Yak-9K
Yak-9K modified with a 45 mm Nudelman-Suranov NS-45 cannon with 29 rounds of ammunition and a distinctive muzzle brake to deal with the massive recoil. Firing the cannon at speeds below 350 km/h (220 mph) caused dramatic loss of control and tossed the pilot back and forth in the cockpit, however accurate shooting was possible at higher speeds and in 2-3 round bursts. The recoil also caused numerous oil and coolant leaks. The heavy cannon installation degraded performance sufficiently to require fighter escort. Yak-9K saw only limited use due to unreliability of the NS-45.
i dont think we should have it cause its to unstable, but it think its cool that it had a 45mm cannon that could totally take down ealry panzers, and bombers.