Ilyushin Il 10

Development

From the beginning of the Eastern Front combat in the World War II, the Soviet Air Force used a successful ground attack aircraft Ilyushin Il-2, powered by the Mikulin AM-38 inline engine. As the war progressed, the Soviets started searching for its successor. The main goal was to increase speed and manoeuvrability on low altitudes, in order to evade small calibre anti-aircraft artillery, which was the main danger for ground attack aircraft, and to remove some other Il-2 faults. The most promising project was a modern light and manoeuvrable close assault aircraft Sukhoi Su-6, developed by Pavel Sukhoi's bureau from 1942. At the same time, Sergey Ilyushin developed heavier aircraft VSh or Il-8 M-71, coming from the Il-2 design, on which it partly based. Both projects were powered by the prototype M-71 radial engine, which was not produced.

In 1943 Ilyushin undertook works upon a new aircraft Il-1, which was to be a 1- or 2-seater heavy armoured fighter-attacker, meant primarily for fighting enemy bombers and transports. The Il-1 was similar to Il-2 design, but was more modern and compact, and powered with a new Mikulin engine AM-42. The airforce however gave up the idea of heavy armoured fighters, due to their low speed, not enough to intercept modern bombers. As a result, Ilyushin decided to turn Il-1 into a 2-seater ground attack plane, with a designation changed to Il-10 in early 1944 (odd numbers were reserved for fighters). In the spring of 1944, the Il-10 was flown, and underwent state trials in June, with a success.

At that time, Ilyushin completed also a prototype of a heavier ground attack plane, the Il-8, with the same engine, coming from the Il-2 design. It carried more payload (1000 kg), but had worse performance, than Il-10. The third competitor was a new variant of the Sukhoi Su-6, also with the AM-42 engine. After comparative tests, the Il-10 was considered the winner and chosen a new ground attack plane, despite that according to some opinions, the Su-6 was better aircraft, with similar performance, but better armament (it is noteworthy, that Su-6 prototype was tested with maximum payload, what caused worse performance, while the Il-10 was tested with normal payload). Some advantage of the Il-10 was its technical similarity to the Il-2.

Production

By decision of the State Defence Committee (GKO) of August 23, 1944, the Il-10 was put into serial production as a new ground attack plane. Its armament was similar to late Il-2s, with two 23 mm WYa-23 cannons and two machine guns in wings, a 12.7 mm machine gun of a rear gunner and 400 kg, or maximally 600 kg of bombs. Contrary to Il-2 and Su-6, initially it was not meant to carry rockets.

A production of Il-10 started in factories no. 1 and no. 18 in Kuybyshev. The first serial plane was flown on September 27, 1944 and 99 aircraft were produced by the end of 1944. Early series planes showed teething problems, most notably engine faults and fires. Most of them were eliminated in 1945. Aircraft produced from April 1945 could carry four unguided air-to ground rockets. Aircraft produced from 1947 were fitted with stronger armament of four 23 mm NS-23 cannons in wings and a 20 mm cannon of a rear gunner. The production ended in 1949, after producing 4600 aircraft Il-10 (in the last two years, they were produced in the factory no. 64).

In 1945-47 there were also produced 280 of trainer aircraft variant UIl-2 or Il-10U. The rear gunner cab was replaced with a longer instructor cab, with dual controls. Its performance and construction were similar to the combat variant, apart from the armament, which was reduced to two cannons, two rockets and a standard load of bombs.

In 1951, the Czechoslovak works Avia took up a licence production of Il-10, under a designation B-33. The first B-33 was flown on December 26, 1951. Initially their engines were Soviet-built, from 1952 they were also produced in Czechoslovakia as the M-42. Apart from the combat variant, there was produced a trainer variant, under a designation CB-33. In total, 1200 Avias were made by 1956.

In 1951, due to the Korean War experience, the Soviet Air Force decided, that propeller ground attack aircraft might still be useful, and decided to renew Il-10 production in a modified variant Il-10M. It was first flown on July 2, 1951. It was a bit longer and had greater wingspan, also steering surfaces were bigger, with a fin under a tail. Four newer cannons NR-23 were mounted in wings, the payload remained the same. A navigation equipment was also newer. Its performance slightly decreased, but a handling improved. In 1953-54, 146 Il-10M were made, all but 10 in the factory no. 168 in Rostov-on-Don.

In total, 6,226 of all Il-10 variants were made, including licence ones.

There were trials of Il-10 with stronger AM-43 and AM-45 engines, but they were not successful. Ilyushin next designed a lighter close assault plane Il-16, with improved performance and a similar armament. It was flown on June 10, 1945, and a manufacturing of a small series started, but the works were cancelled in 1946 because of the AM-43 engine unreliability.

Service

In the Soviet Air Force, Il-10 first entered into training units in October 1944. In January 1945 the first Il-10 combat unit entered service (the 78th Guards assault aviation regiment), but it did not enter action due to unfinished training. However, three other Il-10 units managed to take part in the final combat actions of the World War II in Europe. They were: the 571st assault aviation regiment (from April 15, 1945), the 108th Guards assault aviation regiment (from April 16, 1945) and the 118th Guards assault aviation regiment (on May 8, 1945). About dozen aircraft were destroyed by the Flak or due to engine breakdowns, but the Il-10 appeared a successful design. One was shot down by a Fw 190 fighter, but a crew of the 118th regiment shot down other Fw 190 and probably damaged the next one. On May 10, 1945, there were 120 serviceable Il-10 in Soviet Air Force combat units, and 26 broken down ones.

