I-220, A, MiG-11
The first prototype of MiG-11 was called “A”, and received NKAP designation I-220. Two prototypes were ordered, to be fitted with AM-39 engines, but I-220 No. 01 began its flight-test programme with the AM-38F, with a takeoff power of 1,700hp and maximum power of l,500hp at the low full-throttle height of 4,800m (15,750ft), which was well suited to this engine’s production application, the M-2. Each cylinder had its own ejector exhaust stub, and the propeller was the three-blade AV-5A, with standard diameter of3.6m(11ft9in).
The MiG-11 fuselage was mainly of multilayer shpon construction, with a steel-tube truss to carry the engine. The pilot was placed near the centre of gravity, ahead of the two fuselage fuel tanks. The tail was a light-alloy structure, bolted on to the fuselage longerons, generally similar to the tail of the I-230, with the tailplane mounted high but with its span increased from 3.66 to 3.75m (12ft 3in). The wing was entirely new. Aerofoil profile was a CAIII laminar type, with the maximum thickness at about 40 per cent chord. The horizontal centre wing, with a span of 3.96m (13ft), was entirely of D16 light alloy except for the 30KhGSA booms of the main spar. This duralumin/steel spar was continued in the outer panels, but these were otherwise mainly of wood, apart from being fitted with full-length duralumin slats. Taper on the outer wings was entirely on the leading edge. Large split flaps were fitted to the centre wing and outer panels. It is believed that this and all derived prototypes were designed to an ultimate load factor of 8.
All air inlets were in the leading edge of the centre wing. At the roots were deep 4letterbox’ intakes for the supercharger and for the two oil coolers. Outboard, extending to the end of the region in the propeller slipstream, were shallower inlets serving the very efficient box-type glycol radiators behind the main spar, with controllable exit flaps in the wing upper surface from 52 to 57 per cent chord.
Also novel was the main landing gear. Each unit comprised a main leg of high-strength steel, at the lower end of which was pivoted a forged link projecting ahead, parallel to the ground with the aircraft parked, carrying the wheel 350mm (13.8in) in front of the axis of the leg. A separate olco shock strut was pin-jointed to the top of the leg” and to the top of a n-frame holding the axle. This multiplied the stroke of the shock strut so that on rough ground vertical travel of the wheel could be 515mm (20.3in). Track was 3.652m (143.8in), and tyre size 650 x 200mm (the same as the MiG-3, despite the greater weight). Retraction inwards was pneumatic, the wheel bays being faired by Hat doors hinged on the aircraft centreline. Cables retracted the tailwheel, which was of a new design, tyre size being 350 x 125mm.
Another innovation on MiG-11 was that all fuel tanks were ‘soft’ bladders, made of rubberized fabric with a self-sealing coating. Despite the modest capacity there were six tanks, four small cells in the wings and two in the fuselage. The fuselage tanks were installed from below and supported on an aluminium ‘cup’ inside a container made of special fireproof plywood coated on both sides with chlorovinyl varnish. The broad cockpit was designed for eventual prcssurization, but this was not fitted. The canopy slid directly to the rear. Like Curtiss fighters, the pilot had a limited rear view through the fixed aft canopy past the recessed plywood deck behind his seat. Inside this deck was the radio, served by a wire antenna direct to the fin.
Reflecting combat experience, the intended armament was four 20mm ShVAK cannon, two above the engine and two beside the crankcase, each with 150 rounds. In fact, only the upper pair were actually installed. It is surprising that the lower blast tubes were not faired over.
MiG-11 No. 01 was painted in three-tone dark green/pale brown/ pale grey camouflage, with white-bordered national markings. This aircraft was rolled out at Khodynka in June 1943. It was first flown in July 1943, the assigned pilot being A P Yakimov. Later testing involved other pilots, including PA Zhuravlyov and 11 Shelest. It proved to be an outstanding aircraft, marred only by the low-altitude rating of the engine. Had it gone into production the VVS would have allotted the next fighter (odd-number) designation, MiG-11.
Aircraft A No. 02 was the first of these larger fighters to be powered by the AM-39 engine, with a takeoff rating of 1,800hp and maximum rating of 1,500hp at 7,100m (23,294ft). It had all four guns fitted, though with only 100 rounds each. It is believed to have been the first Soviet aircraft with a whip-type radio antenna, serving an RSI-4 radio behind the cockpit.
Aircraft No. 02 was rolled out in July 1943. Predictably, its empty weight was greater than that of the two-gun No. 01, but what is not explained is how No. 02′s loaded weight could be fighter. Its factory flight-test programme in July-August 1943 was mainly in the hands of Shelest. Later many other pilots were involved, and NII-VVS testing took place between 14-24 July 1944. According to Shavrov, these were halted by engine failure. Among the criticisms were rather heavy elevator and aileron loads, difficulty of getting the landing gear to lock up and inadequate rearward visibility.
Meanwhile, aircraft No. 01 had been re-engined with the AM-39 and subjected to continued factory testing in January-August 1944. Long before this, the design staff had moved on to produce developed versions of the same basic design. In the data below the figures in square brackets refer to I-220 No. 02.