1930s – the “golden age” of biplane fighters. In the Soviet Union, they were designed by N.N. Polikarpov – “the king of fighters”. The first Soviet large-scale fighter I-5 was created by him in 1930.
The next biplane fighter was the I-15. Its main feature is the gull-shaped center section of the upper wing. The aircraft had outstanding maneuverability and was the best in the world for this characteristic.
The I-15bis became a further development of the I-15. Its main differences were the “normal” center section of the upper wing and the NACA hood. Serial production of the I-15bis began in 1937 and continued until 1939.