Arnold workers put alternate fighter jet engine through paces

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  Initial testing of the GE/Rolls-Royce F136 alternate engine for the F-35 Lightning II Joint Strike Fighter is now underway at the U.S. Air Force's Arnold Engineering Development Center's (AEDC) J-2 test cell.

"We're testing engine performance and operability - we have to meet certain specifications that the government gives us," said Gene Klingensmith, AEDC's Air Force project manager on the test. "We're running simulated flight conditions - a full envelope of altitudes and Mach speeds."

Pat Cowden, a GE test engineer at AEDC, said the center's capability to provide realistic simulation of flight conditions was the reason for bringing the engine and augmenter to Arnold.

"AEDC can run the true (simulated) flight conditions where we (GE) can't in our own facility," he said. "You can run all the math models and do all the analysis/calculations you want to, but you've got to run them on an engine to see how it will perform. We have all kinds of pre-test predictions, but we have to validate them."

Aerospace Testing Alliance Project Manager Rich Walker said the ongoing F136 testing is developmental and the data will be used for the production engine design.

"We will focus on getting operational and performance data on the augmenter, but we'll be evaluating the engine as well," he said.

An augmenter, also known as an afterburner, provides a very rapid increase in thrust.

The F136 is an alternate engine being developed by the General Electric/Rolls-Royce Fighter Engine Team specifically for the F-35. AEDC has also conducted testing on Pratt & Whitney's F135 engine, which will be the sole power plant for the F-35 until 2011-12, when the F136 engines will be available to U.S. allies also purchasing the aircraft.

Three System Development and Demonstration F136 engines are tentatively slated to come to Arnold between 2009 and 2013 for further development and qualification testing.

According to Walker, one of the greatest challenges the team has encountered is providing support systems for the engine during the testing.

"Since this is not a full-up engine, we're supplying auxiliary systems that the engine itself would normally supply," he said. "So we have a lot of other stuff that has to be installed in and around the test cell to feed the engine in this particular case. The auxiliary support systems - that's what makes it more challenging."

Cowden said the F136 for the test is a preliminary, 'bare bones' version.
"Like Rich (Walker) says, the engine doesn't have an on board lube system, hydraulics system, etc., so, we're providing all that with these slave carts out here," he said. "This test is the most challenging thing I've worked on in my entire career. I like the challenge." 

Walker said the engine would be tested using three different nozzles.

"There aren't three different nozzles for the F136," he explained. "The first nozzle is a boilerplate to check out everything, make sure it's functioning properly before we install the actual Conventional Takeoff and Landing (CTOL) nozzle and then the Short Takeoff and Vertical Landing (STOVL) nozzle."

The F-35 is a stealth multi-role fighter with both air-to-ground and air-to-air capabilities, and designed to meet the war-fighting needs, including survivability, precision engagement capability and mobility, of the U.S. Air Force, Navy, Marines and the nation's allies. 

The aircraft exploits a high level of commonality and modularity to maximize affordability, keeping life cycle costs down. The Air Force's version is intended to replace the F-16 Fighting Falcon and the A-10 Thunderbolt II. 

The STOVL version will replace the Marine Corp's AV-8B Harrier, the Royal Navy's Sea Harrier and the Royal Air Force's GR7 Harrier.