Pratt & Whitney (P&W) has successfully completed rigorous thermal tests of the F135 short take-off and vertical landing (STOVL) variant propulsion system.

The high-temperature-margin test involved running the engine to turbine temperatures beyond design conditions and simultaneously operating the turbomachinery above 100% of design conditions.

The test was carried out to demonstrate the F135 propulsion system’s ability to produce margin relative to thrust, with the engine producing 28% more thrust than the specification requirement.

The engine will now complete STOVL-powered lift performance qualification tests, one of the final steps prior to receiving initial service release qualification from the US Government.

The F135 has completed more than 19,000 hours of testing and the conventional take-off and landing (CTOL) / carrier variant (CV) engine received initial service release (ISR) in February.

The STOVL F135 engine is expected to receive ISR certification before the end of 2010.