpm
maximum speed: 25 km/h on roads
fuel capacity: for an operational time of 10 h cross-country
range: n. a.
transmisson: 6 forward, 1 reverse
Power/weight ratio: 10 HP/t / 8,57 hp/t
armament: 1 X Type 90 57 mm Tank Gun , 2 X Type Taisho 3 6,5 mm MG, later Type 91 6,5 mm Tank MG



armor
strength


turret front
15 mm @ 80 °


sides
15 mm @ 80 °


rear
15 mm @ 90 °


roof
10 mm @ 0 °


superstructure front
17 mm @ 75 °


sides
11 mm @ 90 °, upper part @ 35 °


rear
8 mm @50 °


roof
6 mm @15 °




http://upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Type_89_Yi-Go_at_Tsuchira.jpg/300px-Type_89_Yi-Go_at_Tsuchira.jpg
The only remaining operational Type 89 Medium Tank Otsu at JSDF Tank School Tsuchiura, Japan


d) Experimental Amphibious Halftrack AMP:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20amp%20amphibischer%20panzerwagen.jpg
Prototype during trials

In 1929 IJA decided to develop a fast amphibious armoured car similar to the french AMC Citroën-Kégresse P 16 for cavalry reconnaissance units. The halfrack system was chosen as it has a better cross-coutry ability than wheels.The Sumida factory of Ishikawajima Automotive Works (later became Isuzu Motors) was ordered to develop such a vehicle. The company was chosen as they also had experiences in shipbuilding. The specifications were:
- amphibious, able to cross rivers with medium current
- maximum weight 2,5 t
- maximum armour able to defeat contemporary infantry rifle AP ammunition
- 2 men crew
- length 4000 mm, width 1600 mm, height 1900 mm
- armament one MG in a revolving turret
- maximum speed 45 km/h, 9 km/h swimming

The design was done quickly using a boat-shaped hull and a french Kégresse suspension. The prototype was finished in summer 1930. It had two drivers positions, one on the track side for driving on land and one on the wheel side for driving in the water. A 40 hp Ford gasoline engine was used. The turret was conical with an extension for the MG. During trials the hull showed very good swimming abilities allowing the projected speed of 9 km/h. The road speed also reached the 45 km/h but the cross country abilities were rated disappointing. In addition the armament of a Type Taisho 3 6,5 mm MG was found too weak. So in late 1930 the decision was made to drop the design in favor of a full-tracked vehicle. The fate of the prototype is unknown but there are photos of the vehicle used without the turret during a 1934 test of an amphibious tank prototype.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20amp%20amphibischer%20panzerwagen%20im%20wass er.jpg

Data
vehicles built: 1
battle weight: 2,5 t
crew: 2 men
armor strength: up to 5 mm
length: 4000 mm
width: 1600 mm
height: 1900 mm
ground clearance: 400 mm
engine: 4-cylinder Ford Type A gasoline
power: 40 hp
maximum speed: 45 km/h on roads, 9 km/h on water
Power/weight ratio: 16 HP/t
armament: 1 X Type Taisho 3 6,5 mm MG


e) Type 92 Heavy Armoured Vehicle:

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/Typ%2092/jap%20typ%2092%20light%20tank%20prototype.jpg
early prototype with a Type 92 13,2 mm MG in the bow

After ending the trials of the Carden Loyd Tankettes and the AMP prototype IJA ordered the development of an armoured reconnaissance vehicle for cavalry units. The specifications were developed until early 1932:
- fully tracked
- maximum possible speed
- maximum possible mobility
- all-welded armour, able to defeat infantry ball ammunition
- 3 men crew
- 2 MGs or one MG, one Machine Cannon
- bow weapon with maximum possible elevation and traverse for indirect and even aa-fire
- a tow-bar in the rear for trailers up to 750 kg

Ishikawajima Automotive Works received the development order in March 1932 as they had experiences in welding thin steel plates for non-warship hulls. The hull was completely electrically welded, only the frames of the access hatches on the bow and on the engine compartment were riveted on the 6 mm thick face-hardened armour. Both rolled and casted steel was used. In the bow the driver sat on the left (in driving direction) , the gunner in the quadrangular armour extension in the right. The bow armament should consist of a Vickers 12,7 mm MG or a Type 92 13,2 mm MG but a Type 91 6,5 mm Tank MG could also be mounted. An enlarged standard MG mount was used for a maximun elevation of around 45° and a traverse of +- 60 °. A special optics allowed firing at high angles while sitting. A revolving conical turret with an MG-port for a Type 91 6,5 mm Tank MG in an extension was placed in the center of the fighting compartment.

The side armour was vertical with sloped upper parts. A 6-cylinder gasoline engine for 40 km/h was placed in the centerline in the rear. It was covered by sloped armour plates. For the suspension two pairs of road wheels were spring-mounted by leaf springs and a forward driving sprocket, a rear idle wheel and three return rollers were used.

Prototype tests of the 3,2 t heavy vehicle started in late 1932 and lead to several changes. The large space between the road wheels led to problems with shed tracks in rough terrain. So a third pair of road wheels was added on each side. The close defence was rated problematic due to blind spots on the forward left and right. So hatches were added in the forward right and left hull armor. The vertical armour of the bow armament extension was identified as a shot trap and so the upper part was arranged sloped. The changes were implemented fast and so the vehicle could be introduced in early 1933. It was designated "Heavy Armoured Vehicle" as IJA had decided that only infantry units should receive "tanks" but it was in fact a light tank.

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/Typ%2092/jap%20typ%2092%20leicht%20frueh%20gelaende.jpg
early production vehicle

Serial production started immediately. First operational use was in March 1933 when 2 pre-series vehicles were used during the Operation Jehol in northern China. During the following years several cavalry reconnaissance units in China were equipped with the Type 92 Heavy Armoured Vehicle. Especially the high speed and good mobility even in rough terrain were badly needed. One of the few things which were criticised were the poor weld seams on some vehicles which lead to cracks between casted and rolled armour parts. This could not be solved until production end.

In 1934/35 after introducing the new standard suspension on the Type 94 Special Tractor IJA ordered to change the suspension to standardise the parts. Therefore two pairs of larger road wheels were attached and a larger return roller in the middle and a smaller directly behind the driving sprocket replaced the old rollers. The changes were taken over into production in 1935.

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/Typ%2092/jap%20typ%2092%20light%20late.jpg
late production vehicle

In 1937 several vehicles were rebuilt as communication tanks with a Type 94 wireless set replacing the bow armament and a rod antenna in the rear of the fighting compartment. To increase the at-abilities trials were made to install a modified Type 98 AA Machine Cannon and even a Type 94 37 mm Tank Gun in the bow but the available space was not enough at least for the tank gun. The vehicle was replaced in the cavalry units by the Type 95 Light Tank Ha-Go but continued its service in the reconnaissance units of the IJA tank regiments from 1937 on. After introduction of the Type 97 Tankette Te-Ke as successor the production of the Type 92 Heavy Armoured Vehicle was stopped in 1939 after delivering 167 of these vehicles.

There was also a trial prototype of an amphibious version without bow armament.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2092%20leicht%20amphibisch.JPG

Data
vehicles built: 167
battle weight: 3,5 (metric) t early version, 14 (metric) t late version
crew: 3 men
armor: up to 6 mm
length: 3940 mm,
width: 1620 mm
height: 1830 mm
ground clearance: 280 mm
track width: 210 mm
trench crossing capability: 1600 mm
climbing capability: 30°
engine: 6-cylinder Mitsubishi gasoline
power: 45 hp at 1600 rpm
maximum speed: 40 km/h on roads
range: 100 km
Power/weight ratio: 12,8 hp/t
armament: 1 X Type 91 6,5 mm, later 1 X Type 97 7,7 mm Tank MG in the turret, 1 x Type 91 6,5 mm, later 1 X Type 97 7,7 mm Tank MG or 1 X Type 92 13,2 mm MG in the bow

Yours

tom! ;)

tom!
01-06-2018, 01:44 PM
Hi.

7) Armored Cars part 1

IJA and IJN used different types of domestic and foreign armored cars from 1920 on. They were used for armored support of the infantry during long-range operations and street fights even if the armor wasn´t satisfying and the mobility on non-paved roads and off-road was quite poor. Most armored cars were removed from active service after the first domestic tanks became avaliable from 1933 on. Informations on these vehicles are quite rare.

Only railway units used armored cars for railroad security and protected transport until 1945. These will be covered in a later post.


a)Austin and Austin-Putilov Armored Car:

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/jap%20austin%20panzerwagen%204.jpg

In 1919 IJA bought two second series Austin Armored Cars in Great Britain to equip the units operating with the international force during the Siberian Intervention. This operation was started in 1917 to support the White Russian forces against the Bolsheviks and the german army and to protect the massive stockpiles of supply and ammunition sent by the Entente to Vladivostok. IJA joined in mid 1918, mainly to expand their territory north of Korea.

The Austin Armored Car was desiged in 1914 by the Austin Motor Company based on a serial production truck chassis after the british army requested an armored vehicle with closed fighting comparment, two seperate MG turrets and a good mobility even on non-paved roads. In 1915 the second series was started with a stronger 50 hp engine. The drivers cabin was remodelled to allow the parallel mounted turrets to fire staight ahead and the basic armor was increased from 3,5 - 4 mm to 4 - 7 mm.

The japanese vehicles were delivered until late 1919. After the crews were trained the vehicles were shipped to Vladivostok. At this time the main purpose of the allied troops changed towards fighting off the advancing Bolshevik troops to allow an organised disarming of the beaten White Russian forces to save their equipment from falling into the enemies hands.

Among tons of rifles, ammunition and other equipment several russian Austin-Putilov Armored Cars were handed over to the Entende troops. Some of these vehicles were taken over by IJA.

This vehicles are remodelled second series Austin ACs. Russia ordered 60 of the truck chassis which were delivered in 1916. At the Putilovski Works in St. Petersburg the vehicles received stronger 60 hp engines and a rear drivers position was added. The (in driving direction) left turret was moved to the rear to allow both turrets to fire at the same side at the same time. Two armor plates were added to both sides of the MGs to protect the cooling water tanks around the barrels.

After the end of the Siberian Intervention IJA used the vehicles during various operations which results in the occupation of Manchuria in 1929. The further fate of the vehicles is unknown.

In the mid-1920th the armor from one Austin AC was removed an mounted on a domestic 6 X 4 truck chassis, but there was no serial production.

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/jap%20austin%20panzerwagen%202.jpg


Data (Austin AC / Austin-Putilov AC)
vehicles bought/captured: 2 / unknown, but less than 10
battle weight: 4,5 (metric) t early version, 4,7 (metric) t late version
crew: 4 men / 5 men
armor 4 - 7 mm
length: 4800mm
width: 2030 mm
height: 2450 mm
engine: Austin 4-cylinder inline gasoline / russian 4-cylinder inline gasoline
power: 50 hp/ 60 hp
maximum speed: 50 km/h on roads / 60 km/h on roads
range: 200 km
Power/weight ratio: 11,1 HP/t / 12,75 hp/t
armament: 2 X 7,7 mm Hotchkiss MG / 2 X 7,62 mm Maxim M1910 MG


b) early Domestic Armored Cars:

http://www.horae.dti.ne.jp/~fuwe1a/images/tank/sac.jpg
experimental light armoured car, based on a 1,5 t commercial light truck chassis, only one known prototype

Besides the Austin Armoured Cars IJA used several experimental domestic armoured cars during the Siberian Intervention based on several light, medium and heavy truck chassis. They were only lightly armoured with the face-hardened armour plates riveted on a frame. All had a rotating turret on the fighting compartment armed with a Type Taisho 3 6,5 mm MG. The heavier vehicle also had several gun ports in the vehicle sides and rear.

http://www.horae.dti.ne.jp/~fuwe1a/images/tank/plac01.jpg
experimental medium armoured car, based on a 3 t commercial truck chassis, at least 2 prototypes were built

The armor was only able to defeat ball ammunition but was penetrated by AP ammunition. In addition the off-road mobility was poor. Nevertheless the vehicles were used with some success during the operations and so the decision was made to continue development. Further data are unknown.

http://www.horae.dti.ne.jp/~fuwe1a/images/tank/phac01.jpg
experimental heavy armoured vehicle, based on a 4 t commercial truck chassis, at least 2 prototypes were built

No further data, sorry.


c) Renault Armoured Car:

http://www.horae.dti.ne.jp/~fuwe1a/images/tank/ruac.jpg
experimental Renault AC with prototype fighting compartment armour

In 1928 IJA bought a Renault 6-wheel 2,5 t truck and developed a modern armour around the vehicle. The vehicle had a drivers position in the bow and in the rear. Armament consited of a Type Taisho 3 6,5 mm MG in a conical turret. In 1929 several trials and tests were made at IJA Cavalry School. In 1929 IJA also bought a Renault prototype of an armoured car based on the same chassis. Both vehicles were used in Manchuria at least in 1929.

No further data avaliable.


d) Type Crossley Armoured Car (Vickers Crossley Model 1925 Armoured Car):

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/Jap%20Crossley%20mk%201%20panzerwagen.jpg

From 1925 on IJA and IJN bought some 12 Vickers Crossley Model 1925 Armoured Cars and used them for infantry and cavalry training. During the late 1920th incidents in Manchuria and northern China the vehicles were used with good success for patrol duties and infantry support.

The vehicles were of standard serial production. The Crew consisted of forward and reverse driver, gunner and commander. The armor strength was 4 - 5,5 mm. Armament consisted of two Vickers 7,7 mm MGs which could be mounted in four gun ports inside the hermispherical turret.

Official designation was "Type Crossley Armoured Car" but western sources also use "Dowa Armoured Car" which is (afaik) caused by a misinterpretation of japanese newspaper reports. The IJN vehicles were stationed in Shanghai for protection of the japanese settlement. The vehicles were used extensively during the 1932 Shanghai Incident. Until 1937 they were replaced by domestic light tanks or tankettes. The final fate is unknown

Data:
vehicles bought: 12
battle weight: 4,85 t
crew: 4 men
armor 4 - 5,5 mm
length: 5020mm
width: 1870 mm
height: 2580 mm
engine: Crossley 4-cylinder inline gasoline
power: 50 hp
maximum speed: 64 km/h forward, 8 km/h reverse
range: 200 km
Power/weight ratio: 11,1 hp/t
armament: 2 X 7,7 mm Vickers MG


e) Wolseley Armored Car / Simple Armored Car:

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/jap%20wolseley%20panzerwagen%204.jpg

In 1928 IJA ordered Isuzu to develop an armored car based on their licence-built Wolseley CP 1,5 t truck chassis. The Vickers-made armour of the Type Crossley AC was taken as basis for the armour scheme. The side extensions of the fighting compartment were removed as they were unnecessary due to the smaller turret. Armament consisted of a Type Taisho 3 6,5 mm MG. The vehicles were operated by a forward and a reverse driver, a gunner and a commander. First reported use of this vehicles was during a 1930 cavalry exercise at Mount Fuji Training Ground. At least two vehicles were built.

The official designation is unknown, some IJA source refere to it as "Simple Armored Car" while most western sources use "Wolseley Armored Car" or even "Vickers Wolseley Armoured Car" due to the copied armour scheme. No further details known.

The vehicles weight of 4,2 t was quite large for a 1,5 t truck chassis so it can be assumed that it had serious problems with the weight of the armour. In addition the engine power of 30 hp was quite weak for such a vehicle making it clumsy.

Data:
vehicles built: at least 2
battle weight: 4,2 t
crew: 4 men
armor 6 mm
length: 5562mm
width: 1892 mm
height: 2615 mm
power: 30 hp
maximum speed: 40 km/h forward, 8 km/h reverse
range: 200 km
Power/weight ratio: 7,1 hp/t
armament: 1 X Type Taisho 3 6,5 mm MG


to be continued in part 2....

tom!
01-06-2018, 01:50 PM
7) Armored Cars part 2


f) Osaka Armored Car:

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/Jap%20typ%2092%20hokoku-go%20panzerwagen%202.jpg

This vehicle was seen during the 1932 Shanghai Incident operated by naval troops. But it was designed by Osaka Army Arsenal from a domestic 2,5 t truck chassis. The armor sheme was similar to the Wolseley Armored Car but built with thicker armor plates. The turret was slightly larger. Armament consisted of one Type Taisho 3 6,5 mm MG in the bow and a second in the turret.

It seems that only one prototype was built as technology test vehicle. The official designation is not known but european sources from 1935 used "Osaka Armored Car" which would fit to the earlier designation system. Today the vehicle is mostly designated "Hokoku-Go Armored Car" but this is a misinterpretation of the writings on the vehicle during the 1932 Shanghai Incident. "Hokoku-Go" or "Hokoku" was a donation organisation which supported IJN with money and military goods. So it seems that the vehicle was bought by Hokoku after the test trials were finished by IJA and then donated to IJN.

Data:
vehicles built: 1
battle weight: 5,85 t
crew: 4 - 5 men
armor 8 - 11 mm
length: 5000 mm
width: 1850 mm
height: 2650 mm
ground clearance: 280mm
engine: 4 cylinder gasoline
power: 35 hp
maximum speed: 60 km/h forward, 7 km/h reverse
Power/weight ratio: 6 hp/t
armament: 2 X Type Taisho 3 6,5 mm MG


g) Chiyoda Armored Car:

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/jap%20aikoku%20armoured%20car%203.jpg

This is the first domestic armored car which was officially introduced by IJA and used in larger numbers. Design started in 1930 at the Chiyoda Motor Car Factory of Tokyo Gasu Denki K. K. (Tokyo Gas and Electric Industries, today Hino Motors Ltd.) based on their Type Q 6-wheeled truck under the development designation "Type QSW. The basic armor scheme was similar to the Wolseley Armored Car. The spoked wheels with pneumatic tired were replaced by disk wheels with fixed rubber bands. The turret had a cylindrical base with a sloped (in driving direction) right upper part. A standard MG mount was placed in this sloped part for air defence. Another MG mount was placed in the turret front and a third in the left bow. In addition three gun / visor ports were placed along each side of the fighting compartment. The standard crew consisted of driver, three gunners and a commander. Armament was three Type Taisho 11 6,5 mm MGs, later three Type 91 6,5 Tank MGs.

The development was finished in 1931 and the vehicle was officially adopted as "Chiyoda Armored Car. In western literature the vehicle is often designated "Aikoku Armored Car" which is a misinterpretation of the writings on a vehicle used during the 1932 Shanghai Incident. This writing referes to "Aikoku-Koto" = "Public Party of Patriots", a nationalistic and militaristic political party which donated money and military material to IJA (as Hokoku did for IJN).

Around 200 Chiyoda Armored Cars were produced and used during several early and mid 1930th IJA operations in northern China for infantry support and security duties in captured regions. They were replaced after 1937 by the Type 97 Tankette Te-Ke.

Data:
vehicles built: ca. 200
battle weight: 5,6 t
crew: 5 men
armor: unknown, most likely up to 6 mmm
length: 5000 mm
width: 1900 mm
height: 2600 mm
engine: 4 cylinder gasoline
power: 75 hp
maximum speed: 60 km/h
Power/weight ratio: 13,4 hp/t
armament: 3 X Type Taisho 11 6,5 mm MG, later 3 X Type 91 6,5 mm Tank MG


h) Sumida Model P Armored Car:

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/jap%20hokoku%20panzerwagen.jpg

This armored car was built in 1930 or 1931 by Ishikawajima Heavy Industries at their Sumida Motor Car Factory based on an own 2,5 t 6-wheeled chassis. It was most likely developed as competitor of the Chiyoda Armored Car. The vehicle had a similar basic armor scheme. The turret was cylindrical with only one MG port in the front. The crew consisted of driver, two gunners and commander. Only one or two of these vehicles were built designated "Sumida Model P Armored Car" .

During the 1932 Shanghai Incident one vehicle was donated by the Hokoku organisation to IJN with the writing "Hokoku" on it. Therefore the vehicle is often wrongly designated "Hokoku Armored Car" in western literature.

In Shanghai few additional soldiers were loaded depending on the orders. At this time the basic armament consisted of one Type Taisho 3 6,5 mm MG in the turret and one Type Taisho 11 6,5 mm MG in the bow. The further fate is unknown.

Data:
vehicles built: 1 or 2
crew: 4 men
armor: up to 6 mmm
engine: 4 cylinder gasoline
armament: 1 X Type Taisho 3 6,5 mm MG, 1 X Type Taisho 11 6,5 mm MG


i) Type 93 Armored Car:

http://www.ww2technik.de/Bilderchen/jappanzer/panzerwagen/Jap%20typ%2092%20marine%20panzerwagen.jpg

This vehicle was developed by Ishikawajima Heavy industries at the Sumida Motor Car Factory in 1932 for IJN. It was based on an european 6-wheeled truck chassis as the drivers position was on the left. In addition the engine compartment was very long which was untypical for contemporary japanese truck designs. The crew consisted of driver, two gunners and commander. A small fighting compartment was placed on the rear axles. The turret was cylindrical with an extension with sloped front for the turret MG. Additionaly one MG-Port was placed on each side of the fighting compartment and on the right in the bow. Armament consisted of a Vickers 7,7 mm MG in the turret and four Type Taisho 11 6,5 mm MGs.

It seems that this vehicles were specially built for street fightings following the lessons learned during the Shanghai-Incident in 1932. The 5 vehivcles built were all used by the Shanghai Special Naval Landing Force from 1933 on for security duties inside the european and the japanese settlements in Shanghai.

Official designation was "Type 93 Armored Car" but in western literature it is often wrongly designated "Type 92 Armored Car" for the development year. In addition it is often mixed up with the Sumida Model P Armored Car.

Data:
vehicles built: 5
battle weight: 4,5 t
crew: 4 men
armor: unknown
length: 4800 mm
width: 1800 mm
height: 2300 mm
maximum speed: 40 km/h
armament: 1 X Vickers 7,7 mm MG, 4 X Type Taisho 11 6,5 mm MG


Yours

tom! ;)

tom!
01-07-2018, 03:28 AM
Hi.

8) Tankettes part 1


a) Type 94 tk Special Tractor:

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2094/jap%20typ%2094%20tk%20prototyp.jpg
first prototype

The 1930/31 trials with the Carden-Loyd Tankette showed the value of small armored tracked transport vehicles for battlefield supply, reconnaissance and liaison duties. So the decision was made to develop a domestic tankette.

In 1933 requirements were given:
- maximum weight 2,65 t
- maximum speed 45 km/h
- trench crossing abilities 1,5 m
- size up to 3400 mm (l) / 1620 mm (w) / 1540 mm (h)
- 2 men crew
- engine placed in the bow to gain maximum storage room in the rear
- driver placed next to the engine
- welded face-hardened armor with a maximum strength of 12 mm, able to defeat infantry AP ammunition
- small revolving turret with machine gun
- good cross-country abilities
- center-guide type tracks
- use of an air-cooled 4-cylinder gasoline engine
- steering system fixed radius with controlled differential
- large rear access door
- towing bar on the rear with a towing capacitiy of up to 1000 kg

In addition requirements for a trailer to be towed by the tankette were given:
- 750 kg payload
- tracked
- minimised height

Tokyo Gas and Electric K.K. (a. k. a. Gasuden, today Hino Motors) was chosen for development in early 1933. They developed a seesaw-type suspension system with two pairs of roadwheels connected by a large horizontally mounted coil spring on each side. The roadwheels were connected by a bell crank. A forward driving wheel, a rear idle wheel and two return rollers completed the suspension. The basic system became standard for all further japanese tanks until 1945.

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2094/jap%20typ%2094%20tk%20anhaenger%20proto.jpg
late prototype with transport trailer

To maximise armor protection the upper frontal armor was arranged sloped. This made an extension necessary for the gearbox, placed in front of the engine. The engine itself was placed on the left, surrounded by a layer of asbestos fiber mats. The driver sat on the right. A quadangular cupola with with visor ports on the sides and the front allowed a good sight. A hatch opening to the front allowed an easy access. A small conical turret with an extension for the Type 91 6,5 mm tank MG´s mount was placed centered on the rear. It also had a hatch opening forward on top. The turret was turned manually by the gunner/commander with the MG stock. The vehicle had a good balance and could easily pushed by few men. but the low weight also led to an instability as weapons platform making aimed MG fire problematic.

The armored trailer had two roadwheels connected with a bell crank between two idle wheels on each side. It had an open top which could be covered by a waterproof canvas. The empty trailer could easily be manhandled.

Test trials started in late 1933 and showed a good manoevrability even in bad terrain. The maximum speed of 45 km/h did also impress IJA officials as they had thought this requirement was too ambitious. Therefore the larger weight of 3400 kg was accepted. But the turret was found too high. So it was remodelled.

After finishing different duration tests the prototype was shipped to Manchuria in spring 1934 and tested under field conditions. It worked fine but the long exhaust pipe to the muffler placed outside the vehicle was critisised as too vulnerable. So the forward part was relocated inside the vehicle. In addition the roadwheels were slightly enlarged for less problems with rocks stuck between them. The instability during firing the MG was found acceptable.

The resulting vehicle was officially adopted as "Type 94 tk" the trailer as "Type 94 3/4 t Trailer". "tk" stands for "Tokusyu Keninsha" = "Special Tractor". Serial production was prepared from fall 1934 and started in early 1935. In spring 1935 the first production vehicles were used to built up the first armored transport companies. Some became organic units of infantry divisions, others became independent units which were attached temporarily to infantry units for special operations . A company consisted of 4 platoons with 4 Type 94 tk each, a company headquater with a Type 94 tk, 2 passenger cars and a motorcycle and a company train with 7 trucks. Other vehicles were used to enstrength cavalry and tank recon units, which received 7 vehicles each. The low weight of the Type 94 tk allowed tranport on heavy trucks during longer relocation cruises.

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2094/jap%20typ%2094%20tk%20lkwverladen.jpg

In mid 1935 the first Type 94 tk were send to China were they were used with good success as transport vehicles. But as they often were the only armored vehicles under direct command of the infantry unit they were also often used as armored spearhead, a task they were not built for. But due to the lack of at-weapons in the attacked chinese units losses were only marginal. For this use the instability as weapons platfform became problematic. Therefore the infantry required several changes to increase stability, cross-country abilities and fire power.

The modification works started in late 1936. The rear idle wheel was enlarged and relocated on the ground to enlength track ground contact by 780 mm to 2300 mm. Additionally it was spring mounted with a coil spring for better stability. This also made the use of a Type 94 37 mm tank gun possible. The turret gun mount was modified to make an easy and quick exchange of the MG with the gun and vice versa. This increased the weight from 3400 kg to 3900 kg. The use as transport and towing vehicle was not affected by the changes, even if the transport space was needed for ammunition when using the gun. All changes could also be easily implemented in the already avaliable tankettes. The vehicle was now rerated from armored transport to light armoured vehicle. From 1937 on the Type 91 MG was replaced by the Typpe 97 7,7 mm Tank MG. There were also trials to use a Diesel engine but due to the introduction of the successor not finished.

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2094/jap%20typ%2094%20tk%20improved.jpg
late version with tank gun. Note the spring system of the idle wheels.

Production numbers were 300 vehicles in 1935, 246 in 1936, 200 in 1937, 95 in 1938 and 1939 an 2 in 1940.

From 1937 chinese forces were more and more equipped with at-weapons and heavy MGs which penetrated the armor easily (the AP-ammunition of the US .50 HMG penetrated the frontal armor on up to 600 m). So losses increased rapidly. Therefore the Type 94 tks were more and more withdrawn from attack duties and used for the intended tasks as transport and recon vehicles.

With the introduction of the Type 97 Te-Ke tankettes the Type 94 tk were withdrawn from the recon units. Transport units used them until surrender.

Special chemical and biological warfare trailers based on the transport version were also developed for spraying and decontamination. The spraying trailer had a conical front. It contained a biological or chemical agent tank and a spraying vent on the upper rear. The decontamination trailer contained a decontamination agent container and a release vent on the lower rear.

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2094/jap%20typ%2094%20gasanhaenger.jpg
spraying trailer

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2094/jap%20typ%2094%20dekontanhaenger%20einsatz.jpg
decontamination trailer

In western literature and on the web the early Type 94 tk is sometimes falsely designated "Type 92 Tankette" .

Several special purpose vehicles and some experimental prototypes were made using the chassis of the Type 94 tk, too.

