Ceramics Moving Into Jet Engines

GE Aircraft Engines is moving heavily into composite materials for its jet engines. These materials include carbon fiber and ceramics. The carbon fiber parts are generally used for the parts of the engine away from where the fuel is burned. Ceramics, with their superior heat tolerance, are used in areas such as turbine blades. If successful, future engines could consist of 50 percent composite parts.

Currently, 10 percent of the parts of an engine are composites. Current use of composites has allowed GE to reduce the weight of the GE90 engine, which is used on the Boeing 777, by 1,200 pounds. Future engines will have greater weight savings. In addition to weight savings, these materials are expected to last longer and to cut maintenance costs.

Using these materials to manufacture the complex parts used in jet engines is a tricky business. Since they are new and the parts complex, GE has been working on ways to build them efficiently. This involves many manual steps. GE is making these parts in its own plants by hand. Evidentially automated manufacture is currently not feasible, and may not be for the foreseeable future. Interestingly, since GE considers this a core technology, it is producing these parts in-house. It is also working to expand the number and types of parts that will be made out of these materials. In addition to a plant in Batesville, Miss., GE is planning to open up another factory next year. This reverses the long-term trend of outsourcing parts manufacture.

GE's competitors, Pratt & Whitney and Rolls Royce, are concentrating on engine design changes to move ahead. They believe that the advanced materials are not the way to go. On the other hand, GE has also been improving the design of its engines. Clean-burning combustors and turbines that use fewer, more efficient blades are just some of the design improvements made in its latest engines. All three of these manufacturers are enhancing diagnostic capabilities and working on more efficient designs. The competition remains strong in the industry.

So, while composites are now being used in the structure of aircraft, GE is extending this trend to the engines that power the aircraft. This has been tried in the past, most notably by Rolls Royce in the 1960s, but it did not work out well. GE, with its track record in engines, hopes to reverse the trend. The structural use of composites was not without its problems. Both the Boeing 787 and the Airbus 380 have experienced problems and delays. Boeing and Airbus continued to pursue the technology, though, because of the savings in fuel and maintenance costs. In the end, the investment has worked out. It is changing the way aircraft are designed and built.

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