No one SM 79 was downed by enemy fighters during Spanish Civil War: nor Russian Chatos or Ratas, or French fighters of first 30's could reach it.
Communist pilots could not find a tactical manoeuvre to attack the SM 79s, unlike the Italian and Spanish pilots with the CR 32s against the faster Tupolev SB2 Katiuskas.

Eagles over Spain

Loading the torpedos at SM 79s before the mission. Photo taken possibly in Italian Dodecaneso. 
In Gadurrà (Rodhes) had base the 278 squadriglia, one of the best units of Italian torpedo bombers.

Loading the torpedo

Italian and German personnel at Melsbroek airfield (Belgium), autumn 1940. On the background, a Fiat BR 20 bomber. Allies and enemies would have discovered soon the inadequacy of Italian equipment. 
Weak ability in modern and mass warfare industy, make unuseful for Regia Aeronautica holding 33 aviation records still in 1939.