IL-22

In May 1946, Ilyushin, on an initiative basis, submitted to the MAP of the USSR a project of a jet bomber for 4 TR-1 A engines. The project was included in the pilot aircraft construction plan, with the proviso that although it is not advanced in comparison with foreign analogues (it was called the captured German Junkers Ju 287 ), but had the advantage of using domestic aircraft engines ^[2] .

The dynamics of a jet flight at a transonic speed was studied on the Il-22; wing and sealed cockpit designs were developed. The turbojet engine was debugged under various modes and in different weather conditions.

IL-22 launched the Soviet jet bomber aircraft. The aircraft installed TR-1 engines designed by A. Lyulka. However, it was not possible to reach the estimated thrust on them. ^[3]

Engine Installation

In the mid -1940s , the installation of jet engines was adopted in closed nacelles pressed to the bottom of the wing, often in a package, that is, several engines were installed in one gondola. This arrangement allowed to reduce drag , however, due to the lack of reliability of the turbojet engine of that time, the failure of one of them could lead to the disconnection of neighboring ones. To solve this problem, an original solution for those times was proposed for the IL-22 - to place the engines in separate gondolas with a pylon mount and to spread them far from each other along the length of the wing. According to the test results, such a suspension was not only more efficient than a batch in aerodynamic parameters, but also provided easy access to each engine, which was especially important for an experimental aircraft.

Fuselage

The Il-22 fuselage section had the shape of a horizontal oval. The horizontal layout made it possible to comfortably accommodate five crew members, as well as fuel in special soft tanks. Due to the small volume of the engine nacelles, the chassis was also mounted on the fuselage. The axis of rotation of the landing gear racks were made inclined so that the distance between the wheels was maximum when fully extended, and when folded, the struts fit in the fuselage in front of the bomb bay.

Wings

The low design speed of the IL-22 made it possible to make the wing straight. As a result, a thin wing (relative thickness 12%) with an estimated specific load of 310-350 kgf / cm² was designed for the IL-22. The maximum thickness is located along the line of 40% of the chord.

Defensive weapons

By the time of the development of the IL-22, the power and weight of aviation weapons had grown so much that it took the creation of remote weapons control systems that quickly and accurately link the sight with the gun. IL-22 had the following weapons:

• The front hemisphere is a fixed NS-23 cannon on the starboard side, 150 rounds of ammunition . Management - crew commander;
• The upper hemisphere is a rotating turret with two twin B-20 E. guns. The total ammunition of 800 shells. Remote electric control - radio operator shooter . The sight was aimed at the target manually, and ballistic corrections , parallax and lead were introduced automatically.
• The rear hemisphere is the Il-KU-3 installation with the NS-23 cannon and 225 rounds of ammunition behind the tail. Range of fire - ± 70º horizontally, 35º up, 30º down.

Placing the shooter outside the turret allowed to place all the elements of the system in an optimal way - guns for the maximum firing sector, and the shooter - in a place with maximum visibility. Reducing the size of the tower reduced aerodynamic drag, and the shooter did not get tired of shaking during shots and when moving a heavy structure.

In order to avoid damage to aircraft parts by their own cannon armament, special switches were installed in the mechanics of controlling the guns, blocking fire in certain positions of the barrel.

The IL-22 crew consisted of five people: two pilots , a navigator-bombardier , a radio operator gunner in the nose of the fuselage, a gunner of the stern cannon mount.

During the tests, it was found that the engine thrust of 1300 kgf is not enough to obtain the necessary flight parameters (it was initially assumed that the thrust could be brought to 1600 kgf). Because of this, the take-off mass had to be reduced by 4000 kg (up to 20,000 kg). The flight time was only 1 hour 25 minutes, range - 885 km. The speed was also insufficient - 656 km / h at the ground and 718 km / h at altitude. The take-off run was 1144 m. Despite the shortcomings, the feedback from the first test pilots, brothers Vladimir and Konstantin Kokkinaki , was positive. They noted good handling and good aerodynamic qualities of the aircraft.

In 1948, the second phase of testing was carried out. Two engines were replaced with new ones, but their thrust was never brought to the calculated one. Also tests of take-off with solid fuel boosters were carried out, which allowed to reduce the take-off run by 38%.

According to the results of two stages, it was decided not to transfer the aircraft to state tests, and all work on it was curtailed. The experience of the development and testing of the IL-22 was later used in work on a production aircraft - IL-28 .

Data Source: ^[1]

Specifications

• Crew : 5 people (two pilots , navigator, bombardier, gunner- radio operator , stern gunner)
• Length : 21.1 m
• Wing span : 23.1 m
• Height :
• Wing Area: 74.5 m²
• Empty weight: 14 950 kg
• Normal take-off weight: 20,000 kg
• Powerplant: 4 × TRD TR-1
• Thrust : 4 × 940 kgf

Flight characteristics

• Maximum speed: 718 km / h
• Cruising speed : 560 km / h
• Practical range: 865 km
• Practical ceiling : 11,100 m
• Takeoff run: 1144 m

Armament

• Rifle-cannon: for firing forward - NS-23 ( ammunition 150 shells); for shelling the upper hemisphere - paired B-20 E (total ammunition of 800 shells); feed plant Il-KU-3 with one gun NS-23 (ammunition 225 shells)
• Bombs : on the internal suspension: normal - 2000 kg, maximum - 3000 kg

• 150 (experienced bomber)
• Su-10
• Junkers ju 287