The first Pratt & Whitney F119 derivative engine for Lockheed Martin's X-35 Joint Strike Fighter (JSF) concept demonstrator began test runs on 11 June.
As Flight International went to press, it was expected to be followed by the engine for Boeing's X-32 contender.
"The engine is running extremely smoothly," says JSF F119 programme manager Bob Cea. "Initial tests are aimed at determining if it works from a structural point of view. All vibration levels are extremely low, and stresses on critical hardware are also low."
The heavily modified F119 has been running for up to 4h at a time, "-which is pretty impressive for a new engine", adds Cea.
The JSF engines use the same core as the F119 powering the Lockheed Martin/Boeing F-22, but they have been adapted to produce "significantly" more thrust and have completely new fans, low pressure turbines and nozzles.
The two engines under test are configured for conventional take-off and landing (CTOL) variants of the JSF.
Two more ground test engines, in short take-off and vertical landing (STOVL) configurations, will be run "in the fall", says Cea. Assembly of the STOVL engines has begun.
During their development, the two JSF engines have been treated as separate programmes. "Each represents different risks, but we have learned a lot of lessons and there has been good synergy by doing them both at the same time," says Cea.
Initial clearance of the engines for stress and vibration will be followed by fan mapping tests. Altitude testing is scheduled to take place later this year at the US Air Force's Arnold Engineering Development Center in Tullahoma, Tennessee.
"We need to certify both the CTOL and STOVL engines for flight by the end of 1999," says Cea.
The first JSF demonstrators are due to begin flight tests in 2000.
Source: Flight International