Data (early / late version)
vehicles built: 843
battle weight: 3,4 (metric) t / 3,9 (metric) t
crew: 2 men
length: 3080mm / 3400mm
width: 1700 mm
height: 1620 mm
ground clearance: 290 mm
track ground contact: 1520 mm/ 2300 mm mm
trench crossing capability: 1300 mm / 1600 mm
climbing capability: 35°
maximum vertical obstacle: 500 mm
engine: Type 94 4-cylinder gasoline
power: 32 hp at 1800 rpm
maximum speed: 45 km/h / 40 km/h on roads
fuel capacity: 106 l
range: 500 km on road, 400 km in easy terrain, 200 km in rough terrain
transmisson: 4 forward, 1 reverse
Power/weight ratio: 9,4 HP/t / 8,2 hp/t
armament: 1 X Type 91 6,5 mm Tank MG, later 1 X Type 94 37 mm Tank Gun or 1 X Type 97 7,7 mm Tank MG



armor
strength


turret front
12 mm @ 90 °


sides
10 mm @ 80 °


rear
10 mm @ 80 °


roof
6 mm @ 0 °


superstructure front
12 mm @ 40 °


sides
10 mm @ 90 °


rear
8 mm @ 70 °


top
6 mm @0 °




to be continued in part 2...

tom!
01-07-2018, 03:32 AM
8) Tankettes part 2


b) Type 97 Light Armoured Vehicle Te-Ke:

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2097/jap%20typ%2097%20tankette%20prototyp.jpg
prototype

Until late 1936 Ikegai Automobile was able to develop a small light Diesel engine for the Type 94 tk but the size was slightly larger than the size of the gasoline engine. Therefore the length of the vehicle had to be increased which complicated the internal crew communitation. A touch code was used for this as the engine noise made voice commands impossible and the use of contemporary earphones was problematic due to the vibrations. . A trial prototype was tested from early 1937 on. It had a much larger ventilation and engine access hatch than the gasoline version.

The larger engine constricted the driver, too. In addition the frontline troops demanded further changes for reconnaissance duties. So the decision was made to develop a new vehicle. Requirements were:
- use of the same suspension, transmission and steering type
- use of as many suspension part of the new Type 95 Light Tank Ha-Go to simplify maintainance
- relocation of the Diesel engine
- increase of frontal armor to 16 mm
- use of welding wherever possible

The prototype was finished in September 1937. Engine and driver changed the side and the engine was shifted slightly to the rear but the stroke was still limited due to the avaliable height which limited the engine power. Due to this relocation the gearbox could be relocated, too, making an extension in the frontal armor unnecessary. In addition the vertical lower frontal armor cold be replaced by a curved casted armor plate. The flat turret hatch was replaced by a curved hatch making low angle fire easier for the gunner. In addition the roadwheels from the Type 95 Light Tank and a similar driving wheel were used. Innitial tests showed that the noise and heat emission of the engine was larger than from the gasoline engine which was found inacceptable. So the design was changed again from November 1937 on.

The engine was now placed lengthwise in the rear inside a separated compartment. The turret was shiftet to front and the rear access hatch was removed. Therefore the vehicle was no longer able to transport supply inside. But the towing bar was still attached. Additionally the armor above the drivers seat was remodelled and streamlined. The drivers hatch was removed. So access to the fighting compartment was now only possible through the turret hatch.
The turret was now partly welded and an acccess hatch was added to the rear mainly to simplify ammunition supply. The gun could still easily be exchanged with the MG.

The innitial factory tests were finished in early 1938 and the vehicle was handed over to IJA Infantry School for field test. In mid 1938 the vehicle was officially adopted as Type 97 Light Armored Vehicle Te-Ke. Production started in early 1939 with 271 produced in 1939, 284 in 1940 amd 41 and 38 in 1942. Production was stopped in 1942 to shift the raw materials to the production of the Type 97 Medium Tanks and aircraft.

http://www.ww2technik.de/Bilderchen/jappanzer/tankette/Typ%2097/jap%20typ%2097%20te-ke%20prototyp.jpg
serial production vehicle

The Type 97 Te-Ke replaced the Type 92 Heavy Armored Vehicles and the Type 94 tk in the infantry and cavalry recon units and was used with good sucess as armored recon vehicle. In the later stages of the war the vehicles were als used for infantry support and against tanks with less success due to the small gun with its bad penetration and poor HE-power.

Data (MG / gun version)
vehicles built: 593
battle weight: 4,5 (metric) t / 4,75 (metric) t
crew: 2 men
length: 3700 mm
width: 1990 mm
height: 1790 mm
trench crossing capability: 1600 mm
maximum vertical obstacle: 810 mm
engine: Ikegai OHV Series 4-cylinder Diesel
power: 65 hp at 2300 rpm
maximum speed: 40 km/h on roads
fuel capacity: 240 l
range: 250 km in easy terrain
transmisson: 4 forward, 1 reverse
Power/weight ratio: 14,8 HP/t / 13,6 HP/t
armament: 1 X Type 97 7,7 mm Tank MG / 1 X Type 94 37 mm Tank Gun
ammunition: 2800 shots for MG or 102 grenades for gun



armor
strength


turret front
16 mm @ 80 °


sides
16 mm @ 80 °


rear
10 mm @ 75 °


roof
6 mm @ 0 °


superstructure front
12 mm @ 40 °


sides
10 mm @ 90 °, upper part @ 45 °


rear
8 mm @ 70 °


top
6 mm @0 °



Yours

tom!;)

tom!
01-07-2018, 09:11 AM
Hi.

9) Light Tank part 1:


a) Type 95 Light Tank Ha-Go part 1 :

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/typ%2095/jap%20typ%2095%20ha-go%20prototyp.jpg
early prototype

After introduction of the next generation trucks in the early 1930th with their maximum speed of 60 km/h IJA deployed a mechanised brigade at Kungchuling/Manchuria in early 1933. This unit consisted of mechanised infantry, artillery and support units plus a company-sized tank unit. Main task was to develop tactics for mechanised units. During the first exercises the avaliable Type 89 tanks with their maximum speed of 25 km/h were not able to follow the fast moving infantry. This was found unacceptable. But several members of IJA High Command weren´t convinced that the japanese heavy industry was able to develop a tracked vehicle with the planned maximum speed of 40 km/h

So IJA Technical Headquaters started a mobile tank development program. First choice seemed to be a wheelcumtrack-vehicle. But first studies indicated that this technology was still very complex and expensive and with the avaliable financial budget a successful introduction was not too sure. The new advanced Christie-suspension was also taken into account but the expected costs for licence and development seemed too high, too. With the success of the new Type 92 Heavy Armored Vehicle for the cavalry the decision was made to built a conventional tracked vehicle instead.

In July 1933 the requirements were given to Army Technical Bureau:

- maximum speed 40 km/h
- maximum weight 7 t
- 3 men crew of driver, commander-gunner and machine gunner-technician
- armament: long 37 mm gun in a revolving turret and bow MG
- face-hardened armor, available to defeat infantry AP-ammunition, maximum strength 12 mm
- use of welding as much as possible
- access through a hatch on the turret
- size up to 4300 mm (l) X 2000 mm (w) X 2280 mm (h)
- use of an air-cooled Diesel engine, placed in the rear right
- engine compartment separated from the fighting compartment but accessible
- clutch-brake-type transmission with forward driving wheel
- development in cooperation with and serial production by Mitsubishi Heavy Industries

Until June 1934 a prototype was finished. Welding techniques weren´t too advanced so many parts still had to be riveted. The vehicle had two pairs of bogie wheels suspended on a single bell crank with two bell cranks connecting them to a large horizontal spring plus one centered return roller on each side. The spring was covered by a hemispherical armor plate. The bow and partly the rear armor were arranged angled, the side armor was vertical. The driver sat on the right (in driving direction). He operated the tank using levers for the track breaks and reduction gears. The bow gunner/technician sat on the left of the driver operating a Type 91 6,5 mm Tank MG in a standard mount. The turret was slightly conical with an extension for the gun. A small two door access hatch in the rear allowed easier ammunition supply. All crew members entered the tank through a large hatch on top of the turret. The commander had to observe the battlefield, to operate the gun, and to turn the turret. Turret traverse was done by turning a small handwheel operating gear wheels in a gear ring. Internal communitation was wire-based with simple headsets.

A small hatch on the upper rear armor allowed service access for the rear engine parts. A large hatch with cooling air intakes on the upper armor allowed engine exchange.

Basic tests including a 700 km endurance trial were finished until October 1934 with good success. The requirements were met including a maximum road speed of 43 km/h and an operational range of 250 km. Only the weigth of 7,5 t was slightly too high. Therefore the armor was modified by slightly decreasing its strength in less vulnerable areas. The armour in front of the driver was now curved and could now be opened to the top for a better view and ventilation. The result was a vehicle with a weight of 6,5 t and a maximum speed of 45 km/h archieved during a second 370 km endurance trial.

The tank was sent to Cavalry School in October 1934 and tested intensely. The results were very good and an immediate introduction as replacement for the quite weakly armed Type 92 Heavy Armored Car was suggested. The prototype was then handed over to Infantry School for further tests. There the power of the Type 94 Tank Gun and the 12 mm maximum armor were rated weak making the tank not really suitable for the contemporary IJA tank doctrine to use tanks for infantry support. Nevertheless the tank was sent to Manchuria in late 1934 for climatic and practical tests. These included maneuvers with a mixed mobile brigade for fast assaults. There the tank showed a very good performance especially in very cold climate and the speed was rated useful for fast assaults. Therefore the infantry branch also requested an immediate introduction.

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/typ%2095/jap%20typ%2095%20ha-go%20prototype.jpg
Second prototype

From June until November 1935 a second prototype was built implementing several small changes suggested after the tests. Stronger sprockets and span wheels were mounted and a second return roller was added to the suspension for more stability. The bow gunner received an armor extension for better handling and engine access was designed easier. In addition special bogies with two small wheel placed between the road wheels were designed to prevent Kaoliang plants which were quite common in northern China and Manchuria pitching them when they get between them. This modification was called "Manchurian Suspension". These were replaced by the standard bogies when tank units left Manchuria for other operational areas.

The vehicle was officially introduced in late November 1935 after few very successful tests as "Type 95 Light Tank" and the internal Mitsubishi development designation "Ha-Go" was adopted officially as short designation. Before start of mass production in mid-1936 more changes were made to increase the combat abilities. The vertical side armor was improved by adding conical hemispheric armor extensions above the tracks to the fighting compartment for a better armor protection and to increase ammo capacity. In addition the upper side armor above the engine was arranged angled and large cooling hatches with vertical slats were added there. The bow gunners armor extension was remodeled and enlarged. An observation cupola with a two-piece hatch replaced the original hatch on the turret. A Type 91 Tank MG facing in 5 o´clock direction was placed in an armor extension on the rear turret to still have firepower in case of a damaged gun (not for close defense). The suspension received standardised road wheels and easier to produce driving sprockets and idle wheels. The weight was now 7,4 t which was accepted.

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/typ%2095/jap%20type%2095%20ha-go%20manchurian%20susp%20nomonhan.jpg
Production vehicle with manchurian suspension captured by soviet troops during the Nomonhan Incident

Due to budgetary problems and the low priority for raw materials for tank production serial production started with low numbers at Mitsubishi:
1936: 31
1937: 80
1938: 53
1939: 115
After the Nomonhan Incident and because of the ongoing China-Incident (as the 2nd Sino-Japanese War was called in Japan) with the intensified support of the chinese government by USA, GB and France military budget and priority of tanks were increased boosting the tank production numbers:
1940: 422
1941: 685
1942: 755
1943: some 234
Due to too low capacities at Mitsubishi Niigata Tekkosho, Kobe Seikosho and Kokura Army Arsenal also started to produce this tank during this periode. In mid 1943 production was stopped mainly to increase the production numbers of the Type 97, Type 1 and Type 3 Medium Tanks. With a total production of ca. 2375 vehicles the Ha-Go was the most numerous japanese armored vehicle.


to be continued in part 2...

tom!
01-07-2018, 09:32 AM
9) Light Tanks part 2


a) Type 95 Light Tank part 2:

Few vehicles were equipped with a thin handrail-type antenna on the turret and wireless communcations equipment (Type 94 Radio) to be used as command tanks.

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/typ%2095/jap%20typ%2095%20ha-go%20ringantenne%202.jpg
Type 95 Ha-Go with antenna

The first operational unit equipped with the Type 95 Light Tank was the tank unit of the Independent Mixed Brigade which received their vehicles in late 1936. First operational use was during the innitial stage of the China Incident at Shansi Province against a retreating enemy. There the tank showed its value as scout tank pursuing the enemy.
It was planned to equip each tank battalion with a light tank company consisting of 13 Type 95 Ha-Go (Command section with one tank and 4 platoons with 4 tanks each). In addition each medium tank company should receive 2 light tanks for the command section and the cavalry recon units should replace their Type 92 Heavy Armored Vehicles with this tank, too. However production numbers were too low to archive this goal especially with the increasing losses after 1939.

After 1937 the Type 91 Tank MGs were replaced by Type 97 7,7 mm Tank MGs and the Type 98 37 mm Tank Gun replaced the Type 94 37 mm Tank Guns.

The tank units of the IJN Special Naval Landing Forces received several Type 95 Light Tanks and used them for garrison duties on several pacific islands. The siamese army also bought some of these tanks.

http://www.ww2technik.de/Bilderchen/jappanzer/thai%20typ%2095%20ha-go.jpg
siamese Type 95 Ha-Go

The Type 95 Light tank was very successful as scout tank especially during the innitial stages of the war against the western allies. During the 1941/42 Malaya campaign these tanks put a high preasure on the retreating Commonwealth units making it almost impossible for them to regroup and build up a successful defence line. They also made the fast success against the ABDA-forces in Duch East-India possible. During the 1941/42 Philippine and Burma campaigns they also did a good job but suffered losses from the US M3 Light Tanks which penetrated them easily on longer ranges while they had to get close to penetrate them. This and the 1939 Nomonhan campaign showed that they were not suitable against modern contemporary light tanks. But they were never intended to fight enemy tanks.

All successes after 1940 were against an inferiour or badly leaded enemy which concealed that the tank was in fact outdated. Many commanders were very pleased with the tank and saw no need for a new design. This lead to the wrong decision to refuse an already production-ready modern successor and even to prohibit further developments to spare ressources until 1944. So in 1944/45 the Type 95 Light Tanks had to withstand tanks and anti-tank weapons which were designed 5 to 8 years later and were easily slaughtered.

After the war few Type 95 Ha-Go with additional armour plates around the turret front and side (ordered by the commanding officer of the japanese unit they belong to) were taken over and used by french colonial forces in Indochina and used until 1948. The additional armor plates had a thickness of 10 mm and were mounted spaced on the turret front and on the bow extension for the MG-gunner/radioman.

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/typ%2095/jap%20typ%2095%20ha-go%20platoon.jpg
Type 95 Ha-Go used by french troops

Data
vehicles built: ca. 2375
battle weight: 7,4 (metric) t
crew: 3 men
length: 4830 mm
width: 2070 mm
height: 2280 mm
ground clearance: 390 mm
track width: 251 mm
ground pressure: 0,63 kg/cm²
trench crossing capability: 2000 mm
climbing capability: 40°
maximum vertical obstacle: 600 mm
engine: Mitsubishi A6120VD 6-cylinder Diesel engine
power: 120 hp at 1800 rpm
maximum speed: 40 km/h on roads, 28 km/h cross-country
fuel capacity: 164 l
range: 248 km on roads
transmission: 4 forward, 1 reverse
Power/weight ratio: 15,6 hp/t
armament: 1 X Type 94 37 mm Tank Gun , 2 X Type 91 6,5 mm MG, later 1 X Type 98 37 mm Tank Gun and 2 Type 97 7,7 mm Tank MG
Ammunition capacity: 119 37 mm grenades, 2940 MG shots



armour
strength


turret front
12 mm @ 80 °


sides
12 mm @ 80 °


rear
12 mm @ 90 °


roof
6 mm @ 0 °


structure front
12 mm @ 70 °, upper part @ 78 °


sides
12 mm @90 °, upper part 10 mm @ 45 °


rear
8 mm @ 90 °, upper part 8 mm @ 30 °


top
10 mm @ 0 °




to be continued in part 3...

tom!
01-07-2018, 09:37 AM
9) Light Tanks part 3


b) Type 98 Light Tank Ke-Ni:

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/Typ%2098/jap%20typ%2098%20ke-ni.jpg

Despite the IJA High Command´s policy that no new light tank design was necessary Army Technical Bureau started a new development in 1938 as technology test program. Since the beginning of the Ha-Go design in 1933 tank technology and metalurgy had made large progress. Welding techniques were improved and sloped armour was about to become standard. Therefore a completely new tank was designed. As it was a test program no official requirements were given. The decision was made to develop two different types of suspension for comparison tests. Both prototypes should use the same armor body. In addition a new armament consisting of a new 37 mm tank gun and a coaxial MG should be developed. Development orders were given to Mitsubishi Heavy Industries and Hino Motors. Mitsubishi should develop a Christie-type suspension, Hino a suspension based on the Type 97 Medium Tank.

The armour body consisted of a 40° sloped lower bow armor with a casted bow. The superstructure was designed pentagonal with a slope of 80° The forward armor consisted of a small center part which could be opened downward with the driver´s optics. The forward side armor ended above the tracks. Visor ports for the driver increased the view angles to the sides. A pistol port on each side allowed close defence. All driver´s visor ports had bullet-proof glass for protection. The rear side armor had just one opening on the rear right side (in driving direction) for the exhaust pipe. The rear armor had two large ventilation air intakes. On the lower rear armor a large access hatch allowed engine maintainance. A second maintainance hatch was placed on the top armor behind the turret. It was not possible to replace the engine through these hatches. So the complete superstructure could be removed. All armor plates where welded together. Rivets were only used to mount the frames of hatches and visor ports.

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/Typ%2098/jap%20typ%2098%20ke-ni%20aufbau%20abgehoben.jpg
lifted superstructure

The engine was placed sidewise in the rear allowing a shorter length of the vehicle. The propeller shaft was placed offset to the left. Maintainance was also possible from the fighting compartment. The driver sat in the center of the tank. He operated the tank with a driving wheel instead of levers. The communication equipment was operated by the commander and consisted of a Type 94 wireless set and a wire-based onboard communication set.

The turret was conical with a large semicircular hatch on top. On each side of the gun mount holes for optics were placed with pistol ports below them. Additional visor ports with gun ports below them were placed on each side and the rear access hatch. Turret crew consisted of the commander/loader on the right side and the gunner on the left side. The turret was turned manually by the commander using a handwheel. This tank was the first japanese tank with a coaxial MG instead of a rear turret MG. The gun mount allowed an elevation of -15° - 25° and a traverse from 5° left - 10° right.

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/Typ%2098/jap%20typ%2098%20light%20tank%20chistie%20prototyp .jpg
Mitsubishi prototype

Mitsubishi developed a suspension using a licence from Christie. It consisted of four large roadwheels with rubber bands, a rear driving sprocket and a forward idle wheel. The vehicle was designated "Experimental Light Tank Prototype Kou(A)".

The Hino suspension consisted of 3 pairs of small roadwheels connected by bogies, 3 return rollers, a forward driving sprocket and a rear idle wheel. The two forward roadwheel pairs were connected by a large horizontal spring, the rear pair was attached to the mid pair by a smaller horizontal coil spring. All springs where placed inside the tank. This vehicle was designated "Experimental Light Tank Prototype Otsu".

In mid 1939 the test trials started. During testing both prototypes reached a maximum speed of above 50 km/h and very good cross-country abilities. Finally the Hino suspension was rated slightly superiour and the Christie system was dropped. Several minor changes were demanded and introduced including a less sloped conical turret for additional turret space and smaller holes for the turret optics. All changes were finished until late 1939. Later the vehicle received the official designation "Type 98 Light Tank Ke-Ni".

Even if the tank was far superiour to the Type 95 Ha-Go IJA High Command saw no need for a new light tank which would increase the number of vehicles to be supplied. Additionally there were not enough raw materials avaliable for a parallel production of a second light tank model and a change of production would have ment a periode with no tank production which was not acceptable. So the plans and the prototype were stored.

In 1942 after facing the superiour contemporary allied tanks and recognising the reports of the japanese observers about T-34 and KV tanks on the german eastern front the general tank policy was changed from "everything is fine" to "we need better tanks". So the already about to be outdated Type 98 Light Tank was finally put into production in mid 1942 but with a Type 1 37 mm Tank Gun instead of the Type 100 gun. 87 vehicles were produced in 1942 and 26 more in 1943. Then production was ceased in favour of the more powerful medium tanks.

It was clear that the 37 mm tank gun was generally outdated and not suitable for anti-tank fights. So the production vehicles were rated as scout tanks and issued to homeland defence tank units. An unknown number of vehicles were send to army airborne units to be tested as airborne tanks carried by KU-7 gliders. The project was cancelled in 1944 and the tanks were handed back to tank units.

None was used operationally.

Data
vehicles built: 113
battle weight: 7,2 (metric) t
crew: 3 men
length: 4110 mm
width: 2110 mm
height: 2820 mm
ground clearance: 350 mm
trench crossing capability: 2100 mm
climbing capability: 30°
maximum vertical obstacle: 700 mm
engine: Mitsubishi Type 100 6-cylinder Diesel engine
power: 130 hp at 2100 rpm
maximum speed: 50 km/h on roads
range: 300 km on roads
transmisson: 5 forward, 1 reverse
Power/weight ratio: 18,1 hp/t
armament: 1 X Type 100 37 mm Tank Gun, later 1 X Type 1 37 mm Tank Gun and 1 Type 97 7,7 mm Tank MG coaxial
Ammunition capacitiy: 106 37 mm grenades, 3160 MG shots



armour
strength


turret front
16 mm @ 80 °


sides
16 mm @ 80 °


rear
16 mm @ 90 °


roof
6 mm @ 0 °


structure front
16 mm @ 40 °, upper part @ 60 °


sides
12 mm @90 °, upper part @ 60 °


rear
8 mm @ 65 °, upper part @ 35 °


top
10 mm @ 0 °




c) Type 2 Light Tank Ke-To:

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/jap%20typ%202%20ke-to%202.jpg

In late 1941 IJA airborne units demanded a tank able to be carried by gliders. So they received several Type 98 Light Tanks in late 1942. After innitial tests an enlargement of the turret was demanded for easier gun handling. So Hino developed an almost cylindrical turret until early 1943.

Due to raw material shortages production of the resulting vehicle could not be started before early 1944. At this time IJA High Command demanded a standardisation of the tracks of light tanks, prime movers and tracked transport vehicles and so the new tracks were added to the design. Shortly after serial production started the glider development program was cancelled and so production was ceased after only 29 vehicles built. All were issued to army airborne units and stored for the expected homeland invasion. None was ever used operational.

Data:
as Type 98 Light Tank Ke-Ni except
Height: 2120 mm
Ammunition capacitiy: 93 37 mm grenades



armour
strength


turret front
16 mm @ 90 °


sides
16 mm @ 90 °


rear
16 mm @ 90 °


roof
6 mm @ 0 °


structure front
16 mm @ 40 °, upper part @ 60 °


sides
12 mm @90 °, upper part @ 60 °


rear
8 mm @ 65 °, upper part @ 35 °


top
10 mm @ 0 °




to be continued in part 4...

tom!
01-07-2018, 09:54 AM
9) Light Tanks part 4


d) Type 3 Light Tank Ke-Ri:

no pic, sorry

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/jap%20typ%203%20ke-ri.jpg

In 1942 IJA started a large program to increase the firepower of its tank force regarding at-power. This included trials to upgun the Type 95 Light Tank. One try was to mount a Type 97 57 mm Tank Gun inside the standard turret of the Ha-Go. 3 vehicles were modified that way and tested in early 1943. Results were unsatisfying as the armour penetration even with HEAT ammunition wasn´t larger than with the Type 98 37 mm Tank Gun. In addition the larger recoil forces damaged the turret ring and gun handling was very problematic inside the narrow turret. Therefore the project was ceased and the tanks rearmed with the standard gun.

Data:
as Type 95 Light Tank Ha-Go except
armament: 1 X Type 97 57 mm Tank Gun


e) Type 4 Light Tank Ke-Nu:

http://www.ww2technik.de/Bilderchen/jappanzer/leicht/jap%20typ%204%20Ke-Nu.jpg

Another try to increase the firepower of the Type 95 Light Tank was to replace the turret with surplus Type 97 Medium Tank Chi-Ha turrets. This was done after the Type 3 Light Tank project was cancelled. For this the turret ring diameter had to be increased from 1000 mm to 1350 mm. The handrail antenna was later removed from the turret as the tank did not have a wireless set.

Tests started in 1944. The modification increased the vehicle weight by 1000 kg making the tank top-heavy and increasing the stress on the suspension. As result the accuracy was decreased and the tanks broke down more often. An additionall armour plate between the bow gunner extension and the driver´s hatch closed a shot trap. With this modification the driver´s hatch couldn´t be opened any more. After several tests the project was cancelled, too. As it was impossible to rearm the 10 converted tanks the decision was made to use them as mobile pillboxes only.

An unknown number of Type 95 Ha-Go were modified the same way by the Kwantung Army in Manchuria at Mukden Army Arsenal. It seems that this conversions were done without official permission. These vehicles can be easily identified by several minor changes compared to the officially converted tanks. Most significant is a slight turret overhang to the left and the missing additional armour plate. One of these vehicles is on display at Kubinka Museum.

Data:
as Type 95 Light Tank Ha-Go except
vehicles built: 10 plus an unknown number of modifications at Mukden Army Arsenal
battle weight: 8,4 (metric) t
height: 2480 mm
ground preasure: unknown
trench crossing capability: 2000 mm
climbing capability: unknown
maximum vertical obstacle: unknown
maximum speed: unknown
range: unknown
Power/weight ratio: 14,3 hp/t
armament: 1 X Type 97 57 mm Tank Gun and 2 Type 97 7,7 mm Tank MG
Ammunition capacitiy: unknown



armour
strength


turret front
25 mm @ 80 °


sides
25 mm @ 75 °


rear
25 mm @ 78 °


roof
10 mm @ 0 °


structure front
12 mm @ 70 °, upper part @ 78 °


sides
12 mm @90 °, upper part 10 mm @ 45 °


rear
8 mm @ 90 °, upper part 8 mm @ 30 °


top
10 mm @ 0 °




f) Experimental Type 5 Light Tank Ke-Ho:

No picture, sorry

http://gunsight.jp/c/image3/Type5ltank-03m.jpg
first proposal but with a Chi-He turret

With the change in tank doctrine in mid 1942 IJA also ordered the development of a new light tank for reconnaissance and liason duties but with limited priority. Most data of this project were destroyed before surrender but the following is known:

Reqirements were among others:
- maximum armor strength 20 mm
- main armament consisting of a shortened version of the Type 1 47 mm Tank Gun to spare weight and one MG
- crew consisting of driver, gunner, loader and commander/wireless operator
- use of standardised suspension parts

Development started in late 1942 in cooperation with Hino Motors. The decision was made to use the Type 98 Light Tank as basis to speed up development. Two proposals were made. The first was to use a lightened version of the standard suspension of the Type 97 Chi-Ha and an armoured body with the basic scheme of the Type 98 Ke-Ni. The second proposal used the suspension of the Ke-Ni with external springs. The superstructure was also based on the predecessor but positioned further to the rear. Both proposals had a maximum superstructure armour strength of 20 mm and used the standard turret of the Chi-Ha KAI.

http://gunsight.jp/c/image3/Type5ltank-02m.jpg
second proposal with a Chi-Ha KAI turret and coaxial MG

The development of the main armament started in September 1942 and it was planned to finish the prototype until June 1943. Due to raw material shortages and the low priority it wasn´t done until March 1945. The gun had a slightly shortened barrel and a modified recoil mechanism. Elevation was -15° to 20°, no traverse. With the standard Type 1 47 mm HEAP grenade a muzzle velocity of around 740 m/sec was planned. The project seemed to be ceased. For the secondary armament there were proposals to mount it coaxial, in the right turret side or the turret rear.

Tokyo Gas and Electric (TGE) developed a small, supercharged 6-cylinder in-line Diesel engine with 150 hp and 9300 cm³. It was based on a truck engine introduced in 1937.

A prototype of the tank was finished in mid 1945 armed with a standard Type 1 47 mm Tank Gun. There are no survivng pictures or drawings showing the outer apperance. But the drawing avaliable on the internet showing a vehicle similar to the Type 1 Medium Tank is definitely far from reality.

