C919 to have integrated propulsion
China’s homegrown Comac C919 will be the first airliner in the world to fly with a truly integrated propulsion system (IPS) combining engines with nacelles for improved overall efficiency. The IPS concept is being pioneered by Nexcelle, a joint company formed last year by GE Aviation’s Middle River Aircraft Systems and the Safran group’s Aircelle. GE and Safran also jointly own CFM International, supplier of the C919’s Leap X1C engine.
“The Chinese could have gone with a traditional nacelle, but they recognized the performance and customer support benefits an integrated propulsion system can provide,” said Nexcelle president Steve Walters.
The application of IPS technologies in the C919 will yield an extra 1.5-percent reduction in fuel burn and a weight reduction of more than 200 pounds per engine, Walters said. This is in addition to the 15-percent fuel saving the Leap X1C engine itself is expected to achieve.
Nexcelle can squeeze the extra efficiency from the design by mounting the engine to the wing pylon in an orientation that minimizes distortion of the compressor and by using more efficient O-duct thrust reversers, which have been used on military aircraft but never an airliner.
The C919’s IPS also incorporates an electric anti-ice system that weighs less and is easier to maintain than traditional bleed-air anti-ice systems. And the design will incorporate a composite nacelle intake, a first for an airliner. Taken together, the technology enhancements add up to an engine/nacelle package that is lighter and
more streamlined than what could have been achieved with traditional engine and nacelle integration techniques.
Nexcelle benefits from a pool of engineering talent at GE’s Middle River group in Baltimore, Maryland, and Aircelle in France. The company is based in Cincinnati, Ohio, near the headquarters of CFM International. CFM and Nexcelle recently completed the C919’s joint definition phase with Comac in Shanghai to freeze the final engine design.
The 168- to 190-seat narrowbody airliner is expected to make its first flight in 2014 and achieve certification in 2016.