In order to replace the reconnaissance-biplan a high-speed machines the Chief Directorate of Aircraft Industry and the Office of the Air Force announced a competition for new aircraft this purpose – VOISKOVOY samolet/military- tactical aircraft: (short-range bomber, reconnaissance and attack plane).
In 1936 the competition program was declared, had called "Ivanov" (It was the telegraph nickname of Stalin)
The first phase: - the requirements for the engine cooling liquid M-34 FRN (1200 hp).
In these works involved design- bureau:
A.N.Tupolev (Brigade P.Sukhoi / future ANT-51)
[Note: The team A.Golubkov worked on the twin-engine, high-speed recon-bomber /
project ANT-56 are working in two versions with engines of air and liquid cooling]
N.N. Polikarpov ,
I.G. Neman ,
S.A. Kocherigin ,
D.P. Grigorovitch
and S.V Ilyushin.
OKB Polikarpov’s and Grigorovitch developed sketch projects straightway in two versions:
scheme with low-wing and high-wing , remaining only on the low-wing scheme.
Project S.Ilyushin not extant (or have not yet found).
Later, the technical requirements have changed in favor of air-cooled engine: M-62 (1000hp) and the number of developers dropped to three: Sukhoi, Neman and Polikarpov.
It was decided to build a recon/attack plane in three versions -
all-metal - P. Sukhoi / «SZ»; «BB-1» (later the Su-2),
all-wood - I. Neman / KhAI-52 and
mixed construction - N. Polikarpov
OKB Kocherigin and Grigorovitch initiative further work in this subject, at first there were several experimental machines and their modifications, the second one shortly before his death began to work on the dive-bomber DG-58 (PB-1) and high-speed scout fast recon, at its base DG -58R (R-9).
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P.Sukhoi /A.N.Tupolev
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