|Ilyushin Il-22 in front view|
|National origin||Soviet Union|
|First flight||22 July 1947|
The Ilyushin Il-22, USAF/DOD designation Type 10,was the first Soviet jet-engined bomber to fly. It used four Lyulka TR-1 turbojets carried on short horizontal pylons ahead and below the wing. The engines did not meet their designed thrust ratings and their fuel consumption was higher than planned. These problems meant that the aircraft could not reach its required performance and it was cancelled on 22 September 1947.
The Council of Ministers ordered the Ilyushin design bureau on 12 February 1946 to begin work on a bomber that would use four of the new TR-1 jet engines. Experiences with the first generation of jet fighters had revealed unsuspected problems involved with high-speed flight and Ilyushin devoted much effort to mitigate them. The long and thin unswept wing was conventional in appearance, but it was shaped to improve lateral stability at high angles of attack and to prevent the onset of tip stall.
Another problem discovered by the jet fighters was unexpectedly dropping a wing at high speeds and high altitudes. This was traced to manufacturing defects in the wings that made no difference at low speeds and altitudes, but meant that each wing had a slightly different airfoil and, hence, a different amount of lift. To counter this Sergey Ilyushin and his team developed a new manufacturing technique that reversed the traditional practice where the internal supporting members were affixed to the assembly jig and the aircraft's skin panels were then attached. This new method meant that the skin panels were placed in the jigs where the correct curvature and shape could be guaranteed and the internal structure was then fastened to them. This required that manufacturing joints be used along the chord lines of the wings and tail surfaces, which split the spars and ribs in half. Similarly, the fuselage was built the same way, although it was split vertically along the centerline. This new technique did impose a small weight penalty but had the unexpected advantage of greatly accelerating the assembly process, as the internal equipment could be installed before the halves were joined together. This allowed several teams to work on a single sub-assembly before they were mated.
Most of the other multi-engined jet aircraft in existence, when the Il-22 was being designed, either had the engines in a nacelle (singly or in pairs) directly attached to the underside of the wing or were buried in the wing itself. Clustering them in a nacelle offered several advantages over individual nacelles, as it reduced overall drag and minimized interference drag, but had the major operational disadvantage that an uncontained fire in one engine could disable its neighbor as well. Early jet engines were not reliable, so this was a significant risk. Ilyushin chose to put the TR-1 engines ahead and below the wing leading edge on short horizontal pylons. This gave them the beneficial effect of acting as anti-flutter weights and proved to be more efficient aerodynamically than underwing nacelles. This also facilitated engine changes and maintenance by making them more accessible to the ground crews.
Neither the thin wing nor the engine nacelles offered any place to store the main landing gear so the fuselage was designed as a flattened oval to give them as wide a track as possible. This also provided plenty of room for the 9,300 kg (20,500 lb) of fuel stored in three bags, one each ahead, above and behind the bomb bay. This could carry up to 3,000 kg (6,600 lb) of bombs. The stepless fuselage nose was largely glazed and came to a rounded point (similar to the noses of the Boeing B-29 Superfortress, Heinkel He 111 and Arado Ar 234) to reduce drag. The Il-22 had a crew of five, two pilots in the nose, the bombardier-navigator in front of them in the tip of the nose, the dorsal gunner/radio operator immediately behind the pilots and the rear turret gunner behind the tail.
A 23-millimetre (0.91 in) Nudelman-Suranov NS-23 autocannon with 150 rounds was fixed on the lower starboard side of the nose; it was fired by the pilot who had a primitive ring sight to use for aiming. The dorsal turret mounted two 20-millimetre (0.79 in) Berezin B-20E guns with 400 rounds per gun and was capable of 360° of traverse, with special microswitches preventing the gunner from firing into the bomber's tail. The turret was remotely controlled by the radio operator and was powered by electric motors for both traverse and elevation. The gunner and his gunsight used a small observation blister at the rear of the main crew compartment to lay the guns on their target. The sight automatically compensated for parallax between the gunner and the turret as well as the required amount of target lead and the shell's ballistics. The remote-control system offered several advantages including a smaller turret that had less drag, the guns could be fixed more rigidly to their mounts, the sight was not exposed to vibrations from firing and could track targets more smoothly and the gunner's comfort did not have to be sacrificed to optimize the performance of the turret. The major disadvantage, of course, was that the analog computer remote control system was exceedingly complicated for the period and prone to breaking down, just like the even more complex systems in use on the B-29 Superfortress. The rear gunner was placed at the very tail of the Il-22 to optimize his field of fire in an electro-hydraulically powered Il-KU3 turret that mounted another NS-23 cannon. The turret could traverse a total of 140°, elevate 35° and depress 30°.
