Pratt & Whitney is "optimistic" of overcoming development problems with the Lockheed Martin and Boeing Joint Strike Fighter (JSF) short take-off and vertical landing (STOVL) engine contenders by mid-year, and is to begin preparations for qualification tests and first flight by September.

P&W JSF programme director Bob Cea says: "I'm fairly confident on the CTOL [conventional take off and landing] side that we will be able to go to flight test soon. The challenge will be STOVL development, completing the necessary tests and software and getting ready for flight.

"There have been problems with the lift fan that are slowing down development of the propulsion system, and those fixes are being made. Within months, Rolls-Royce will have incorporated those fixes into the Lockheed Martin and Boeing engines."

Problems with a bearing on the R-R (Allison)-built lift fan for the P&W JSF119-611 STOVL engine for Lockheed Martin's X-35 JSF concept demonstrator were discovered late last month, compounding delays caused by software integration issues (Flight International, 29 February-6 March).

R-R is addressing design changes to the lift module in the JSF119-614 for Boeing's X-32 demonstrator, the test schedule for which may also be threatened with delay by the company's engineers' strike. The delays have had knock-on effects for development, test and verification of the critical software that integrates the flight controls and propulsion system of the JSF contenders.

Cea was commenting as P&W delivered the JSF119-614 CTOL flight-test engine to Boeing. Having just delivered the equivalent engine to Lockheed Martin, "we have essentially completed development of the CTOL engines", says Cea, who adds that "up and away performance is meeting every requirement, and probably exceeding it in terms of thrust".

Source: Flight International