CFM Claims Leap Performance Lead Over Pratt

By Graham Warwick graham.warwick@aviationweek.com
Source: AWIN First
June 17, 2013
Credit: CFM

CFM International has opened Paris with a shot across the bow of competitor Pratt & Whitney, claiming its Leap-1A engine has up to 3% lower specific fuel consumption (sfc) than the rival PW1100G geared turbofan on the A320NEO family.

“The Leap will go into revenue service on the A320NEO 1% better than the competition, based on testing to date,” Chaker Chahrour, executive vice president of CFM told the press here on Saturday.

“And it will retain that 1% better than the competition, which when you integrate over time adds up to another 1%,” he says. “And on the A321, because of the longer legs and our better cruise sfc bucket, we get another 1%. So on the A321, 1 plus 1 equals 3.”

CFM calculates the 3% better fuel burn on the A321NEO than the PW1100G is worth $2 million per aircraft net present value (NPV). In addition, Chahrour says, the Leap’s longer time on wing will translate into two fewer shops visits over the life of an engine, “for the bulk of another $2 million” in NPV.

The General Electric/Snecma joint venture calculates an NPV advantage of $4 million per aircraft on the A320NEO for the Leap-1A, up from the $3.5 million claimed at last year’s Farnborough show.

Lower line maintenance costs for the fan case-mounted accessories make up the rest of the calculated advantage. “The line replaceable units do not see the temperatures” of the core-mounted accessories on the geared turbofan, he argues.

CFM’s claims are based on the results of just-completed tests of the third eCore demonstrator — comprising the high-pressure compressor, combustor and high-pressure turbine of the Leap-1. The core completed 203 hr. of tests with “better component efficiencies than expected,” Chahrour says.

Composite fan-blade and low-pressure turbine tests have also produced “excellent results,” he says. The first Leap-1A, meanwhile, is on schedule to begin ground tests “in the fall.” CFM is aiming for a 15% sfc reduction over the CFM56-5B engine now powering the A320.

CFM is making much of the Leap’s performance advantage versus the PW1100G. This is based on the incorporation of variable bleed valves (VBV), first introduced on the larger GE90 and GENx. These are eight doors that extend into the flow entering the compressor to divert debris into the bypass duct.


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