Lacking the time for a redesign of the MiG-1 to eradicate the fighter's less acceptable characteristics, a series of ‘fixes’ were applied to the basic design to result in the MiG-3.
Power plant and (initially) armament remained unchanged, but some structural simplification and strengthening was introduced. The engine was moved forward 10cm and dihedral of the outer wing panels was increased by one degree. A 250 lt supplementary fuel tank was introduced beneath the pilot's seat, the aft fuselage decking was cut down, and the radiator bath fairing was enlarged and extended forward. The supercharger intakes were revised; 9mm seat armour was provided, together with radio, and four wing hardpoints were introduced for a maximum external load of 220kg.
The first MiG-3 left the factory in December 1940, 11 being completed by the end of the month. 140 were produced in January 1941, and, by June, production had peaked at 25 aircraft every 24 hours. The first MiG-3 was delivered to a VVS regiment in April 1941, simultaneously with the MiG-1, and production continued until 23 December 1941 with approximately 3,120 built, but 50 more were completed from component stocks in the early summer of 1942.
Some MiG-3s had a supplementary pair of 12.7mm BK machine guns under the wings, raising take-off weight to 3510kg, and others were fitted with two 12.7mm UBK guns in the wings.
Tests were also performed with two fuselage-mounted 20mm ShVAK cannon.
Engine: Mikulin AM-35A, 1200 hp.
Wingspan: 10.20 m / 33 ft 6 in
Length: 8.25 m / 27 ft 1 in
Height: 2.65 m / 8 ft 8 in
Wing area: 17.44 sq.m / 187.72 sq ft
Max take-off weight: 3350 kg / 7386 lb
Empty weight: 2699 kg / 5950 lb
Max. speed: 360 mph
Range: 820 km / 510 miles
Armament: 2 x 50 mg, 2 x .30 mg