Aviation of Word War II
On July 21, 1941 S.V. Ilyushin turned to the People's Commissariat of the Aviation Industry with a proposal to install an M-82 air-cooled engine with a takeoff power of 1,675 hp on the aircraft. This proposal was as relevant as possible, given that the rapid advance of German troops deep into the country jeopardized the serial production of engines for Il-2 attack aircraft. A number of specialists from the Air Force KA and NKAP also advocated the installation of such an engine on an attack aircraft. In addition, when the Il-2 was converted to the M-82 engine, it was supposed "... based on the experience of the war ... to make the aircraft two-seater. The second crew member will mainly protect the tail of the aircraft from an air attack. Under this condition, the aircraft will be almost invulnerable ... "
Already on July 29, 1941. issued an order on NKAP No. 760, according to which S.The. Ilyushin was supposed to manufacture and launch a modified Il-2 with M-82 on its maiden flight no later than 30 August.
Exactly one month later, on August 29, 1941, the State Defense Committee issued Decree No. 327 on the construction of an IL-2 with an 82nd engine and an AV-5L propeller at the 39th aircraft plant. After another 9 days, on September 8, 41st, V.K. Kokkinaki from the LII NKAP airfield made its first test flight on a new attack aircraft.
For the construction of this aircraft, part of the armored hull of the serial Il-2, up to the front spar of the center section, which was the hood of the AM-38 engine, was removed, and a double armored partition was installed along the front spar of the center section, which took all the loads from the welded tubular motor mount of the M-82 engine. At the same time, the motor was not booked. It was covered with a conventional NACA-type hood made of lightweight aluminum alloy with a controllable skirt at the rear outlet slit. The bonnet frame was attached only to the engine and was not connected to the rest of the aircraft structure. This design greatly simplified the change of the motor, especially in the field. The transition from the M-82 to the Il-2 fuselage turned out to be uneven and rather greatly worsened the aerodynamics of the aircraft.
Instead of the rear gas tank, located behind the armored partition of the pilot's cabin, the gunner's cabin was equipped with a blister mount for a 12.7 mm UBT machine gun with 280 rounds of ammunition.
The shooter, like the pilot, was quite well protected by armor: the rear and lower armor walls of the cockpit were 8 mm thick, the side walls were up to 6 mm, and the armor above the shooter's head was 5 mm. In addition, bulletproof glass with a thickness of 64 mm was installed on the blister.
The UBT machine gun was placed on a pivot mount and, due to the strong armoring of the gunner's cockpit, had rather limited firing angles - 38 ° vertically and 22 ° to the sides.
To maintain the same flight range, the capacity of the fuel tank under the pilot's seat was increased to 724 liters, and in order to increase the combat survivability of the vehicle, a system for filling gas tanks with neutral gas from the engine exhaust system was installed on the attack aircraft.
On the plane, instead of the VISH-22T propeller, an AV-5V propeller with a diameter of 3.4 m was installed.
The program of factory tests of the new attack aircraft was carried out at an accelerated pace and completed in eight days (together with V.K. In conclusion, according to the results of factory flight tests, the pilots noted that almost all the flight characteristics of the Il-2 M-82, in comparison with the production machines with the AM-38, have deteriorated, the new Il has no features, the armor provides protection for the crew and fuel from defeat, defects dangerous for flight were not found, and the attack aircraft can be transferred for the production of state tests.
Immediately after the end of the factory flight tests, S.V. Ilyushin approached the leadership of the NKAP and the Air Force with a proposal to immediately release 30 two-seat Il-2 M-82s at the 18th aircraft plant in order to conduct comprehensive military tests. From this number, it was proposed to form one air regiment, fully equipped with new machines, and one mixed air regiment, equipped with both single Il-2 AM-38 and two-seat Ilami with M-82 in a ratio of 2: 1, that is, every two single. " Ilyushins "to give one " ... a two-seater Il-2, which would solve the tasks of the group leader. In this case, the Il-2 with the M-82 would be referred to as the Il-4 ".
S.V. Ilyushin as a whole received support from both the leadership of the NKAP and the Air Force of the spacecraft, but the final decision was postponed until state tests were carried out.
In the middle of December of the 41st, the specialists of the Air Force Research Institute came up with a proposal to install the M-82 112I (M-82IR) engine on a new attack aircraft with a single-speed supercharger and boosted in power at low altitudes, which in November successfully passed 100-hour tests at the stand. The proposal was accepted, and the modified engine was installed on the attack aircraft.
Unfortunately, state tests of the IL-2 with the M-82IR, due to the evacuation of production, were started only on February 20, 42nd. Despite the decrease in the mass of the empty aircraft, the Il-2 M-82IR, with a normal flight weight of 5655 kg, showed a maximum horizontal speed at the ground of 365 km / h, and at an altitude of 5.5 km - 406 km / h. At the same time, the ascent time to a height of 5000 m was 10.6 minutes. Static longitudinal stability, due to the rearward alignment of the aircraft, has deteriorated. The piloting technique has also become more complicated. The takeoff and landing characteristics of the aircraft also deteriorated. The maximum flight range in the nominal mode, despite the increase in the capacity of the gas tank to 724 liters, decreased to 700 km.
The armament of the Il-2 M-82IR consisted of two ShVAK cannons (210 rounds per barrel), two ShKAS machine guns (750 rounds per machine gun), one UBT for firing backwards (280 rounds), 8 RO-82 and 400 kg bombs (overload 600 kg).
Note that the ShVAK cannons on the new attack aircraft were located closer to the axis of the aircraft, and machine guns - farther away. This circumstance increased the accuracy of cannon fire in the air.
In the act on state tests of the Il-2 M-82IR, approved by the commander of the Air Force of the spacecraft A.A. Novikov on March 23, 1942, noted that "... the Il-2 double aircraft with the M-82 engine designed by S.V. Ilyushin tested at the Air Force Research Institute should be considered expedient to be introduced into serial production." the plane was recommended to install the SPU and the RPK-10 radio semi-compass.
In accordance with the Decree of the State Defense Committee No. 1502 of 03/28/42, the Il-2 with the M-82IR was launched into serial production at the aircraft plant No. 381 with the manufacture of the first serial machine by May 1, 42nd. In total, 56 copies of the Il-2 with the M-82IR were to be produced in May. The same number - in June.
However, due to the fact that by this time the mass production of AM-38 engines and single-seat Il-2 attack aircraft with them had already been established, and it was decided to install the M-82 engine on the LaGG-3, making it possible to create the famous La-5.
Further work on the Il-2 M-82IR was discontinued. S.V. Ilyushin was asked to consider the possibility of converting a single production Il-2 aircraft with an AM-38 engine into a two-seater version with a rear firing point and introducing it into serial production without stopping the factory conveyor.