There has been a great deal of debate over whether Boeing can meet the SFC reduction targets for its 737 MAX. This debate revolves in part because neither Boeing or CFM have been forthcoming about details how the CFM LEAP engine is being optimized for MAX.
We’ve obtained some details to explain how CFM is proceeding.
Details are still sketchy and hard to come by. But our source has direct knowledge of the program.
Our source compared the requirement to reduce the fan size of the 737 LEAP from 78 inches on the Airbus A320 neo to 68 1/2 inches on the MAX to the fan reduction on the GEnx from the 787 to the 747-8. The 747-8 engines are optimized for this aircraft despite the smaller fan size.
Reducing the fan enables CFM to eliminate some LPT stages, our source explains, which also cuts other parts.
This eliminations allow the LEAP to be shorter, which also allows the engine mounting to be shorter.
CFM is also using ceramics to the MAX LEAP.
These are some of the key ways CFM is optimizing LEAP for MAX.