Pratt & Whitney plans to begin test runs of the first two Joint Strike Fighter (JSF) engines in the "April-May timeframe" and will begin initial tests of the short take-off and vertical landing (STOVL) variants in the third quarter of this year.

The first two cores, the SE611 for Lockheed Martin and the SE614 for Boeing, will be "completed before the end of the month", says Robert Cea, JSF engine programme manager for P&W's Large Military Engines unit. "Fans are being produced, the low pressure [LP]turbine has been manufactured in our Connecticut site and STOVL components are coming from partners Rolls-Royce and Allison," he adds.

Initial tests of the JSF powerplant, which is based on the F119-100 used in the US Air Force's Lockheed Martin/Boeing F-22 Raptor fighter, will be focused on the CTOL (conventional take-off and landing) versions and it will take place at four dedicated test sites close to the manufacturer's West Palm Beach factory in Florida. More complex testing of the STOVL variants is planned at new STOVL sites, "where we will be able to measure six-axes of thrust", says Cea. The first is virtually complete and will be joined by a further two sites.

The STOVL tests will focus on the performance of the SE611's shaft-driven lift fan, three-bearing swivel nozzle and control system. They will also be used to evaluate the operability of the larger fan of the SE614 as well as its direct-lift nozzles, lift module and integrated control system.

The development programme began in December 1996 when P&W won the propulsion contest for the competing Boeing and Lockheed Martin JSF demonstrators. The critical design review was passed successfully in November 1997, although assembly of the first engine components had already begun by then. Cea says that 1997 "was the year for design,1998 will be the year for test".

The speed of the effort is attributed largely to high commonality with the F119 and a host of critical systems and rig tests, many of which were associated with a recently completed phase of the CAESAR (components and engine structural assessment research) programme. CAESAR is part of the US Defense Department/NASA/industry Integrated High Performance Turbine Engine Technology programme, and was focused on vital JSF technology.

This included gamma titanium aluminide components in the compressor, as well as advanced cooling for the blades and vanes in the HP turbine. These latter tests were particularly critical to the JSF engines which will run at higher turbine inlet temperatures than the F119-100. "Tests have boosted our confidence we can operate at JSF temperatures," confirms Cea.

"After a tear-down and inspection we're going to take those same parts and put them back into a CAESAR engine which will then complete another 1,500 [endurance] cycles this year," he adds. Both JSF contenders are due to have first flights in 2000.

Source: Flight International