Photos have appeared on Chinese websites of an Ilyushin Il-76 testbed fitted with a large high-bypass-ratio turbofan under the port inner pylon. The engine is believed to be the WS-20 (also reported as WS-118), which is under development as a possible powerplant for the Xian Y-20 airlifter. The prototype Y-20s, the first of which flew on January 26 last year, are powered by the NPO Saturn D-30KP-2 imported from Russia. This engine is also used by the Il-76 itself, and by China’s H-6K missile-carrying bomber.
While the performance of the 26,500-pound-thrust D-30KP-2 is adequate for initial flight-testing of the Y-20, and perhaps limited initial operational use, it is not powerful enough for ultimate requirements set for the Y-20. To meet those needs, at least three powerplant programs have been mentioned as potential engines for the production airlifter, which is scheduled to enter service in 2017.
Shenyang-Liming has been developing the WS-20, using the core of the WS-10A fighter engine as a basis. This engine, though it has gone through many troubles, is now in production for the J-11B, a Chinese development of the Sukhoi Su-27 "Flanker." The relative maturity of the WS-10A core has given the WS-20 a lead in terms of development of a large fan engine, although it may still not deliver the desired power levels.
Two other programs that may be applicable to the Y-20 are the 30,000-pound-thrust ACAE CJ-1000A, primarily intended to power the Comac C919 regional airliner, and the SF-A engine. The latter is under development at Xian and is based on the WS-15 fighter engine core.
In any case, flight testing of the WS-20 represents a major milestone for Chinese industry, as it is the first indigenous high-bypass-ratio powerplant to take to the air. China’s aero engine industry has been struggling to match the technological achievements of other areas of the country’s aerospace sector. The advanced metallurgy required to fabricate efficient high-temperature blades has reportedly been lacking, and help has been sought from outside.