After the USSR entered the war against Japan, from August 9, 1945, one Il-10 unit - the 26th assault aviation regiment of the Pacific Navy Aviation, was used in combat in Korean Peninsula, attacking Japanese ships in Rasin and rail transports.

After the war, until the early 1950s, the Il-10 was a basic Soviet ground attack aircraft. They were withdrawn in 1956. At the same time, works upon new jet armoured ground attack planes (like Il-40) were canceled, and the Soviets turned to fighter-bomber aviation. Il-10 and its licence variant B-33, became also a basic ground attack plane of the Warsaw Pact countries. In Poland, from 1949 until 1959 there were used 120 Il-10 (including 24 UIl-10) and 281 B-33. The B-33 was modified in Poland to carry 400 l additional fuel tanks under wings. In Czechoslovakia 86 Il-10 (including 6 UIl-10) and about 600 B-33 were used in 1950-60. In Hungary, 159 Il-10 and B-33 were used in 1949-56. Romania used 30 Il-10 and 150 B-33 in 1953-60. Also Bulgaria used these aircraft.

In the late 1940s, 93 Il-10 and UIl-10 were given to the North Korea. They were next used in the 57th assault aviation regiment during the early phase of the Korean War. They were initially used with a success against weak anti-aircraft defence of South Korean forces, but then they suffered heavy losses in encounters against the US fighters and became bombed on the ground themselves. After several weeks, there remained about 20. In summer of 1950, North Korea received some further aircraft from the USSR. The North Korean claimed to sink a warship on August 22, 1950 with Il-10, but it is not confirmed.

From 1950, Il-10 were used by China, in two regiments of an assault aviation division. They were used in combat during conflict with Taiwan on border islands in January 1955. They remained in service as long, as until 1972. From 1957, 24 B-33's were used by Yemen.

Technical description

Single engine two-seater monoplane of metal construction, metal-covered. Front part of a fuselage, with a crew cab, was a shell of armour plates 4-8 mm thick. Thickest plates 8 mm were under engine, above engine there was no armour. Front windshield was made of armour glass 64 mm thick. Armoured were also: a roof above the pilot, side window frames in the pilot's cab, a wall between crewmen seats and a rear wall behind a cab. A total weight of armour was 994 kg, including its attachment. The wing consisted of a central section, with two bomb bays, and two detachable outer sections. Retractable undercarriage, main gear was folding rearwards, after turning at 86°.

Gunnery armament: early Il-10 had two autocannons 23 mm WYa-23 (150 rounds each) and 2 machine guns 7.62mm ShKAS (750 rounds each) fixed in wings, and a 12.7 mm UBT machine gun in a rear gunner station BU-8, with 150 rounds. A horizontal angle of a rear machine gun fire was 100°. From 1947 the aircraft were armed with four 23 mm cannons NS-23 in wings (150 rounds each) and 20 mm B-20T cannon in a rear gunner station BU-9 (150 rounds). IL-10M had four 23 mm NR-23 cannons in wings (150 rounds each) and 20 mm B-20EN cannon in a rear gunner station BU-9M (150 rounds). Avia B-33 had four 23 mm NS-23RM cannons in wings and 20 mm B-20ET cannon in a rear gunner station BU-9M.

Normal bomb load was 400 kg, maximum 600 kg. There could be used small fragmentation or anti-tank bomblets, put in bomb bays, or four 50 - 100 kg bombs in bomb bays and externally under wings, or two 200 - 250 kg bombs attached under wings. Small bomblets were put directly on bomb bay floor, in piles. Typical load was for example 182 (maximum 200) of 2 kg AO-2,5-2 fragmentation bombs, or 144 of PTAB-2,5-1,5 anti-tank HEAT bombs. Apart from bombs, four unguided rockets RS-82 or RS-132 could be carried on rail launchers under wings. Avia B-33 was also fitted to carry other rocket types. Late Soviet aircraft could carry ORO-82 and ORO-132 tube launchers. In a tail section, there was a DAG-10 launcher with 10 anti-aircraft or anti-personnel grenades AG-2 (after being thrown, they would fall with parachutes and then blow up - but they were not widely used in practice).

Engine: 12 cylinder inline (V) engine Mikulin AM-42, liquid-cooled, power: 1770 hp, start power: 2000 hp. Three-blade propeller AV-5L-24 with a diameter of 3.6 m. Two fuel tanks in a fuselage: upper 440 l over engine, before crew cab, and lower 290 l below a crew cab. The aircraft had a radio set and a camera AFA-1M in a rear section of fuselage.

Specifications (Il-10)

General characteristics
Crew: Two - pilot and gunner
Length: 36 ft 6 in
Wingspan: 44 ft 0 in
Height: 13 ft 5 in
Wing area: 322.9 sq. ft
Empty weight: 0,305 lb
Loaded weight: 14,000 lb
Maximum gross takeoff weight: 14,410
Powerplant: 1× Mikulin AM-42 liquid-cooled V-12, 1,770 hp (1,320 kW)

Performance
Maximum speed: 5at ground level 340 mph at 8,860 ft / 310 mph
Range: 500 mi)
Service ceiling: 13,120 ft
Wing loading: 43.2 lb/ft²

Armament
4x 23 mm Nudelman-Suranov NS-23 cannons in wings, 150 rounds each
1x 20 mm Berezin B-20T cannon in the BU-9 rear gunner station, 150 rounds
Up to 600 kg (1,320 lb) of various weapons