Yak-1 - single-seat fighter aircraft. Initial production version. 1 x 20 mm ShVAK cannon + 2 x 7.62 mm ShKAS machine guns.
Yak-1b - after October 1942, all Yak-1 were built with bubble canopy with lowered rear fuselage, increased armor, single 12.7 mm Berezin UBS machine gun replaced the two 7.62 mm ShKAS machine guns (with 1 x 20 mm ShVAK cannon), new gunsight, airtight fuselage, retractable tailwheel, improved engine cooling, Klimov M-105PF engine with better low-altitude performance. 4,188 were built.
Battle of Stalingrad [23 Aug 1942 - 2 Feb 1943] - Germany fought the Soviet Union for control of the city of Stalingrad (now Volgograd) in Southern Russia.