The Pratt & Whitney F135 turbofan engine has returned to Arnold Engineering Development Complex (AEDC) for another round of testing, with a fresh engine component the focus of the latest efforts.
The F135 engine, which powers the F-35 Lightning II aircraft, is currently undergoing testing in one of the Sea Level Test Cells at Arnold. Since late June, a newly-designed fan rotor installed in the engine has been subjected to endurance and Accelerated Mission Testing.
Accelerated Mission Testing, or AMT, is a testing method used to rapidly age an engine, allowing for the identification and correction of issues before they would occur in normal use. Through AMT, a tested engine will accumulate several years of normal life in a short amount of time.
Not only does the AMT consist of testing at ambient air conditions, but it also includes RAM. The term “RAM” refers to the use of test facility compressors to increase the engine inlet pressure and temperature to more closely simulate actual flight conditions. RAM simulates high speed travel at a low altitude, allowing engineers to assess how these conditions impact the engine and its components.
After testing has concluded, the engine will be disassembled and examined.
The F135 also underwent testing last year to cover pre-AMT objectives. That testing concluded in late 2018, around six months before the AMT involving the newly-designed fan rotor began. Testing of the F135, which is sponsored by the F-35 Joint Program Office, is set to continue into 2020.
Prior to the testing that began last year, the F135 program had tested well over 5,500 hours in various test cells across AEDC.
Pratt & Whitney F135
The Pratt & Whitney F135 is an afterburning turbofan engine developed by American aerospace manufacturer Pratt & Whitney for the Lockheed Martin F-35 Lightning II single-engine stealth strike fighter.
Developed from the Pratt & Whitney F119 engine used on the F-22 Raptor, the F135 produces around 40,000 lbf of thrust. The F135 competed with the General Electric/Rolls-Royce F136 to power the F-35.
The F135 family has several distinct variants; a conventional, forward thrust variant – F135-PW-100 – and a multi-cycle Short Take-Off Vertical Landing STOVL variant – F135-PW-600 – that includes a forward lift fan. The engine and Rolls-Royce LiftSystem make up the Integrated Lift Fan Propulsion System (ILFPS).
The first production F135 engines were delivered in 2009.