Pashinin I-21
Paschinin I-21 (Russian Пашинин И -21) is a Soviet fighter aircraft of the late 1930s. It was ultimately unsuccessful attempt to replace the obsolete Polikarpov I-16.
The Paschinin I-21 was built as part of the modernization program of the Soviet Air Force from 1938/1939, but did not reach the series production. The symbol " I" stands for Istrebitel ( Истребитель ), the Russian word for fighter aircraft. The aircraft (now Nizhny Novgorod ) developed in OKB- 21 of the aircraft plant in Gorky. However, the designation I-21 does not derive from the number in OKB -21, since the numbers of Soviet fighter projects were assigned consecutively (I- 1, I- 2, I- 3, etc.). Initially, the project was accompanied by the letter "P" for the designer Paschinin (IP -21).
Development
The designer M. M. Paschinin (Russian Михаил Михайлович Пашинин ) designed the I-21 as a cantilever low-wing monoplane in wood construction with easily swept airfoil outer edge. The cockpit was relatively far back. The guy should get a V-engine M -107 with 1,210 kW and 7,000 m in height can achieve a speed of 680 km / h. Due to the unavailability but had to resort to a weaker M- 105P. Paschinin put in the design value on a clean aerodynamic shape at the same time simpler mode of production.
The I-21 represented a fundamental modernization of the obsolete Polikarpov I-16 by the water-cooled aircraft engine M -105 was installed. Therefore, 60-70% of the components of the I-16 could be used for the I-21. Paschinin used for the wing tips, a symmetrical torque -free profile (NACA-0012 - 0009, NACA 0012 at the wing root and NACA 0009 at the wing tip ). With this profile the wing speeds stopped at the dive ( dive bomber ) of up to 950 km / h. At the time of development of this aircraft, the then new request was made, swoop to achieve high speed and do not lead to the air combat on spiral trajectories.
In July 1940, flight testing with test pilot P. Stefanowski began. The first flight of I-21 took place on July 11, 1940 with the test pilots U. P. Fokin. On August 18, 1940, the aircraft was demonstrated at the air parade of Soviet forces in Tushino and then passed for state testing, which was completed in December 1940. The insufficient stability and very high landing speed was criticized. When subsequently tested the second prototype, completed in October 1940, the stability of defects could be remedied. In January 1941 a third prototype with a reduced wingspan yet emerged (first flight April 5, 1941 ).
Ultimately, however, was decided not to build the I-21 in series, since the relatively high landing speed of 165 km / h and the resulting long runways would have to be used under conditions at least difficult front. At the time of the attack of the German Empire to the Soviet Union, there was indeed a pre-series of five aircraft under construction, was not completed by the evacuation of the plant in the east of the country. Instead, the parallel designs were Yak- 1 and LaGG -1 / LaGG -3 already gone into mass production.