Paris Air Show

CFM takes LEAP into green future

 - December 15, 2006, 9:55 AM

CFM International has launched a new technology development program, LEAP56, that aims to ensure successors to its market-leading CFM56 engines can meet future airline demands for improved fuel consumption and reliability along with tougher environmental regulations.

“In the future we will need a suite of technologies that advances the state of the art significantly on all fronts,” said executive vice president–and newly knighted Chevalier of the Légion d’Honneur –William Clapper at a briefing yesterday in downtown Paris. “So we have decided to launch the leading edge aviation propulsion, or LEAP56, program.”

Future challenges in propulsion systems for single-aisle aircraft are the continuing drive for reductions of as much as 10 percent in fuel burn and 25 percent in maintenance costs, Clapper said. First, though, “we have to achieve extended on-wing life beyond today’s typical 20,000-plus hours, which equates to about six years in service.” There will also be significant challenges in terms of noise and emissions over the next 20 or 30 years, “so we will have to achieve the fuel and maintainability improvements in the context of a much tougher environmental regulatory regime.”

Basic design elements of the program include new fan technology, innovative power generation strategies to avoid bleeding air from the engine–which should improve fuel burn in the descent and to some extent in the cruise–and high- and low-pressure turbine technology.

Another is lightweight structures, Clapper said, so the program will include a new fan case of aluminum, composite and titanium that aims to be 10 percent lighter than today’s equivalent, plus a 3-D woven composite fan blade using resin transfer molding technology. A six-stage compressor will give a higher pressure ratio for greater efficiency, lower fuel burn and better productivity for the airlines.

There are also system considerations, Clapper said. Outside the engine, lighter, more reliable and more maintainable starters and gearboxes will be required, along with better controls to measure vibration and other parameters to support improvements in trend monitoring and engine health prediction. On the environmental front, a second-generation twin annular pre-swirl combustor intended to lower NOx emissions has already logged 800 test hours.

He envisions testing getting under way in 2007 at the component level to demonstrate the basic technologies, followed by systems-level demonstrations in the subsequent two or three years. The earliest date expected for entry into service of any resulting new engine is 2012-13.

“Today’s aircraft are setting new standards for performance and reliability,” Clapper summed up. “To maintain those standards while achieving the fuel burn and maintainability improvements, there will need to be a quantum leap in technology that will require significant investment and significant time to achieve. Adding the environmental challenges requires the most aggressive suite of technologies ever seen in this industry, so we are launching LEAP56 to lay the foundation for the future so CFMI can maintain the leadership it has today.”