The Yakovlev Yak-4 (Service names Yak-4, BB-22bis (Blizhnij Bombardirovschik, "short-range bomber")) was a Soviet light bomber used during World War II. It was developed from the Ya-22/Yak-2. Design and development The Yak-4 was an improved version of the Yak-2 with more powerful Klimov M-105 engines and a number of other changes that were made to try to rectify the problems of the Yak-2. Two additional fuel tanks were added in the outer wings to bring the total capacity up to and the gunner's canopy was bulged to give him more room to use his ShKAS machine gun. The upper fuselage was redesigned to improve the gunner's field of fire and the oil coolers were relocated from the sides of the engine nacelles to the 'chin' position to improve their performance. Operators VVS Specifications (Yak-4) References Further reading External links Yak-4 description on aviation.ru Yak-004 1940s Soviet bomber aircraft World War II Soviet bombers Aircraft first flown in 1940 Twin piston-engined tractor aircraft