IL-8 AM-42
To correct all the shortcomings of the Il-2, what should have been a new model of the “Stormtrooper” was ordered in the summer of 1942 as a bomb-assault vehicle that would lift up to 1000 kg of bombs. Ilyushin decided to adapt for this project the already tested Il-AM-42 aircraft - an upgraded two-seater Il with a new powerful AM-42 engine. which was supposed to correct all the shortcomings of attack aircraft associated with low resistance and overweight. The AM-42 engine of the designer Mikulin was a development of the AM-38 and had a power of 2000 kW at 2500 rpm, due to which the aircraft was supposed to be faster by 20–30 km / h. In addition to a number of design changes, the power was increased and by reducing the compression ratio to 5.5 (for AM-38 - 6.0), the reduction rate was reduced to 0.60 (for AM-38 and AM-38F - 0.732). The engine rotated the AB-5L-18V propeller with a diameter of 3.8 m
Work on the new version of IL (with the provisional name IL-8) was started in the summer of 1942 ... at about the same time as work began on the two-seat version. At first, they were closely related, since Ilyushin believed that in order to avoid the deterioration of the piloting properties of a two-seater plane, a more powerful engine is needed. Therefore, most likely the design work on the IL-8 and IL-AM-42 were two different, albeit closely related areas of work of the design bureau. Their common disadvantage was the initial design of the IL-2, which served as the basis for various calculations and experiments, due to the fact that the final result of all the work was to be a deep modernization of this aircraft.
In order to compensate for the mass and power of the new engine, as well as to increase its thrust, it was necessary to increase the length of the fuselage by 1278 mm, move the center of gravity back and increase the area of ??stabilizers (in the case of the horizontal very significantly). The armor hull was also continued behind the cockpit, new, more capacious fuel tanks were used (allowing a distance of 1100 km to be reached), enlarged bomb compartments were placed in the modernized center section, and new outdoor bomb locks were installed in them. 500 kg (total weight 1000 kg). In the modernized wings, space is allocated for alternative sets of small arms, which consist either of 2 machine guns and 2 guns of 23 mm caliber, or from 2 machine guns with reduced ammunition and 2 guns of 37 mm caliber. In the design of the fuselage was made a lot of changes and simplifications.
The engine systems underwent a deep modification. The oil radiators, the Achilles' heel of the IL-2, were “let in” from under the fuselage into the armored hull. However, this decision gave designers a lot of trouble.
Tests of experimental IL-AM-42 were carried out for almost a year, before May 10, 1943, the first flight of the IL-8 was completed. Again Kokkinaki sat at the helm of the new car. which, after landing, made a number of comments related primarily to the operation of the engine and its cooling. Despite this, the car reached a speed of 470 km / h at an altitude of 2,240 m with a starting weight of 7,250 kg and, in general, showed good flight data. However, the shortcomings associated with the propulsion system depreciated him as a combat aircraft, as a result, work began on its further "development" in the same month.
Immediately after the end of state tests, during the “window” between May and August 1944, Ilyushin very actively began to modify the IL-10, creating on its basis two different branches of his descendants. The first of them was represented by IL-8 No. 2 (on which work had been going since March 1944). and the second - a completely new IL-16.
IL-8 number 2 was compared with the IL-8 number 1 almost new aircraft, which could be described as a heavier twin IL-10. A variety of improvements, enhancements and “dovronirovaniya” (mainly the latter) increased its weight compared with the IL-10 by 1275 kg. This led to a multitude of problems that were attempted to be solved by installing a new four-bladed screw. The search for the corresponding model took a lot of time, so even for the first flight of the Il-8 No. 2, carried out on October 13, 1944, Kokkinaki, these problems were not yet finally resolved. Only by the end of the year the propeller AB-9L-22B was “found”. which turned out to be ideal, but at the same time showed that the weight deficiencies in the work of the propulsion system were not connected with the propeller.
Modernization and testing took the next six months and only May 27, 1945. The IL-8 number 2 was sent to the Air Force Scientific Research Institute for a series of state tests, which showed that although the car was not bad, it was inferior to the IL-10 in all flight characteristics: it has a lower maximum flight speed, climb rate, and much worse maneuverability. For these reasons, it was decided to abandon this type of attack aircraft. It was all the more easy because the war was already actually ended.
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