The fan spinner is designed to push heavier particles to the outside of the flow entering the core and at lower power, during taxiing or reverse thrust when debris is highest, the VBVs open to reject particles to the fan stream, reducing erosion of the compressor blades over time.
“We get at least 1% better performance retention” than the PW1100G, says Gareth Richards, Leap program manager. The VBVs are closed at high power and in the cruise to avoid a performance penalty.
Performance and durability will be confirmed over a planned 60 test engines – 28 for ground testing at CFM and 32 for flight testing by customers – with 40,000 cycles expected to be accumulated before entry into revenue service, compared with around 10,000 cycles for the CFM56-5B/7B program
CFM, meanwhile, is gearing up to produce 1,700 engines in 2020, almost all Leap-1s. This will be an increase from the 1,500 engines planned for this year and 1,540 for 2014, all CFM56s. The transition to Leap will begin in 2016.
Already the Leap makes up almost half of the roughly 10,000 engines the joint venture has in backlog: 1,392 Leap-1As for the A320NEO, 2,470 -1Bs for the Boeing 737MAX and 760 -1Cs for the Comac C919.