Data
(without guarantee)

vehicles built: 1
battle weight: 9 (metric) t empty, 10 t battle weight
crew: 4 men
length: 4110 mm
width: 2230 mm
height: 2270 mm
track width: 305 mm
ground contact length: 3000 mm
ground preasure: 0,555 kg/cm²
trench crossing capability: 2100 mm
climbing capability: 34°
fordability: 1000 mm
engine: TGE 6-cylinder in-line Diesel engine
power: 150 hp at 2000 rpm
maximum speed: 50 km/h on roads
fuel capacity: 163 l
Power/weight ratio: 14,8 hp/t
armament: 1 X Type 1 47 mm Tank Gun, 1 X Type 97 7,7 mm Tank MG
Ammunition capacitiy: 90 47 mm grenades, unnknown number of MG shots



armour
strength


turret front
19 mm


sides
16 mm


rear
16 mm


roof
10 mm @ 0 °


structure front
20 mm


sides
16 mm


rear
12 mm


top
[td]8 mm /td]




Yours

tom! ;)

tom!
01-08-2018, 07:34 AM
Hi.

10) Medium Tanks part 1:


a) Type 97 Medium Tank Chi-Ni:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2097%20chi-ni%202.jpg

During the development of the Type 95 Light Tank Army Technical Bureau kept an eye on new european tank designs. The development of the british A6 and A7 Medium Tank series showed that the next generation of tanks would be heavier with thicker armor and new tasks will be covered. In addition the low maximum speed of the Type 89 Medium Tank became more and more unsuitable for fast operations which were expected on future battlefields even if the frontline commanders were very satisfied with the vehicle. So in 1936 IJA High Command decided to start the development of a fast medium tank to replace the Type 89 tanks.

At this time the available budget was quite low as IJA had to support many garrison troops in Manchuria and northern China. In addition the parliament was still angry about being by-passed by IJA regarding the foreign politics how to deal with China in the early 1930th and saw no need to increase the military budget. So the decision was made to develop two different vehicle. One should be lightweight, cheap and easy to be built, the other should be heavier and built using modern techniques without having a too harsh look on the costs.

The development order for the cheap tank was given to Osaka Army Arsenal under the designation "Medium Tank Project Plan 2". The requirements were:

- maximum weight 10 (metric) t
- maximum armor strength 20 mm
- 3 men crew consisting of driver, bow gunner/technician and commander/gunner/loader
- maximum speed 27 km/h
- trench crossing capability 2200 mm, 2400 mm with a ditching tail
- armament consisting of a 57 mm gun and one MG

The prototype was finished in June 1937. The first design used the suspension from the Type 95 Light Tank but is was soon clear that this configuration wouldn't be able to cope with the weight. In addition the bigger vehicle length made this concept prone to mechanical breakdowns. So another suspension was designed based on the Type 94 Special Tractor. It used four pairs of small roadwheels connected with bogies. Bell cranks connected each two pairs with a large horizontal spring which was covered by a hemispherical armor plate. Three return rollers, a forward driving sprocket and a rear idle wheel completed the suspension. Idle wheel and driving sprocket were the same as used on the Type 95 Ha-Go.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2097%20chi-ni%20front.jpg
front view

The lower bow armor was negative angled while the upper bow armor was very flat. Two large access hatches in the upper bow armor allowed maintainance of the reduction gears. The superstructure was similar to the Ha-Go but bow gunner and driver changed place. This was necessary due to the limited space inside the vehicle and the position of the driving shaft. The driver sat below a semi-hexagonal conical armor extension with a big viewport in the center plate and a pistol port in each side. The trapezoid viewport had bullet-proof glass for protection and could be opened upward. The tank was operated with levers for track brakes and reduction gears.

The bow gunner operated a Type 91 65 mm MG mounted in a standard mount riveted to a sloped armor plate. Welded semi-hexagonal conical armor extensions were mount over each track to the fighting compartment to enlarge the available space. Each had a pistol port facing to the rear and a third port was placed next to the bow gunner The engine was placed lengthwise in the center behind the fighting compartment. Sloped armor plates covered it from the sides and the rear. On the (in driving direction) right side a large ventilator and access hatch with vertical slats was mounted which could be opened upward. The exhaust pipe left the vehicle below the hatch and let to a muffler on the rear right. A large two-door access hatch on the upper armor allowed engine exchange. A large cooling air intake and access hatch was mounted in the left engine compartment door. The lower rear armor was curved. A short ditching tail was mounted in the center of the rear armor.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2097%20chi-ni%20heck.jpg
rear view

A small conical turret was placed offset to the left behind the driver. It was turned manually by turning a handwheel. One pistol port was on the left of the gun and a second in the rear turret in the access door for ammunition supply. A two-door rectangular hatch and a ventilator were placed on top of the turret. The crew could only enter the tank through this hatch. The space inside the turret was very limited and made gun handling problematic.

During the competitive tests with the "Medium Tank Project Plan 1 prototype" the vehicle showed good maneuverability and handling characteristics. All requirements were not only met but exceeded. The weight limit was undershot so much that vulnerable parts could receive 25 mm armor instead of the required 20 mm and the weight still did not exceed 9,8 t. The maximum speed was 30 km/h with a 135 hp Diesel engine and the trench crossing capability was 2500 mm with tail. The limited internal space was found acceptable. The competitor also met all requirements easily but there were still the budget problems. So in early July 1937 IJA High Command inclined to order the plan 2 vehicle now designated "Type 97 Medium Tank Chi-Ni". But before the final decision the China Incident broke out. Suddenly budgetary problems were wiped off and the decision was made to order the more advanced plan 1 prototype instead.

The Chi-Ni prototype was scrapped even if it was superior to the Type 95 Light Tank and Army Technical Bureau made the suggestion to replace the Ha-Go with this tank.

Data:
only few data survived the war
vehicles built: 1
battle weight: 9,8 (metric) t
crew: 3 men
armor: up to 20 mm
length: 5260 mm
width: unknown
height: unknown
trench crossing capability: 2200 mm, 2500 mm with tail
engine: Ikegai 8-cylinder Diesel engine
power: 135 hp at 1800 rpm
maximum speed: 30 km/h on roads, 12 km/h cross-country
Power/weight ratio: 13,8 hp/t
armament: 1 X Type 97 57 mm Tank Gun, 1 X Type 91 6,5 mm MG
Ammunition capacity: 60 57 mm grenades, 3000 MG shots


to be continued in part 2...

tom!
01-08-2018, 09:49 AM
Hi.

10) Medium Tanks part 2


b) Type 97 Medium Tank Chi-Ha part 1:

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%2097/jap%20typ%2097%20chi-ha%204.jpg

The prototype development order for the "Medium Tank Project Plan 1" was given to Mitsubishi. Requirements were:

- Maximum weight 13,5 t
- Maximum armor strength 25 mm
- 4 men crew consisting of driver, bow gunner/wireless operator, commander/loader and gunner
- Maximum speed 35 km/h
- Trench crossing capability 2500 mm
- Armament consisting of a 57 mm gun and 2 MG

Until June 1937 the prototype was finished. The first suspension version was also derivated from the one of the Ha-Go. It had 3 pairs of roadwheel with rubber bands. The rear 2 pairs were connected with a large horizontal coil spring by bell cranks. The forward pair was connected the same way with the center pair but a smaller coil spring was used. A forward driving sprocket , a rear idle wheel and three return rollers completed the suspension. idle wheels and roadwheels were not massive to spare weight. The rear return roller was thinner and supported only the inner half of the track.

All armor plates made of face-hardened rolled steel. They were welded together but also riveted to enstrengh the connections. Hatch frames, visor slits and MG ports were riveted on the armor, too. The lower bow armor was angled negative, the upper bow was very flat. The superstructure was arranged angled with a slanting rear part. The driver sat below a semicircular extension in the (in driving direction) left side. A large rectangular visor port protected with bullet-proof glass allowed good sight. The bow gunner operated a Type 91 6,5 mm Tank MG in a standard mount on the right side. The wireless equipment, a Type 94 Radio Set, was mounted in a frame below the MG. An ammunition rack for 30 X 20 shot MG magazines was placed on the right side. Additional ammunition was stored to the rear right of the gunner seat and below the floor plates.

The engine was placed lengthwise in the center behind the fighting compartment. An access hatch allowed maintenance from inside the vehicle. Additional maintenance access hatches with ventilation grilles were placed in the rear superstucture armor. A large access hatch with a large grille for engine exchange and cooling air intake was mounted in the upper rear armor. The fuel rank was placed in the rear of the engine, a 180 Ah battery and a lubricant tank were mouted above it. Exhaust pipes lead to mufflers on the rear mudguards on both sides. The rear armor was arranged curved.

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20shi-ki%20proto.jpg
prototype of the command tank version showing the innitial armor sheme

The turret was conical with a large cylindrical commanders cupola in the rear right. He was placed offset to the left behind the driver. A large access hatch with an integrated periscope on the cupola allowed the crew to enter the tank. A short rod antenna was on the front right of the cupola. The tank gun was mounted in the turret front and a standard MG mount was placed in a rear extension in 7 o´clock direction.

During the trials the prototype met the requirements. Maximum speed was 38 km/h with a 170 hp Diesel engine. Even if it was the more potent tank design budgetary problems made it unlikely to introduce it. Then China Incident started in July 1937 leading to a massive increase of the military budget from 500.000.000 Yen to 1.700.000.000 Yen in 1937 alone. So finally the decision was made to introduce this tank, now designated "Type 97 Medium Tank Chi-Ha". Several changes were demanded regarding suspension, armor and turret.

Driver and bow gunner changed the sides to meet the now standardised IJA layout. The driver´s visor port was remodelled to make production easier and a second hatch to enter the fighting compartment was added above the bow gunner. Therefore the turret changed the side, too. The comander´s cupola was redesigned to lower the height. An unusual two-door hatch was installed. It consisted of a long center rectangular door with one semicircular end and a second door around it with the shape of an open lobster shear. The periscope was placed in the center door. The turret ring diameter was increased to allow the use of larger turrets if upgunning would become necessary. A handrail type antenna around the forward hemispere of the turret replaced the rod antenna for a better communication quality. The wireless equipment was changed to a Type 96 Mark 4 Version Bo Radio Set. Armament now consisted of Type 97 MGs instead of the Type 91 MGs. The exhaust pipes were now protected against bullets and splinters by vertical armor plates.

The suspension should be remodelled to increase stability during firing. Therefore the forward pair of roadwheels was removed. The remaining roadwheels were placed centered and two single roadwheels were mounted forward and in the rear. These were connected with a bell crank and a small diagonal coil spring to each roadwheel pair mounting. A second design used a totally different suspension using a modified Horstmann system similar to the one used on the british Vickers Light Mk VI with partly overlapping roadwheels. Finally the first modification was chosen.

These changes were finished until March 1938 and the second prototype was tested in spring. In summer 1938 Mitsubishi was ordered to built up a production line which was finished until late that year. Production numbers were 25 in 1938, 202 in 1939, 507 in 1940 and 315 in 1941. Several other factories were also ordered to produce this tank in 1939 as Mitsubishi was not able to provide the necessary capacities for a production increase. With the introduction of the Type 1 47 mm Tank Gun it was planned to stop the production of the 57 mm version but Osaka Army Arsenal was not able to build enough weapons to equip all production tanks. So between 1942 and production end in 1944 approximately 400 more Type 97 tanks with short 57 mm gun were produced. In 1944 production was stopped in favour of the superiour Type 1 and Type 3 Medium Tanks and due to increasing raw material shortages. Total production was around 1450 vehicles.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%2097/jap%20typ%2097%20chi-ha%20links%20hinten.jpg
second production version with armour plates above the ventilation and access hatches on the rear sides

The first serial production vehicles were delivered in early 1939. One of the first units equipped with this tank was the 3rd Tank Regiment which used 4 Type 97 Chi-Ha as command tanks during the Nomonhan Incident, one was lost. Each tank regiment should receive 31 vehicles for 3 medium tank companies and a command tank in the command section (each regiment only had battalion size following western standards). The production numbers were high enough to equip each regiment planned but it was nearly impossible to reequip units fast after heavy losses.

From mid 1939 Type 97 Medium Tanks were used on most battlefields including the Pacific Islands. They were main attack force during the Malaya Campaign smashing through several allied defence lines with a total loss of 11 (6 destroyed, 5 damaged beyond possible repair) vehicles during the whole campaign, 14 more were damaged and repaired. During several campaigns in China and Burma these tanks also showed their value as mobile platform and infantry support vehicle. Therefore the tank became basis for a large number of vehicles and the workhorse of IJA armored forces.

During production the tank received a hinged additional armor plate on the ventilation and access hatches on the rear side to increase protection against splinters. This armour plate was later replaced by a hinged spaced armour with sloped upper part. An AA-mount for the (removable) turret MG was added on the rear or the left of the commander´s cupola for at least symbolical fire against attacking aircraft during resting.

On the other hand several confrontations with allied contemporary medium tanks in 1942 and 1943 also showed that armor and armament was insufficient for battles against other tanks. But they were never really intended for this task. Trials to develop 57 mm HEAT projectiles weren´t succesful and so the tank was outdated from 1942. Nevertheless it did a good work against infantry, soft targets and field fortifications.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%2097/jap%20type%2097%20schussdarstellungsger%e4t.jpg
Type 97 with a special rifle mounted instead of the gun to simulate shooting during exercises

After the japanese surrender several Type 97 Chi-Ha were handed over by US Army to Kuomintang-Forces while the soviet Red Army handed over several vehicles captured in Manchuria to the Chinese People´s Army. Both sides used them with success against each other. Other vehicles left behind in Duch East India were used by the indonesian liberation forces during liberation war.

The Type 97 Medium Tank also participated in the last engagement of IJA against invading soviet units landing hostile on Shimushu Jima (northern Kuriles) 3 days after surrender almost pushing the landing forces into the sea again.


to be continued in part 3.....

tom!
01-08-2018, 09:53 AM
Hi.

10)Medium Tanks part 3


b) Type 97 Medium Tank Chi-Ha part 2:

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%2097/jap%20typ%2097%20chi-ha%20einsatz.jpg
tank with troop made smoke discharger

Data:
vehicles built: ca. 1450
battle weight: 15 (metric) t
crew: 4 men
length: 5520 mm
width: 2330 mm
height: 2230 mm
ground clearance: 400 mm
track width: 305 mm
ground contact length: 3708 mm
ground preasure: 0,66 kg/cm²
trench crossing capability: 2500 mm
climbing capability: 34°
maximum vertical obstacle: 900 mm
fordability: 1000 mm
engine: Mitsubishi SA12200VD 12-cylinder Diesel engine
power: 170 hp at 2000 rpm
maximum speed: 38 km/h on roads
fuel capacity: 235 l
range: 210 km on roads
transmisson: 4 forward, 1 reverse
Power/weight ratio: 11 hp/t
armament: 1 X Type 97 57 mm Tank Gun , 2 X Type 97 7,7 mm Tank MG
Ammunition capacitiy: 114 57 mm grenades, 4220 MG shots



armour
strength


turret front
25 mm @ 80 °


sides
25 mm @ 75 °


rear
25 mm @ 78 °


roof
10 mm @ 0 °


superstructure front
25 mm @ 78 °


sides
25 mm @ 75 °


rear
20 mm @ 25 °


top
10 mm @ 10 °


suspension front
25 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm curved




c) Experimental Type 98 Medium Tank Chi-Ho:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2098%20experimental%20chi-ho%204.jpg
only known picture

This tank is still a mystery in literature. It seems that it was developed as technology test vehicle in 1939 to test new ideas for medium tanks including a new armament. The suspension used components of the Type 95 Light tank (forward driving sprocket and rear idle wheel) and of the Type 97 Medium Tank (roadwheels and return rollers). The rear single roadwheel was removed and the spring of the forward roadwheel was mounted with a higher angle. The center return roller was removed and the rear roller mounted in the center instead.

The armor scheme was similar to the Type 97 Chi-Ha but simplified. The driver´s extension was removed and the superstructure was higher. All armor plates seemed to be welded. A smaller Diesel engine was also used so the length could be reduced and there was only one muffler on the (in driving direction) left side. The forward mudguards were enlengthened and the rear mudguards placed higher on the vehicle. A short ditching tail increased the trench crossing ability.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2098%20experimental%20Chi-ho.jpg
Type 97 Medium Tank Chi-Ha with a modified version of the turret which finally became the Shinhoto turret

Main difference was the turret which was enlarged to house the planned 47 mm tank gun. It was placed centered on the vehicle. The turret had a semicircular front and a box-shaped rear. A large trapezoid hatch on top opening to the front allowed access to the vehicle. A standard AA-mount was mounted on the right of this hatch. There was no rear MG but a modified standard MG mount was placed on the lower left of the gun mount.

The vehicle never left the prototype stage but it seems that the tests lead to the Shinhoto turret and the new armor scheme as used on the Type 1 Medium Tank.

Data:
vehicles built: 1
battle weight: 12,5 (metric) t
crew: 3 men
length: 4750 mm
width: unknown
height: 2300 mm
maximum armor: 25 mm
engine: Diesel engine
power: 160 hp
maximum speed: 30 km/h on roads
Power/weight ratio: 12,8 hp/t
armament: not mounted


to be continued in part 4...

tom!
01-08-2018, 10:16 AM
Hi.

10) Medium Tanks part 4


d) Type 97 Medium Tank Chi-Ha KAI:

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/shinhoto/jap%20typ%2097%20shinhoto%20chi-ha%204.jpg

During the first operational use of the new Type 97 Chi-Ha at Nomonhan IJA had to recognise that the avaliable 37 mm and 57 mm tank guns were not able to penetrate the soviet BT-5, BT-7 and T-26 light tanks on average combat ranges. But the soviet 45 mm tank guns easily penetrated the japanese tanks even on longer ranges. So it became clear that a better high velocity tank gun was necessary. Therefore IJA started the development of a 47 mm gun to be used as tank and anti-tank gun in late summer 1939 based on theType 97 experimental 47 mm Anti-tank Gun developed and tested in 1937/38. The expected characteristics (recoil, recoil forces, handling) of this gun made it impossible to use it inside the standard turret of the Type 97 Medium Tank.

So a new larger turret had to be developed. The first design of 1940 was based on the turret developed for the Chi-Ho. It had a semicircular front and a box-shaped rear with a modified MG port on the (in driving direction) lower left side of the gun. A cylindrical commander´s cupola with a two door hatch on top was placed offset to the right in the middle. A turnable periscope was in front of the cupola. A small ventilation hatch with visor slit and pistol port was mounted in each turret side. A large rear access hatch allowed easier ammunition supply. Due to the larger size of the turret the access hatch above the bow gunner position couldn´t be opened any more. Tests were made in late 1940. There the new MG position was found impractical and several details should be modified, too.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/shinhoto/jap%20typ%2097%20shinhoto%20chi-ha%20tarnmuster.jpg
tank with new turret and AA-mount

The second design had the frontal MG port removed. Instead a standard MG port was placed on the left side of the rear armor. The rear access hatch was moved offset to the right. The ventilation hatch on the left (gunner) side was replaced by a visor slit only. A large one door access hatch was placed above the gunner´s seat to compensate the missing hatch above the bow gunner. The handrail antenna was relaced by a rod antenna on the left side behind the turret. A standard AA-mount for the rear turret MG was placed in front of the gunner´s hatch. The final turret design had a length of 1930 mm and a width of 1430 mm. The height increase compared to the old turret was 100 mm, the weight increase 500 kg. This was found acceptable. The tank received the official designation "Type 97 Medium Tank Chi-Ha KAI". It seems that the now popular additional designation "Shinhoto" = "new turret" was first used by IJA tank crews but there is no indication that it was adopted officially.

The final tests were made in fall 1941. At this time additional armor skirts for additional protection of the superstructure sides were used but they were abandoned. After the begin of the war against the western allies IJA tanks had to fight against US light M2 and M3 during the Philippine campaign. The US tanks were also impenetrable for the Type 95 Light Tanks and Type 89 Medium Tanks on average combat ranges (There was just one Type 97 Chi-Ha issued to the IJA tank units used during this campaign). Therefore production start was hurried and first serial production vehicles left the production lines in early 1942. The first tank company equipped with this tanks was sent to the Philippines in April 1942. But at this time US forces had withdrawn to Bataan and Corregidor Island leaving all tanks behind. First operational use of the Chi-Ha KAI was during the assault on the island of Corregidor. One of this tanks landed with the third wave on the island together with two captured Light M3 and two Type 95 Light Tanks. After the US surrender shooting tests showed that the Type 1 47 mm Tank Gun penetrated the frontal armour of the Light M3 easily on 400 m.

http://www.ww2technik.de/Bilderchen/jappanzer/jap%20beschusstest%20typ%201%2047%20mm%20gun%20geg en%20us%20light%20m3.jpg
US Light M3 after japanese penetration tests with the Type 1 47 mm Tank Gun on the Chi-Ha KAI.

The upgunned Chi-Ha KAI should become standard tank of IJA medium tank companies but Osaka Army Arsenal wasn´t able to produce enough guns even to equip all newly produced tanks. So the 57 mm version was also produced continuously. Several tanks received the new turret but only the Type 97 57 mm Tank Gun was mounted. In mid 1942 new trials were made to increase armour strength but nothing was standardised. Nevertheless several Chi-Ha KAI received additional 25 mm armor plates on the bow and the forward superstructure or arond the turret front (but not both). Between 1942 and 1944 757 vehicles were built. Production was stopped in spring 1944 in favour of the Type 1 and 3 Medium Tanks.

The Type 97 Chi-Ha KAI was the only japanese tank used outside the home islands able to penetrate US medium tanks. The M3 Lee and M4 Sherman could be penetrated frontally on average combat ranges (300 - 500 m). But both could penetrate the japanese tanks even on longer ranges. Late-war US trials showed that the M4A1 was penetrated by the 47 mm gun at 90° below 450 m frontally and below 700 m from the sides. During the US 1944/45 Luzon campaign IJA tankers could damage and destroy several M4 with suicide attacks but this had no impact on the campaign. US after action reports mention several frontal penetrations on 150 m at 75°.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/shinhoto/jap%20typ%2097%20shinhoto%20chi%20ha%202.jpg
Type 97 Chi-Ha KAI on the island of Corregidor

The Type 97 Chi-Ha KAI was built to fight late 1930th light tanks and he was able to do this. But he lacked armour so he had no chance against early and mid-war light and medium tanks. The gun would have been a good light tank armament until surrender but it was outdated as medium tank armament in 1943.

After the war several Type 97 Medium Tanks Chi-Ha KAI were used by both armies of the chinese civil war. One of these tanks became famous for :

"This is one of the earliest tanks used by the PLA. In the battle for Kamzhou, Communist party member Comrade Dong drove this tank and penetrated deeply into the defences of the Nationalist Army to complete its mission successfully. For this, Comrade Dong was honoured with an award and this tank was given the honourable designation of a "Merit Tank". In 1949 during the Inauguration Ceremony of the Peoples' Republic, this tank was paraded in front of the leaders of the Communist Party and the Motherland."

He is now on display at the Military Museum of the Chinese People's Revolution in Beijing.

Data:
As Type 97 Medium Tank Chi-Ha except:

vehicles built: 757
battle weight: 15,8 (metric) t
crew: 4 men
height: 2330 mm
Power/weight ratio: 10,76 hp/t
armament: 1 X Type 1 47 mm Tank Gun or 1 X Type 97 57 mm Tank Gun, 2 X Type 97 7,7 mm Tank MG
Ammunition capacitiy: 100 47 mm grenades, 4220 MG shots



armour
strength


turret front
25 mm @ 78 ° curved


sides
25 mm @ 75 °


rear
25 mm @ 90 °


roof
10 mm @ 0 °


superstructure front
25 mm @ 78 °


sides
25 mm @ 75 °


rear
20 mm @ 25 °


top
10 mm @ 10 °


suspension front
25 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm curved




to be continued in part 5...

tom!
01-08-2018, 10:31 AM
Hi.

10) Medium Tanks part 5


e) Type 1 Medium Tank Chi-He:

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%201/jap%20typ%201%20chi-he.jpg

After the Nomonhan Incident IJA first focused on increasing the firepower of its tanks. With the introduction of the Type 1 47 mm Tank Gun in 1941 the focus changed towards increasing the armor strength, too. IJA Technical Bureau was ordered to develop a tank using the suspension of the Type 97 Chi-Ha with a maximal armor strength of 50 mm. The armor scheme should be simplified and welding should replace the rivets wherever possible. Prototype development and production should be done in cooperation with Mitsubishi Heavy Industries. Prototype production started in late 1941 but with very low priority as IJA was still very pleased with the Chi-Ha and Chi-Ha KAI.

The test results gathered with the Type 98 Chi-Ho were used to design the armor. Only flat face-hardened steel plates were used. The driver´s armor extension was removed and the whole frontplate mounted several cm further to the bow. This allowed mounting the access hatch above the bow gunner again. The new standardised Type 100 12-cylinder Diesel engine was longer than the SA12200VD of the Chi-Ha. So the engine compartment had to lengthened and the sloped upper armor had to be arranged flat. The rear armor now consisted of a vertical upper plate and a sloped lower plate. All armor plates were welded together. Only the access hatches, viewports and the bow MG port were riveted on the armor.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%201/jap%20vergleich%20heck%20chi-he%20-%20shinhoto%20chi-ha.jpg
rear view of Chi-Ha (left) and Chi-He, note the enlarged engine compartment and the additional armor plate on the turret front

The forward and rear mudguards were also lengthened. A headlight on each forward mudguard replaced the headlight on the upper bow armor. The mesh cover around the mufflers were now rectangular instead of curved. Long rod antenna could be mounted on both sides in front of the exhaust pipe outlets. The vehicle use the riveted turret from the Chi-Ha KAI with 25 mm additional armor plates around the front. A loader placed behind the gunner was added to the crew making it quite tight in the turret.

Due to the low priority the prototype wasn´t finished before June 1943. Due to the thicker armor and the new engine the total weight was now more than 17 t but the stronger engine also increased maximum speed and agility of the vehicle. Comparison tests with the Chi-Ha KAI showed a large superiority of the vehicle now designated "Type 1 Medium Tank Chi-He" and so the decision was made to start a serial production as soon as possible.

The first vehicles left the factory in February 1944 and a total of 155 vehicles were built in this year. It was planned to produce more than 400 of this tanks in 1945 but it was difficult to gather the necessary raw materials. So only few vehicles were finished in 1945. The total production number is unknown but at least 171 Chi-He were built until surrender.

It is not sure if the Type 1 Medium Tank was used outside the homeland. Some sources claim that at least 2 vehicles were used by IJA 2nd Tank Division during the 1944/45 Luzon campaign but this is debated. The rest of the vehicles were issued to the tank regiments of IJA 4th Tank Division for homeland defence. Using the same gun as the Type 97 Chi-Ha KAI the tank was still outdated as medium tank even if the thicker armor was a good step forward. He would have been a good light tank, compareable to the US M5 or the Pz II Luchs. But he came too late and in too low numbers.

One Chi-He was sent to Aberdeen Proving Ground after surrender and scrapped after tests. The fate of the other vehicles is unknown but they were either scrapped or sunk in lakes. There is no vehicle on display or in depots so it can be assumed that all were destroyed.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%201/jap%20typ%201%20Chi-He%20vergleich%20bug%20shinhoto.jpg
Chi-He and Chi-Ha KAI bow comparison

Data
vehicles built: ca. 170
battle weight: 17,2 (metric) t
crew: 5 men
length: 5730 mm
width: 2330 mm
height: 2380 mm
ground clearance: 400 mm
trench crossing capability: 2500 mm
climbing capability: 35°
fordability: 1000 mm
engine: Mitsubishi Type 100 12-cylinder Diesel engine
power: 240 hp at 2000 rpm
maximum speed: 44 km/h on roads
fuel capacity: 330 l
range: 210 km on roads
transmisson: 4 forward, 1 reverse
Power/weight ratio: 14 hp/t
armament: 1 X Type 1 47 mm Tank Gun , 2 X Type 97 7,7 mm Tank MG
Ammunition capacitiy: 121 47 mm grenades, 4220 MG shots



armour
strength


turret front
25 + 25 mm @ 72 ° curved


sides
25 mm @ 75 °


rear
25 mm @ 90 °


roof
10 mm @ 0 °


superstructure front
50 mm @ 78 °


sides
25 mm @ 75 °


rear
20 mm @ 90 °


top
10 mm @ 0 °


suspension front
50 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm @ -85 °




To be continued in part 6....

tom!
01-08-2018, 10:45 AM
Hi.

