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GE Aviation Moving To Apply Ceramic Matrix Composites to the Heart of Future Engines

March 09, 2009

EVENDALE, Ohio -- It is no simple feat introducing durable, lightweight composite components into the "hot section" of a flying jet engine. But GE Aviation is achieving this elusive, technical milestone. 

The GE Rolls-Royce Fighter Engine Team's F136 development engine for the Joint Strike Fighter (JSF) contains third-stage, low-pressure turbine vanes made by GE from ceramic matrix composites (CMC). This could lead to the first commercial use of CMCs in a jet engine's hot section (combustor and turbine areas) when a F136-powered JSF begins flight testing in 2010. 

CMC development is a key initiative at GE Aviation, and an enabling technology in several of GE's private and government-funded engine demonstrator programs now underway. Also, CMC components are a key feature of GE's eCore program, the cornerstone for the company's next-generation of jet engines for narrow-body, regional, and business jets. 

CMCs are made of silicon carbide ceramic fibers and ceramic resin, manufactured through a highly sophisticated process, and further enhanced with proprietary coatings. 

They are highly desirable for jet engine components for two main reasons: 1. They are lightweight - one-third the density of metal - providing weight reduction and thus, better fuel efficiency. 2. They are durable and more heat resistant than metals, requiring less cooling air, and thereby improving overall engine efficiency. Simply put, removing cooling air allows a jet engine to run at higher thrust and/or more efficiently. 

GE Aviation and GE's Corporate Research Center have pursued CMC technology for more than 15 years. Several years ago, GE Aviation ran a government demonstrator engine with a combustor liner and low-pressure turbine blades. GE Aviation produces CMC at its facility in Newark, Delaware. 

"Developing new jet engine materials takes many years of investment and commitment," said Robert Schafrik, GE Aviation's general manager of materials and process engineering. "But the benefits can provide a considerable competitive advantage. CMCs are a new frontier that will raise the bar in jet engine performance." 

GE Aviation has already led the jet propulsion industry in advancing composites in the "cold section" of jet engines with polymeric matrix components made of carbon fiber and epoxy resin. In 1995, GE introduced the first carbon fiber composite front fan blade in an airline engine with its GE90, which powers the Boeing 777. For the new GEnx engine, which will power the Boeing 787, GE will introduce both composite fan blades, using the same fibers, resin, and manufacturing processes as the GE90 blade, and a fiber-braided composite fan case. Both will provide dramatic weight savings. 

Schafrik sees a day when CMC components will populate many areas in the engine's hot section, including high- and low-pressure turbine vanes and blades, turbine shrouds, and combustor liners. For example, CFM International, a 50/50 joint company of Snecma (SAFRAN GROUP) and GE, will run a Leap-X demonstrator engine in 2010 with CMC components as CFM pursues technologies for next-generation engines for narrowbody aircraft. Also, CMC combustor liners are under consideration for future GEnx production models. 

"Over the next 15 years, jet propulsion advances at GE could help to lay the groundwork for a broader use of CMCs across several industrial sectors," said Roger Doughty, manager of CMC Design and Technology at GE Aviation. 

GE Aviation, an operating unit of General Electric Company (NYSE: GE), is a world-leading provider of commercial and military jet engines and components as well as integrated digital, electric power, and mechanical systems for aircraft. GE Aviation also has a global service network to support these offerings.