GE Aviation's carbon fiber turbine blade turns 20

GE Aviation (Evendale, OH, US) is celebrating the 20th anniversary of the first jet engine to certify with composite fan blades. Powering an early model of Boeing’s 777 aircraft, the first GE90 engine certified in February 1995—and thus marked the first aviation use of carbon fiber composite material on a jet engine’s front fan blade.

In the 1980s, GE Aviation gained experience with composite fan blades on its experimental GE36 open rotor jet engine that successfully ground-tested and flew. This bolstered GE to use composite fan blades for the GE90 engine, which required a lightweight, durable material solution for the engine’s large front fan.

The GE90-powered Boeing 777s are among the most fuel-efficient and reliable commercial jetliners in history. With more than 2,000 GE90 engines delivered, the composite fan blade has become a landmark technology for GE and has influenced succeeding generations of GE commercial engines, including the GEnx and the new GE9X.

GE reports, however, that achieving certification of that first composite fan blade was no easy feat. GE encountered challenges in the design, certification and manufacture. “For our engineers, one of the biggest hurdles for the composite fan blade was understanding the characteristics of the new carbon fiber material,” says Nick Kray, a consulting engineer for composite design at GE Aviation. “GE conducted hundreds of intensive tests on the new composite material to determine its breaking points. The results gave us enormous confidence in the composite material’s durability.”

To manufacture the composite fan blade, GE teamed up with Snecma of France to create CFAN in 1993, located in San Marcos, TX, US. “CFAN has really perfected the production process for composite fan blades,” says Kray. “At the start of production, the yield rate for composite fan blade was less than 30%. Today, CFAN has a yield of greater than 97%, and the business has doubled its fan blade production in the last five years from 5,000 blades in 2009 to 14,000 fan blades last year.”

The next-generation GE90 engine, the GE9X, will feature fewer and thinner composite fan blades than any GE widebody engine in service. To do this, GE is designing a new composite fan blade using next-generation carbon fiber composite material. The GE9X will have just 16 fan blades on its 3,404-mm front fan. Almost 700 GE9X engines have been ordered since it was launched on the Boeing 777X aircraft last year. The first engine will test in 2016, with flight-testing on GE’s flying testbed anticipated in 2017. Engine certification is scheduled for 2018.