10) Medium Tanks part 6


f) Type 3 Medium Tank Chi-Nu:

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%203/jap%20typ%203%20chi-nu%208.jpg

The Type 1 47 mm tank gun was able to penetrate the US Medium M4 frontally on up to 450 m but only if the impact angle was around 90°. If the impact angle was lower the tank had to come closer making it an easy target. So a gun able to penetrate the M4 reliable on medium and longer ranges was necessary. Discontinuing the development of a long 57 mm tank and anti-tank gun in 1943 IJA had no better tank armament avaliable and the new tank designs wouldn´t be production ready before early 1945.

Therefore in mid 1943 IJA decided to upgun the Type 1 Chi-He as soon as possible as stopgap solution. First plans showed an upgraded version of the Type 2 Gun Tank Ho-I using the short-barreled Type 99 75 mm Tank Gun inside a better armoured turret. The AP-round of this gun was able to penetrate the side of a M4 on 950 m but the low muzzle velocity of 520 m/sec made aiming and accuracy problematic.

So the decision was made to use a modified version of the the Type 90 75 mm Field Gun similar to the main armament of the Type 1 Gun Tank Ho-Ni I. With its muzzle velocity of 680 m it was able to penetrate 65 mm armour on 1000 m with AP grenades. This was found acceptable. The gun became Type 3 75 mm Tank Gun. But recoil forces, recoil length and size of the ammunition made a new turret necessary. Prototype production started in May 1944 and in October tests started.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%203/jap%20typ%203%20chi-nu%20unit.jpg
Type 3 Chi-Nu of IJA 4th Tank Division after surrender

The new turret was based on the turret of the Type 1 Chi-He. The chassis was not modified besides the turret ring which was enlarged from 1350 mm to 1700 mm. Flat armor plates were welded together in a hexagonal shape. A commander´s cupola with a two door hatch was placed offset to the right. Visor ports were mounted to the front, left, rear and right of the cupola. On the left side on the turret a large access hatch for gunner and loader was mounted. An AA-mount was placed in front of the hatch. Additional access hatches with visor slits and pistol ports were in each turret side. An ammunition hatch was in the rear turret but there was no MG in the turret. Due to the higher weight an electrical turret rotating system was used but it was still possible to turn it by hand.

Serial production of the tank designated "Type 3 Medium Tank Chi-Nu" was started in December 1944. Due to raw material shortages only between 150 and 166 vehicles were built, details were destroyed at surrender. The first six production vehicles were issued to IJA Tank School for crew training. From spring 1945 completed vehicles were used to equip two tank regiments and an independend tank brigade. None of these units reached operational status before surrender. But they would have been a nasty surprise for any US invasion force in late 1945/early 1946 as IJA managed to keep development and build-up secret. US Army inspectors were very surprised to find these tanks in the japanese tank force barracks.

http://www.ww2technik.de/Bilderchen/jappanzer/mittel/typ%203/jap%20typ%203%20chi-nu%20fabrik.jpg
Type 3 Medium Tank on the assembly line

After surrender one vehicle was sent to Aberdeen Proving Ground and scrapped after tests. A second vehicle was on display at US Army Akabane Arsenal in Tokyo and then handed over to Japanese Ground Self-Defence Force Ordnance School at Tsuchiura, Kanto Province. There it was restaurated and became an exhibit. It´s the only survivng Type 3 Chi-Nu, all other vehicles were destroyed.

Data:
As Type 1 Medium Tank Chi-He except

vehicles built: between 150 and 166
battle weight: 18,8 (metric) t
height: 2610 mm
maximum speed: 39 km/h on roads
Power/weight ratio: 12,8 hp/t
armament: 1 X Type 3 75 mm Tank Gun , 1 X Type 97 7,7 mm Tank MG
Ammunition capacitiy: 70 75 mm grenades, 3670 MG shots



armour
strength


turret front
50 mm @ 78 ° curved


sides
20 mm @ 80 °


rear
25 mm @ 90 °


roof
12 mm @ 0 °


superstructure front
50 mm @ 72 °


sides
25 mm @ 75 °


rear
20 mm @ 90 °


top
10 mm @ 0 °


suspension front
50 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm @ -85 °




Yours

tom! ;)

tom!
01-08-2018, 01:50 PM
Hi.

11) Heavy Tanks part 1


a) Experimental Type 91 Heavy Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20type%2091%20heavy.jpg

After finishing the tests with the Experimental Tank No. 1 Army Technical Bureau decided to continue development of this design. Goal was to meet the original requirements and to implement new design ideas. Development started in March 1928 at Osaka Army Arsenal using the Experimental Tank No.1 as test vehicle.

First changes were made regarding the suspension. The general scheme was not changed but minor improvements were added. Two of the single roadwheels were removed and the remaining was slightly enlarged. The number of return rollers was increased by 2 (one forward and one in the rear) and they were placed in-line removing the track buckling. The suspension armor was simplified and the upper part was arranged sloped to improve mud removal. The weight was reduced significantly.

The engine was modified by using aluminium for several parts increasing the power while reducing weight. Power transmission was also improved. This lead to a maximum speed of 25 km/h. The exhaust pipe was placed inside the tank and the muffler was covered with a mesh wire netting against small rocks and debris.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20experimental%20typ%2091.jpg
First tests with modified suspension and the new main turret

The armor scheme of the superstructure wasn´t changed too much but vulnerable parts received a strength of 20 mm instead of 17 mm and more sloped parts were used. A new turret with a smaller commander´s cupola was developed with a MG port in the 7 o´clock position. Armament was changed to a Type 90 57 mm Tank Gun.

Continuous tests were made and every change was tested until it worked. Final weight was 16t as required for the Experimental Tank No. 1. In April 1930 the resulting vehicle was again showed to IJA High Command under the designation "Experimental Type 91 Heavy Tank" with mild steel armor plates. They were very pleased with the mobility but also demanded several changes:
- the main armament was found too weak for such a heavy vehicle
- the armor strength was found too weak for future fightings
- a stronger engine should be used

Development of the Type 91 Heavy tank was ceased in February 1932.

Data:
vehicles built: 1 as continuous development of the Experimental Tank No. 1
battle weight: 16 (metric) t
crew: 5 men
armor: up to 20 mm
length: 6300 mm
width: 2470 mm
height: 2570 mm
ground clearance: 400 mm
track width: 350 mm
trench crossing capability: 3000 mm
climbing capability: 43°
maximum vertical obstacle: 1000 mm
engine: modified BMW 6-cylinder in-line gasoline aircraft engine
power: 224 hp
maximum speed: 25 km/h on roads
transmission: 6 forward, 2 reverse
armament: 1 X Type 90 57 mm Tank Gun , 1 X Type Taisho 3 6,5 mm MG in the turret, 2 X Type Taisho 3 6,5 mm MG in separate turrets


b) Type 95 Heavy Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2095%20schwerer%20Panzer.jpg

The development of a successor of the Experimental Type 91 Heavy Tank started in December 1932 at Osaka Army Arsenal. The changes demanded lead to several reconstruction works. Additionally several new developments had to be started.

The suspension was changed completely to the system used on the Type 89 Medium Tank. It consisted of a see-saw type suspension using two pairs of 4 roadwheels connected with a bar and a single frontal roadwheel for increased climbing abilities. The driving sprocket was placed in the rear. A frontal idle wheel and four return rollers completed it. The external suspension armor sheme was changed to the Type 89 late production standard.

The superstructure was slightly remodeled raising it and increasing the length of the upper slope of the side armor. Maximum armor was now 35 mm. The forward turret was exchanged with a larger cylindrical turret housing a Type 94 37 mm Tank Gun to increase at-power of the vehicle. The main turret armament was changed to a Type 94 70 mm Tank Gun. The commander´s cupola was replaced by a flatter one with a two-door access hatch. Both remaining Type 3 MGs were replaced by Type 91 6,5 mm Tank MGs. The engine was remodeled, too.

The prototype was completed in September 1934. It had a combat weight of 26 t and the 290 hp engine only allowed a speed of 22 km/h. In addition the vehicle was now too large to be transported on narrow mountain railroads. Nevertheless 3 more vehicles with face-hardened armor plates instead of the mild steel plates used on the prototype were built at Osaka Army Arsenal prior to the official presentation in mid 1935. IJA officials were not pleased with this tank:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2095%20schwer.jpg
Type 95 Heavy Tank on display at Yasukuni Shrine

- the speed was found to low and the size too large
- use of a gasoline engine
- the armor strength was again considered too weak against contemporary tanks.
- in 1935 IJA tank doctrine does not need a heavy breakthrough tank as the main enemy was now considered China not the Soviet Union
- the military budget expected after 1935 did not allow the introduction of such an expensive vehicle

Therefore the decision was made to discontinue the development of a multi-turret tank design. One of the prototypes was handed over to Chiba Tank School for basic crew training, two were used for the development of heavy SPGs at Osaka Army Arsenal and the last became exhibit at Yasukuni Shrine in Tokyo. None survived the war.

Data
vehicles built: 1 as continuous development of the Experimental Type 91 Heavy Tank + 3
battle weight: 26 (metric) t
crew: 5 men
length: 6470 mm
width: 2700 mm
height: 2900 mm
ground clearance: 510 mm
track width: 480 mm
ground contact length: 4400 mm
trench crossing capability: 3000 mm
climbing capability: 43°
maximum vertical obstacle: 1100 mm
fording: 1100 mm
engine: remodeled BMW 6-cylinder in-line gasoline engine
power: 290 hp at 1600 rpm
maximum speed: 22 km/h on roads
fuel capacity: 400 l
lubricant oil capacity: 40 l
range: 110 km on roads
transmission: 6 forward, 2 reverse
Power/weight ratio: 11,15 hp/t
armament: 1 X Type 94 70 mm Tank Gun and 1 X Type 91 6,5 mm Tank MG in the main turret, 1 x Type 94 37 mm Tank Gun in the forward turret, 1 X Type 91 6,5 mm Tank MG in the rear turret
Ammunition capacity: 100 70 mm grenades, 250 37 mm grenades, 2940 MG shots



armour
strength


turret front
30 mm @ 80 °


sides
25 mm @ 90 °


rear
25 mm @ 90 °


roof
16 mm @ 0 °


superstructure front
35 mm


sides
30 mm


rear
25 mm


top
10 mm°


suspension front
35 mm


sides
unknown + 6 mm external


rear
25 mm




to be continued in part 2...

tom!
01-08-2018, 02:13 PM
Hi.

11) Heavy Tanks part 2


c) Experimental Superheavy Tank O-I:

no pic, sorry

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20O-I%20seite%20schnitt%20skizze.jpg

The Nomonhan incident in 1939 showed that the japanese tanks were unable to cope with its tasks due to the superiority of the soviet tank models but also due to the use of massive artillery barrages used by the Red Army to stop enemy tank advances. So in late 1939 IJA high ranks decided to give the multiturret tank design a new chance. This time there should be no limitations towards weight and size of the vehicle. It only should be able to move at infantry speed in manchurian terrain and it should withstand direct hits of soviet contemporary 122 mm artillery gunfire. Transport should be done disassembled.

In early 1940 IJA 4th Technical Research Bureau and Mitsubishi were ordered to develop a prototype. Soon it became clear that at least 150 mm of armor would be necessary, resulting in a weight of more than 120 t. Therefore the existing tank technologies could not be used as they only allow a maximum weight of up to 30 t. So much basic development work had to be done first. As the project was rated top secret most development and production work was done in small, separated and even soundproofed barracks at 4 th Technical Research Bureau in Tokyo using the designation "Mi-To" (for Mitsubshi -Tokyo) to cover it. Even the engineers in charge with the design were not convinced that it would work.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20O-I%20Laufradpaare%20skizze.jpg

The suspension consisted of eight pairs of 2-wheeled bogies, each bogie sprung by a massive vertical coil spring. The driving wheel was located at the rear. The armor was partly arranged sloped but the side armor was vertical. Basic armor strength was 75 mm on turrets, bow, rear and upper side armor, 35 mm on lower side armor and 50 mm on the roof to simplify handling. The final armor strength was achieved by bolting additional armor plates on near the frontline.

The tank was separated internally into three compartments by two bulkheads consisting of 20 mm armor plates with two doors each. There was the forward fighting compartment with the central drivers seat and the ammunition racks for the 47 mm turrets, the main fighting compartment below the central turret and the engine compartment in the rear half of the vehicle. The engines were placed side by side with a small maintenance corridor between them. The rear turret was placed above the gearbox making it a quite loud place.

Development was done in March 1941 and prototype production started on 14.04.1941. It was planned to build a less armored test vehicle within 3 months. Many non-secret parts were delivered by private companies. The rest was built at the barracks. But after just one month it became clear that the amount of raw materials provided by the army for the project would not be enough. Several rare metals were depleted and due to the war against China there was no chance to get further material soon. In addition there were problems with the cooling system. So the decision was made to postpone the production for 9 months until January 1942.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20O-I%20raumaufteilung%20skizze.jpg

The hull was finished on 08.02.1942 for first mobility tests. The turrets should be built by Mitsubishi until May 1942 but only the bow and rear turrets were finished until then. Due to the lack of steel the main turret could not be finished with the upper armor plate missing. Nevertheless the superstructure was built and the smaller turrets implemented. With a basic armor strength of 75 mm and 35 mm turret roofs the total weight was already 96 t. The necessary remaining raw materials were not available before 1943 and it was impossible to continue without them. So the development was again postponed. Only mobility and basic handling tests were done with more or less success. Until summer 1943 the final tests of the prototype were done and the project officially demonstrated to IJA High Command. At this time the vehicle received the official short designation "O-I" (O = short for superheavy, I = first design). The tank impressed the spectators and therefore an immediate start of field trials was ordered. These should be done at Sagami Army Arsenal. So the prototype was disassembled within one night and the parts were sent to the arsenal during several nights by truck. On 01.08.1943 assembly was finished and tests started the same day. The vehicle had no problems with hard and semi-hard terrain but after driving on muddy terrain it sank in up to the coil springs, damaging the suspension. It was recovered and several tests were finished on concrete. The damage to the suspension had to be repaired as it inflicted damage to the concrete. So further tests had to be postponed. So the tank was disassembled from 03. to 08.08.1943 and sent back to 4 th Technical Research Bureau.

The further fate is unknown but the project wasn´t continued. It´s possible that it was shipped to Manchuria for further trials but there is no evidence of this. Soviet sources mention a motorised wooden mock-up found in Manchuria.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20O-I%20Panzerungsschema.jpg

Even if the tank would have reached operational status there are several questions regarding a use. Main problem was the raw material situation making it almost impossible to produce such massive constructions. In addition vehicles like these were prime (and easy) artillery and aircraft targets making a successful use very unlikely. And the contemporary development of AT-weapons did not stop making even 150 mm of armor not impenetrable in 1944.

Data:
vehicles built: 1
battle weight: 150 (metric) t
crew: 6 men
length: 10100 mm
width: 4833 mm
height: 3600 mm
track width: 800 mm
engine: Kawasaki Type 98 V12 gasoline X 2
power: 550 hp X 2
maximum speed: 29,4 km/h on roads
transmisson: 6 forward, 2 reverse
Power/weight ratio: 7,3 hp/t
armament: 1 X Type 96 15 cm howitzer, 1 X Type 1 47 mm Tank Gun in each bow turret, 1 X Type 97 7,7 mm MG in the rear turret
Ammunition capacitiy: ca. 100 150 mm grenades, ca. 200 47 mm grenades, ca. 4000 MG shots



armor
strength


turret front
150 mm @ 90 °


sides
150 mm @ 90 °


rear
150 mm @ 90 °


roof
50 mm @ 0 °


superstructure front
150 mm @ 71,4 °


sides
105 mm @ 90


rear
150 mm @ 47 °


top
50 mm° @0 °


suspension front
150 mm @ 33,7 °


sides
70 mm @ 90 °


rear
150 mm @72 °, lower part @ -57 °




to be continued in part 3...

tom!
01-08-2018, 02:43 PM
Hi.

11) Heavy Tanks part 3

The following tanks are added here as they fit into the original IJA definition for a heavy tank.


d) Type 4 Tank Chi-To part 1:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%204%20chi-to%203.jpg

In mid 1942 IJA had to realise that they had massively fallen back in tank technology and that it would be suicide to continue the contemporary general outline for tank usage and development. Especially the new soviet tanks T-34 and KV-1 were far superiour to anything they even thought of but the US Medium M3 and the british cruiser and infantry tanks were also more or less outclassing everything in the own arsenals. Therefore a large development program was started including new tanks, gun tanks and gun carriers able to fight contemporary and future enemy tanks.

One of these developments was a tank to replace all the medium tanks as soon as possible. Requirements were among others:
- maximum weight 20-22 t
- armament consisting of the Type 1 47 mm Tank Gun and two MGs, but the use of the 57 mm tank gun under development at this time should be possible
- crew consisting of driver, bow gunner/wireless operator, commander, loader and gunner
- maximum armor strength 50 mm
- suspension using already standardised elements of the predecessors
- road speed 40 km/h
- no size limitations regarding railway transport

Army Technical Bureau started development in cooperation with Mitsubishi in September 1942. It was clear that the 57 mm tank gun needed a larger turret than the 47 mm gun. This lead to the necessity to use a stronger engine which would be larger than the Type 100 engine used for the Type 1 Chi-He which was under development at the same time. So the suspension had to be lengthened. Therefore the single roadwheels of the Chi-Ha suspension were removed and the center pairs were mounted at the front. A single roadwheel and a third pair of roadwheels connected with bell cranks to a second large horizontal coil spring were added in the rear.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%204%20chi-to.jpg
Type 4 Tank after surrender with MGs removed

The chassis armour was similar to the one used on the Chi-He but with a longer engine compartment. There was no access hatch above the bow gunner. The rear armour consisted of a sloped upper part, a vertical center part and a negatively angled lower part. A large two-door engine access hatch was placed above the engine compartment ventilation and combustion air intakes covered with armor plates were mounted in the center of the access doors. The exhaust pipes lead directly to wire netting covered mufflers on each rear mudguard.

The turret was similar to the one used on the Type 3 Chi-Nu which was designed one year later but casted. This caused massive problems as casting wasn´t often used in Japan. So the technology was not very sophisticated. There were many quality problems but these were finally solved. It had a hexagonal shape with smaller sides to the front and longer rear sides. The turret rear overhang was shorter. There was one access hatch in the rear for ammunition supply and a large two-door hatch above the gunner´s position on the (in driving direction) left turret top but none in the turret sides. A cylindrical commanders cupola with observation ports and a two-door hatch was placed on the right side. A standard AA-mount for a tank MG was positioned in front of the gunner´s hatch. The turret was placed centered on the fighting compartment. The gun mantlet was also similar to the later Chi-Nu and there was also no rear turret MG. But it was planned to add a coaxial MG.

The prototype development was done until June 1943. At this time the 47 mm tank gun was rated to be too weak against future tanks as faced by german forces in Africa or the Soviet Union. So in July 1943 after examining a Panzerkampfwagen V Panther Ausführung A and a Panzerkampfwagen VI Tiger Ausführung E (these were donated to Wehrmacht after finishing the tests because there was no chance to ship them to Japan) bought in Germany IJA changed the requirements to:

- use of the 57 mm main gun
- 75 mm maximum armour
- maximum weight 25 t

Therefore the design had to be improved regarding armour and suspension which was done until late 1943. A prototype of the tank was produced at Mitsubishi´s Maruko factory until May 1944. The main gun was problematic as the basic development made for a anti-tank gun was ceased in late 1942 due to a lack of power and a too high weight. During a test of the tank gun prototype under perfect conditions in March 1944 only a penetration of 60 mm at 90° on 1000 m was achieved which was rated far too low against future tanks. Therefore the decision was made to discontinue this development and to change to a 75 mm main armament in April 1944.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%204%20chi-to%20seite.jpg
vehicle ready to be shipped to the USA

First designs used the turret of the type 3 Medium Tank with its Type 3 75 mm Tank Gun but this gun was also not really suitable against heavy enemy tanks. So in July 1944 the decision was made to develop a tank gun based on the newly introduced Type 4 75 mm AA-Gun. But first trials were done in August 1944 using a Chi-Nu turret. The trials with a dummy of the gun mounted inside the Chi-Nu turret showed problems regarding handling due to narrowness. So the decision was made to develop a new larger turret, too.

This turret also had a hexagonal basic shape but the side armour was made out of a single curved armour plate. The turret rear was casted, all other armour plates were made of rolled homogenous steel. A two-door access hatch and a standard AA-mount were placed above the gunner´s seat on the left side of the turret top. The commander entered the tank through a cylindrical commanders cupola with a two-door access hatch. A periscope was mounted in front of the cupola. A standard MG port was placed on the rear right of the turret side armour to be operated by the loader. The coaxial MG had been abandoned.

The turret was placed offset to the right on the fighting compartment. Due to its larger size the driver and bow gunner position had to be shifted forward a little bit which resulted in a reduction of the slope of the upper frontal armour. This also allowed the use of an access hatch above the bow gunner again. To reach the expected necessary engine power Mitsubishi developed a new Diesel engine based on a small ship engine.

In February 1945 the turret was finished and prototype tests of the vehicle now designated "Type 4 Tank Chi-To" started in March. The gun development was delayed until late March 1945. Due to raw material shortages only two tank guns and five pre-production vehicles could be built until June 1945. At this time final operational tests started at IJA Chiba Tank School which lasted until surrender. First tests showed a very good mobility and a potent armament. Therefore IJA decided to scrape together raw materials for 200 vehicles by ceasing most other tank and also many other weapon productions. Mitsubishi was ordered to start production in September 1945, delivery should be done until December 1945 which was nearly impossible with the increasing damages due to US strategical bombings. There were plans to use fully casted turrets but the producing company Japan Steel announced that they wouldn´t be able to deliver so many turrets in such a short time. Another idea was to use parts of the Chi-Nu turret production for completely welded turrets but this was rejected as it would have lead to a production decrease of this tank type. So the mixed prototype turret type should be used. Another simplification of the production model should have been the removing of the air intake armour protection.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%204%20chi-to%202.jpg
rear view, note the wrong US designation.

The development of this tank was also kept in secret making it a big surprise for the US Army, too. One of the completed vehicles should be sent to Aberdeen Proving Ground but there is no record of a test there. There are rumors that the prototype was either lost during transport or that it was mixed up with the Type 5 Chi-Ri prototype (see US designation on the last picture) and never shipped. Several Type 4 Tanks were sunk together with other tanks in Lake Hamana, Shizuoka prefecture, after surrender. In 2003/04 there was a campaign to rise at least one of the tanks by japanese military enthusiasts but with no success. There are trials to start a new campaign at the moment.


to be continued in part 4...

tom!
01-08-2018, 02:57 PM
Hi.

11) Heavy Tanks part 4


d) Type 4 Tank Chi-To part 2:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%204%20chi-to%204.jpg

Data:
vehicles built: 6 (4 without main armament)
battle weight: 24 (metric) t empty, 30 t fully loaded
crew: 5 men
length: 6340 mm
width: 2860 mm
height: 2670 mm
ground clearance: 420 mm
track width: 450 mm
trench crossing capability: 2700 mm
climbing capability: 35°
fording: 1200 mm
engine: Mitsubishi Type 4 V-type 37.700 cm³ 12-cylinder Diesel engine
power: 412 hp at 1800 rpm
maximum speed: 45 km/h on roads, 28 km/h cross country
range: 250 km on roads
transmission: 4 forward, 1 reverse
Power/weight ratio: 13,8 hp/t
armament: 1 X Type 5 75 mm Tank Gun , 2 X Type 97 7,7 mm Tank MG
Ammunition capacity: 65 75 mm grenades, 5400 MG shots



armor
strength


turret front
75 mm @ 75 °


sides
50 mm @ 75 °


rear
50 mm @ 75 °


roof
20 mm @ 0 °


superstructure front
75 mm @ 75 °


sides
35 mm @ 65 @


rear
50 mm @ 90 °, upper part @ 40 °


top
16 mm° @ 0 °


suspension front
75 mm @ -20 °


sides
25mm @ 90 °


rear
50 mm @ -40 °




e) Experimental Type 5 Tank Chi-Ri:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%205%20chi-ri.JPG

With the decision to equip the Type 4 Tank at least with the 57 mm tank gun in July 1943 IJA also ordered the development of a larger version. Requirements were among others:
- use of a 75 mm tank gun
- 75 mm maximum armor, 50 mm upper side armor
- maximum weight 35 t
- operational range 200 km
- use of a 105 m tank gun should be prepared
- up to 130 mm maximum armor should be possible
- semi-automatic loading mechanism to increase fire cadence
- maximum use of already standardised suspension parts

Design started on August 19th, 1943. Until September 23rd, 1943, a wooden mock-up was finished as basis for further developments. It was planned to develop the tank within one year and to start serial production within two years. Several design features were built following the results of the examination of the Panther and Tiger I tank bought and examined in Germany from Mai 1943. Other details were following domestic solutions.

The suspension of the Type 4 Tank under development was enlarged by an eighth roadwheel paired with the single roadwheel of the Chi-To. A stronger driving sprocket was designed and more massive bell cranks, thicker rubber bands plus heavier coil springs were used. The highest possible weight was calculated around 55 t which wouldn´t be enough for all required upgrade possibilities. But this was accepted to get the tank into production.

The lower bow armor was similar to the Chi-To, the superstructure armor scheme was similar the Tiger I but with a slight slope. Both edges of the upper frontal armor were arranged diagonal. Instead of the standard MG mount a Type 1 37 mm Tank Gun with a coaxial MG was mounted in the bow. This arrangement should increase the fighting power as the 37 mm gun was able to take out MGs and infantry in field fortifications as well as soft skinned and thinly armoured fighting vehicles. So the main gun could fire on harder targets and in addition the tank was still able to fire during reload.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%205%20chi-ri%202.jpg

The rear armor consisted of a vertical plate with a negatively sloped lower part. The rear vertical edges were also arranged vertically sloped. A multi-door engine access hatch with ventilation and cooling air intakes with grilles along the center line covered the engine compartment. The exhaust pipes were exiting the vehicle in the rear leading to two mufflers placed on the upper rear armor.

The turret was massive and large enough to house the Type 5 105 mm gun, a semi-automatic loading mechanism and if necessary a second loader. The basic shape was hexagonal with a lengthened rear part. For the first time in Japan the turret crew stood or sat in a basket rotating with the turret. In each forward side armour plate a visor slit with a pistol port below was placed. A standard MG mount was mounted in the forward part of the (in driving direction) left rear side armor operated by the gunner. In the center of each rear side armor a small access hatch for ammunition supply with a visor slit was added. Above the gunner´s seat was an access hatch in the left top armor. Behind this hatch a periscope for the commander was placed. Behind it a cylindrical commanders cupola with a two-door access hatch was mounted. The top armor armour was arranged slightly angled with a kink at the center of the cupola. An antenna base was mounted on each side of the turret at the kink. The loader/s was/were placed on the right side of the turret. A simple gun stabilisation and an electrical turret rotating mechanism were planned.

For the expected weight a stronger engine than for the Type 4 Chi-To was necessary. Mitsubishi saw no chance to develop an air-cooled engine with more than 500 hp in time. So they developed a liquid-cooled, supercharged 550 hp Diesel engine from the Kawasaki Type 98 C9- IIb V-type 12 cylinder liquid-cooled 800 hp aircraft engine, a license-built version of the BMW VI (aka BMW 106) aircraft engine. The tank was operated with a driving wheel over hydraulical elements.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%205%20chi-ri%20heck.jpg
rear view, exhaust pipes are missing

All armor plates were still face-hardened but due the thickness the producing company had problems to reach the expected quality. Therefore the prototype had to be built with several steel plates not reaching the projected hardness. Until surrender only the armor body and the turret were finished. The engine wasn´t mounted and also no gun. The semi-autoloader had already been abandoned in mid 1945 due to development problems. Many parts of the interiour including, ammunition storage, turret rotating mechanism and stabilisation weren´t finished, too.

After surrender the US Army observers were very surprised to see such a heavy vehicle under construction. The prototype should be shipped to Aberdeen Proving Ground but there is no known test report. So the fate is unknown.