The prototype Il-22 was rapidly assembled and made its first flight on 24 July 1947. It proved to have docile handling characteristics, but was severely underpowered as the TR-1 engines produced only 80% of the required thrust. During the latter part of the manufacturer's flight tests the Il-22 made the first-ever Soviet jet-assisted (rocket-assisted, RATO) takeoff on 7 February 1948 with a pair of SR-2 boosters. As the thrust of the engines could not be increased in a timely manner Ilyushin made the decision not to submit the bomber for state acceptance trials as its performance did not meet the requirements laid down for it in 1946.
Data from Early Soviet Jet Bombers
Aircraft of comparable role, configuration, and era
The Ilyushin Il-4 (DB-3F) was a Soviet twin-engined long-range bomber and torpedo bomber, widely used by the Soviet Air Force and the Soviet Naval Aviation during the World War II.
The Ilyushin Il-28 is a jet bomber of the immediate postwar period that was originally manufactured for the Soviet Air Forces. It was the Soviet Union's first such aircraft to enter large-scale production. It was also licence-built in China as the Harbin H-5. Total production in the USSR was 6,316 aircraft, and over 319 H-5s were built. Only 187 examples of the HJ-5 training variant were manufactured. In the 1990s hundreds remained in service with various air forces over 50 years after the Il-28 first appeared. The only H-5s in service currently are approximately 80 aircraft which operate with the Korean People's Air Force. The Il-28 has the USAF/DoD reporting name "Type 27" and NATO reporting name "Beagle", while the Il-28U trainer variant has the USAF/DoD reporting name "Type 30" and NATO reporting name Mascot.
The Tupolev Tu-14, was a Soviet twinjet light bomber derived from the Tupolev '73', the failed competitor to the Ilyushin Il-28 'Beagle'. It was used as a torpedo bomber by the mine-torpedo regiments of Soviet Naval Aviation between 1952–59 and exported to the People's Republic of China.
The Ilyushin DB-3, where "DB" stands for Dalniy Bombardirovschik meaning "long-range bomber", was a Soviet bomber aircraft of World War II. It was a twin-engined, low-wing monoplane that first flew in 1935. It was the precursor of the Ilyushin Il-4. 1,528 were built.
The Ilyushin Il-6 was a Soviet long-range bomber developed from the Ilyushin Il-4 during 1942. Originally intended as a high-speed replacement for the Il-4, it was recast as a very long-range bomber with fuel-conserving diesel engines before production of the single prototype began in December 1942. Flight testing showed controllability issues when landing at high weights and the engines proved to be hard to start at low temperatures and were slow to respond to throttle movements. Further development was canceled in 1944.
The Ilyushin Il-30 was a Soviet turbojet-powered tactical bomber designed as a higher-performance, swept wing version of the Ilyushin Il-28, in the late 1940s. Its thin wing and engine nacelles necessitated the use of tandem landing gear, the first Soviet aircraft to do so. It was apparently canceled before the prototype made its first flight, although sources disagree with this.
The Sukhoi Su-6 was a Soviet ground-attack aircraft developed during World War II. The mixed-power high-altitude interceptor Su-7 was based on the single-seat Su-6 prototype.
The Sukhoi Su-10 or Izdeliye Ye was a Soviet turbojet-powered bomber aircraft built shortly after World War II.
The Ilyushin Il-20 was a Soviet prototype for a heavily armored ground-attack aircraft to replace the Ilyushin Il-10. It featured a number of innovative concepts including a cockpit mounted on top of the engine, directly behind the propeller, and wing-mounted autocannon that could be adjusted on the ground to fire level or depressed 23° to allow the aircraft to strafe ground targets while remaining in level flight. However it was slower than the Il-10, and its M-47 engine was problematic in flight tests in 1948–49. It was not placed into production. The test pilots called the aircraft the Gorbach (Hunchback).
