Lockheed Martin X-35 JSF completes structural loads testing

26 June 2000

Lockheed Martin's second X-35 concept demonstrator aircraft for the Joint Strike Fighter (JSF) programme has successfully completed structural loads testing at company facilities in Palmdale in California.

A test fixture with 90 hydraulic actuators applied stresses to different parts of the aircraft to simulate in-flight aerodynamic pressure loads on the aircraft. The aircraft tested is the X-35C, which is configured as the US Navy carrier variant and is the second demonstrator aircraft assembled. Because the different variants are structurally very similar, the load-test results apply to all three concept demonstrator variants.

The aircraft was tested to 100 percent of design limit load, minus 3 gs and plus 8 gs. This means the wings were stressed to carry about 180,000 pounds, or the weight of 50 mid-size cars. Test conditions also included wing torsional testing that represents aircraft rolling manoeuvres.

Proof-of-operations tests confirmed the control surfaces would not bind against aircraft structure during full control surface deflections while the aircraft is in manoeuvring flight. Testing also included operation of the propulsion doors for the X-35B short takeoff and vertical landing (STOVL) variant.

"These structural testing results validate our design, modelling, analyses and testing methodologies for the JSF program,'' said Rick Rezabek, X-35 chief engineer. "By achieving a good correlation between predicted analyses and test results, we have shown we have a solid understanding of the JSF design, including the details that go into every frame, rib and spar.''

Lockheed Martin and Boeing each received a JSF Concept Demonstration contract from the US Department of Defense in November 1996. The Lockheed Martin JSF team includes Northrop Grumman and BAE SYSTEMS. Flight evaluation of the demonstrator aircraft is scheduled to take place in 2000, with government selection of a single contractor for the Engineering and Manufacturing Development phase set for 2001.


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