Several western authors assert that it was planned to use a 88 mm main gun as armament but there was no evidence found so far among primary sources. It´s only sure that the prototype should be tested with a Type 5 75 mm Tank Gun. Everything else is just an assumption.

Data
vehicles built: 1, not finished
weight: 37 (metric) t empty, 46 t fully loaded
crew: 5 men
length: 8467 mm
width: 3050 mm
height: 3100 mm
ground clearance: 400 mm
track width: 600 mm
ground preasure: 0,6 kg/cm²
trench crossing capability: 3000 mm
climbing capability: 30°
fording: 1200 mm
engine: modified Kawasaki Type 98 C9 IIb liquid-cooled 12-cylinder Diesel engine with supercharger
power: 550 hp at 1500 rpm
maximum speed: 42 km/h on roads
range: 180 km on roads
Power/weight ratio: 14,9 hp/t
armament: 1 X Type 5 75 mm Tank Gun and 1 X Type 97 7,7 mm Tank MG in the turret, 1 X Type 1 37 mm Tank Gun and 1 X Type 97 7,7 mm Tank MG coaxial in the bow, 1 X Type 100 8 mm Submachine Gun for close defence
Ammunition capacity: 100 75 mm grenades, 102 37 mm grenades, 5400 MG shots



armor
strength


turret front
75 mm @ 72 °


sides
50 mm @ 74 °


rear
50 mm @ 90 °


roof
20 mm @ 0 °


superstructure front
75 mm @ 72 °


sides
35 mm @ 74 °@


rear
50 mm @ 90 °


top
12 mm° @ 0 °


suspension front
75 mm @ -20 °


sides
35 mm @ 90 °


rear
50 mm @ -10 °



Yours

tom! ;)

tom!
01-09-2018, 01:06 PM
Hi.


12) Gun Tanks part 1

During the late 1930th IJA 1st Army Technical Bureau in charge of artillery equipment made several suggestions to mobilise several artillery pieces using medium and heavy tank chassis. Most remained projects but at least two different suggestions were built as prototypes. After 1941 all close support, anti-tank and self-propelled artillery vehicles used by tank units were designated "Gun Tanks". They were all build in small numbers only. Data on the early and later vehicles are quite rare.

It was planned to equip each tank regiment with a 5th company of 10 gun tanks after 1943 (1 gun tank and 2 light tanks in the command section, 3 platoons with 3 gun tanks each). But this never happened due to the low production priority. In addition a lot of different gun tanks were developed and produced making it hard to equip a company with a single type. Many tank regiments received medium tanks instead of gun tanks for their 5th company


a) early projects:

http://www.ww2technik.de/Bilderchen/japari/spg/jap%20typ%2095%20exp%20spg.jpg
experimental self propelled gun, second suggestion

In 1937/38 IJA Technical Bureau suggested the use of tank chassis to motorise heavy artillery pieces. In 1938 two of the rejected Type 95 Heavy Tanks were used to demonstrate the possibilities of these suggestions. The first version used a Type 92 10 cm cannon which was mounted in an enclosed fighting compartment on the rear of the remodeled vehicle. To do this the engine compartment was shifted to the center. This vehicle is known as "Jiro" or "Jiro-Sha" in literature, short for "Jidosoho Ro-Go" = "Motorised Gun, 1st Version". No picture was found so far.

The second suggestion was to simply mount a gun instead of the bow turret and to remove the main turret and parts of the fighting compartment to get space for the crew. Armament ist unknown but it seems to be a 12 cm or 15 cm gun in a pivot mount The designation of this vehicle ist unknown but in western literature and on the web it is known as "Hiro" or "Hiro-Sha" but this seems to be fictional.

The fate of the prototypes is unknown but the second suggested vehicle was found at Tateyama barracks after surrender.

no further data.


b) Type 2 Gun Tank Ho-I:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/ho%20i/jap%20typ%202%20experimental%20Ho-I%20sfl.jpg
first prototype during tests

During the innitial stages of the China Incident IJA suffered heavy losses during the Shanghai street fightings. The 57 mm guns of the Type 89 tanks were useful but could not destroy heavy fortified positions fast. So after the decison was made to introduce the Type 97 Medium Tank Chi-Ha ideas came up to develop a close support version with a larger gun similar to the british CS-tanks. The main gun should be based on the obsolete Type Meiji 41 75 mm Mountain Gun which was used as infantry gun since 1935. Design started in July 1937 but with low priority. Main task was to develop a new turret as the Chi-Ha turret was too narrow to use a bigger gun

The prototype wasn´t finished until late 1940. The final turret design was an improved version of the new turret for the Chi-Ha KAI with welded, flat armor plates. The basic shape was hexagonal with a lengthened rear part. Frontal armor strength was 25 mm. A small access hatch with visor slit was mounted each rear side armor. A large ammunition suply hatch was mounted in the rear. Loader and commander were placed on the (in driving direction) left side of the turret. A cylindrical commanders cupola with a two-door access hatch on the left and a one-door access hatch on the right above the gunner´s position allowed entering the vehicle. A periscope was monted in front of the cupola. To reduce height the upper parts of the turret were arranged sloped. Besides an increase of the turret ring diameter the chassis of the Chi-Ha wasn´t changed.

Tests with this vehicle started in spring 1941. In September operational tests were done at Chiba tank school. They showed good performance agains stationary targets but due to the quite low muzzle velocity it was very problematic to hit moving targets. In addition the armour piercing capacity of 40 mm at 100 m/90° was rated too weak which lead to the development of a HEAT grenade.

In 1942 the turret was simplified by Hitachi. The upper slope was removed and the sides heightened. Now the upper armor had a kink in the middle. The side armor plate connections were now strengthened by rivets. The frontal armor strength was increased from 25 mm to 50 mm. A flatter commander´s cupola was mount and an AA-mount was added in front of the gunner´s hatch. The recoil mechanism armor was remodelled and received a better bullet deflecting shape. In addition the chassis of the Type 1 Chi-He was used. The better armor protection was appreciated.

http://www.ww2technik.de/Bilderchen/jappanzer/spg/ho%20i/jap%20typ%202%20Ho-I%202.jpg
Serial production vehicle

Preparations for serial production did not start before 1943 due to a very low priority. At this time there were ideas to upgun this vehicle with the 57 mm tank gun under development at this time making it an upgunned Chi-He. After finishing the development of the HEAT ammunition the decision was made to introduce this tank under the designation "Type 2 Gun Tank Ho-I". Production did not start before 1944 and only 30 vehicles were finished by Mitsubishi. Then the production was changed to the more powerful Type 3 Medium Tank. The vehicles produced were issued to the regiments of IJA 4th Tank Division stationed in Japan for homeland defence. All were destroyed after surrender with one being sent to Aberdeen Proving Ground first.

The Type 2 Gun Tank was a good step into the right direction, especially after introducing the Type 1 47 mm tank gun with its limited HE-power. But it was inferiour to the Type 1 Gun Tanks Ho-Ni I and II and so keeping the raw material shortages in mind the production should not have been started.

The first prototype is sometimes wrongly designated "Type 1 Gun Tank Ho-I" in western literature.

Data
as Type 1 Medium Tank Chi-He except

vehicles built: 30
battle weight: 15,4 (metric) t empty, 16,7 t fully loaded
crew: 5 men
height: 2580 mm
armament: 1 X Type 99 75 mm Tank Gun, 1 X Type 97 7,7 mm Tank MG
Ammunition capacitiy: 63 75 mm grenades, 2120 MG shots



armour
strength


turret front
50 mm @ 80 °


sides
35 mm @ 75 °


rear
20 mm @ 78 °


roof
10 mm @ 0 °


superstructure front
50 mm @ 78 °


sides
25 mm @ 75 °


rear
20 mm @ 90 °


top
16 mm @ 0 °


suspension front
50 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm @ -85 °




To be continued in part 2...

tom!
01-09-2018, 01:28 PM
Hi.

12) Gun Tanks part 2


c) Type 1 Gun Tank Ho-Ni I:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%201/jap%20typ%201%20ho-ni%201.jpg

The second idea for a close support vehicle was to mount the very good Type 90 75 mm Field Gun on the Type 97 Chi-Ha. The design started with low priority in December 1939 at 1st Army Research Institute (in charge of developing artillery guns and equipment) because it was rated as self-propelled gun not gun tank at this time. The prototype based on the Type 97 Medium Tank Chi-Ha was built by Hitachi. It was finished in May 1941.

The turret and the top armor of the fighting compartment were removed. Instead a large, slightly sloped armor shield was mounted directly behind the upper frontal armor. Small vertical armor plates with rectangular upper part and trapezoid lower part on the sides and an armor plate with the same width as the upper side plate on top completed crew protection. Visor hatches were mounted in each sides armor plates. A Type 93 0,75 m rangefinder was mounted on the (in driving direction) right side of the top armor plate. It was operated by the commander. The gunner stood on the left side of the gun protected from ejected shell cases by a simple deflector. Therefore the bow gunner´s seat was removed and the MG port was replaced by a 16 mm armor plate. Ammunition racks were also stored there. More ammunition was placed on each side of the fighting compartment and below the floor plates next to the driving shaft. Two loaders and the driver completed the crew. A standard Type 90 Field Gun with parts of the recoil mechanism was mounted in a special lafette with two coil springs below the rear of the cradle to lower recoil forces. This allowed using the gun without its muzzle break. Instead a 70 mm thick muzzle ring with an outer diameter of 160 mm was added to reduce attrition. An armor plate mounted on the gun closed the necessary opening in gun shield. The elevation was limited to 20° due to the limited space below the gun reducing the maximum range. This was found acceptable due to the massive increase in mobility. Maximum traverse was 25° to each side.

First vehicle tests started in June, operational tests were done at Army Field Artillery School from October. Until late 1941 all tests were done and the decision was made to introduce this vehicle not as gun carrier for artillery unit but as gun tank for tank units. The further development before serial production was made by 4th Army Research Institute (in charge of develop tanks and equipment). The changes included a simple notch and bead sight for direct fire against enemy targets (mainly tanks) and several simplifications. The rangefinder was removed. To increase protection the side armour was enlarged, the sides of the gun shield were bend backwards and the frontal armour strength was increased to 50,8 mm. The visor hatches were now placed on the upper part of the side armour and a third hatch was added to the left forward side armour. The upper armour was remodeled and shortened. A V-shape cut was added on the gunner´s side for a different indirect fire sight. Later a standard AA-mount was added on the left of the cut in the top armour. The changes were done until early 1943 but due to the lack of raw materials and capacities at Hitachi serial production did not start before November 1943. At least 124 Ho-Ni I were produced until surrender.

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%201/jap%20typ%201%20ho-ni%201%203.jpg
prototype with 0,75 m rangefinder

The produced vehicles were issued to tank regiments and so called Armored Mobile Artillery Regiments and Battalions. Each mobile artillery company consisted of two observation tanks and 4 platoons with one gun tank and one armoured transport vehicle each (following the contemporary artillery buildup). Two companies were in each battalion and two battalions in each regiment. But most tanks were used in gun tank companies (for OOB see introduction of this post). Ho- Ni I and Ho-Ni II were used side by side.

First operational use was with the IJA 14th Tank Regiment during the 1944/45 retreats in Burma but with only few vehicles. Tank regiments in China used several Ho-Ni I , too. A transport of 14 Ho-Ni I and II for 10th Tank Regiment, 2nd Tank Division, to Luzon was attacked by US aircraft and only 2 vehicles made it to the Philippines. The 2nd Armored Mobile Artillery Regiment´s transport convoy was also attacked en route to Luzon and lost half of its 8 Ho-Ni I. Both units were later wiped out during the final stages of the US Luzon campaign but two Ho-Ni I were captured damaged. Both were sent to Aberdeen Proving Ground, one is on display there today. It´s the only known surviving vehicle.

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%201/jap%20typ%201%20ho-ni%201%202.jpg
rear view of the fighting compartment, note the unit insignia of the 2nd Armored Mobile Artillery Regiment (Hinomaru with white circle)

The Type 1 Gun Tank Ho-Ni I was a good SPG with a small but powerful gun. For its caliber it had a good HE power and (compared to the other IJA tanks before introduction of the Type 3 Chi-Nu) the AT-power was superiour to anything else available. For penetration data see Type 3 75 mm Tank Gun. It was intended to support attacking units with close-range indirect artillery fire but was mainly used for direct fire. The missing special direct fire optics made it very hard to hit targets with the first shot and it was almost impossible to hit moving targets. In addition the relatively weak armor made it vulnerable if facing enemy at-fire. Nevertheless it provided useful heavy fire support.

Data
as Type 97 Medium Tank Chi-Ha except:

vehicles built: ca. 124
battle weight: 14,7 (metric) t
crew: 5 men
length: 5900 mm
height: 2290 mm
maximum speed: 40 km/h on roads
armament: 1 X Type 90 75 mm Field Gun in a special mount,
Ammunition capacity: 24 75 mm grenades



armour
strength


gun shield front
50,8 mm @ 75 °


sides
12 mm @ 90 °


rear
none°


roof
10 mm @ 0 °


superstructure front
25 mm @ 78 °


sides
25 mm @ 75 °


rear
20 mm @ 25 °


top
10 mm @ 10 °


suspension front
25 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm curved




d) Type 1 Gun Tank Ho-Ni II part 1:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%202/jap%20typ%201%20ho-ni%202%204.jpg

During the final stages of the development of the Ho-Ni I the idea came up to use the larger caliber Type 91 105 mm Howitzer with its shorter barrel on such a vehicle, too. The first design studies were made in March 1941. A prototype was built by Hitachi until June 1942.

The basic vehicle was the same as the Ho-Ni I. The main gun was replaced by a howitzer barrel making only minor changes to the mount necessary. Only disadvantages were a minimum range of 485 m due to recoil mechanism limitations and a maximum range of 10800 m (at 22° elevation) due to the limited space inside the vehicle. These were accepted. As the vehicle should only provide indirect fire the thickness of the armor shield was reduced to 25 mm.

Functional tests at Osaka Army Arsenal and operational tests at Army Field Artillery School followed. During winter 1942/43 climatic tests in Manchuria showed problems with the gun mount brackets if firing with maximum traverse of 25° at -27°C. Therefore the maximum traverse was limited to 10° to each side. The ammunition load of 16 grenades and charges was criticised and so additional ammunition racks for 4 grenades and charges were mounted on the engine room behind the fighting compartment. To maintain the engine the rack had to be removed.

In mid 1943 IJA decided to use the vehicle as gun tank and not as self-propelled gun, too. Direct fire should be possible now and so the armor thickness of the gun shield was increased to 41 mm and a simple notch and bead sight was added. These changes were done fast and so serial production could start in November 1943 at Hitachi parallel to the Ho-Ni I. The total production numbers are unknown but did not exceed 55 vehicles.

The produced vehicles were mainly issued to the Armored Mobile Artillery Regiments of the tank divisions. 8 Ho-Ni II were sent to Luzon with the 2nd Armored Mobile Artillery Regiment but only 6 survived the US attacks on the convoy. The unit was wiped out during the final stages of the US Luzon campaign in 1945. All other production vehicles were issued to homeland defense units. There is no known surviving vehicle.

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%202/jap%20typ%201%20ho-ni%202%20von%20hinten.jpg
rear view, note the different breech and the additional ammunition racks on the engine compartment

The vehicle had an at-power comparable to the Ho-Ni I (83 mm on 100 m/90°, 70 mm on 1000 m/90° with AP ammunition, 120 mm with HEAT ammunition) but the HE-power was superior. On the other hand the lower muzzle velocity and lower firing speed made it even harder to hit moving targets. So direct fire wasn´t really a good option. But it was a good SPG.


To be continued in part 3...

tom!
01-09-2018, 01:40 PM
Hi.

12) Gun Tanks part 3


d) Type 1 Gun Tank Ho-Ni II part 2:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%202/jap%20typ%201%20ho-ni%202%20wintereinsatz.jpg

Data:
as Type 97 Medium Tank Chi-Ha Except:

vehicles built: ca. 55
battle weight: 16,3 (metric) t
crew: 5 men
height: 2290 mm, 2390 mm at maximum elevation due to the protrusion of the armour plate on the gun Barrel (see first picture)
maximum speed: 38 km/h on roads
armament: 1 X Type 91 105 mm Howitzer in a special mount,
Ammunition capacity: 20 105 mm grenades



armor
strength


gun shield front
41 mm @ 75 °


sides
12 mm @ 90 °


rear
none°


roof
10 mm @ 0 °


superstructure front
25 mm @ 78 °


sides
25 mm @ 75 °


rear
20 mm @ 25 °


top
10 mm @ 10 °


suspension front
25 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm curved




e) Type 3 Gun Tank Ho-Ni III:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%203/jap%20typ%203%20ho-ni%203%203.jpg

During the operational tests of the Ho-Ni I the open fighting compartment and the missing direct fire optics were problematic. But these problems were accepted to get the vehicle ready for serial production. In 1943 a trial was started to remodel the Ho-Ni I to solve these problems.

The armour shields were replaced by a heptagonal construction consisting of a frontal plate, two forward side armour plates, two side armour plates (all arranged sloped) add two vertical rear armor plates. Armor strength did not exceed 25 mm, just enough against splinters and infantry AP ammunition. Visor slits with pistol ports below them were placed on both sides of the gun and in each forward side plate. A small access hatch opening upwards with a pistol port below it was in each side plate. A large access door with a small access hatch in each of the rear armor plates in combination with a pentagonal hatch in the rear top armor allowed entering the fighting compartment. A hatch with a rectangular and a crab shear type door above the gunner´s position allowed using an indirect fire sight. A simple optical sight for direct fire was also added. Another hatch was placed above the commander´s position. An additional small gun shield to protect the gun slit was placed outside of the vehicle.

Prototype tests started in early 1944 and were finished successfully fast So IJA decided to introduce this vehicle, too. Later that year after finishing the development of the Type 3 75 mm tank gun it was decided to use this gun instead of the Type 90 Field Gun which was badly needed as artillery gun. Changes were done fast and serial production started in summer 1944. Total production numbers are not known but at least 38 vehicles leaved the assembly lines. They were issued to the gun tank companies of the tank regiments of 4th Tank Division for homeland defense. All were destroyed after surrender.

http://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%203/jap%20typ%203%20ho-ni%20III%20einblick%20kampfraum%20hinten.jpghttp://www.ww2technik.de/Bilderchen/jappanzer/spg/Ho%20Ni%203/jap%20typ%203%20ho-ni%203%20von%20hinten.jpg
rear views with opened and closed rear doors

Besides the indirect fire sight the Ho-Ni III was more an assault gun comparable to a contemporary StuG III than a SPG. HE-power was limited but the armor penetration was enough to penetrate the US Medium M4. Only the height and the armor thickness were criticised. It replaced the Ho-Ni I in several gun tank companies. US Army did not know about its existence before surrender.

Data:
as Type 97 Medium Tank Chi-Ha except

vehicles built: ca. 38
battle weight: 17 (metric) t
crew: 5 men
length: 5900 mm
height: 2370 mm
maximum speed: 38 km/h on roads
Power/weight ratio: 10 hp/t
armament: 1 X Type 3 75 mm Tank Gun
Ammunition capacity: unknown



armor
strength


fighting compartment front
25 mm @ 75 °


sides
12 mm @ 75 °


rear
25 mm @ 90 °


roof
16 mm @ 0 °


superstructure front
25 mm @ 82 °


sides
25 mm @ 75 °


rear
20 mm @ 25 °


top
10 mm @ 10 °


suspension front
25 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm curved




to be continued in part 4...

tom!
01-09-2018, 02:06 PM
Hi.

12) Gun Tanks part 4


f) Type 4 Gun Tank Ho-Ro:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/ho%20ro/jap%20typ%204%20ho-ro.jpg

In 1944 IJA decided to to use everything available to increase the firepower of their armored units. One of the resulting projects was a gun tank using the obsolete Type Meiji 38 15 cm Howitzer as main armament. The basic shape was similar to the Type 1 Gun Tank Ho-Ni I but the crew protection was completely remodelled and simplified. The upper frontal armor was removed and a single 25 mm thick armor plate also serving as gun shield was mounted with a slope instead. On the (in driving direction) left of the gun a long small hatch for a simple direct fire optic was mounted. On the right a driver´s optic in the lower part and a hatch for the commander were placed. A second visor hatch for the commander was mounted on the forward side armor. The side of the crew protecting armor had a step following the upper superstructure of the tank. The top armor was as wide as the side armor and a hatch was mounted above the commander´s position. The armor was welded, the visible rivets are used for mounting interiour elements only.

The gun including the upper lafette was mounted in a trestle riveted to the gun shield. Due to the stress of the recoil forces on the structure the traverse was limited to 3° to each side. Elevation was -10° to 20 ° reducing the maximum range from 5900 to 4850 m. This was accepted in exchange for a massively increased mobility (horse-mounted the gun had to be transported in 2 loads). The heavier ammunition (35,9 kg instead of 6,56 kg for the Type 90 75 mm Field gun and 15,8 kg for the Type 91 105 mm Howitzer) made a third loader necessary. The ammuniton capacity of 16 genades and charges of the fighting compartment was increased by a large ammunition rack on the engine compartment for 12 grenades and charges.

Development and tests started in July 1944 and were finished quickly. Serial production started in late 1944 at Mitsubishi´s Maruko factory. Total production numbers are unknown but estimated between 12 and 25 vehicles only. On August 12th, 1944, the first unit (Sumi Independent Self-Propelled Gun Company) started training at Army Field Artillery School without vehicles to archieve operational status as soon as possible. This unit received four vehicles before it was sent to Luzon on December 22nd 1944. The convoy was attacked by US aircraft who destroyed two Ho-Ro on board Aoba Maru. The rest of the unit was wiped out at the end of the US Luzon campaign in 1945. One vehicle was heavily damaged by US M2 .50 MGs using AP ammunition, the other one was captured. Combat records of the japanese unit mention at least seven destroyed and several damaged US tanks during the whole campaign, at least one was destroyed at a range of just 100 m. The other production vehicles were issued to the divisional artillery of the 4th Tank Division for homeland defence.

The vehicle captured on Luzon was sent to Aberdeen Proving Ground for examination in mid 1945. It is still existing at the National Museum of the Marine Corps near Quantico Marine Corps Base but it´s not on display there. All other Ho-Ro were destroyed postwar.

http://www.ww2technik.de/Bilderchen/jappanzer/spg/ho%20ro/jap%20typ%204%20ho-ro%204.jpg
the captured vehicle after transport to Aberdeen Proving Ground

The Type 4 Gun Tank Ho-Ro was developed as heavy assault gun for direct fire. For this task it was too high and armor was too weak. The gun was able to destroy everything in the US arsenal with its HE-power. But the low muzzle velocity of 282 m/sec made it hard to hit moving targets and firing speed was slow due to the seperate ammunition. There were no special anti-tank grenades. Nevertheless the vehicles were quite effective on Luzon.

Data
as Type 97 Medium Tank Chi-Ha except

vehicles built: between 12 and 25
battle weight: 16,3 (metric) t
crew: 6 men
height: 2360 mm
Power/weight ratio: 10,4 hp/t
armament: 1 X Type Meiji 38 150 mm Howitzer
Ammunition capacity: 28 150 mm grenades and charges



armor
strength


fighting compartment front
25 mm @ 70 °


sides
20 mm @ 90 °


rear
none


roof
12 mm @ 0 °


superstructure front
25 mm @ 70 °


sides
25 mm @ 75 °


rear
20 mm @ 25 °


top
10 mm @ 10 °


suspension front
25 mm @ 42 °


sides
25 mm @ 90 °


rear
20 mm curved




g) Experimental Type 4 Gun Tank Ho-To:

http://www.ww2technik.de/Bilderchen/jappanzer/spg/jap%20exp%2012%20cm%20spg%20Ho-To.jpg
only known picture

Parallel to the development of the Type 4 Gun Tank Ho-Ro the development of a gun tank using the also obsolete Type 38 120 mm Howitzer was started, too. The vehicle was based on the Type 95 Light Tank Ha-Go. The tank was modified in a similar way. Turret and superstructure of the fighting compartment were removed. A gun shield was mouted sloped on the upper bow armor. The sides were bend to the rear. Two side plates completed the armor. It is unclear if there was a top armor but it is most likely. A driver´s visor port was mounted on the right side below the gun. The bow gunner was removed. A hatch for the a siple direct fire optic was placed on the left side next to the gun. There is no hatch or visor port for the commander on the gun shield. It is most likely that he used a periscope. In each side armor plate a small hatch opening to the rear is mounted. The rear of the fighting compartment was open. Gun and the upper lafette were mounted in a trestle riveted to the gun shield.

Armor strength is unknown but it can be assumed that it was similar to the basic vehicle (12 mm maximum) due to the weight limitations of the suspension. Gun and fighting compartment armor lead to an operational weight of 8,5 t. To cope with this higher weight production vehicles should use tracks with a width of 450 mm.

Design was not finished before February 1945 and a prototype was finished in July. First functional tests showed that the stress on the vehicle structure during firing was less than expected. There were no special AP-grenades but the development of a HEAT grenade was started in mid 1945.

Further data and fate of the prototype are unknown.

Data
as Type 95 Medium Tank Ha-Go except

Weight: 8,5 t
armament: 1 X Type Meiji 38 120 mm Howitzer


h) Experimental Type 5 Gun Tank Ho-Ru:

no picture, sorry

https://i.imgur.com/3dpKYMg.jpg

In February 1945 the decision was made to develop a light tank destroyer based on the Type 95 Light Tank Ha-Go using the Type 1 47 mm Tank Gun. The vehicle height should be as low as possible. Turret and superstructure of the fighting compartment were removed and replaced by an octogonal (some sources say hexagonal) armour. At least the forward 2/3 received a top armour. The gun was mounted slightly offset to the right replacing the bow gunner.

Prototype production started in April 1945, tests started in June.

There are several drawings and scale model kits each with massive differences. There is no evidence that any of these shows the real prototype. Armor scheme and other details are unknown.

Data:
As type 95 Light Tank Ha-Go exept

armament: 1 X Type 1 47 mm Tank Gun


Yours

tom! ;)

tom!
01-10-2018, 09:55 AM
Hi.


13) Gun Carriers part 1

Following the IJA designation system infantry and cavalry were not allowed to operate tanks or vehicle based on tanks. So those vehicles were designated "Armored vehicle", "Gun Carrier" or received a designation based on their special purpose. "Gun Carriers" were all vehicles using tank chassis or suspensions and armor independend from the armament (artillery, anti-tank or anti-aircraft gun).

During the Siberian Incident 1919-21 IJA units mounted light field artillery guns or mountain guns on trucks and prime movers to increase their mobility. These vehicles were not too effective due to the instability of the wheeled vehicles as gun platforms but they were fast and also had a psychological effect. In the mid 1920th IJA decided to start a massive mobilisation program but due to the limited ressources regarding industrial capacities, raw materials an money special gun carrying vehicles were not developed. This changed with the beginning of the China Incident in mid 1937. First projects and prototypes were not successful and due to the war production ressources became low again. In 1942 the situation changed once more. IJA decided to start a massive military program to fill the gap in tank technology. In addition the anti-tank doctrine was changed, too. Now gun carriers with large caliber anti-tank guns and self-propelled artillery guns were also in focus.

Many vehicles remained designs only, others were built as prototype but only one was adopted officially for serial production. Here I will focus only on vehicles which were buit at least as prototype.

Data on gun carriers and pictures are generally rare.


a) Experimental 3,7 cm Gun Carrier So-To:

no picture, sorry

https://i.imgur.com/vvRLwK0.png
Details do not fit 100%

After introduction of the Type 97 Tankette Te-Ke the idea came up to use this vehicle to mobilise light infantry support weapons like AA-machine cannons and the Type 94 37 mm Rapid-Fire Infantry Gun (IJA official designation for what is also known as Type 94 37 mm AT-Gun). These weapons were designed light-weight for easy and fast man-drawn transport on the battlefield. So the Type 97 Te-Ke would have been able to carry them.

Removing the turret wouldn´t have been enough to allow operating the guns on the tank. So the vehicle was lengthened by adding a fifth roadwheel which was attached to the rear idle wheel with a bogie.The driver´s armour was changed to a box shape and heightened. For close defence an armored extension with a standard MG port was added next to the driver on the (in driving direction) right side. The forward upper edges were arranged sloped. An access hatch for driver and gunner was mounted in the forward top armor. The gun platform was a little bit lower than the crew compartment to increase crew protection at the now vulnerable space below the gun shield. It is unknown if there was an access hatch on the gun platform or the rear but it is most likely. Armor strength is also unknown but did not exceed the basic vehicle armour (up to 16 mm).

