Ilyushin Il-6

Ilyushin Il-6

Picture - Il-6 with Charomsky ACh-30 B diesel engines.

Role: Long-range Bomber
National origin: Soviet Union
Manufacturer: Ilyushin
First flight: 7 August 1943
Number built: 4
Developed from: Il-4

The Ilyushin Il-6 was a Soviet long-range bomber developed from the Ilyushin Il-4 during 1942. Originally intended as a high-speed replacement for the Il-4, it was recast as a very long-range bomber with fuel-conserving ACh-30 diesel engines before production of the single prototype began in December 1942. Flight testing showed controlability issues when landing at high weights and the engines proved to be hard to start at low temperatures and were slow to respond to throttle movements. Further development was canceled in 1944.

Development

Outwardly similar to the Il-4, the Il-6 was faster and had a longer and slimmer fuselage fitted with a completely new, highly tapered wing with an aspect ratio of 8. The engine nacelles were streamlined to reduce drag and increase speed as the engine radiators were mounted in the wing center section, fed by slits in the leading ege of the wing. Defensive armament was greatly improved with five 20 mm (0.79 in) cannon fitted on flexible mountings in the nose, dorsal turret, two beam positions and a ventral blister forward of the tailplane.

The Il-6 was originally intended as a high-speed replacement for the Il-4. But after the initial design was completed in August 1942, the VVS requested that the bomber have extended range instead of high speed. So the original M-71 radial engines were replaced by Charomskiy ACh-30 diesel engines with low fuel consumption which promised to give the Il-6 the required range, especially when operated at moderate weights. The revised design was completed in December 1942 and production of the prototype was initiated. First flight of the Il-6 was made in Irkutsk on 7 August 1943 with lower-powered ACh-30B engines substituted for the unavailable ACh-30BF engines.

Flight tests revealed difficult handling, and a lack of power due to the non-availability of the intended ACh-30BF engines. Flight tests continued without the beam guns and their gunner until the ACh-30BF's were fitted between May and July 1944. Despite modifications the aircraft still suffered from poor controlability at low speeds and high weights as well as very poor gliding performance. Throughout the flight tests the engines performed satisfactorily in the air, but were found to be very difficult to start in low ambient temperatures and had slow response to throttle movements. Further development was canceled.

Variants

Il-6 - intended production version with Charomskiy ACh-30BF engines (also known as M-30).
Il-6 - bomber with M-90 engines - projected variant with M-90 engines, production drawings were issued but nothing further was heard of it, presumably as all effort was focused on the diesel-powered version.

Specifications (Il-6)

Data from Gordon, OKB Ilyushin: A History of the Design Bureau and its Aircraft.

General characteristics

Crew: 6
Length: 17.38 m (57 ft 0 in)
Wingspan: 26.07 m (85 ft 6 in)
Wing area: 84.8 m² (912.9 ft²)
Empty weight: 11,930 kg (26,301 lb)
Gross weight: 19,600 kg (43,220 lb)
Powerplant: 2 x— Charomskiy ACh-30BF (M-30), 1,417 kW (1,900 hp) each

Performance

Maximum speed: 464 km/h (288 mph)
Range: 5,450 km (3,387 miles)
Service ceiling: 7,000 m (22,970 ft)
Rate of climb: 2.9 m/s (571 ft/min)

Armament

5 x— 20 mm (0.79 in) Shpital'nnyy Sh-20 cannon in a dorsal turret, and flexible mountings at the nose, beam and ventral positions.
2,500 kg (5,500 lb) of bombs, maximum, internally
2 x— 1,000 kg (2,200 lb) bombs on external racks
or 2 x— 1,000 kg (2,200 lb) torpedoes on external racks

Comparable aircraft

North American XB-28
Junkers Ju 86P
Junkers Ju 86R
Vickers Warwick

Bibliography

Gordon, Yefim; Komissarov, Dmitriy and Sergey (2004). OKB Ilyushin: A History of the Design Bureau and its Aircraft. London: Ian Allan. ISBN 1-85780-187-3.
Nemecek, Vaclav (1986). The History of Soviet Aircraft from 1918. London: Willow Books. ISBN 0-00-218033-2.

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Source: WikiPedia