I-5, N.N.Polikarpov/ D.P.Grigorovich

18k b/w photo from the "History of aircraft construction in the USSR", Vol.1 p.436

Biplane fighter, designed by N.N.Polikarpov and D.P.Grigorovich while imprisoned.

N.N.Polikarpov was assigned to develop the I-6 (primarily wooden) fighter (delivery July/August 1930) under provisions of the Five Year Plane for experimental aircraft design (starting 1928). At the same time D.P.Grigorovich was working on his his own I-5 design, different from Polikarpov's (and A.N.Tupolev's I-5).

When the unrealistic Plan obviously failed, N.N.Polikarpov, D.P.Grigorovich and other ~450 aircraft designers and engineers were arrested by the NKVD as "saboteurs and enemy infiltrators" (Fall 1929?). Some 300 survived, and were arranged to work in the police supervised design bureaus and experimental factories.

The VT-11 and two other prototypes were tested in April-May 1930 by test pilot I.U.Pavlov. Some tests were performed with Townend-ring cowling, which was found reducing drag and was added to the production I-5.

Two pre-series aircraft with M-15 engine were planned for factory trials on February 15, 1932 and be ready for State Trials on April 1. But the M-15 was not well suited for production. M-22 (license built Bristol-Jupiter) was fitted on the production aircraft.

Production started at Gorkij Factory N°21 in the very end of 1932, where special 'launch bureau' under leadership of I.M.Kostkin was established to handle production problems as they surface.

Fuselage frame was of welded steel tubes. Front and cockpit sections were covered with removable duralumin alloy panels. The rest of fuselage had fabric cover. Wings had wooden construction, while the tail plane and fin had metal frame and fabric cover.

Production faced serious complications because had to be started at new built plant (unfinished Factory-21). As a result it took 2 years for aircraft created from scratch in one month to enter mass production...

10 I-5 were armed with four PV-1 machineguns with 1000rpg, but this version failed to became a series aircraft. Among other experiments carried out on I-5 - interceptors on wing struts for enhanced maneuverability.

Some were still in service as trainers in 1941.

803 built.

This image is a fragment of photo (30k) in article "Vakhmistrov's Zveno" posted at Alexej Gretchihine Russian Aviation Page;

• VT-11;
• "Klim Voroshilov";
• "Present to the XVI Party Congress";

• UTI-1 2-seat trainer;
• TsKB-3, a prototype of the I-15;