On the vehicle two u-shaped profiles were mounted for the gun wheels. The rear parts could be drawn out to tow the gun on and off the vehice easily. On the vehicle the gun was fixed with clamps on the wheels and the trail.

Further details and data are unknown but at least one prototype was built.

Later the idea came up to remodel the vehicle for more crew protection. The gun should be mounted without gun shield behind an armour plate on the rear of the vehicle. This project was stopped during the design stage.

Data:
unknown


a) Experimental Anti-Aircraft Tank No. 1 Ki-To:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20exp%20flakpanzer%20Ki-To.jpg

At the same time as the 3,7 cm gun carrier a second version carrying a Type 98 20 mm Automatic Gun was developed and built as prototype. There are some differences to the So-To:

at least
- no u-shaped profiles as the gun was mounted on the vehicle operational.
- two small armor plates behind the crew compartment
- two fastening rods on the rear armor for the wheels of the gun

At least two vehicles were built and tested in 1940. The concept was found good but the crew positions were too vulnerable to enemy fire and splinters. It became clear that more armor protection was necessary

The fate of the prototypes is unknown.

Data:
unknown


c) experimental Type 2 Gun Carrier Ku-Se:

No picture, sorry

In 1944 a gun carrier using a Type 99 Tank Gun and the chassis of the Experimental Type 5 Light Tank Ke-Ho was under development. The designation indicates that the design order was already given in 1942. Most data are lost at surrender but it seems that at least one prototype was finished in summer 1945.

A 20 mm gun shield and short 12 mm side armour plates replaced the turret similar to the Ho-Ni series. The gun was installed in the gun shield with the standard mount as used with the Type 2 Gun Tank Ho-I. To increase armour penetration a HEAT grenade was developed at surrender.

In literature the vehicle is often mentioned with the short designation "Kusae" which is wrong. There is also an artist impression on the internet showing a vehicle with a chassis similar to the Type 1 Chi-He which is far from reality.

Data

unknown


d) experimental Anti-Aircraft tank No. 2 Ta-Se:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20exp%20aa%20tank%20ta-se%20single.jpg

In 1943 a new anti-aircraft tank based on the Type 98 Medium Tank was developed. There were some changes made with the vehicle:

at least
- a box-shaped armor extensions added above the tracks on each side of the fighting compartment for additional ammunition
- turret replaced by a slightly conical, circular turret with a box-shaped extension on the rear.
- main armament a Type 98 2 cm Automatic Gun
- elevation was enlarged to 90 °
- no gun shield, so a very vulnerable gun position in the turret

The prototype tests were quite successful regarding the vehicle but the vulnerable open gun position was disliked. In addition the Type 98 machine cannon wasn´t really suitable to damage or destroy enemy aircraft any more. Therefore a newly designed, more powerful 2 cm machine cannon was tested.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20exp%20aa%20tank%20ta-se%20single%202.jpg

Still the destructive power was rated too weak and so the design was cancelled.

Data:

unknown


To be continued in part 2...

tom!
01-10-2018, 10:21 AM
Hi.

13) Gun Carriers part 2


e) Experimental Anti Aircraft Tank No. 3 So-Ki:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20exp%20aa%20tank%20ta-se%20twin.jpg

After the development of the Ta-Se was cancelled a similar design using a Type 4 2 cm Twin Automatic Cannon was tested. The vehicle was changed again:

- the turret was removed.
- semi-high armor plates were wplaced around the now open fighting compartment with the side armor being able to be lowered to enlarge the crew space
- a gun shield gave protection from the front
- a large ammunition box with a bench seat above it was placed in the rear of the fighting compartment

Test showed again that the 2 cm caliber was outdated even using two barrels. As IJA officials disliked medium caliber anti-aircraft guns the whole project was cancelled.

Data:

unknown


f) Experimental Type 4 Heavy Mortar Carrier Ha-To:

http://www.ww2technik.de/Bilderchen/japari/spg/Ha-To/jap%20typ%204%20300mm%20moerser%20sfl%20Ha-To%20seite%202.jpg

In December 1942 IJA ordered the development of a gun carrier to mobilise the new muzzle loaded Type 3 30 cm Trench Mortar. This gun was developed to fire 170 kg HE-grenades with a smooth-bore barrel over short ranges (maximum range 3145 m) for massive fire support during attack or defense. Muzzle velocity was 183 m/sec. The massive gun weight of 5 t made a large carrying vehicle necessary.

So in 1943 the decision was made to use the chassis of the Experimental Heavy Crawler Truck Chi-So which used the suspension of the Type 4 Tank Chi-To. This vehicle had an armored driver cabin with a maximum armor of 12 mm. The rear 2/3 were load space.

The gun was mounted with a hinged loading crane on the rear of the vehicle. The loading mechanism was operated with a supporting hydraulic system. During moving the whole gun was lowered on the drivers cabin. Before firing it had to be erected. A circular base plate lowered to the ground below the barrel was used for stabilisation. The firing angle was fixed at 50°. Range was regulated by the size of the used propellant charge. To minimise stress on the vehicle stucture traverse was limited to 3,5° to each side. Due to the necessary preparation time a fast change of the firing position was not possible making the vehicle vulnerable for counterbattery fire.

http://www.ww2technik.de/Bilderchen/japari/spg/Ha-To/jap%20typ%204%20300mm%20moerser%20sfl%20Ha-To%20seite.jpg
firing position

The prototype was finished in late 1944. In early 1945 three more pre-production vehicles were built. At the same time IJA already used heavy 20 cm and 40 cm for the same purpose. Compared to these very simple weapons which were easy and cheap to operate from simple wooden launch platforms the mortar vehicles were expensive to produce and much more vulnerable to enemy fire. So the project was ceased. One vehicle was sent to Aberdeen Proving Ground after surrender. All were scraped.

Data:

vehicles built: 4
weight: 14,3 (metric) t
crew: 7 men
length: 6800 mm
width: 2400 mm
height: 2750 mm
ground clearance: 400 mm
engine: Mitsubishi Type 100 8-cylinder Diesel engine
power: 165 hp
maximum speed: 40 km/h on roads
armament: 1 X Type 3 300 mm Trench Mortar


g) Experimental Type 5 7,5 cm Gun Carrier Na-To:

http://www.ww2technik.de/Bilderchen/jappak/fahrzeuge/jap%20typ%205%2075%20mm%20panzerjaeger%20na-to%20rechts%20vorn.jpg

After ceasing the development of the 57 mm gun in 1942 IJA lacked a larger caliber anti-tank gun able to defeat future enemy medium and heavy tanks. Therefore the decision was made to develop a new 75 mm at-gun.

The results of the predecessor development were still present. IJA standard doctrine was that all support weapons had to be light enough to be manhandled easily. This would be impossible for a larger caliber gun. It was well known that such a gun would be very heavy (above 1000 kg) and unhandy. On the other hand too strict weight limitations also limits the possible power of the gun.

Development started on February 23rd 1942. First studies were made until April 1943 showing a vehicle-drawn standard at-gun with an estimated weight of around 1500 kg. IJA still disliked the idea of such a heavy gun. So the decision was made to develop a tank hunter similar to the german Marder-series instead for better mobility. Basic vehicle should also be the Experimental Heavy Crawler Truck Chi-So. The gun should be based on the AA-gun under development in 1943 which became Type 4 75 mm AA-Gun. Gun development started in mid 1943.

The result was a potent gun with the following data:
- length: 4230 mm
-barrel weight: 761 kg
- lafette weight: 1150 kg with a 12 mm thick, rectangular gun shield
- total weight: 1845 kg
- recoil length: 1250 mm
- recoil reaction: 3000 kg
- grenade weight: 6,6 kg
- muzzle velocity: 830 m/sec
- elevation: -8° to 19°
- traverse: 20° to each side
- penetration: as Type 5 75 mm Tank Gun

http://www.ww2technik.de/Bilderchen/jappak/fahrzeuge/jap%20na-to%2075%20mm%20gun%20%20Mark%20I.jpg
first gun prototype

The gunner sat on the (in driving direction) left side of the gun, the commander on the right side. Four loaders and the driver completed the crew.

The gun was mounted behind the driver´s cabin on a closed ammunition rack. On each remaining side of the fighting compartment 12 mm armor plates were mounted. The side armor was as high as the cabin in the forward 1/3 for better protection. A large two-door access hatch was mounted in the rear. The whole fighting compartment could be covered with a canvas.

Gun tests started in July 1944, vehicle tests in January 1945. Then IJA decided that producing a special gun for such a vehicle would be a waste of the scarce production capacities avaliable. So the gun design should be changed to allow usage of the Type 5 75 mm Tank Gun barrel and recoil mechanism. So the gun had to be remodelled. The result had the same firepower but due to the more massive recoil mechanism the gun shield had to be enlarged. The data were the same except:

- barrel weight: 840 kg
- lafette weight: 1770 kg with a 12 mm gun shield
- total weight: 2680 kg
- recoil length: 400 mm
- recoil reaction: 8400 kg

http://www.ww2technik.de/Bilderchen/jappak/fahrzeuge/jap%20typ%205%2075%20mm%20gun%20na-to%203.jpg
second gun prototype

First gun tests started in May 1945. Later that month a complete prototype tests started. These showed that the gun mount suffered from the recoil forces. Therefore it had to be reinforced which was done until July 1945. A second vehicle was finished in July, too. Both vehicles were used for crew training. Until surrender preparations for serial production were started which should have started in September.

http://www.ww2technik.de/Bilderchen/jappak/fahrzeuge/jap%20typ%205%20Na-to%20trials%202.jpg
prototype during firing tests

The fate of the prototypes is unknown.

Besides its size and the low armor strength the Na-To would have been a good tank hunter. The gun was able to penetrate even heavier vehicles on medium ranges.

Data:

vehicles built: 1
weight: 13,7 (metric) t
crew: 7 men
length: 5700 mm
width: 2400 mm
height: 2640 mm
ground clearance: 400 mm
ground preasure: 0,66 kg/cm²
trench crossing capability: 2500 mm
climbing capability: 30°
fordability: 700 mm
turning radius: 10 m
engine: Mitsubishi Type 100 8-cylinder Diesel engine
power: 165 hp
maximum speed: 40 km/h on roads
armament: 1 X Type 5 75 mm Anti-Tank Gun


Yours

tom! ;)

tom!
01-11-2018, 01:47 PM
Hi.


14) Army Amphibious Tanks:

A less known fact is that IJA was quite busy developing amphibious vehicles in the 1930th. Starting with the the Experimental Amphibious Halftrack AMP at least five different vehicles were developed and tested. As all trials were finally cancelled informations are rare.


a) Ishikawajima Amphibious Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2092%20leicht%20amphibisch.JPG

The tests with the AMP showed that such a vehicle would be useful for reconnaissance duties. So after introduction of the Type 92 Heavy Armoured Car Ishikawajima was ordered to develop an amphibious version of this tank, too. This was done until 1933. The official designation is unknown.

The vehicle used suspension, turret, engine and steering from the Type 92. The armour scheme was changed massively. The bow armament extension was removed and the driver was shifted to the center. A boat-shaped hull and large floats on the bow, sides and rear made the vehicle suitable even for heavier swell. Small propellers and rudders next to the tracks allowed manoevring in the water. Armor strength is unknown but did not exceed the basic vehicle (6 mm maximum).

Tests were quite satisfying and a small (unknown) number of pre-series vehicles was built for operational tests, too. Details are unknown but the final results lead to the decision to drop this design in favour of a special development program. The existing vehicles were later used for exercises and then scrapped.

Data

unknown


b) Experimental Amphibious Tank SR I-Go:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20exp%20amphibienpanzer%20sr%20I.jpg

After finishing the tests with the Ishikawajima Amphibious Tank IJA ordered Mitsubishi to develop a new design for such a vehicle. Requirements are unknown but it seems that a vehicle weight below 4 t was one of basic demands.

The prototype was finished in 1934. The suspension was similar to the one used on the Engineer Vehicle SS-Ki. It consisted of eight roadwheels, three return rollers, a rear driving sprocket and a frontal idle wheel. Each two pairs of roadwheels were connected by leaf springs and mounted on the hull. The hull had several seperate chambers to retain buoyancy if pentetrated by bullets or splinters. The bow was not really boat-shaped. The driver sat below a cylindrical cupola in the (in driving direction) right. A simple visor port was used. The commander/gunner operated a Type 91 6,5 mm Tank MG inside a small conical turret in the centerline of the vehicle. Both had a large two-door access hatch above their position to enter the tank. All armor plates were riveted.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20exp%20amphibienpanzer%20sr%20I%202.jpg

Afoat a small rudder below the rear allowed steering. Propulsion was generated simply by operating the tracks, there was no propeller. A large hingeable steel plate mounted on the frontal bow armor was used as splash shield.

The final weight without armament and anmmunition was just 3,7 t which indicates that the armor strength was very low. During the innitial tests the vehicle reached a maximum speed of 24 km/h on land with a 70 hp gasoline engine. The maximum speed of 9 km/h afloat could only be reached after a long acceleration periode. This propulsion was rated too weak. In addition the small rudder made steering problematic. Armament and armor were also rated too weak. So this design was dropped.

The prototype was used during exercises and was last seen on a parade in China in summer 1938. After development of its successor the numbering suffix "I-Go" = "Version 1" was added to the vehicle designation. Short designation became SR-I with SR = "Suiriku-Ryoyo sencha" = "Amphibious Tank"

Data:

vehicles built: 1
weight: 3,7 (metric) t
crew: 2 men
length: 4950 mm
width: 2400 mm
height: 1650 mm
engine: Mitsubishi 4-cylinder gasoline engine
power: 70 hp
maximum speed: 24 km/h on roads, 9km/h afloat
armament: 1 X Type 91 6,5 mm Tank MG


c) Experimental Amphibious Tank SR Ro-Go:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20SR2%20amphibenfahrzeug%203.jpg

The problems with the SR-I led to the decision to start a new trial in late 1934. This time Ishikawajima was in charge of development again. Now weight should be up to 7 t, maximum armor strength 10 mm. A second MG should increase firepower.

The prototype was finished in mid 1935. It had a completely new Horstmann-type suspension consisting of three roadwheels, one return roller, a frontal driving sprocket and a rear idle wheel. The two forward roadwheels were connected by a small coil spring and a bogie. The rear roadwheel was connected the same way with the idle wheel. The roaswheel was placed between the second and third roadwheel. The bow was now boat-shaped increasing acceleration afloat. An armor plate integrated in the middle of the bow armor could be raised as splash shield.

On the bow and each side several flotation chambers were mounted. These were designed flatter to lower the silhouette. The driver now had a rectangular cupola with visor ports on the front and right side. He entered the vehicle through a large rectangular hatch above his position. On his left side the bow gunner was placed below a slightly larger rectangular cupola. A cap on his hatch increased his firing angle. He operated a Type 91 6,5 mm Tank MG in a standard mount. A closable visor port was placed in the left side next to the gunner.

The turret had an octogonal basic shape with sloped sides. A standard MG mount for a Type 91 6,5 mm Tank MG was mounted in the frontal plate. Closable visor ports were placed in each forward side and side armor plate and in the rear. The commander/gunner entered the tank through a large access hatch with a big cap. A grid construction behind the turret simplified access to the vehicle afloat.

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20SR2%20amphibenfahrzeug%204.jpg

The engine was placed lengthwise in the rear. Exhaust pipes lead from the rear to a muffler and raised tail pipes behind the turret on each side. Two 500 mm propellers with rudders were attached to the rear.

The vehicle was designated "SR Ro-Go" = Amphibious Tank Version 2, short designation SR-II. During innitial tests the vehicle showed a good mobility on land and afloat. A small pre-production series was finished until late 1935. Operational tests were successful but the armament was rated too weak. Nevertheless the concept was rated good.

The fate of the vehicles is unknown. At least one was captured 1945 by soviet units in Manchuria. There is no known survivor.

vehicles built: 1
weight: 6,9 (metric) t
crew: 3 men
length: 4100 mm
width: 1800 mm
height: 1600 mm
engine: gasoline engine
armament: 2 X Type 91 6,5 mm Tank MG


d) Experimental Amphibious Tank SR Ha-Go:

https://forum.axishistory.com/download/file.php?id=359298&t=1

In late 1935 Mitsubishi was ordered to remodel the SR-II design. Goal was to increase firepower and armor. Only limit was a maximum weight of 7,5 t.

The basic shape reminds of a Vickers Light Amphibious Tank. One was captured in China and it seems that many design features were copied. To get a stable gun platform afloat the flotation chambers were enlarged to the sides and front. Welding was used instead of rivets as far as possible to spare weight. The maximum armor was increased to 13 mm. The turret was similar to the Type 94 tk turret. A prototype was built until mid 1937 designated "Amphibious Tank Version 3", short Designation "SR-III" or "SR Ha-Go".

Trials to mount a Type 94 37 mm Tank Gun lead to a maximum weight above 7,5 t. This was also rejected as the proposals to mount a Type 92 13,2 mm Tank Machine Cannon or to lower the armor strength to reach 7,5 t. Both guns would have needed a larger turret. Mitsubishi saw no chance to archive the expected result with the weight limit. In addition there was a lack of ressources regarding production capacities, raw materials and money. So IJA decided to cancel the whole project in 1938. The development results were handed over to IJN.

The prototype was sent to Rabaul in 1942 or 1943 for further tests and transport purposes. The remains are on display at Kokopo Museum, Rabaul.

vehicles built: 1
weight: 7,5 (metric) t
crew: 2 men
length: 4100 mm
width: 2000 mm
height: 1800 mm
engine: gasoline engine
armament: 1 X Type 91 6,5 mm Tank MG


Yours

tom!

tom!
01-13-2018, 11:05 AM
Hi.

15) Engineer AFV part 1

Since the early 1930th a number of special vehicles for different tasks were developed and built. Among these a few were used by IJA engineers. These included chargelayers, obstacle removing and mineclearing tanks. The remote controlled vehicles are subject of a later post.


a) Armored Working Vehicle SS:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20ss-ki%20bo%20auf%20bruecke.jpg

During the late 1920th the Soviet Union was rated the biggest danger for the japanese plans in East Asia. So with the new development and mobilization plan from 1929 a specialized engineer vehicle able to destroy bunkers and roadblocks should be developed. Design started in 1930 at 2nd Army Technical Bureau based on the technologies gathered during the development of the Experimental Tank No. 2 and the early design stages of the Type 89 Medium Tank. Because of the problematic financial situation instead of just two tasks the vehicle should be able to fulfill several:
- bridge laying
- mine clearing
- obstacle removing
- gas and decontamination agent scattering
- charge laying
- crane operating
- trench digging
- smoke laying
- flame oil throwing

Therefore a versatile and mobile vehicle with several modules for the different tasks was developed. The suspension was similar to the Type 89 Medium Tank with two sets of two pairs of small, bogie connected roadwheels sprung by large packs of leaf springs each. A large driving wheel was at the bow, a large idle wheel in the rear. Four return rollers completed the suspension. The armor was between 6 and 25 mm thick. The frontal armor had a sloped center part, a vertical lower part and an almost vertical upper part. On the left side of the upper armor a large mount for a Type 93 Flamethrower was added. The driver´s visor hatch on the right was openable to the top. The side armor was vertical with the upper part arranged sloped. Diagonal armor plates connected the sides with the bow and rear armor. The rear armor was vertical. A hemispherical commander’s cupola was mounted centered on the forward top armor. The suspension was covered by 6 mm trapezoid armor plates . A large, two-part access hatch in the top armor allowed engine change. The rear engine compartment was accessible from the forward fighting compartment, too. A 105 hp gasoline engine was used which should be replaced by a Diesel engine as soon as possible.

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20ss-ki%20hei%20bug%20sprengladung.jpg
Version Hei with explosive charge mounted on the bow

There were several attachment points on the bow, top and rear. On the bow mine forks plus an obstacle clearing wedge or a 300 kg explosive charge could be added. On the top a crane, smoke agent canisters and/or two different types of bridges (7 m and 10 m scissor type) could be carried. On the rear a fluid tank for chemical agents or flame oil or a large trench plough could be attached. The chemical agents could be dispersed by a spray nozzle attachable inside the flame thrower mount. The vehicle was able to fulfill all demanded tasks but not at the same time as some modules couldn´t be used parallel.

First operational tests started in 1933. In 1934 two vehicles were send to China to be tested at 1st Mobile Brigade. Due to the available space inside the vehicle the new Type 94 Model 4 radio set was added in 1935. Several necessary changes and a low priority delayed official introduction until 1936. As this vehicle was developed for engineer units which were not allowed to operate “tanks” the designation “Soko Sagyosha” = “Armored Working Vehicle” was chosen, short designation “SS”.

There were five versions during the years:

Version Kou(A) = A:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20ss-ki%20zug.jpg

Basic production version with a 140 hp gasoline engine. 13 were built.


Version Otsu = B

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20ss-ki%20otsu.jpg

Version Otsu had a modified suspension with one return roller removed, and modified Driving and idle wheels. The vehicle seemed to be specialised to flame throwing. Four small, armored flame oil tanks were mounted fixed between the suspension parts. Due to the tanks the suspension armor could not be used any more. A concrete made flame oil tank was added to the rear. An additional flame thrower mount was implemented in the remodeled forward side armor. In addition the bow armor was remodeled similar to the Type 89 tank with a sloped lower part and a vertical upper part.
The commander´s cupola was now quadratic with sloped sides and a two-part hatch on top. 8 vehicles were built


Version Hei = C

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20ss-ki%20hei%20early.jpg

Version C was a remodeled Version A. The suspension also had three return rollers and modified driving and idle wheels but the flame oil tanks were not used. The suspension armor consisted of several welded armor plates instead of a harder to produce single plate. The two additional flamethrower mounts were placed in the forward side armor. The commander´s cupola was hemispherical again. The now used Mitsubishi I6 Diesel engine with 145 hp at 1800 rpm allowed a maximum speed of 37 km/h. 1 vehicle was built


Version Tei = D

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20ss%20pionierpanzer%20version%20tei%20r echts.jpg

Version D was a remodeled version B. Driving wheels and idle wheels were modified again to spare weight. The shape of the driver´s hatch and the bow flamethrower port were modified and a standard MG mount for a Type 97 7,7 mm MG was added between them for better close defense. The Type 93 flamethrowers were later replaced by the lighter Type 100 Flamethrowers. The commander´s cupola was now conical. And the Diesel engine was used. 20 vehicles were built.


Version Bo = E

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20ss-ki%20bo%20bruecke%203.jpg

Modified version D. The suspension was simplified by removing another return roller and the armor plate wasn´t used any more but suspension side armor was increased to 13 mm. The commander´s cupola was now cylindrical. Armament consisted of three standard infantry Type 100 Flamethrowers and a Type 97 7,7 mm MG. 77 vehicles were built.


The need to exchange the modules for different tasks finally leads to the decision to develop special purpose-built vehicles as replacement around 1940. None of these developments was introduced. They will be covered in a different post. Several Independent Engineer units and after 1942 especially the tank division engineers were equipped with the SS.

Data:

vehicles built: 119
weight: Kou(a) 9,6 (metric) t , Otsu 9,8 t, Bo 13 t
crew: 5 men
length: 4865 mm
width: 2520 mm
height: 1800 mm
armor: 6 – 25 mm
engine: Kou(A) 120 hp gasoline, Hei 145 hp Diesel
maximum speed: 37 km/h on roads
armament: 1 – 3 X Type 93, later Type 100 Flamethrower; 1 X Type 97 7,7 mm MG for Hei and Bo


to becontinued in part 2...

tom!
01-14-2018, 05:35 AM
Hi.

15) Engineer AFV part 2


b) Type 95 Crane Vehicle Ri-Ki

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2095%20pionierpanzer%20ri-ki.jpg

Informations on this vehicle are also rare. In 1935 the decision was made to develop a special crane vehicle for heavy engineer duties. The suspension was similar to the Type 97 Medium Tank Chi-Ni with four pairs of small roadwheels. The engine was placed left of the driver in the armored driver´s cabin. On the rear a medium size, 3t boom crane with a 4,5 m jib was mounted turnable. Crew consisted of driver, commander and crane operator.

Data:

weight: 7800 kg
crew: 3 men
length: 5620 mm
width: 2000 mm
height: 2280 mm
armor: 6 mm
engine: 60 hp gasoline
maximum speed: 32 km/h on roads


c) High Voltage Dynamo Vehicle Ka-Ha:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20high%20voltage%20dynamo%20vehicle%20ka-ha.jpg

In late 1938 a special vehicle for the destruction of enemy wire based communication equipment was developed. It was based on the Type 97 Medium Tank Chi-Ha. The superstructure was heightened to allow mounting a generator and a 10.000 V alternating current dynamo inside. The bow MG was removed and the driver sat in centerline. A small turret with a dummy gun and a hatch was added to keep the outer shape of a regular tank.

The vehicle was driven to a telephone or telegraph cable and earthed. Then the current was sent into the cable destroying attached equipment and killing users in up to an unknown maximum distance.

A total of 4 vehicles were built and used by the 27th Independent Engineer Regiment in China.

Data:

unknown


d) Type 4 Generator Vehicle:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20Type%204%20generator%20vehicle%20prototype.j pg

In 1944 a special generator tank was developed and built, based on the Type 2 Light Tank Ke-To. Main purpose was to deliver power for larger electric machinery like pumps, saws and jackhammers. A large 30 kW generator driven by the vehicle´s engine was mounted inside the fighting compartment. A small cylindrical turret with an extension for a standard MG mount replaced the original turret. A medium sized spotlight was mounted on the rectangular turret hatch. A small crane was placed on the rear of the turret.

25 vehicles were built and tested in 1944/45. None was issued to operational units until surrender

Data:

unknown


Yours

tom! ;)

tom!
01-15-2018, 10:03 AM
Hi.

16) Railroad AFV part 1

After taking over northeastern China in the late 1920th IJA developed and used several AFV for railway security and repair purposes. Most of these vehicles had more or less complex dual suspensions for road and railroad usage. As IJA High command didn’t wanted to have tanks outside tank units it was not allowed to mount a fixed armament and possible armor strength was limited. Additionally the designation was again just “vehicle” .

There were also armored trains and handcars used by railway regiments and a single railway gun used by a railway artillery unit.


a) Sumida Type RSW Railroad Vehicle.

http://www.ww2technik.de/Bilderchen/japbahnkampfmittel/jap%20Sumida%20RSW%20railroad%20car.jpg

In the late 1920th IJA ordered Ishikawajima´s Sumida factory to develop a special armored car for railway use. Main purposes should be guard duty, transport, towing of small wagons and armored reconnaissance. The development started under the internal designation RSW using an own 4X2 truck chassis.

The armor consisted of 6 mm face-hardened steel plates riveted to a frame. The armor was mainly arranged vertical with only the upper engine cowling and the driver cabin´s frontal armor arranged sloped. A large cylindrical rotating turret was mounted on the top. There was no fixed armament installed but it was possible to mount the standard light MGs issued to the railway regiments. The MGs could be mounted in several MG ports on each side of the vehicle and the turret.

The suspension was powered by standard gasoline truck engine and transmission. Due to its limited power the heavy vehicle was underpowered and there was just one reverse gear limiting the reverse speed. Road usage was not possible limiting the operational possibilities.

At least one vehicle was produced and tested 1929 in Manchuria. There was no serial production. The whole concept was rated useful even with its several design problems.

Data:

unknown


b) Type 90 Railroad Vehicle:

no picture, sorry

After testing the RSW Railroad Vehicle the decision was made to use a larger 6X4 truck chassis as basis for such a vehicle. Sumida used its Type P Truck to develop a new railway vehicle with better performance. Internal factory designation was “Type PA”.

The prototype was similar to the parallel developed Type P Armored Car but it had no rubber rings on the steel wheels making road usage still impossible. The more powerful engine allowed a maximum speed of 40 km/h forward but due to the single reverse gear reverse speed was still low. A coupling on bow and rear allowed connecting railway cars to the vehicle.

The vehicle was rated superior to the RSW and so the official introduction followed 1930 as “Type 90 Railroad Vehicle”. Production number is unknown.

