Before World War II, almost all fighter aircraft in service with the Soviet Air Force were created in the design bureau of N.N. Polikarpva. Between 1934 and 1942, aircraft factories produced more than 16 thousand I-16, I-15, I-15bis and I-153 fighters. A significant part of this winged armada took part in air battles from 1936 to 1945. The I-15bis sesquiplane looks average among other Polikarpov fighters. It did not shine with any particular merits; moreover, before it even appeared, it was almost hopelessly outdated in all its characteristics. Nevertheless, it turns out that this well-ordered and harmonious-looking airplane managed to “make its mark” almost everywhere: in Spain, China, Khalkhin Gol , in the winter war with Finland, went through the entire Great Patriotic War until the Japanese campaign.