Two days after F-35 Joint Strike Fighter (JSF) engine rival Rolls-Royce unveiled plans for a dramatic engine upgrade after 2020, a Pratt & Whitney executive fired back with a strong defence of its current improvement plans for the F135.
P&W does not see a requirement to develop an all-new powerplant for the F-35, says P&W military engines president Thomas Farmer.
Noting that the F135 is scheduled to deliver a 5% thrust upgrade in 2010, Farmer compared the F-35's propulsion needs to the 30-year development trajectory of the Lockheed F-16.
"The F-16 began at 24,000lb thrust and for P&W, it [has increased] up to 29,000lb of thrust as the aircraft evolved," Farmer says. "The same will occur with the JSF and P&W has the thrust and performance improvement plans that will accommodate the needs of the JSF."
Farmer's comments came after a Flightglobal report on 11 June that the General Electric/Rolls-Royce fighter engine team plans to dramatically boost the F136's power and fuel efficiency after 2020 using technology acquired from the Air Force Research Laboratory's adaptive versatile engine technology (ADVENT) programme.
Rolls and GE are competing to be selected by AFRL in September to develop ADVENT's variable-cycle engine technology, which is expected to generate a 25% improvement in fuel efficiency.
Meanwhile, the F135 is nearing a key milestone. First flight of BF-1, an F-35 prototype for short take-off and vertical landing (STOVL), is expected to take place mid- to late summer out of Fort Worth, Texas.
The STOVL tests will follow P&W's recent completion of successful hover pit testing.
More rigorous flight tests "where we'll really engage in short take-off" will take place at the firm's Patuxent River test centre in Maryland, says Farmer.
The hover testing "to get the STOVL vehicle ready to fly" has gone "extremely well", says P&W president Dave Hess. "We are going to focus on executing perfectly and delivering a great engine for the Air Force, Navy and Marines."
Responding to customer requirements remains P&W's key focus at a time when there remains a lack of clarity on whether the F136 will play a role in the JSF. While the Department of Defense has proposed killing the F136 funding again for the fourth year in a row, some lawmakers have proposed restoring the funding.
However, notes Hess, US President Barack Obama recently singled out the F136 as an example of government waste "and frankly we'd agree with that". He says the near $5 billion required to fund an alternative engine "could mean 50 less JSF" aircraft purchased over the next six years, which could drive up cost per aircraft as the production ramp slows down.
Additionally, he says, the data "does not appear to be there that it saves money for the taxpayer". Rather, "the contrary seems to be true" - that it is going to cost more money.
"But again we can't control Congress. All we can continue to do is develop a great engine and an affordable engine," adds the P&W executive.