Data:

unknown


c) Type 91 Broad Gauge Railway Vehicle:

http://www.ww2technik.de/Bilderchen/japbahnkampfmittel/Typ%2091%20panzerwagen/jap%20typ%2091%20Strasse%20Schiene%20Panzerwagen%2 0details.jpg

Updated version of the Type 90 Railway Vehicle. Main changes were an enlarged fighting compartment and special rubber tires for road usage. To change from railway to road and vice versa the vehicle was lifted by two large hydraulic jacks on bow and rear. Then the steel tires for railways were exchanged by the rubber tires for roads or reversely. The wheels could be mounted with spacers if necessary. With them it was possible to use the vehicle on standard gauge and broad gauge railroads.

The transmission still had only 5 forward and one reverse gear making it slow driving backwards. So most of the time the vehicles were used in pairs connected with their rear couplings. That way there was always one driving forward.

Again no fixed armament was mounted but it was possible to use standard infantry MGs through several ports around the armored body. Armor strength was only 6 mm making it hard even to defeat infantry ball ammunition on shorter ranges. Total weight with a 6-cylinder gasoline engine was 7700 kg.

http://www.ww2technik.de/Bilderchen/japbahnkampfmittel/Typ%2091%20panzerwagen/jap%20typ%2091%20strasseschiene%20panzerwagen%205. jpg

Production started 1932 at Ishikawajima´s Sumida factory. A total of around 1000 vehicles were built. They were issued to Railway Regiments bound for continental services and garrison units of the South Manchurian Railway Company. Main usages were armed transport, guard duties and railway repairs. During the 2nd Sino-Japanese War some vehicles were also used for armed reconnaissance on railways.

Data:

vehicles built: ca. 1000
weight: 7700 kg
crew: 4 men + 2 passengers
length: 6580 mm
width: 1900 mm
height: 2950 mm
armor: 6 mm
engine: 75 hp gasoline
maximum speed: 65 km/h on roads 40 km/h on railroads
armament: none, infantry MGs could be mounted in several gun ports around the body


to be continued in part 2...

tom!
01-15-2018, 02:46 PM
Hi.

16) Railroad AFV part 2


d) Type 95 Armored Railway Vehicle So-Ki

http://www.ww2technik.de/Bilderchen/japbahnkampfmittel/typ%2095%20panzerwagen%20so-ki/jap%20typ%2095%20eisenbahnpionierpanzerwagen%20so-Ki%203.jpg

In 1934 a special vehicle for railway engineers was ordered for the South Manchurian Railway Company. It should be able to use narrow, standard and broad gauge railroads. To increase cross-country abilities a tracked suspension should be used off the railroads. The change between the suspensions should be done easily and quick. For better crew protection the armor should be up to 8 mm thick. Tokyo Gas and Electric (TGE) was ordered to develop the vehicle.

The resulting proposal was a tankettes-style vehicle similar to the Type 94 tk Special Tractor but larger. The tracked suspension was a TGE development from the early 1930th. It was similar to the Armored Working Vehicle SS and consisted of two sets of two pairs of roadwheels. Each pair was connected by a bogie and each two pairs were connected to a large leaf spring package. Forward driving wheels and rear idle wheels were used as well as three return rollers. The railroad suspension consisted of four steel wheels on two axles mounted inside the vehicle. Steel plates covered the moving parts. The gauge could be easily adjusted by pushing the wheels along the axles to special fixing points. Then the whole construction was lowered to the tracks through holes in the lower armor by a hydraulic system able to lift the whole vehicle. Changing to railroad suspension took 3 minutes, to ground suspension 1 minute.

http://www.ww2technik.de/Bilderchen/japbahnkampfmittel/typ%2095%20panzerwagen%20so-ki/jap%20typ%2095%20eisenbahnpionierpanzerwagen%20so-Ki%20zugang%20bahnantrieb%20von%20innen.jpg

The armor scheme was similar to the Type 94 tk but without the armor extension on the bow and the driver´s visor port integrated in the upper superstructure armor. A small slightly conical turret with a gun port in the front side was mounted centered on the fighting compartment. There was no fixed armament but a standard infantry MG could be mounted.

In early production a TGE DB51B 6-cylinder gasoline engine was used. Later it was changed to an Isuzu DA6 6-cylinder Diesel engine with 84 hp, allowing a maximum speed of 72 km/h on railroads

Main purpose of the vehicle was armored transport of men and material to damaged tracks. Two couplings on the front and the rear allowed towing of light wagons or the Type 91 Railway Vehicle. A total of 121 So-Ki were produced by TGE and Mitsubishi. One vehicle remained at the Kubinka Museum near Moscow and another one in a museum in Beijing.

Data:

vehicles built: 121
weight: 9800 kg
crew: 6 men
length: 4900 mm
width: 2560 mm
height: 2540 mm on railroads, 2430 mm on the ground
armor: 4 - 8mm
engine: gasoline, later 84 hp Diesel
range: 250 km on roads, 123 km on railroads
maximum speed: 72 km/h on railroads, 40 km/h towing, 30 km/h on roads, 20 km/h offroad
armament: none, infantry MGs could be mounted in several gun ports around the body


e) Type 95 Railway Crane Vehicle

http://www.ww2technik.de/Bilderchen/japbahnkampfmittel/eisenbahnkranfahrzeug/jap%20eisenbahnkranfahrzeug%204.jpg

This vehicle is not well known and informations are rare. After developing the Type 95 So-Ki TGE was ordered to develop a special lightly armored crane vehicle using the same railroad suspension. This time the suspension of the type 89 Medium Tank was used for ground travelling. A lightly armored superstructure was added with a semi-open driver´s cabin in front and the engine in the rear. On the center of the vehicle a 5 t boom crane for railway repairs and recovering of trains was mounted. Production data are unknown.

Data:

unknown


Yours

tom! ;)

tom!
01-16-2018, 11:11 AM
Hi.

17) Remote Controlled Vehicles


a) Nagayama Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20nagayama%20tank.jpg

In 1929 engineer corps Major Nagayama suggested to use unmanned, radio-controlled vehicles for dangerous tasks like mine clearing and charge laying. Until early 1930 a Fordson Model F tracked prime mover was reworked as lightly armoured vehicle. The tractor was covered with face-hardened armour plates able to defeat infantry AP ammunition. The 20 hp gasoline engine was placed in the center. The steering mechanism was placed in the forward part. On the rear a payload container e. g. for ammunition or an explosive charge could be mounted.

The radio equipment was mounted in a superstructure in the center of the vehicle. The control orders were transmitted by a modified infantry radio powered by lead accumulators. Two antennas on the superstructure received and transmitted data. Further details are unknown.

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20nagayama%20tank%202.jpg
control equipment, note the large number of accumulators

In late February 1930 a public demonstration was made at Tokyo Army Arsenal. The tank was a sensation in european and US newspapers. The development was discontinued most likely due to the limited mobility of the suspension but the basic idea was rated useful. The fate of the prototype is unknown.

Data:
unknown


b) Remote-Controlled Type 94 Special Tractor TK

no picture, sorry

After the tests and trials with the Nagayama Tank were finished in the early 1930th the decision was made to continue development using a Type 94 Special Tractor in 1935. The conversion of the prototype was done fast and first tests were successful. So the decision was made to convert at least a second vehicle for operational tests. Further data are unknown. In 1936 the vehicles were reconverted to the standard configuration. The concept of a radio-controlled vehicle was also abandoned in favor of remote-controlled vehicles using electrical commands transmitted by cables.

Data:
unknown


c) Type 98 Miniature Engineer Vehicle Ya-I-Go

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2098%20ya-i-go.jpg

In 1932 Scientific Research Section No. 1 of Army Technical Bureau proposed the development of a remote-controlled tracked vehicle to fight enemy pillboxes and fortifications by laying explosive charges. Control orders should be send to the vehicle through a multipolar cable. The charge should be jettisoned close to the target. Then a 30 second delay was started firing the charge. During the delay time the vehicle and the command tank should leave the blast radius. The Type 89 Medium Tank should be used as basis for the carrier and the command tank. The first design did not reach the prototype stage due to mechanical and electrical problems.

In 1933 the concept was still rated good and a second development program was started on a wider base. But instead of a large tank a small electrically powered tracked vehicle should be developed. Works started in late 1933. The vehicle frame was made out of a light-weight but very stable Aluminium-Silicon alloy. Suspension consisted of two pairs of small roadwheels, a fifth raised forward roadwheel to increase cross-country maneuverability, a forward idle wheel, a rear driving sprocket and two return rollers. Tracks with 87 links were used. Two watertight 600 V electrical engines delivering 1 hp each were placed in the rear half inside the frame. Each engine powered one of the tracks. The control/power cable reached the vehicle from the rear. A barrel with a cone on its end was mounted on the vehicle as strain relief. On the bow was a metal box for the explosive charge. The cable had 13 wires, two for power supply and 11 for control commands. It was covered by a layer of rubber and hamp fabric. For an easier transport cable segments of 250 m length were used which could be connected. Maximum allowed length of a connected cable was 500 m on even ground. Cross-country only one cable segment should be used. The total height was just 460 mm, length 1425 mm. With a 35 kg charge the total weight was below 200 kg. On roads up to 18 km/h were reached, 4 km/h cross-country.

During first tests in 1935 the vehicle worked very well. Nevertheless several changes were done. The cable was additionally surrounded by a dense wire mesh for additional stability and protection against splinters. This allowed to use cables with up to four segments increasing the maximum range to 1000 m. Cross-country the range should not exceed 750 m. The charge was rated too weak against pillboxes. So a charge of 40 kg using stronger explosives was developed. The metal box on the bow was removed and the charge was mounted directly on the bow. In addition a Bangalore-type charge with a length of 1075 mm and a 2,7 kg charge was developed to be used against wire entanglements and obstacles. Additional mounts for smoke canisters were added on the vehicle. This vehicle was introduced in 1937 under the designation "Type 97 Miniature Engineer Vehicle" and received the short designation "I-Go"

The 40 kg charge was still too weak against thicker bunker walls. So the decision was made to develop a larger version, too. It used the similar basic scheme but the roadwheels were bigger. In addition two 2 hp engines were used to cope with the total weight of 400 kg. A charge of up to 300 kg could be carried. An improved Bangalore-type charge with a length of 1151 mm and a 3,2 kg charge was introduced, too. In addition low-power shaped-charge warheads for these charges with a penetration of 30 mm steel and 110 mm concrete were also developed. This vehicle was introduced in 1938. The official designation of both vehicles was changed to "Type 98 Mini Engineer Vehicle", short designation became "Ya-I-Go". The small vehicle received the additional designation "Version Kou(A)", the bigger one "Version Otsu".

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20miniengineering-yigo%20sprengladungstraeger.jpg
rear view, the upright stick on the rear is the body of a Bangalore charge.

The first unit using this vehicles was raised in early 1939 and stationed in Manchuria. A squad consisted of 12 men which operated a vehicle, a second was held in reserve. Besides the charge layers equipment consisted of a generator vehicle based on the Type 94 6-wheel Truck and several standard Type 94 Trucks for vehicle and equipment transport. For version Otsu a special armour shield made of 5 mm face-hardened steel was introduced to allow carrying a human observer under protection. An auxiliary generator vehicle based on version Otsu for heavy terrain was developed, too. This was replaced in 1943 by a generator vehicle based on the Type 98 Transport Tank So-Da. A standard attack was done by three squads. The first blows wire entanglements with the version Ko, the second destroyed obstacles with the version Ko and the third finally destroyed the bunker with a version Otsu. Standard starting position was between 200 m and 500 m away from the target. During exercises ranges up to 1500 m in easy terrain were reached. Larger ranges caused a current drop due to the cable resistance stopping the engines.

In 1940 the units stationed in Manchuria were combined to 27th Independent Engineer Regiment. The nominal strength was around 2000 men operating 108 chargelayers of both versions. The rest of the 300 production vehicles was stored in Japan for homeland defense. In April 1945 27th Independent Engineer Regiment was relocated to Honshu for the expected homeland decisive battle. At surrender the unit sunk their vehicles in rivers and lakes. The others were destroyed, too. There is no known survivor.

There were also versions tested for attacks on targets in the water and with larger charges towed behind the vehicle. None was introduced.

Data (Ko/Otsu)

vehicles built: 300
battle weight: 200 kg / 400 kg
crew: unmanned, one person could be carried with version Otsu
length: 1425 mm / 1980 mm
width: 635 mm / 1170 mm
height: 460 mm / 560 mm
trench crossing capability: 850 mm / 1100 mm
climbing capability: 40° / 30°
engine: 2 X 600 V electrical
power: 1 hp at 2000 rpm /2 hp at 2000 rpm
maximum speed: 18 km/h on roads, 4 km/h cross-country
range: 1500 m on roads, 1000 m cross-country
armament: 1 x 40 kg charge or Bangalore torpedo with 2,7 - 3,2 kg explosive / 1 X up to 300 kg Charge


Yours

tom! ;)

tom!
01-19-2018, 11:46 AM
Hi.

18) Other Special Purpose AFV


a) Type 97 Armored Cable Layer:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20kabelleger%20details%20vorn.jpg

Special version of the late production Type 94 Special Tractor for communication units. The bow armor was heightened but still had the armor extension above the gearbox. The driver sat behind a windshield in an open driver´s and engine compartment with the engine placed on the left. Two hinged armored caps were added for protection against rain or snow.

The rear half of the vehicle was a large storage with components to unwind cable reels. The cable could be unwinded to the rear or redirected to the a small support sustainer on the right bow holding the cable up and so making cable attaching to poles easier. Storages were added for several cable reels. The whole storage could be covered with a canvas.

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20kabelleger%20details%20hinten.jpg

The total production numbers are unknown but low.

Data:

unknown


b) Type 97 Armored Pole Planter:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20armoredpoleplanter.jpg

Another special version of the late production Type 94 Special Tractor for communication units. It had the same bow as the cable layer and a similar driver´s compartment. But it was covered by a fixed armor plate. The rear storage compartment was covered by a steel roof and had side armor. A collapsible ladder could be erected on the roof to reach the top of higher poles. On each side of the vehicle two pairs of mounts were welded to the driver´s compartment and the rear roof trestle to carry a total of six wooden poles.

On the storage compartment a large earth drill was mounted. The vehicle drilled a hole in the ground, a pole was placed inside it and a cable was attached to the pole. Pole planter and cable layer should work as pairs.

The total production number is unknown but low.

Data:

unknown


c) Type 97 Recovery Vehicle Se-Ri:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20se-ri%202.jpg

Special recovery vehicle based on the Type 97 Medium Tank Chi-Ha. The basic vehicle was identical. The turret was replaced by a smaller conical turret with a round hatch and a standard MG mount in the front. On the rear armor a 2,5 t crane was mounted to tow other vehicles . On the side armor and on the rear storages for additional equipment were placed. A total of 3 Se-Ri were built and used by vehicle test facilities.

Data:

as Type 97 Chi-Ha except
height: 2210 mm
armament : 2 X Type 97 7,7 mm MG


d) Type 97 Command Tank Shi-Ki:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20command%20tank%20shi-ki.jpg

Special command tank based on the Type 97 Medium Tank Chi-Ha. The suspension was identical. The upper bow armor was flat instead of slightly curved. The bow MG was replaced by a Type 98 37 mm Tank Gun mount making a slightly higher superstructure necessary. The turret was replaced by one without a tank gun. Only the rear MG remained but in 180° position. Instead of a gun a small table and additional observation devices were mounted. The commander´s cupola was centered and shifted to the front of the turret .

Production numbers are unknown but low. It is unknown if it was planned to equip each regimental command section with such a vehicle. Only Chiba Tank School used it for unit training.

Data:

as Type 97 Chi-Ha except
armament: 1 X Type 98 37 mm Tank Gun in the Bow, 1 X Type 97 7,7 mm MG in the rear turret


e) Type 100 Artillery Observation Vehicle Te-Re:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%20100%20te-re%20front.jpg

Special observation vehicle based on the Type 97 Tankette Te-Ke. The suspension was identical. The engine was shifted to the right front next to the driver. The fighting compartment was enlarged to the rear and the sides. The commander sat behind the driver under a rectangular conical cupola. On his right side a 0,75 m rangefinder could be mounted on the engine compartment. Crew consisted of up to 8 men: driver, commander, rangefinder operator, protractor operator, observer and 1 – 3 radio operators.

Each mobile artillery battery should receive such a vehicle but only few were built and issued to homeland defence units.

Data:

weight: 4,9 t
crew: 6-8 men
length: 4070 mm
width: 1990 mm
height: 1900 mm
armor strength: 6 mm
engine: 6-cylinder Diesel engine
power: 65 hp at 2300 rpm
maximum speed: 40 km/h on roads
armament: none


f) Armored Lumberjack Ho-K:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20armoured%20lumberjack%20ho-k.jpg

Special construction vehicle based on the Type 1 Medium Tank Chi-He. The basic vehicle was identical. The turret was replaced and the upper superstructure heightened. A large triangular cutting wedge was mounted on the bow. Main purpose was to cut paths through dense woods under enemy fire. The first production vehicles were issued to 12th Independent Engineer Regiment in Manchuria but later the vehicles were sent to the other theatres as airfield and road construction vehicles.

A total of 40 vehicles were built.

Data:

vehicles built: 40
weight: 15 t
crew: 5 men
length: 7580 mm with nose
width: 2700 mm
height: 1800 mm
engine: Mitsubishi 6-cylinder Diesel engine
power: 240 hp at 2000 rpm
maximum speed: 39 km/h on roads
armament: none


g) Lumber Sweeper Basso-Ki:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20exp%20roder.jpg

Special construction vehicle based on an experimental prime mover. The suspension was similar to the Type 97 Chi-Ha but had only five roadwheels with the rear one mounted separate. In the bow a Diesel engine was placed. On the lightly armored engine compartment two small cranes were mounted to carry chopped trees. Behind the engine the driver´s compartment was placed. The rear half of the vehicle consisted of a storage compartment for tree chopping and removing equipment including a powered chainsaw.

Total production number is unknown. The Vehicle should work as team with the Armored Lumberjack Ho-K.

Data:

unknown


Yours

tom! ;)

tom!
01-21-2018, 11:37 PM
Hi.

19) Experimental Engineer AFV

The following engineer vehicles are less known and most data is lost.


a) Experimental Charge Layer:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20exp%20ladungsleger.jpg

A Type 97 Chi-Ha was tested with a retractable massive crane structure mounted on the front of a modified turret. On the forward end of the crane a small charge was placed. Then the crane was extended several meters to place the charge directly inside a bunker through an embrasure. The crane was retracted and the charge exploded destroying the interior. The whole concept only works with larger embrasures like for a gun etc. But this would have exposed the tank to counter fire. The vehicle was not introduced.

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20exp%20ladungsleger%20einsatz.jpg

Data:

unknown


b) Experimental Obstacle Clearer:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20exp%20drahthindernisraeumpanzer%20einsatz.jp g

Another trial was to use a Type 97 Chi-Ha as special wire obstacle clearing tank. The turret was replaced by a long turnable firing device for four long Bangalore torpedoes. The vehicle drove near the obstacle and fired a charge at it using a spring mechanism on the rear end of the firing device. Again the vehicle was exposed to covering fire as the range was limited. It was not introduced.

Data:

unknown


c) Experimental Minesweeper G:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20typ%2097%20chi-ha%20mit%20chi-yu%20mineplower%20seite.jpg

A Type 97 Chi-Ha was equipped with an experimental mine clearing device designated Chi-Yu consisting of two flail drums, three girders and a bow mounted lifting device operated hydraulically. The drums where placed in front of the tracks and rotated driven by the driving wheels exploding the mines below it.

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20type%2097%20Chi-Yu%20mine%20plow%20front.jpg

Data:

Unknown


d) Experimental Minesweeper GS:

no picture, sorry

http://gunsight.jp/c/image2/Type97Mtank-gs.jpg

Another special purpose vehicle based on the Type 97 Chi-Ha. Development started in 1943. Main turret armament and antenna were removed. It is not sure if the gun or the MG, but one of them was replaced by a spigot type launcher for a small explosive charge against obstacles. On the rear armor a rocket thrower with eight rocket launchers in two rows was mounted angled. Small boxes with explosive ropes were placed below the wire made launching tubes. After firing a rocket the attached rope fell over the minefield and detonated exploding all mines next to it. There are reports of two prototypes tested.

Data:

unknown


e) Experimental Trench Excavator:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20typ%2097%20based%20trench%20excavator%20seit e.jpg

Experimental vehicle based on the Type 97 Chi-Ha. The tank was heavily modified. The last road wheel was removed and the idle wheel lowered to the ground to increase track ground contact. The superstructure was replaced by a shorter fighting compartment without bow MG or driver´s extension. A small conical turret with a standard MG mount was placed offset to the left on the new superstructure. Due to a smaller engine the engine compartment was smaller. On the rear a massive construction for a trench plough was added to cope with the forces while trench digging.

At least one prototype was tested in Manchuria and later sent to Wewak where it was found sunk into the sand of a beach. The further fate is unknown

Data:

Unknown


f) Experimental Bridge Laying Vehicle TG:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20brueckenleger%20t-g.jpg

Special purpose vehicle based on the Type 1 Chi-He. The turret was removed. Instead a bridge laying device for a 1850 kg 9 m bridge was added on the vehicle. The bridge was layed using a fast pulling mechanism based on an aircraft catapult used on Navy ships. The mechanism was powered by combustion gases of gunpowder charges. With it the bridge could be thrown 10 m. To increase this range to 11,4 m small rockets could be added to the front of the bridge. A winch powered by the engine was used to reload the bridge after usage. This took 5 minutes.

Data:

unknown


Yours

tom! ;)

tom!
01-22-2018, 09:59 AM
Hi.

20) Other Experimental AFV:

Some more vehicles with almost all data lost.


a) Experimental Lumberjack No. 1:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20exp%20holzfaeller%20nr%201.jpg

In 1933 Tokyo Gas and Electric (TGE) was ordered to develop a special tracked armored vehicle able to clear roads through the soviet taiga. The resulting vehicle was similar to the Armored Working vehicle SS but with a TGE developed suspension. A large triangular wedge was mounted on the bow which simply pushed away trees knocking them down and rooting them out. At least one prototype was built and tested but there was no serial production. Later the concept was taken over for the more powerful Armored Lumberjack Ho-K

Data:

unknown


b) Experimental Lumber Sweeper:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20roder%20basso%20ki.jpg

This vehicle was a side development of the Experimental Lumberjack No. 1.Purpose was to move away the trees cut down by the lumberjack. It used a similar suspension but with slight differences. On the bow two small cranes able to lift medium loads were placed. The driver sat behind the cranes. The engine was mounted in the rear. The concept was later taken over for the Lumber Sweeper Basso Ki.

Data:

unknown


c) Experimental Glider Tank So-Ra:

http://www.ww2technik.de/Bilderchen/jappanzer/experimentell/jap%20exp%20typ%203%20luftlandepanzer%20so-ra%20holzmodell.jpg

Specially designed tank for airborne units. With the delay of the Ku-7 gliders a proposal was made to develop a tank able to fly as glider. The resulting vehicle was small with an aerodynamic bow, a small driver´s cupola a small turret in the center and an engine compartment in the rear. It should be armed with a 3,7 mm gun, a flamethrower or a MG. A detachable empennage could be mounted behind the turret and detachable wings on the sides of the vehicle. The whole construction should be able to be towed with a Ki-57 transport plane. Only a wooden mockup was built in 1943.

Data (planned):
Crew: 2 men
weight: 2,9 t, 4,2 t with aeronautical elements
length: 4070 mm, with aeronautical elements 12800 mm
width: 1440 mm, with wings 22000 mm
height: 1890 mm, with aeronautical elements 3000 mm
engine: 4 cylinder gasoline
power: 50 hp at 2400 rpm
speed: 43 km/h on roads
armament: 1 X Type 1 37 mm Tank Gun or 1 X Type 100 Flamethrower or 1 X Type 97 7,7 mm Tank MG


d) Experimental Gun Tank Ho-Ri:

https://2.bp.blogspot.com/-MDwSzuF_rtA/WahFG444PoI/AAAAAAAABQc/xWYZOrhmK5AjSh4lVfhtUGH131A4HwVdgCLcBGAs/s640/Ho-Ri0004.jpg

In late 1943 the decision was made to mount the at this time experimental 105 mm Tank Gun in a fixed fighting compartment on the chassis of a Type 5 Tank Chi-Ri. There are two different versions discussed in the web, one with the fighting compartment in the center, the other with it in the rear. Both have the bow armor of the Chi-Ri.

But the only existing contemporary picture of a wooden mockup shows a vehicle similar to the german Ferdinand with the fighting compartment in the rear and a sloped frontal armor instead of the stepped of the Chi-Ri. This way the vehicle could withstand hits of US 76 mm tank guns without needing a more massive armor. There are no infos about the later development stages so the web discussion is more or less based on fictional facts. There was at least one prototype under construction before surrender.

Data:

unknown


e) Experimental Working Vehicle:

http://www.ww2technik.de/Bilderchen/jappanzer/spezial/jap%20Type%204%20generator%20vehicle.jpg

Special construction duty version of the Type 4 Generator Vehicle. The vehicle was largely remodeled to add a dozer blade. It still had a generator for powered tools. Serial production was planned but did not start.

Data:

unknown


Yours

tom! ;)

tom!
01-23-2018, 11:53 AM
Hi.

21) Infantry AFV:

IJA developed a small number of special afv for infantry use. These were mainly used to transport men and supply.


a) Type 98 Armored Transport So-Da:

http://www.ww2technik.de/Bilderchen/japinfwaffen/Transport/gepanzert/jap%20typ%2098%20so-da.jpg

With the introduction of the Type 97 Tankette Te-Ke a special version for armored ammunition transport was developed. The engine was moved to the right of the driver. The fighting and engine compartments were replaced by an open top cargo bay. It was possible to transport up to 1 t of cargo or 4-6 soldiers. The tank could be loaded and unloaded through a large vertical two hatch door on the rear. A towing bar was mounted for lighter weapons up to the Type 1 47 mm Rapid-fire Gun.

Data:

Vehicles built: unknown
crew: 2 men
capacity: 1 t of cargo or 4 – 6 soldiers
length: 3800 mm
width: 1900 mm
height: 1600 mm
weight: 5000 kg empty
armor strength: 6 – 12 mm
engine: 4-cylinder Diesel
power: 65 hp/2300 rpm
speed: 45 km/h on roads
range: 200 km
armament: none


b) Type 1 Armored Personnel Carrier Ho-Ki:

http://www.ww2technik.de/Bilderchen/japinfwaffen/Transport/gepanzert/ho-ki/jap%20typ%201%20apc%20ho%20ki.jpg

In the late 1930th the development of full tracked transport vehicles started. After several trials with different suspensions Hino Motors developed a version with a semi-Christie suspension consisting of four large road wheels, a rear driving wheel, a forward idle wheel and two return rollers. Driver and engine were placed in the bow. On the rear a large open top transport compartment for up to 14 men was mounted. Access was possible by a large two door hatch on the rear. There was also a towing bar but with a trailer or gun towed it was a problem to unload the soldiers quick.

The 6 mm armor was vertical with a slightly sloped bow armor. It was possible to mount a standard heavy MG on the driver´s compartment for defense. A 6-cylinder Diesel engine was used. Due to a low priority production did not start before early 1944. Several vehicles were sent to China and the Philippines but most of the limited serial production was issued to the 3rd Tank Division in Japan for homeland defense.

Data:

Vehicles built: at least 200
crew: 2-3 men
capacity: 2 t of cargo or 12 - 13 soldiers
length: 4780 mm
width: 2190 mm
height: 2580 mm
weight: 5500 kg empty
armor strength: 6 mm
engine: 6-cylinder Diesel
power: 134 hp/2000 rpm
speed: 42 km/h on roads
range: 300 km
armament: none, a Type 92 7,7 mm HMG could be mounted


c) Type 1 Armored Personnel Carrier Ho-Ha:

http://www.ww2technik.de/Bilderchen/japinfwaffen/Transport/gepanzert/ho-ha/jap%20typ%201%20halbkette%20ho-ha%20links%20grabenhilfe.jpg

In 1941 IJA ordered Hino Motors to develop a fast half-tracked APC similar to the german SdKfz. 251. It should carry up to 12 soldiers or 2 t of cargo under armor protection against infantry small rounds at a maximum speed of 50km/h. The halftrack design should be taken as it was expected that fully tracked vehicles of that size wouldn´t be able to drive at the necessary speed.

