WWII Soviet fighter
The Yak-9K is a front-line fighter with heavy cannon armament. It became a continuation
 of the Yak-9 fighter line and a modification of the serial Yak-9T aircraft. Its feature was
 a 45-mm gun NS-45, which was placed in the vee of the engine  and fired through the
 gearbox shaft. To reduce the force of recoil when fired, the barrel of the gun was equip-
 ped with a clearly visible muzzle brake, which absorbed up to 85% of the energy of the
 shot and was the main visual difference of the aircraft. The armament also included a
 large-caliber UBS machine gun. Shooting from a cannon and a machine gun could be
 conducted simultaneously, and they could also be used separately. The ammunition
 consisted of 29 cannon shots and 200 cartridges for the machine gun. Powerful gun
 armament made it possible to hit enemy aircraft with a single projectile. These
 aircrafts were involved in combat operations at the front and were recommended
 for adoption as one of the main types of fighters. However, its 45 mm gun was
 underdeveloped, and despite its powerful armament, the fighter was only produced
 in a small series.