GE Adaptive Combat Engine Moves To AEDC For New Test Phase

XA100
Credit: GE

COLORADO SPRINGS—General Electric is preparing to begin a second phase of ground tests of the XA100 adaptive cycle combat engine after successfully completing evaluations of the second of two full-scale test units at its Evendale altitude test facility in Ohio. 

Developed by GE’s Edison Works advanced programs unit, the XA100 is one of two experimental adaptive demonstrators contracted under the U.S. Air Force’s Life Cycle Management Center’s Adaptive Engine Transition Program (AETP). The other engine, the XA101, is under development by Pratt & Whitney and completed initial ground tests in September.

Following a series of ground runs that began in August, the second GE engine has already been shipped to the U.S. Air Force’s Arnold Engineering Development Complex (AEDC) in Tullahoma, Tennessee, in readiness for more extensive testing starting in the first quarter of 2022. Mechanically identical to the initial prototype, which completed tests in March 2021, the second XA100 is configured with updated instrumentation and control software which will enable more precise performance analysis across a wider simulated height and speed envelope at AEDC.

The adaptive technology in the AETP engines enable the engine cycle to be reoptimized in flight from cruise to combat performance, and vice versa. Sized in the 45,000 lb. thrust class, the engines are also designed to meet growth requirements for Lockheed Martin’s F-35. In particular, the third airflow stream in the engines incorporate enhanced thermal management capabilities which will provide a greater cooling margin for systems due to be included in the F-35’s upcoming Block 4 upgrade. 

Both the XA100 and XA101 have therefore been designed as drop-in replacements for Pratt’s F125-100 and F135-400 used in the F-35A and F-35C respectively. Neither are compatible, however, with the F-35B short takeoff and vertical lift variant, which is configured with a shaft-drive lift fan connected to the aircraft’s F135-600 engine.

The AETP aims to improve thrust and fuel efficiency by 10% and 25% respectively compared to a 2015 state-of-the-art fighter engine. GE says tests of the first prototype have already exceeded these targets across the flight envelope, including up to 20% more thrust in some test conditions. Testing planned by GE and P&W in 2022 marks the finale of the AETP initiative, which was launched in 2016 to develop three-stream demonstrators for full-scale development from earlier research efforts. These included the Air Force Research Laboratory’s Adaptive Engine Technology Demonstration and Adaptive Versatile Engine Technology programs.

Guy Norris

Guy is a Senior Editor for Aviation Week, covering technology and propulsion. He is based in Colorado Springs.

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Jet engines are eighty years old and are stil being improved!!!!! Chris Bacchus
Jet engines are eighty years old and are stil being improved!!!!! Chris Bacchus