The resulting vehicle had similarities with the SdKfz 251 but was a different design. The front axle wasn´t powered and should only be used to steer on harder ground. The rear suspension consisted of two pairs of large road wheels, a forward driving wheel, a rear idle wheel and a single return roller between the center road wheels. Both sides could be used for steering separately by using the reduction gears or the breaks.

A 6-cylinder Diesel engine was mounted in the bow. A crew compartment for driver and commander was mounted behind the engine. The rear 2/3 of the vehicle were a large storage room. The 6 mm armor was arranged sloped to the front and the sides with the lower bow and side armor negatively and the upper armor positively angled. The rear armor was vertical. A large two-door hatch opening to the sides allowed access to the storage compartment. The whole rear structure was open top but could be covered by a canvas. For close defense three LMG could be mounted on each side behind the crew compartment and on the rear.

http://www.ww2technik.de/Bilderchen/japinfwaffen/Transport/gepanzert/ho-ha/jap%20typ%201%20halbkette%20ho-ha%20hinten%20offen.jpg

Production did not start before 1944 with ca. 300 vehicles built. Most production vehicles were issued to homeland defense units. Only a few were sent to China and the Philippines with fewer reaching their targets due to the large air and sea superiority of the Allies. After the war some of the surviving vehicles were used for civil purposes but most were destroyed.

Vehicles built: ca. 300
crew: 2 -3 men
capacity: 2 t of cargo or 12 - 13 soldiers
length: 6100 mm
width: 2100 mm
height: 2510 mm
weight: 7200 kg empty
armor strength: 6 mm
engine: 6-cylinder Diesel
power: 134 hp/2000 rpm
speed: 51 km/h on roads
range: 300 km
armament: none, three LMG mounts were placed behind the crew compartment and the rear


d) Experimental Amphibious Landing Vehicle:

http://www.ww2technik.de/Bilderchen/japinfwaffen/Transport/gepanzert/jap%20experimental%20lvt%20toyota.jpg

Amphibious wheeled vehicle with a lightly armored fighting compartment developed by Toyota. It was based on the Amphibious Truck Su-Ki. The boat-shaped hull made it possible to use the vehicle even in rougher sea. Details are unknown.

Data:

unknown



That´s the actual state of my research on this topic. Feel free to ask or to correct things I got wrong.

Yours

tom! ;)

tom!
01-23-2018, 12:27 PM
Hi.

Somewhat off topic but related:


Navy Armoured Fighting Vehicles part 1

The Imperial Japanese Navy used AFV since the First Shanghai Incident in 1932. First vehicles were domestic and foreign armoured cars like the Type Crossley Armoured Car or the Osaka Armoured Car. The first tank unit was raised in 1936 as part of the Tokubetsu Rikusentai = Special Naval Landing Forces (japanese Marines). It was equipped with standard Type 89 Medium Tanks. Later navy tank units were based on various pacific islands equipped with Type 95 Light Tanks, Type 97 Medium Tanks and Type 97 Medium Tanks KAI. IJN tanks used an anchor instead of a small yellow star as national emblem. Several units also painted the Rising Sun Flag (the navy war flag) on their tanks. IJA units only used the Hinomaru Flag (the army war flag) on captured tanks to mark them as own vehicles. After 1940 IJN developed several special tank and armoured vehicle types which are covered here.


a) Special Type 2 Motor Launch part 1:

http://www.ww2technik.de/Bilderchen/jappanzer/marine/typ%202/jap%20typ%202%20ka-mi%20amphibienpanzer%202.jpg

After taking over the results of the army amphibious tank project in 1937 IJN start to think about how to use this kind of vehicles for amphibious operations of their Special Naval Landing Force (SNLF). Several studies were made regarding potential operational use, necessary features and possible tactics. With the decision to start a war in the Pacific in 1940 IJN increased the efforts and in early 1941 the decision was made to develop an amphibious tank. In cooperation with Army Technical Bureau and Mitsubishi such a vehicle should be built based on the Type 95 Light tank. Requirements were among others:

- watertight construction
- fully seaworthy even in heavy weather
- fully welded
- range afloat at least 100 km
- speed afloat 10 km/h
- floating devices removable from inside
- armament consisting of a Type 98 37 mm Tank Gun and two Type 97 7,7 mm Tank MGs
- easy to be build

The first tests with the incomplete prototype started in late 1941 at Lake Hamada, Shizuoka Prefecture. The vehicle was finished until early 1942. It consisted of the tank, two large detachable pontoons, a detachable conning tower and a detachable special air intake extension. All hatches openings and holes were made watertight by rubber seals or bulletproof glass. Crew consisted of driver, bow gunner, commander, gunner, ammunition supplier and mechanic. As IJN was not allowed to operate tanks the vehicle received the designation "Special Motor Launch" instead.

The vehicle was very different from the Type 95 Light Tank. Suspension and power transmission were similar but most parts were newly developed to cope with the weight. The rear idle wheel was relocated to the ground to increase ground contact. The springs and bell cranks were all mounted inside the vehicle to protect them from corrosion by sea water.

The armor scheme was completely different. Bow and rear armor were optimised for easy removal of the pontoons. All armor plates were flat and welded together. The lower bow armor consisted of two flat 12 mm armor plates with different negative angles. The upper part covered the tracks. Two clamps were mounted in the upper armor plate to fix the forward pontoon afloat. The upper bow armor was arranged sloped with both sides bent to the rear. A visor port for the driver was mounted on the (in driving direction) right side. In the center a third clamp for fixation of the pontoon was placed. On the left a standard MG mount was riveted to the armor plate. With the MG removed a detachable hemispherical cap covered the MG port watertight. Just before going ashore the cap was dropped off and the MG was mounted.

http://www.ww2technik.de/Bilderchen/jappanzer/marine/typ%202/jap%20typ%202%20Ka-Mi%20front.jpg
frontal view

The side armor was arranged vertical. Flotation chambers were placed above the tracks on each side which also gives additional protection by the spaced armor effect. There was no access hatch for driver and bow gunner. On each side a ventilation air intake for the fighting compartment was mounted on the top armor next to the rear part of the turret. Both were covered with a hatch. Above the driver the steering cable for the rudders is starting. Several guide pulleys leads the cable to the rear along the right upper edge of the fighting compartment.

The turret was a modified version of the turret from the Type 98 Light Tank. It was slightly conical with a large hole for optical equipment on each side of the gun mount. A large semicircular hatch on the turret with a two-part lid allowed access. Armament consisted of a Type 98 37 mm Tank Gun and a coaxial Type 97 7,7 mm Tank MG mounted slightly offset to the left. A semicircular handrail was welded on the rear turret to make entering the tank afloat easier. A removable steering mechanism for the propellers and rudders was inside the turret. Afloat the commander steered the tank from there. The gunner left the turret during that phase.

The top armor of the engine compartment was arranged sloped to the rear. The side armor was slightly sloped, too. The side parts next to the engine compartment were arranged sloped with a much lower angle to simplify slipping of the rear pontoon when removing it. The rear armor had a nearly vertical upper part and a negatively angled lower part. Clamps on the armor on the side of the engine compartment and on the upper rear armor fixed the rear pontoon afloat.

The engine was mounted lengthwise in the rear. There was no separating steel plate between fighting compartment and engine making it quite loud inside the tank during movements. Three hatches in the rear top armor allowed access to the rear fighting compartment and the engine. The center hatch was the largest. It had a large air intake covered with a grid. The detachable air intake extension could be mounted on this grid using clamps and hooks. A rubber band on the armor plate made the connection watertight. The mesh-covered muffler was placed on the right side, the tail pipe was raised.

The ammunition supplier and the mechanic had their seats between turret and engine. The ammunition supplier had to help the commander by giving him the ammunition loaded inside the vehicle. He also moved MG ammunition from the transport racks to the bow gunner and gunner. The mechanic had to watch and maintain the complex machinery especially during operations afloat. During operations on land he was not really needed (repairs could be done faster by the maintenance units) and so not inside the tank most of the time.

[http://www.ww2technik.de/Bilderchen/jappanzer/marine/typ%202/jap%20typ%202%20Ka-Mi%20frontponton.jpg
improved forward pontoon

The forward pontoon had a u-shape and was designed streamlined for an excellent driving quality. He had three flotation chambers with a total volume of 6,2 m³. The pontoon could be lifted by a collapsible jib boom (part of the equipment) over three hooks on the upper edge and two short handling rods on the lower part. With the pontoon attached the driver´s visor port was completely covered. A small recess allowed mounting the MG.

The rear pontoon was also u-shaped with the rear edges rounded. It was had three flotation chambers but only with a volume of 2,9 m³. The rudders were mounted under the pontoon on long axles which reached through the whole pontoon to the steering mechanism on top. Six hooks are mounted on the upper edge and two handling rods on the lower part for handling the pontoon with a jib boom.

Afloat the tank was operated from a small detachable conning tower mounted on the turret which could be easily detached. This was necessary as the view from inside the turret was too bad for navigation on the sea. The tower was conical with three visor ports next to each other in the forward part and three more mounted in each side and the rear. On top was a small access hatch. On the ocean the commander steered the rudders from inside the tower.

To prevent spray from the waves to get inside the engine a conical rectangular air intake with a wider cap could be mounted on the engine compartment. This was necessary in bad weather or heavier sea.


To be continued in part 2...

tom!
01-23-2018, 12:32 PM
Hi.

Navy Armored Fighting Vehicles part 2


a)Special Type 2 Motor Launch part 2:

http://www.ww2technik.de/Bilderchen/jappanzer/marine/typ%202/jap%20typ%202%20Ka-Mi%20heckponton%20aufsicht.jpg
rear pontoon

The pontoons, the conning tower and the air intake extension were welded using 3,2 mm thick face-hardened armor plates. It was possible to transport both pontoons with a single Type 94 6X4 Truck. All parts necessary to get the tank ready for operation could be mounted by the crew within 15 minutes with the equipment of the tank.

Afloat two large screws next to the tracks moved the tank. The driving shafts were connected with the engine over a power dispensing devise which separates the two types of propulsion. This device was also responsible for sending power to the bilge pumps. The rudders were mounted on the rear pontoon.

The concept worked very well and so in mid 1942 the decision was made to start a serial production immediately. Official designation was "Special Type 2 Motor Launch". It seems that the popular short designation "Ka-Mi" wasn´t adopted officially but it was used by the units operating the vehicles. 300 vehicles were ordered. The first unit using this tank was formed in late 1942. There are few US reports of early version Type 2 armed with the Type 94 37 mm Tank Gun but there was no japanese source yet.

After the first exercises some changes were demanded by the soldiers. So a radio was added, the antenna base was welded on the rear right of the turret. The forward pontoon was remodeled to improve detaching. Therefore it was cut along the center line making it two-piece. The recess for the bow MG was widened to make the driver´s visor port accessible. The clamp in the upper bow armor was now surplus. A handrail was added to the pontoon. Other changes were made inside the tank to simplify handling. Most important was the installation of an onboard communication system with headphones to compensate the engine noise. The changes were adopted officially in summer 1943.

Only 184 vehicles were produced by Mitsubishi until surrender due to raw material shortages and a change in IJN strategy. They were issued to independent tank companies of the SNLF. Several units fought against US invasion forces in 1944 and 1945. Most spectacular was the attack of the 101st SNLF which swam from Luzon via Samar to Leyte during the US Invasion in late 1944. Due to the weak gun the success was limited. Nevertheless the US Army and Navy was impressed by the good seaworthiness which was far superiour to any other contemporary amphibious tank in the world. It was even possible to carry the tanks with submarines and launch them shortly below the surface.

http://www.ww2technik.de/Bilderchen/jappanzer/marine/typ%202/jap%20typ%202%20Ka-Mi%20hinten%20rechts.jpg
rear view

In western literature the first production version is sometimes designated "Type 1 Ka-Mi" or "Type 1 Ka-Sha" which is not correct. There was no change in the official designation.

There are still several Type 2 Ka-Mi rusting on different pacific islands. Only few are on display in museums. A vehicle with both pontoons and the air intake extension can be seen at Kubinka Tank Museum near Moscow.

Data

vehicles built: 184
battle weight: 9,15 (metric) t, 12,5 t with floating equipment
crew: 5-6 men
length: 4800 mm, 7420 mm with pontoons
width: 2800 mm
height: 2300 mm
track width: 305 mm
engine: Mitsubishi A6120VD in-line 6-cylinder air-cooled Diesel engine
power: 115 hp at 1800 rpm
maximum speed: 37 km/h on roads, 9,5 km/h afloat
range: 320 km on roads 140 km afloat
transmisson: 8 forward, 2 reverse
armament: 1 X Type 98 37 mm Tank Gun , 2 X Type 97 7,7 mm Tank MG
Ammunition capacitiy: 132 37 mm grenades, 3900 MG shots



armor
strength


turret front
12 mm @ 85 °


sides
12 mm @ 85 °


rear
12 mm @ 85 °


roof
6 mm @ 0 °


superstructure front
12 mm


sides
6 + 6 mm @ 90 °


rear
12 mm


top
6 mm





b) Special Type 3 Motor Launch:

http://www.ww2technik.de/Bilderchen/jappanzer/marine/jap%20typ%203%20amphibienpanzer%20Ka-Chi%203.jpg

After introduction of the Type 2 Ka-Mi SNLF demanded a similar vehicle with more armour and a 47 mm gun. The development of a successor was started in early 1943. Most data were lost after surrender. So many details are unknown.

Development was done in cooperation with Mitsubishi. To speed up the process many parts of the Type 1 Chi-He were used including the turret, the engine, suspension elements and parts of the transmission and steereing. Other elements were modified from the predecessor like the pontoons, steering and propulsion afloat and internal structure. But it was not developed from the Type 1 Chi-He as stated in many sources.

The hull was huge and bulky. Bow, side and rear armor were almost vertical making it easy to penetrate it. Only the upper front and side armor was arranged sloped. There were four access hatches to the flotation chambers in each side armor. Two clamps each in the bow and upper bow armor fixed the frontal pontoon. Driver´s visor port and bow MG were arranged as in the Type 2 Ka-Mi. The turret was placed in the center line. There were two pairs of ventilation hatches on the sides of the top armor, one between driver and turret and one next to the turret overhang. The cable for operating the rudders started on the right side in front of the turret. Number and location of the access hatches to the fighting and engine compartment are unknown. The air intake extention was mounted at the rear end of the engine compartment. So it can be assumed that the main engine access hatch was there, too. There was an exhaust pipe with muffler and raised tail pipe on each side of the vehicle´s rear top armor. Four clamps on the rear armor fixed the rear pontoon.

The suspension consisted of four pairs of roadwheels. Two pairs each were connected with bell cranks to a large vertical coil spring covered by a semicircular armor plate. The rear idle wheel protruded the vehicle completely. The frontal driving sprocket and four return rollers completed the suspension. All parts were mounted outside the vehicle.

Both pontoons were quite similar to the pontoons of the predecessor but they were larger to cope with the weight. The rear pontoon did not enclose the vehicle rear. It was completely behind the tank. A similar conning tower for the commander´s cupola and a similar air intake extension completetd the equipment for seaworthiness.

Only the prototype and 19 pre-series vehicles were built in late 1944. It is unknown if the short designation "Ka-Chi" was adopted officially. The vehicles were only used for exercises. Some internet sources claim that there was a successful test launch from a submerged submarine from a depth of 100 m but I found no more reliable sources yet. There is no known survivor today.

The whole vehicle was far too large for the chosen armament and the armor scheme and strength would have made it an easy to destroy target.

Data

vehicles built: 20
battle weight: 28,25 (metric) t with floating equipment
crew: 5-6 men
length: 10300 mm with pontoons
width: 3000 mm
height: 3820 mm
engine: Mitsubishi Type 100 V-type 12-cylinder air-cooled Diesel engine
power: 240 hp at 2000 rpm
maximum speed: 32 km/h on roads, 10,5 km/h afloat
range: 320 km on roads 140 km afloat
transmisson: 8 forward, 2 reverse
armament: 1 X Type 1 47 mm Tank Gun , 2 X Type 97 7,7 mm Tank MG


to be continued in part 3...

tom!
01-23-2018, 12:45 PM
Hi.

Navy Armored Fighting Vehicles part 3


c) Special Type 4 Motor Launch:

http://www.ww2technik.de/Bilderchen/jappanzer/marine/ka%20tsu/jap%20typ%204%20amphibientransporter%20Ka-Tsu%205.jpg

After the Battle of Wake IJN decided to make a larger survey about the causes of the quite large losses. One main cause found was that the landing craft used were open to the top exposing the passengers to enemy small arm fire and especially splinters. In addition the armor was relatively weak making it easy to penetrate the sides and the bow with heavier weapons. This problem became urgent again during the 1942 Solomon Island campaigns. There landing crafts were often attacked by aircraft which shot into the cargo bay from above. As result the decision was made to develop a better protected landing craft for these kind of operations. Requirements were among others:

- easy to unload and load for transport ships
- usable on land and in the water
- closed cargo compartment
- armed with one or two Type 93 13,2 mm Machine Cannons for close defence


In 1943 the US presence was increased especially in the south and central pacific. This lead to increasing losses among transport and supply shippings because of submarines and long-range aircraft. Especially forward garrisons on smaller island were sometimes cut off from supply. So the landing craft should additionally be able to be transported and launched from submarines.

A prototype was finished in late 1943 at Kure Naval Yard. Operational tests were finished in March 1944. Crew consisted of driver, navigator, two gunners and a mechanic. The vehicle had a boat-shaped armored hull with a maximum armor strength of 10 mm. Afloat the landing craft was powered by two propellers in the rear. Rudders were behind them for steering. For movenments on land a track suspension was added. The suspension was similar to the Type 98 Light Tank Ke-Ni. It consisted of four pairs of roadwheels connected with bogies. Each two pairs were connected by bell cranks with large horizontal coil springs. These elements were placed inside the vehicle for protection against corrosion by seawater. A forward driving sprocket, five return rollers and a rear idle wheel completed suspension.

The whole vehicle was covered by an armored deck. Internal chambers on the bow and rear delivered additional buoyancy for stabilty. Crew and engine compartment was in the forward half. A driver and a navigator operated the landing craft from an armored cabin with two visor ports on the bow. The rudders were operated over a cable mechanism similar to the Special Type 2 Motor Launch. During the final approach to the shore the driver could change to a steering position on the deck behind the cabin. There he was protected by armor plates from the front and the sides. The rear was open for a better overview. A visor port was placed in the frontal plate. A Type 93 13,2 mm AA-Machine Cannon could be mounted on a pivot on each side of the steering position on deck.

The vehicle was powered by the Mitsubishi A 6120 1 in-line 6-cylinder Diesel engine, a modified version of the engine of theType 97 Medium Tank. The air intakes on deck were made water-tight with float valves. A long exhaust pipe lead to the rear mounted muffler with raised tail pipe. A cargo compartment was placed behind the engine compartment. Maximum payload was 4 t or up to 40 men (some of them on deck). It was possible to carry larger loads on deck but vehicles could not be carried. There were three watertight access hatches on the crew compartment and three more on the cargo compartment. Several hooks around the deck allowed easy loading and unloading from ships

During tests the vehicle was easy to steer but slow. Nevertheless the design was accepted under the designation "Special Type 4 Motor Launch".It is unclear if the short designation "Ka-Tsu" was introduced officially.

http://www.ww2technik.de/Bilderchen/jappanzer/marine/ka%20tsu/jap%20typ%204%20ka-tsu%20details%20oberdeck.jpg

In January and February 1944 US forces captured the central pacific atolls of Eniwetok, Kwajalein and Majuro. During the following months US-Navy expanded the already built japanese air and naval bases to a a large forward base for future operations against Truk and the Marianas (Saipan, Tinian, Guam). Japanese submarines and long-range reconnaissance aircraft delivered good reports about these works. So in April 1944 IJN started to plan a massive attack on these bases (Operation Yu-Go). Part of these plans was to launch special attack units using torpedo vehicles from submarines to attack anchorages. For this operation the vehicles should be used. This made several modifications necessary.

The exhaust pipes and the steering mechanism for the rudders were relocated below the deck. On each side a mount for a modified Type 91 Model 3 450 mm aircraft torpedo was welded on the deck above the fighting compartment (Many western sources claim that the torpedoes were Type 93 610 mm Long Lance but almost all japanese sources say Tpe 91 Model 3). A simple aiming device was mounted in the driver´s cabin. Special hooks to carry the vehicle with submarines were also added. To mount the torpedoes the machine cannons had to be removed. During the first trials the crew had problems to keep the vehicle watertight submerged. The air intakes finally had to be sealed with special coverages to prevent the engines from flooding but it took some 20 minutes to remove them and to make the vehicles ready to start. During this time the submarine had to stay at the surface. A submerged start as planned was not possible. Nevertheless IJN decided to introduce the vehicle with these changes. Production numbers are unknown but at least 50 vehicles were built.

Operation Yu-Go was cancelled in mid 1944 due to the fast US advance to the Marianas. The operating soldiers disliked the slow speed afloat but they had to use the vehicles because there was nothing similar avaliable. Crew training continued and until late 1944 800 soldiers were trained on these vehicles. In late 1944 operations against US ships at Luzon were planned but cancelled after a tanker destined for fuel supply was sunk during a convoy mission.

Some sources claim that the unit was used in 1945 to resupply cut-off pacific island garrisons. The plans for homeland defence included suicide torpedo attacks of the Special Type 4 Motor Launches on the invasion fleets.

http://www.ww2technik.de/Bilderchen/jappanzer/marine/ka%20tsu/jap%20typ%204%20ka-tsu%20uebung.jpg
2 vehicles equipped with torpedoes carried by the B2-class submarine I-41

Most vehicles were scrapped postwar but at least one is on display at WWII and Korea LVT Museum, Camp Del Mar, Marine Corps Base Camp Pendleton, California, USA

Data

vehicles built: 50 or more
battle weight: 16 (metric) t
crew: 5 men
maximum armor: 10 mm
length: 11000 mm with pontoons
width: 3300 mm
height: 2250 mm to deck, 4050 mm maximum
engine: Mitsubishi A 6120 1 in-line 6-cylinder air-cooled Diesel engine
power: 120 hp at 2000 rpm
maximum speed: 20 km/h on roads, 8 km/h afloat
range: 300 km afloat
armament: 2 X Type 93 13,2 mm Machine Cannon or 2 X Type 91 Model 3 450 mm Torpedo


to be continued in part 4...

tom!
01-23-2018, 01:03 PM
Hi.

Navy Armored Fighting Vehicles part 4


d) Special Type 5 Motor Launch:

no picture, sorry

http://www.wardrawings.be/WW2/Images/1-Vehicles(bis)/Japan/Files/5-AmphibiousTanks/Type5-ToKu/Type5-02.jpg

There are only few informations about this vehicle avaliable. It is even not sure that the prototype was finished before surrender.

Upon the avaliable drawings (which differ largely in details) it can be assumed that the tank was a try to remodel the Special Type 4 Motor Launch to make it less vulnerable against enemy fire. Size and shape are similar, most known data also fit for both vehicles. The most significant changes are a far better bullet deflecting armor scheme, a change in armament and different pontoons.

The upper bow armor was now sloped with a lower angle. The lower part was still negatively sloped but with a shallower angle. The superstructure armor wasn´t changed on front and sides. The rear armor was now similar to the Special Type 2 Motor Launch.

The Type 1 47 mm Tank Gun was now mounted on the position of the bow MG. The MG was replaced to the right between gun and driver´s visor port. In the turret a modified Type 96 25 mm Machine Cannon replaced the gun.

The frontal pontoon was now flatter to allow using the bow armament during landing. The rear pontoon was shorter and had the shape of the rear pontoon of the Special Type 2 Motor Launch

http://image2.fg-site.net/image/lrg/37/lrg36348_0_234188.jpg
Scale model, details are surely different to the historical vehicle

Due to an error in the book "Tanks of the World 1915-1945" from Peter Chamberlain and Chris Ellis many internet sources show a picture of the Special Type 2 Motor Launch without floating equipment as a picture of this tank. This is definitely wrong. There is no known picture of the Special Type 5 Motor Launch.

Data

vehicles built: 1
battle weight: 29,1 (metric) t
crew: 5-7 men
maximum armour: 50 mm
length: 10800 mm with pontoons
width: 3000 mm
height: 3380 mm
engine: Mitsubishi Type 100 V-type 12-cylinder air-cooled Diesel engine
power: 240 hp at 2000 rpm
armament: 1 X Type 1 47 mm Tank Gun, 1 X Type 96 25 mm Machine Cannon, 2 X Type 97 7,7 mm Tank MG


e) Short Barrel 120mm Gun Tank:

http://www.ww2technik.de/Bilderchen/jappanzer/marine/jap%20typ%2097%20120%20mm%20gun%20tank.jpg

In late 1944 the SNLF demanded a gun tank similar to the IJA Type 2 Gun Tank Ho-I but with a larger gun for close support. So the decision was made to upgun the Type 97 Medium Tank KAI with the short 12 cm gun developed in 1942/43 for close defence of transport ships.

The hull of the tank was not changed. The gun mount was replaced by a massive mount with a large recoil mechanism. There were several recoil cylinders mounted around the barrel and covered with a round armour for protection. This recoil mechanism was still not able to cope with the recoil forces and so a flat muzzle break had to be added, too.

The gun was developed as high-angle multi purpose gun. It should provide close-range fire against aircraft , submarines and small attack boats. Due to the short barrel it was almost impossible to hit moving targets so only barrage fire was made. Data for the gun are:
- caliber: 120 mm
- gun length: 1510 mm
- bore length: 1440 mm (L/12)
- rifling length: 1127 mm
- grooves: 24 (1.0 mm x 11.78 mm)
- lands: 3,93 mm
- twist: Increasing RH 1 in 30 to 1 in 13
- weight: 2950 kg with mount
- chamber volume: 3 dm³
- muzzle velocity: 290 m/sec
- rate of fire: up to 15, 10 for continuous fire
- ammunition: HE, Incendary, Chemical, Anti-submarine
- grenade weight: HE 11,8 kg with a warhead of 2,5 kg and a propellant charge of 0,49 kg
- fuzes: time, impact, anti-submarine (time and/or preasure)
- maximum range: 5300 m
- maximum ceiling: 3100 m

Maximum range was reduced due to the limited elevation of the gun mount. Due to the screw-type breech of the new gun the already low space inside the turret was reduced. In addition the ammunition was heavy.

Further details are unknown.

An unknown number of Chi- HA KAI were modified this way in 1945. After surrender US units found at least 4 vehicles at Sasebo SNLF base and 10 more at Yokosuka SNLF base. All were scraped postwar.

Data
as Type 97 Medium Tank Chi-Ha KAI except:

vehicles built: at least 14
armament: 1 X Navy Short 12 cm Gun , 1 X Type 97 7,7 mm Tank MG


[f) Long Barrel 120 mm Gun Tank:

[http://www.ww2technik.de/Bilderchen/jappanzer/marine/jap%20typ%2097%20chi-ha%20long%20120%20mm%20gun.jpg
only known picture

Informations on this vehicle are rare. After surrender US forces found at least one vehicle at Yokosuka Naval Yard. It is unknown if it was a local conversion or an official development.

A Type Taisho 10 120 mm gun was mounted on the hull of a Type 97 Medium Tank. The turret was removed and the hole closed by steel plates. Additional steel plates were welded on each side of the fighting compartment to create a platform for the gun crew.

Data of the gun are:
- caliber: 120 mm
- gun length: 5600 mm mm
- bore length: 5400 mm (L/45)
- rifling length: 4649 mm
- grooves: 34 (1.45mm x 6.688 mm)
- lands: 4,4 mm
- twist: uniform RH 1 in 28
- weight: 218 kg without pivot
- chamber volume: 10,774 dm³
- muzzle velocity: HE 830 m/sec Illuminating 700 m/sec, anti-submarine 250 m/sec
- rate of fire: up to 11 per minute, 7 for continuous fire
- ammunition: HE, AP , Incendary Shrapnel (AA), Illuminating, Anti-submarine
- grenade weight: HE 34 kg with a warhead of 1,9 kg and a propellant charge of 5,5 kg
- fuzes: time, impact, anti-submarine (time and/or preasure)
- maximum range: 16000 m
- maximum ceiling: 10000 m

There are no further infos. Due to the gun weight and dimensions it can be assumed that the vehicle was top-heavy making it a quite unstable firing platform.

Data:

unknown


Yours

tom! ;)