Although consigned to history, the furiously-debated battle over the F-35 Joint Strike Fighter engine continues to stir up controversy. A day or so after Aviation Week’s Dec 5 story of General Electric and Rolls-Royce’s decision to terminate the F136 alternate engine, my inbox began to fill with e-mails from supporters of both the victors and the vanquished.
Top of the agenda was the usual debate at the root of the alternate engine question and the apparent mystery over whether the Pentagon ever ‘directed’ the use of the Pratt & Whitney F119-based concept. A retired top Pratt executive who was involved in the program at the time wrote to say categorically that “no-one ever “directed” the use of a derivative of the F119 engine for the JSF (called JAST at the time). All three airframe competitors came to that decision on their own. They decided that for the cost savings and maturity benefits, but it was not directed.”
Insiders from the GE-Rolls Fighter Engine Team were meanwhile just as adamant that JSF/JAST contenders were ‘directed’ to adopt the Pratt engine. “The word ‘directed’ was used specifically because it came from correspondence from McDonnell Douglas with GE,” said one. “They were told by the USAF to go with the F119, period,” added another.
A glimpse up the business end of AA-1 (Guy Norris)
Having battled for some 15 years to compete for the JSF, the GE-Rolls team has now bowed out leaving the field clear for Pratt which is busy ramping-up production. Assembly of production engines, as well as additional F135s for flight testing, continues with up to 32 production-standard units expected to deliver by year-end versus 12 in 2010.
Additional engines, added to the program through the TBR [technical baseline review] restructuring process announced early this year, will boost deliveries to between 45 and 50 engines in 2012. To read more about progress on the F135 program check out the F-35 special coverage in the Dec 12 edition of AW&ST. Click here to view a specially created cutaway graphic of the F-35B.Here’s a final timeline outlining the mixed fortunes of the two JSF engine contenders from the earliest years.
Timeline of Pratt & Whitney F135 and GE Rolls-Royce F136 programs
1995: For reasons of commonality with the Pratt & Whitney (P&W) engine for the F-22, the P&W engine concept is used during the JSF aircraft down-select process. P&W becomes the uncontested primary JSF engine.
1996: Congress provides initial seed money to GE to study a competing engine. Rolls-Royce joins GE on the engine program
1997: Congress further funds GE/Rolls and directs the Pentagon to ensure a full development program is launched. Pentagon structures the GE/Rolls program to enter production four years after the P&W engine.
1998: First P&W CTOL and STOVL JSF119 engines fire up for first time.
1999: Pentagon introduces “plug and play” engine interchangeability, whereby the competing engines are designed to the same external dimensions for easy change out of engines. P&W JSF119 STOVL engine runs in afterburner for first time. JSF119 CTOL goes for initial altitude tests at AEDC.
2000: P&W JSF119 powered X-35A flies for first time, followed in December by X-35C. Successful “core” F136 engine test and fan rig tests.
2001: P&W awarded $4.8 billion full-scale development contract (SDD) for F135 engine. First flight of X-35B STOVL, later conducts first supersonic flight with vertical landing.
2002: GE/Rolls create a joint company, GE Rolls-Royce Fight Engine Team, to develop and produce the F136 engine.
2003: First P&W F135 engine goes to test.
2004: First GE-Rolls F136 full engine run.
2005: GE/Rolls awarded $2.4 billion full-scale development contract (SDD), with completion in 2013. First F135 flight test engine built.
2006-2009: Each year, the U.S. Department of Defense cancels the F136 program, citing budget constraints. Engine funding restored each year by Congressional (House and Senate) support.
2006: First flight of F135-powered F-35A (AA-1)
2007: F135 propulsion system damaged during deliberate hard stall of shaft-driven lift as part of STOVL flight release testing. Three months later LP turbine failure occurs on F135 ground test engine FX634 during powered-lift qualification.
2008: F135 flight test engine FTE06 suffers LP turbine blade failure during proof tests. First flight of F135-powered F-35B (BF-1), and first supersonic flight of F-35A (AF-1)
2009: First “production-configuration” F136 engine goes to test. F135 damaged due to worn bushings. F136 suffers damage after ingesting sensor in September and the following month another engine suffers turbine damage after ingesting loose bolt.
2010: First production F135 CTOL/CV engine delivered and ISR granted. A Congressional “Nunn-McCurdy Breach” of JSF program results from costs growing beyond 50% of plan. P&W’s development costs forecasted to grow to $7.3 billion. For the fifth year, the Department of Defense cancels the GE/Rolls program.
First F-35B STOVL hover and landing in March. In May, the full U.S. House of Representatives “authorized” to restore funding for the FY2011 budget. However, the FY2011 budget process was not completed during 2010, and moved into the next year.
First supersonic flight of F-35B STOVL in June, with first flight of F-35C (CF-1) in June. Six F136 development engines run, preparing for flight tests in 2011. First P&W-Rolls STOVL production propulsion system delivered and ISR granted.
2011: After the House approved an amendment that removed F136 funding from the 2011 continuing resolution, the F136 program was terminated by the Department of Defense. A self-funded F136 development effort was passed by the House Armed Services committee. However, continued uncertainty in the development and production schedules for the JSF Program led GE and Rolls-Royce to discontinue the self-funded effort in December.