Testing of the Pratt & Whitney F135 engine in the U.S. Air Force's Arnold Engineering Development Center's (AEDC) C-1 test cell began Dec. 7, and represents a critical transition between the development and qualification phases of the overall F135 program. The engine is the powerplant for the F-35 Joint Strike Fighter (JSF).

The primary objective of this program is Initial Flight Release (IFR) altitude qualification testing in support of attaining approval to begin flight testing. While the majority of this testing addresses performance and operability, secondary objectives include failure detection and accommodation (FDA) validation, as well as obtaining structural and internal environmental data.

"This testing is a transitional part of the overall F135 program," said John Kelly, one of the ATA project engineers on this program. "Flight testing is dependant on the testing we are doing in C-1. Without this testing, flight testing cannot begin."

The F135 engine has unique capabilities for land-based conventional take off and landing (CTOL), carrier-variant takeoff and landing (CV) and short takeoff and vertical landing (STOVL).

"The F135 is scheduled to be in the F-35 airframe and flying in 2006," said Rich Walker, ATA project manager for the program. "However, before the engine can fly it has to complete qualification testing which demonstrates that it is really ready to fly. The data from our tests will prove this."

The F135 is an evolution of the Pratt & Whitney F119-PW-100, a technologically advanced turbofan that powers the Air Force's F/A-22 Raptor. It integrates the proven F119 core, a high-performance six-stage compressor and single-stage turbine unit with a new low-pressure spool. In addition, the propulsion system features advanced prognostic and on-condition management systems that provide maintenance awareness, autonomic logistic support, and automatic field data and test systems.

The first production propulsion system for operational service is scheduled for delivery in 2008. The F-35 is scheduled to replace the Air Force's F-16 Fighting Falcon and A-10 Thunderbolt II, the Marine Corps AV-8B Harrier and the Navy and Marine Corps F/A-18A/B Hornet and will serve the U.S. Air Force, Navy and Marines, Britain's Royal Air Force and Navy and other international customers.

During the next two years, four F135 engines are expected to be tested in the C-1. Although this entry marks the first time an F135 has been tested in this cell, the engine has already tested in two other AEDC test cells. In addition to the tests in C-1, F135 engines are undergoing developmental testing in test cell J-2 and accelerated mission testing in test cell SL-3.

FMI: www.arnold.af.mil