Mikoyan-Gurevich MiG-3U / I-230

With the primary objective of improving the aerodynamics of the basic MiG-3 design, the OKB began work late in 1941 on an enhanced version of the fighter to which it gave the Izdeliye designation of D. Known officially as the I-230, and later as the MiG-3U - the suffix letter signifying uluchshenyi (improved) - the new fighter was first flown in August 1942.

Whereas the fuselage of the MiG-3 was primarily of steel tube with duralumin skinning, that of the I-230 was almost entirely of wood owing to the contemporary metal shortages. By comparison with the MiG-3, the fuselage was lengthened by 37cm, but the Mikulin AM-35A engine was retained and the wing of the first prototype was unchanged, armament consisting of two 20mm SP-20 (ShVAK) cannon mounted above the engine.

The second prototype differed in having a larger wing of 18.00sq.m area and spanning 11.00m. Performance proved good during factory and state trials, but it was not possible to reinstate production of the AM-35A and production of the I-230 was therefore restricted to a pre-series of five aircraft which were assigned to a Guards Regiment (1 GvIAP) on the Kalinin front for service evaluation.

Prototype 1
Engine: Mikulin AM-35A, 1200 hp
Wingspan: 10.20 m / 33 ft 6 in
Length: 8.62 m / 28 ft 3 in
Wing area: 17.44 sq.m / 187.72 sq ft
Max take-off weight: 3285 kg / 7242 lb
Empty weight: 2612 kg / 5759 lb
Max. speed: 660 km/h / 410 mph
Range: 1350 km / 839 miles