Fighter Jet News

F-35 Lightning II News

F-35 fuel tests confirm solid, well-built design; structural testing begins

March 24, 2006 (by Jeff Hollenbeck) - The F-35 Joint Strike Fighter completed "leak-free" fuel-system checkout testing achieving another major success milestone on the fighter program. Engineers and technicians have concluded, on schedule, an extensive fuel-system checkout on the first JSF and are making final preparations for a series of structural tests on the aircraft planned to begin today.

The finalized external design of the F-35A Joint Strike Fighter, top, is shown over the JSF X-35A demonstrator aircraft, which successfully completed its flight-test program in 2001 [LMTAS photo]

The fuel-system tests included methodically filling, measuring, weighing and emptying each internal tank with jet fuel, leading up to filling all tanks at operational pressure. The air-refueling system also was checked for proper function.

Throughout the testing process, the fuel system proved to be free of leaks. "Fuel leaks are a typical problem for modern high-performance fighter aircraft, so this success is an early indication the F-35 is a solid design and a well-built fighter aircraft," said Doug Pearson, vice president of the F-35 Integrated Test Force. "The F-35 is a stealthy aircraft built with very tight tolerances, and it is remarkable that during the entire comprehensive fuel system testing there were no external leaks from any of the fuel tanks."

The fuel-system checkout concluded on March 12 and took less than a third of the time to complete than in other recent developmental aircraft programs. The F-35 was then moved to a Lockheed Martin run station to begin equipment and component installations for structural-coupling testing and ground-vibration testing, set to begin March 24.

Structural coupling is the interaction between the flight-control system and the structural dynamics of the airframe. It is tested to ensure that F-35 flight controls do not interact with structural vibrations within the aircraft. Ground-vibration tests certify the airframe is resistant to flutter, which can cause sudden, destructive vibration levels in an aircraft.

The inaugural flight of the first F-35, a conventional takeoff and landing version, remains on schedule for this fall. The aircraft is the first of 15 F-35s that will be flight-tested, and another seven that will undergo a battery of ground-based tests. Additionally, a full-scale, high-fidelity F-35 model will be used to validate the aircraft’s stealth properties.