Pratt & Whitney is confident that the problems with the STOVL version of the F135 engine powering the F-35B have been solved. At the Paris Air Show last week, Chris Flynn, vice president of fifth-generation programs, said that solutions to the lift-fan clutch engagement, driveshaft expansion and roll-post heating were all in production. Flynn noted that F-35Bs had amassed 508 flight test hours, and 116 vertical landings. Shipboard trials are scheduled for October, when two F-35Bs will deploy to an LHD-class vessel for two weeks.
Flynn said that the company is exploring improvements to the F135 based on its increasing maturity. Margins, performance, thrust growth, affordability and life-cycle costs would all be addressed. With today’s high oil prices, reducing the fuel burn is of great importance, and Pratt will apply its commercial engine experience, he said. The company also hopes to pursue durability improvements that will allow the intervals between shop visits to be extended to 10 years from the currently planned seven.
With the competing F136 engine officially dead (absent further Congressional action), Pratt is anxious not to be seen as enjoying the fruits of its sole-source status. “Our price for the engines in the last low-rate production lot was 15 percent below the previous lot,” Flynn noted. The contract terms were fixed-price-incentive-fee. The Senate Armed Services last week called for the next lot of F-35 engines and airframes to be purchased on a pure fixed-price basis.