P&W Hits Adaptive Fan Milestone


Pratt & Whitney has completed testing on a proof of concept adaptive bypass variant of the F135 fighter engine. The adaptive three-stream fan test was completed as part of the U.S. Air Force Research Laboratory’s Adaptive Engine Technology Development (AETD) program at Arnold Air Force Base in Tullahoma, Tennessee. Modern jet engines utilize two flow streams: one through the combustion section of the engine and a one that bypasses the combustion section around the outside of the engine. By changing the ratio of air going through the combustion section to air going around the outside of the engine, the bypass ratio, engine designers are able to trade off maximum thrust and fuel efficiency. The Air Force wants its next-generation fighter engine to be able to adjust the bypass ratio in flight by adjusting a third flow stream, providing 25% better fuel consumption in cruise and 10% higher peak thrust compared to current fighter engine technology.

“Preliminary data from the test indicates our three-stream fan has met or exceeded expectations with respect to performance as well as the integrity of the turbofan machinery and fan module,” said Matthew Bromberg, president of Pratt & Whitney Military Engines. “This is an important milestone on the path toward the advancement and maturation of a next-generation adaptive engine which will enable the warfighter to stay well ahead of future and emerging threats.” Production versions of the F135 engine, also made by Pratt & Whitney, are used to power all three variants of the F-35 Lightning II. The company reports that they plan to conduct additional testing later this year on a high-efficiency engine core also developed under the AETD program.