Central Aerohydrodynamic Institute
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TsAGI centenary in history: the Bereznyak-Isayev BI-1

31 May 2019

The first Soviet short-range rocket powered interceptor BI-1 took its maiden flight on May, 15, 1942. It was the opening of the jet aviation era in our country.

The idea of creating a new type of fighters was first proposed by S.P. Korolev in 1938. He believed it would be an air defense interceptor, flying up rapidly, attacking enemy targets straight off and shooting them down by a powerful cannon fire. It was planned that the liquid rocket engine would provide unprecedented climbing rate and speed, but it was impossible to ignore the huge fuel consumption, which reduced the flight time.

A. M. Isaev, the designers of Bolkhovitinov Design Bureau started to develop a project of a short-range interceptor with liquid rocket engine designed by Leonid Dushkin. The work was started in the spring of 1941. A.M. Isaev completed the engine development and the plane was called “BI” for Bereznyak and Isaev or for Blizhnii Istrebitel (close-range fighter). The aircraft was built of wood and cloth without detailed drawings. Its parts were contoured in natural scale on the plywood. TsAGI specialists tested the aircraft in a wind tunnel. They evaluated its flying qualities and gave recommendations. The work was carried out under the leadership of G.S. Bjushgens and A.l. Reich. Flight tests where the aircraft was towed by the PE-2 twin-engined dive bomber started immediately after the aerodynamic research. At low speeds all the obtained results agreed with the calculated data.

The BI-1 took its maiden flight in the evacuation, from the airfield near the town of Koltsovo (Ural), in the spring of 1942. The flight lasted for 3 minutes and 9 seconds. The rocket engine worked for 60 seconds and the interceptor reached the altitude of 840 m and the speed of 400 km/h. The test pilot G.Ya. Bakhchivandzhi piloted the airplane. “Unusually fast getting up the speed, the aircraft got off in 10 seconds and receded from the view in 30 seconds,” recalled V.F. Bolkhovitinov. “Only the engine’s flame pointed at the place where it had been. Several minutes passed. I must admit that my knees were shaking. Finally Bakhchivandzhi was back and landed.”

Due to nitric acid vapor the first flight model was retired and the second and the third prototypes — the BI-2 and BI-3 were made. At the same time it was decided to mass-produce a small series of BI-VS aircraft for troop trials, the fighters of which were equipped with bomb clusters with bomblets of great explosive power.

On March 27, 1943, the BI-1 was preparing for the maximum flight speed tests. To do this, the pilot Bakhchivandzhi had to accelerate to a horizontal flight speed of 750-800 km/h at an altitude of 2000 m. Before the engine cut off when the fuel was over, everything was going fine, and then the plane went into dive and crashed into the ground, killing Bakhchivandzhi. Later, when TsAGI’s T-106 wind tunnel was put into operation, a BI-1 model was tested and a new phenomenon was revealed: the nose-heaviness of a straight-wing aircraft of a usual airfoil at transonic speed. They BI production stopped. Its futility was explained by the limited flight duration as well.

Nevertheless, the working experience from the aircraft proved to be extremely useful in further establishing of the Soviet rocket and space technology. As Yury Gagarin, the first USSR pilot-cosmonaut put it “without Gregory Bakhchivandzhi’s flights, perhaps, there would have not been the 12th of April, 1961.”

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