In the thirties it was the era of biplane fighters. In the Soviet Union they were designed by N. N. Polikarpov – “The King of Fighters”. The first Soviet mass-production fighter aircraft I-5 has constructed by him in 1930. Two prototypes, named “VT-11” and “Klim Voroshilov”, and first serial aircraft had individual cylinder cowers. Late series had “Townend ring” engine cower. I-5 were the basis of Soviet fighter aviation in early 30s. Some machines took part in 1941-1942 battles in the Soviet-German front as ground-attack aircraft.