Chair Force Engineer

Sunday, January 22, 2006

Engine Competition

The 2007 DoD budget request will supposedly drop funding for the F136 jet engine, which was supposed to be a competitor to the F135 engine that will power the F-35 Joint Strike Fighter. If history is any indication, the availability of alternate engines would have been a blessing for the JSF.

General Electric (who would have produced the F136) also makes the F110, which validated the soundness of having an alternate jet engine for supersonic fighters. Specifically, the F110 replaced the disappointing engines that had previously powered the F-14 Tomcat & F-16 Fighting Falcon. Derivates of the F110 (known as F118) also went on to power the B-2 Stealth Bomber and U-2S spy plane.

When the Tomcat was first built in 1972, it was powered by the Pratt & Whitney TF30. While this engine was the first turbofan designed for supersonic aircraft, it had many faults, especially the all-too-frequent compressor stall. The engine had already proven to be a disappointment in the F-111 and A-7, but it was the only engine that met the Tomcat's requirements at the time. Likewise, the F-15 Eagle and F-16 Fighting Falcon were designed around the Pratt & Whitney F100, another large turbofan with reliability problems.

In the late 70's, General Electric came up with a Derivative Fighter Engine (DFE) variant of the F101 it had created for the B-1A. With the B-1A cancelled by President Carter, GE needed to find a new market for the engine. the F101-DFE was successfully tested in an F-16 and an F-14.

The results of these trials were so impressive that future F-14's and F-16's were built with the DFE, put into production as the F110. The GE-powered Tomcats and Falcons had better reliability and more thrust. For the Tomcat, the airframe's full potential was finally reached, and the Tomcat could accelerate in a vertical climb. The F-16's powered by the F110 can break the sound barrier without the gas-guzzing afterburner. In short, the healthy competition between Pratt & Whitney and GE resulted in better engines for two fighters.

Surprisingly, the Air Force did not choose to incorporate the F110 into the F-15 Eagle. The logic behind this choice is because the F-15 had an established logistics system and billions of dollars invested into the old F100 (although a similar investment had been made into the F100 engine for the F-16.) However, South Korea announced within the past year that it will be buying F-15K Strike Eagles equipped with the F110, further cementing the reputation of the GE engine.

It's been speculated that if GE loses the F136 contract, it will be put out of the fighter engine business. For GE, the only hopes of future fighter engine sales will be F110's for future F-16's (although the future market for F-16 sales looks bleak,) and more F414's for the Navy's Super Hornet. While the F110 has also been mentioned for the proposed FB-22 "Strike Raptor," the FB-22's chances for production are bleak at best.

In the absence of competition from GE, Pratt & Whitney will likely become fat and complacent (even as it loses market share in the airliner engine segment t0 GE and Rolls Royce.) Most importantly, sole-sourcing the engine buy means that the entire JSF fleet can be crippled by an engine defect.