The MiG-3 is a further development of the MiG-1 with only minor differences. To cure the poor spin performance of the MiG-1, automatic slats were added. No other country had such a high-speed, high-altitude interceptor in service, and even the Luftwaffe was taken by surprise when some of its high-altitude reconnaissance planes were lost to unseen Soviet fighters. The MiG-3 was almost perfectly suited for its designated role, but the well-known events of 1941 forced pilots to engage the MiG-3 as a replacement for conventional fighters or even ground attackers. It was a forced misuse of a good high-altitude interceptor with limitations in low-altitude performance. At the beginning of the Great Patriotic War (what was WWII for Soviet people) many MiG pilots rammed German bombers after running out of ammunition - often the order was "to stop bombers by any means". All were equipped with protected fuel tanks with neutral gas filling. This somewhat 'cushioned' other low-altitude deficiencies. The Soviets built 3,322 MiG-3 variants. The aircraft was in service almost until the end of the war, thanks to exceptionally easy maintenance, reparability and part compatibility. Generally, a flying MiG-3 could be assembled in the field from two or three irreparable aircraft.