Designed to meet the demands of a twin-engined all-weather fighter programme initiated in January 1948, the MiG OKB offered the Izdeliye R, a side-by-side two-seat swept-wing fighter with the engines in tandem. The nose intake fed a plenum chamber around the forward engine compressor, this engine exhausting below the fuselage and a duct leading back to the aft engine which exhausted via an orifice in the extreme tail. Armament comprised three 37mm N-37 cannon.
Competing with proposals from the Lavochkin and Yakovlev bureaux - all three contenders being awarded three-prototype contracts - the MiG fighter was assigned the official designation I-320.
The first prototype, the R-1 powered by two 5,005 lb st (2270 kgp) RD-45F engines, was flown on 16 April 1949.
The R-2 and R-3 were each powered by paired of 5,952 lb st / 2700kg VK-1 engines and embodied various modifications, the R-3 featuring a strength-ened wing. The VK-1-powered prototypes could take-off and cruise on the power of either engine, and the I-320 was initially tested with Torii-A (Thorium-A) radar mounted in a cone above the air intake. This single-antenna radar which demanded manual tracking was succeeded by the basically similar but improved Korshun (Kite) radar with which the I-320 was tested during July-August 1951. Development of the I-320 was discontinued when the requirement to which it had been designed was overtaken by a more advanced one. Develop-ment was discontinued in favour of the Yak-25 which was capable of accommodating a larger radar.
Engines: 2 x RD-45F, 5,005 lb st (2 270 kgp)
Max speed, 658 mph (1 060 km/h) at 14,765 ft (4 500 m)
Ceiling, 49,540 ft (15 100 m)
Endurance, 3.0 hrs
Empty weight, 16,241 lb (7 367 kg)
Loaded weight, 22,630 lb (10 265 kg)
Span, 46 ft 7 in (14,20 m)
Length, 51 ft 8 7/8 in (15,77 m)
Wing area, 443.47 sq ft (41,20sq.m)
Max take-off weight: 12095 kg / 26665 lb
Wingspan: 14.20 m / 46 ft 7 in
Length: 15.77 m / 51 ft 9 in
Wing area: 41.20 sq.m / 443.47 sq ft
Max. speed: 1090 km/h / 677 mph
Range: 1205 km / 749 miles