We picked up information that Boeing’s announcement at ISTAT in March that it had settled on a 68.4 inch fan for the 737 MAX LEAP-1B wasn’t a done deal. Now Buckingham Research comes out of Tuesday’s Boeing’s investors’ day with this notation:
A 70” fan for the 737MAX
BA noted that 737MAX development is proceeding on schedule with firm configuration expected in 2013 and first flight in 2016. Further, BA sees more upside than downside risk to the plane’s 13% efficiency improvement. BA is now looking at a slightly larger 70” fan for the LEAP-X engine vs. 68.4″ previously. While that might reinforce investor concerns regarding the GE LEAP-X engine performance, we see the change as part of the design optimization process. A number of factors impact engine fan size, including drag (larger engine fans have more drag), bypass ratio, core size, core temperature, etc. With the 737MAX recently undergoing wind tunnel testing, we think the revised engine fan size has more to do with optimizing the engine than a means to overcome performance deficiencies.
Note that this is not speculation on Buckingham’s part; it cites Boeing as the source.