GE Set To Build On XA100 For NGAD Engine Prototype

Credit: GE

General Electric is working with the U.S. Air Force on potential next steps for evaluating the three-stream XA100 demonstrator after completing runs of the second adaptive test engine at the service’s Arnold Engineering Development Complex (AEDC).

The test work, which marks the final major contract milestone of the Air Force’s Adaptive Engine Transition Program (AETP), comes as GE begins development on its prototype future engine contender for the Air Force’s Next Generation Air Dominance (NGAD) fighter. The next-generation engine will build on much of the architectural and materials technology demonstrated during AETP, but will be sized differently to the 40,000 lb.-thrust-class XA100 that was designed to fit the Lockheed Martin F-35.

In August GE’s NGAD prototype engine work was awarded test and developments contracts under the Next Generation Adaptive Propulsion (NGAP) engine program. Pratt & Whitney, which is currently testing its own XA101 adaptive engine under AETP, was also awarded an NGAP test and development contract. Propulsion integration-related NGAP contracts were also issued to airframers Boeing, Lockheed Martin and Northrop Grumman.

Tests of the GE XA100 showed the design is a “flight-weight, highly product-relevant engine that would provide the F-35 with 30% more range, greater than 20% faster acceleration, and significant mission systems growth to harness the F-35’s full capabilities for Block 4 upgrades, and beyond,” says David Tweedie, GE Edison Works’ vice president and general manager for Advanced Products.

Following an initial contract award in 2016, GE ran the first of two XA100 demonstrators at the company’s facility in Evendale, Ohio, in August 2021. The second test engine began runs at AEDC in March 2022. The engine design modulates airflow via an adaptive fan to provide either a high-thrust mode for combat power or a low-fuel-burn mode for longer range and loiter time. The additional bypass airflow, described as a third-stream, also passes through heat exchangers to provide increased thermal management capability.

GE says the first XA100 “is in the process of disassembly and evaluation which is a standard process to validate the design of any new engine. The second engine has been transported back from AEDC to Evendale, and GE is working closely with [the Air Force] Life Cycle Management Center to determine what level of evaluation would be beneficial to the program.”

Completion of tests at AEDC, meanwhile, comes as the Defense Department weighs whether to launch a re-engining effort for the F-35 based on one of the AETP engines. Air Force Secretary Frank Kendall says a decision could possibly be made as part of the fiscal 2024 budget but has cautioned that the price tag of developing and installing an adaptive engine could run to $6 billion. GE’s Tweedie adds the company “now stands ready to transition to an Engineering and Manufacturing Development program and bring this engine to the field with the F-35 before the end of this decade.”

Guy Norris

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