Lofty Russian experience of the war showed that all of the stormtroopers had fought one significant drawback is the limited review of the front bottom of the sphere. It is difficult to precision bombing, especially in horizontal flight. Still in the process of the war in the spring of 1942 Ilyushin Design Bureau has drafted a single armored attack MSH-AM-38 with a pretty decent overview forward. This was achieved by installing the motor back and pass the wine of the shaft under the cabin floor forward on the propeller. But because of the difficulty of creation form hulls and the lack of rear firing point of the work was stopped.
In accordance with the decree of the USSR Council of Ministers of 11 March 1947 on the Ilyushin Design Bureau assigned task to build a new ground attack with a massive cannon and missile weapons. It was the last piston military aircraft design bureau. Preliminary design of the aircraft, received the title of Sludge-20, was aimed at the Air Force Institute in February 1948 Its main features are — a good view down from the cockpit, brand new weapons plant layout, enhanced reservations. It was suggested that the two projects with different variations of offensive and defensive weapons.
IL-20 was a single-engine single-metal nizkoplan conventional empennage and retractable landing gear in the wing. Assembling the fuselage was very unusual and not previously encountered in the practice of world aircraft. Cockpit was located exactly on the engine and has been pushed forward to the max. The front of the cabin has formed delivered at an angle of 70 'longish windshield 100-mm thickness. One end of it actually rests on the edge propeller hub. This provided an overview of forward and down in the sector 37 ", and in the dive the pilot actually beheld the goal directly below the aircraft. During the pilot's cabin housed the oil and gas tanks, and then the gunner with a remote-controlled 23-mm gun, placed in a special mobile unit of IL- VU-11 with hydraulic drive mechanism to bypass the gun barrel contour fuselage and empennage (in order to protect them from hitting his weapon).
The plant is designed to Ilyushin Design Bureau. It provided a huge firing angles in the upper part of the back hemisphere: 80 degrees — up and 90 degrees — on the right and left. The highest speed of the tool in the mobile unit was 4-45 deg. / Sec. Since the bottom quarter of the hemisphere is not defended gun mount, bottom fuselage is further placed tape for 10 aircraft grenades AG-2, organizing those partial protection. Cabin pilot and arrow, motor, fuel supply system and lubrication, cooling system were inside bronekorobki. The total weight of the iron armor was 1840 kg, and transparent — 169 kg. Reservation provided in the main protection from bullets 12.7 mm and to a large extent — from the 20-mm shells.
Offensive armament in the first version included two wing-mounted cannon and two at an angle 22 ° to the flight strip for the bombardment of targets with strafing. In the 2nd version of offensive weapons planned introduction of a 45-mm cannon, 2-23-mm and 6 rockets ORI-132. Regardless of the number of unique thoughts, preliminary design of the IL-20 rejected as not corresponding decree and technical requirements. It was noted that the firepower of the IL-20 is smaller than that of IL-10. Once it was possible to conduct a consuming only 2-guns — or wing or fuselage. Very awkward was the approach to the motor and its units. With all the work connected with the shooting of blocks required disassembly of the engine from the aircraft.
The empennage was a single-fin, wing and horizontal tail — trapezoidal in plan. Water and oil cooler located in the center section, engine air intake — at the bottom of the fuselage near the front shotgun wing. The aircraft was equipped with a perfect flight navigation and radio communication equipment, thermal anti-icing system. It expanded the capabilities of its use in bad weather.
The layout of the IL-20 mock-up committee was presented in July 1948, Air Force Commander Air Marshal KA Vershinin for previously approved layout, but did not find a suitable construction of the aircraft to the final approval of the layout. But the plane in the first version built. December 5, 1948 test pilot VK Kokkinaki for the first time raised the prototype into the air. Because of the low flight data, failure to comply with the armament and nedovedennosti motor M-47 work Sludge-20, in accordance with the decision of the Council of Ministers of 14 May 1949, ended. Hope to solve the problem of view forward and down through the assembly of non-standard attack aircraft was not justified.
The performance properties of IL-20
Length, m 13.58
Wing area, m2 44.00
— Empty 7535
— normal takeoff 9500
— maximum take-off 9780
Motor Type 1 PD M-47
— Take-off 1 x 3000
— nominal 1 x 2300
— flight 1 x 2400
The highest speed, km / h
— at the ground 450
— at a height 515
Ferry range, km 1700
Range, km 1045
Rate of climb, m / s 375
Service ceiling, m 7750
Armament: One 23-mm gun NA-23, two 23-mm cannon NS-23
normal bomb load — 1190 kg,
with bombs up to 500 kg on external sling.
under the console — 8 RS-82 or RS-132 4.