General Electric (GE) and partner Rolls Royce have stopped financing their F136 afterburning turbofan designed for the F-35 Lightning II, the two companies announced Dec. 2.
The pair had been privately funding the developmental effort - dubbed the alt-engine - after the U.S. Defense Department formally terminated the project in April.
"The decision, reached jointly by GE and Rolls-Royce leadership, recognizes the continued uncertainty in the development and production schedules for the JSF Program," the companies said in a joint statement. "Following termination, the GE Rolls-Royce [Fighter Engine Team] had offered to self-fund F136 development through fiscal year 2012, but will now end its development work."
The two companies' decision marks the end of a 15-year effort to develop an alternative to the Pratt and Whitney F135 engine that would eventually be fitted into later F-35 production lots. The process was supposed replicate the so-called "Great Engine War" between the GE F110 and Pratt and Whitney F100, which power different blocks of Lockheed Martin's F-16 Fighting Falcon. Lockheed also builds the F-35.
The Defense Department, however, had been trying to cancel the F-136 program for the last five years because it said it can't afford to fund an extra engine. Until last year, DoD had been thwarted by Congress in those efforts.
Before DoD issued a "stop work" order March 24 for the 43,000-pound-thrust-class engine, GE claims that F136 development was about 80 percent complete. Six developmental engines had accumulated more than 1,100 hours since early 2010, the company said.
The two companies often touted advantages the F136 potentially offered over its Pratt and Whitney rival.
"The engine demonstrated significant thrust margin for much lower operating temperatures than the competing JSF engine," the GE and Rolls Royce statement reads. "This creates up to a 25 percent maintenance cost advantage for the F136 because of the engine's higher airflow design."