Ilyushin Il-10 - Development

Development

From the start of Eastern Front combat in World War II, the Soviet Air Force (VVS) used the successful ground attack aircraft Ilyushin Il-2 Sturmovik, powered by the Mikulin AM-38 inline engine. As the war progressed, the Soviets laid plans for that aircraft's successor. The main goal was to increase speed and maneuverability at low altitudes, mainly to evade small-caliber anti-aircraft artillery, which was the main threat for ground attack aircraft, and to remove some of the Il-2's faults. The most promising project was a modern, light and maneuverable close assault aircraft, the Sukhoi Su-6, developed by Pavel Sukhoi's bureau from 1942. At the same time, Sergei Ilyushin developed a heavier aircraft, the VSh or Il-8 M-71, derived from the Il-2 design, and on which it was partly based. Both projects were powered by the prototype M-71 radial engine, which did not enter production.

In 1943, Ilyushin started work on a new aircraft, Il-1, which was to be a 1- or 2-seat heavily armoured fighter-interceptor, meant mainly for fighting enemy bombers and transports. The Il-1 was similar to the Il-2 design, but was more modern, compact, and powered with a new Mikulin engine: the AM-42. But the VVS gave up the idea of heavy armoured fighters, due to their low speed, which was not enough to intercept modern bombers. As a result, Ilyushin decided to turn the Il-1 into a two-seat ground attack plane, with the designation changed to Il-10 in early 1944 (odd numbers were reserved for fighters).

At that time, Ilyushin also finished a prototype of a heavier ground attack plane, the Il-8, using the same engine, and more closely derived from the Il-2. It carried a higher payload (1,000 kg/2,204 lb), but had lower performance than the Il-10. Both types first flew in April 1944, the Il-10 proving greatly superior to the Il-8, which had poor handling. The Il-10 successfully passed trials in early June 1944.

The third competitor was a new variant of the Sukhoi Su-6, also powered by the AM-42 engine. After comparative tests, the Il-10 was considered the winner and was chosen as the new ground attack plane, despite some opinions that the Su-6 was a better aircraft, notwithstanding inferior performance and payload, with better gun armament. Notably, the Su-6 prototype was tested with maximum payload, causing lowered performance, while the Il-10 was tested with normal payload. Some advantages of the Il-10 came from its technical similarity to the Il-2.