The Yakovlev Yak-4 was a mixed Soviet light reconnaissance and bomber in a low wing configuration. The drive was provided by two Klimow M-105 engines with 1100 HP each . The flight of the prototype took place in 1939, and in the years 1939-1941 serial production continued, which led to the creation of about 90 aircraft of this type. They were armed with two 7.62 mm SzKAS machine guns and a load of up to 600 kg of bombs.
The Yak-4 was created in response to the demand of the Soviet military aviation for a new light bomber. Aleksander Jakowlew, when designing the new plane, put emphasis on the best possible performance and high top speed. These assumptions were met because one of the first prototypes (designation: Yak-2), without bombs and combat equipment, achieved a speed of 567 km / h during the tests! This result so impressed Stalin that he immediately sent the plane to mass production. However, in the course of its course and further trials, it turned out that the machine required replacement of engines, which also happened in 1939, and the new plane already had the Yak-4 designation. However, despite the fact that the engine was changed, the Yak-4 was far from perfect: it had too weak defensive armament, it had poor maneuverability and slightly worse performance than the prototypes when loaded with bombs and combat equipment. Despite these shortcomings, the aircraft entered line service from 1940. In 1941, he fought in Belarus and Ukraine against the advancing German units, but due to poor methods of using these machines, they suffered considerable losses in the summer of that year. In the same year, its production was stopped, and the surviving machines served as reconnaissance planes.
