Tests this year on an F135 core engine paired with an experimental fan module featuring adaptive bypass airflow to improve fuel efficient and cooling capacity “met or exceeded expectations”, says engine manufacturer Pratt & Whitney.
The testing on a full-scale powerplant for the Lockheed Martin F-35 wraps up P&W’s role under a four-year adaptive engine technology development (AETD) programme sponsored by the Air Force Research Laboratory (AFRL).
The testing was intended to understand the maturity of so-called “three-stream” adaptive turbofan technology as AFRL launches a $1 billion programme to develop a full-scale, 45,000lb-thrust-class prototype engine under the Adaptive Engine Transition Programme (AETP) that could be used to re-engine the F-35 and power a future combat aircraft.
“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,” says Matthew Bromberg, president of P&W Military Engines, in a news release.
The AFRL is using a competitive development approach for adaptive engine technology, supporting P&W and GE Aviation through the full-scale prototype stage in AETP.
With a goal to improve specific fuel consumption by 25% compared to a 2000-baseline combat aircraft engine US Air Force and Navy have been pursuing adaptive engine technology since 2006.
The adaptive engine is designed to improve efficiency by inserting a valve in the fan module that in cruise mode opens to permit a third stream of airflow – in addition to core flow and bypass flow. The third stream increases the volume of bypass flow to make the engine more efficient in producing thrust. It also creates a new heat-sink within the engine, which allows the designers to improve fuel efficiency by increasing temperatures inside the core.