The Ivchenko AI-20 is a Soviet turboprop engine developed by the Ivchenko design bureau in the 1950s. It has been built in large numbers, serving as the powerplant for the Antonov An-12 transport and the Ilyushin Il-18 airliner.
Design and development 
The AI-20 was the first gas turbine engine developed by the design bureau led by Oleksandr Ivchenko based at Zaporozhye, Ukraine, which had previously concentrated on small piston engines such as the Ivchenko AI-14 and AI-26 radials. It was designed as a prospective powerplant for the new large Ilyushin Il-18 airliner and the Antonov An-10, to be powered by four turboprops, in competition with the Kuznetsov NK-4. Both engines were tried out on the pre-production batch of 20 Il-18s, but the Ivchenko engine was chosen for full production, possibly due to a crash caused by an in-flight failure of an NK-4 engine, and possibly due to the desire for the engines of the Ukrainian An-10 to also be built in Ukraine.
The AI-20 is a single shaft turboprop with a ten-stage axial compressor and a three stage power turbine, and is designed to run at a constant speed. The overhaul life of the engine was initially poor compared with contemporary western engines, being reported as 600–750 hours in 1964, but was later improved to 6,000–7,000 hours, with a service life of 20,000 hours.
It entered production at Zaporozhye and at Perm, USSR in 1958, also being built under licence in China as the WJ6. About 14,000 AI-20s have been built in total.
Specifications (AI-20M) 
Data from Jane's All The World's Aircraft 1993–94.
- Type: Single-shaft turboprop
- Length: 3,096 mm (121.89 in)
Width: 842 mm (33.15 in)
Height:1,180 mm (46.46 in)
- Dry weight: 1,140 kg (2,293 lb)
- Compressor: 10 stage axial compressor with 4 bypass valves for starting and transient ratings
- Combustors: Annular with 10 burner cones
- Turbine: 3 stage axial flow
- Oil system: Pressure type feed, fully recirculating
- Maximum power output: 3,149 kW (4,250 ehp) (take-off), 1,938 kW (2,600 ehp) (max cruise)
- Overall pressure ratio: 7.6:1 (take-off) to 9.2:1 (cruise)
- Turbine inlet temperature: 900°C (1,652°F)
- Power-to-weight ratio: 2.8 kW/kg (1.9 hp/lb) (take-off power)
See also 
- Comparable engines
- Related lists
- Gunston, Bill. World Encyclopedia of Aero Engines. London:Guild Publishing, 1986.
- Lambert, Mark. Jane's All The World's Aircraft 1993–94. Coulsdon, UK: Jane's Data Division, 1993. ISBN 0-7106-1066-1.
- Stroud, John. Soviet Transport Aircraft since 1945. London:Putnam, 1968.
External links