Sperry ball turret on a B-17 Flying Fortress - 1942

Ball turret

B-24 crew

B-24 prophetically named 'Flak Magnet' by her crew depicting a sharks mouth nose art. Note also the extra armored plate added to the pilot's side. 'Flak Magnet' was hit and set on fire by flak over Hamm, Germany on the 22nd April 1944 while being flown by another crew (the original crew was on leave).

The story of that mission as told by some of the crewmembers flying the plane on that fatidic day (click the link 'crew 33' (in blue) in the text for that crew's history: 

http://www.458bg.com/crew33flakmagnet.htm