As we reported earlier today, Boeing and CFM didn’t stop with the previously announced 68.4 inch fan for the LEAP-1B engine on the 737 MAX.
Buckingham Research, citing Boeing at the investors’ day, wrote that Boeing talked about a 70 inch fan. Jon Ostrower–now at the Wall Street Journal–confirmed the larger fan, but at 69.4 inches (70 inches apparently was a rounded number) as well as pursuit of a smaller core.
The smaller core is important for two reasons: a larger fan and a smaller core provide for a higher by-pass ratio, increasing fuel burn reduction performance. The smaller core also enabled the engine to be mounted closer to the wing, which in turn means the previously announced 8 inch nose gear extension remains valid.