OKB AS. Yakovlev in the prewar years, has created several types of light aircraft, distinguish good aerodynamic shape. On these machines, the Soviet pilots have established more than a dozen world records altitude and flight speed for cars respective weight categories. Drawing on the experience gained, Yakovlev decided to develop a twin-engine bomber, which would have the ceiling and the rate of not less, than the best foreign fighter. For the bomber was elected circuit nizkoplan DIVERSITY tail. The machine was calculated by two serial engine liquid cooling capacity M-103 960 HP. Aircraft design, learn some factory designation «№ 22» (As zatem 2), - mixed.
Wing dvuhlonzheronnoe smooth plywood sheathing. Aft fuselage - truss, of steel pipes, sheathe, as rudders, cloth. To achieve a high maximum speed the designers a lot of attention was paid to improving the aerodynamics and the general layout of the aircraft. navigator cabin was located in the middle part of the fuselage, but in order, to the navigator had a good view of the back hemisphere and could fire on the attackers from the rear hemisphere opponent, upper trim gargrota tail portion designed descending.
Factory testing of the aircraft in bomber version conducted a test pilot YI. Piontkovsky. The tests were successful, they confirmed designers calculations. The aircraft accelerated momentum 567 kmh, ceiling - 11 800 m, and range - 1050 kilometers. aircraft armament consisted of two rapid-fire machine gun 7.62 mm, set one (fixed) the forward fuselage, second - (turret) in the cab of the navigator for bombardment rear hemisphere. The bay, placed in the middle part of the fuselage, plane carrying 400 600 kg bombs various calibers. It was suggested to run the plane in series at two plants. However, Yakovlev is anticipated and before the display of the aircraft in parades began to transmit a copy of his drawings to the plant, which it was organized by a special CB-70 for the implementation of. The first serial aircraft made its first flight 20 February 1940 g.
Almost simultaneously with one bomber, who had the designation BB-22 (How-4), the same scheme and structure reconnaissance version of the aircraft was built, were designated P-12. On it in the navigator's cabin installed aerial camera "AFA", and the bomb bay adapted to load flares. At some later built fighter embodiment, which had a designation of I-29, It was significantly enhanced by onboard weapons. In addition to the two machine-guns at the bottom of the fuselage installed two 20-mm cannon. On the test machine showed approximately the same with the BB-22 (How-4) flight data. However, to mass production was brought only option Bomber.
Mass production of Yak-2 engine M-103 and Yak-4 engine M-105 was short-lived. It was released about 600 machines, which applied only at the beginning of the war. Compared with other domestic bombers Yak-4 was the clear underdog in solving any combat mission. It should be recognized, that the adoption of the Air Force of the aircraft is a blunder UWS and Defense Committee. Real combat value he had no idea, but the forces and means at its introduction in the series and in the development of many parts of it has been spent. But AS. Yakovlev for this car was awarded the Order of Lenin, ZIS and a premium of 100 thousand. rubles.
Tactical-technical characteristics Yak-4
– First flight: March 1940 of the year
– End of operation: 1942 year
As a crew-4
– 2 man
The dimensions of the Yak-4
– Length: 10,18 m
– Wingspan: 14 m
– wing area: 29,4 m²
As Wes-4
– empty weight: 4 000 kg
– curb weight: 5 845 kg
Once the engine 4
– 2× liquid cooled V-12 M-105
– Power: 2× 1100 hp.
How to Speed 4
– full speed: 574 kmh
– Cruising speed: 545 kmh
– Skoropodъёmnost: 15,33 m / s
Flight range Yak-4
– 960-1200 km
Practical ceiling Yak-4
– 9 500 – 10 000 m
As Vooruzhenye 4
– Pulyemyotnoye: 2-3 × 7,62 mm machine gun ShKAS
– bomb-load: 400-800 kg
As photo-4