The Ilyushin Il-40 was a two-seat Soviet jet-engined armored ground-attack aircraft. The first prototype flew in 1953 and was very successful except when it fired its guns, as their combustion gasses disturbed the airflow into the engines and caused them to flameout or hiccup. Remedying this problem took over a year and involved the radical change of moving the engine air intakes all the way to the very front of the aircraft and repositioning the guns from the tip of the nose to the bottom of the fuselage, just behind the nosewheel. The aircraft, now resembling a double-barreled shotgun from the front, was ordered into production in 1955. Only five production aircraft had been completed before the entire program was canceled in early 1956 when the VVS discarded its close air-support doctrine in favor of tactical nuclear weapons on the battlefield.
The Tupolev Tu-12 was an experimental Soviet jet-powered medium bomber developed from the successful piston-engined Tupolev Tu-2 bomber after the end of World War II. It was designed as a transitional aircraft to familiarize Tupolev and the VVS with the issues involved with jet-engined bombers.
The Il-54 was a transonic bomber developed in the USSR in the 1950s. Only two examples were built before the project was abandoned.
The Ilyushin Il-46 was a jet-engined bomber produced in the USSR during 1951-2, as the result of a directive to redesign the Il-42 project. The revised specification was for an aircraft with twice the range and 1 1/2 times the bomb load, with a prototype ready to be submitted for state acceptance trials in July 1952. The Ilyushin design bureau set about designing two versions of the same aircraft, the straight-wing (Il-46) and the swept-wing (Il-46S), with as much as possible common to both aircraft. To meet the schedule for state acceptance trials Ilyushin built only the straight-wing version, fearing that the design, manufacture and flying characteristics of the swept-wing aircraft might cause delays.
The OKB-1 '150' was a jet bomber designed and produced in the USSR from 1948.
The Ilyushin Il-8 was a Soviet ground-attack aircraft developed by Ilyushin to replace the Ilyushin Il-2. The first two prototypes were significantly faster than the older aircraft, but proved to be less maneuverable. It was redesigned, incorporating many features of what would become the Ilyushin Il-10, but proved to be inferior to that aircraft in testing. It was not ordered into production.
The Ilyushin Il-16 was a Soviet lightweight armored ground-attack aircraft developed at the end of World War II by the Ilyushin Design Bureau. It was in essence a scaled-down version of the Ilyushin Il-10, but was fitted with a newly developed Mikulin AM-43 engine with the expectation that it would be faster and more maneuverable than its predecessor. However, the engine's defects proved to be impossible to rectify and further development was canceled in mid-1946.
The Polikarpov VIT-2 was a Soviet twin-engined ground attack aircraft developed before World War II. A single prototype was built in 1938 for evaluation purposes. Although a promising design it was recommended that it be introduced into production as a high-speed dive bomber with a reduced armament to increase its speed.
The Polikarpov NB was a Soviet twin-engined bomber designed during World War II. Only a single prototype had been built before the program was terminated upon the death of Nikolai Nikolaevich Polikarpov, the head of the aircraft's design bureau, in 1944.
The Ilyushin DB-4 or TsKB-56 was a Soviet twin-engined bomber aircraft of the early 1940s. It was a development of the Ilyushin DB-3 and was intended as a replacement for the earlier aircraft, but only two prototypes were built; engine problems and the need to concentrate production on existing types following the German invasion of the Soviet Union in June 1941 meant that no more examples were built.
The Ilyushin Il-26 was a late 1940s project for a strategic heavy bomber by the Ilyushin Design Bureau. There were a variety of alternative engines proposed for the Il-26, including the 3,400 kW (4,500 hp) Shvetsov ASh-2TK piston engine and 4,500 kW (6,000 hp) Yakovlev M-501 diesel engine. The specifications varied according to the number and type of engines proposed.
|Wikimedia Commons has media related to Ilyushin Il-22 (bomber) .|