Ilyushin Il-8

Ilyushin Il-8

Company type	Aircraft prototype
Industry	Aerospace
Founded	1943
Founder	Sergey Ilyushin
Products	Ground-attack aircraft
Parent	Ilyushin Design Bureau

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The Ilyushin Il-8 was a Soviet ground-attack aircraft developed by Ilyushin as a successor to the Ilyushin Il-2. Although the initial two prototypes demonstrated a notable increase in speed compared to the Il-2, they exhibited reduced agility. Subsequent redesign efforts incorporated numerous elements that would later be seen in the Ilyushin Il-10, yet testing revealed the Il-8 to be less capable than that model. Consequently, it never entered mass production.

Development

In the summer of 1942, Sergey Ilyushin received a directive to create a heavy attack plane capable of carrying up to 1,000 kg (2,200 lb) of bombs. His approach involved enlarging the single-engine Il-2 framework to accommodate the new, more powerful Mikulin AM-42 engine, which was essentially an enlarged variant of the Il-2's Mikulin AM-38 powerplant. Initially designated as the Il-AM-42, the aircraft was soon assigned the factory code Il-8. Despite drawing from the Il-2's design, the Il-8 was fundamentally a new aircraft.

The cooling system combined the oil cooler and coolant radiator within a large air scoop positioned atop the engine cowling, closer to the cockpit than on the Il-2. Unlike its predecessor, the gunner's compartment was fully enclosed within armored plating and equipped with a 12.7 mm (0.50 in) Berezin UBK machine gun mounted on a VU-8 flexible mount. The forward armament mirrored that of the Il-2, featuring two 23 mm (0.91 in) Volkov-Yartsev VYa-23 cannons with a total ammunition capacity of 300 rounds and two 7.62 mm (0.300 in) ShKAS machine guns loaded with 1500 rounds housed in the wings. Optionally, two 37 mm (1.5 in) Nudelman-Suranov NS-37 cannons could replace the VYa-23s. To improve airflow, the rear fuselage was extended by 1.42 metres (4 ft 8 in) and landing gear legs were lengthened to fit a larger propeller; landing gear nacelles were also adapted accordingly.

Two Il-8 prototypes were constructed: the first armed with VYa-23 cannons and featuring a wooden rear fuselage, and the second equipped with NS-37 cannons and a metal rear fuselage. The maiden flight occurred on 10 May 1943. Both prototypes underwent testing as attack aircraft and as artillery spotters with reduced range but enhanced radio equipment. Flight evaluations indicated that at low altitude, the Il-8 was nearly 50 faster than the Il-2, climbed 15% quicker, and boasted almost double the operational range. However, testing was delayed due to persistent issues with the AM-42 engines, which suffered from unreliability, excessive smoke, and vibration problems. Additionally, handling tests revealed that the Il-8 was less agile than its predecessor in both horizontal and vertical maneuvers. State acceptance trials ran from 26 February to 30 March 1944, resulting in conditional approval for production pending resolution of these shortcomings.

Believing that key advantages from the two-seat Ilyushin Il-1 prototype could enhance the Il-8 design, Ilyushin secured authorization on 1 July 1944 for another prototype development. This new version—confusingly also referred to as Il-8-2—bore strong resemblance to what would become the Il-10 but featured a longer fuselage and a four-bladed propeller. Armament changes included replacing VYa-23 guns with Nudelman-Suranov NS-23 cannons and upgrading the rear armament from a UBK machine gun to a 20 Berezin B-20 cannon mounted on a VU-9 mount. Rear defense was further enhanced by fitting a cassette containing ten AG-2 aerial grenades. The bomb capacity increased to 1,000, compared to 800 on earlier models. The revised Il-8-2 took flight for the first time on 13 October 1944; however, flight trials were again hampered by engine difficulties. State acceptance testing concluded on 7 July 1945, confirming that although this iteration improved upon its predecessor, it still lagged behind the already operational Il-10 in performance and thus was not adopted for production.