[Editor's note: Filing this aboard an American Airlines 737-700, DCA-DFW. Will post updates as possible. Technically-speaking, I'm supposed to be on vacation!]Boeing has decided to adopt a 20.3cm (8in)
nose gear extension and control the spoilers using fly-by-wire among other
design changes revealed today for the 737 Max family.
The company's announcement clarifies
several key design features first discussed by Boeing Commercial Airplanes
president and chief executive Jim Albaugh in November.
Albaugh had previously said the nose-gear
extension could range between 15.2-20.3cm, accommodating the larger diameter of
the CFM Interanational Leap 1B engine. CFM has initially sized the engine with
a 1.74m-wide fan, but the precise dimensions could change before the design is
frozen in the fourth quarter.
By using the maximum extension in the trade
study, Boeing potentially opens the door to slightly increasing the diameter of
the turbofan. The longer nose gear also means Boeing must alter the door.
Meanwhile, the new 737 Max will be
integrated into the wing in a design similar to the 787, the company adds.
All flight controls will remain
mechanically-driven except for the spoilers, which will be based on fly-by-wire
inputs, Boeing says. The 737 Max also will adopt an "electronic bleed air
system", which is also used on the Airbus A350. The electronic bleed air system
can reduce fuel burn by improving cabin pressurization and anti-icing systems
without adopting the 787's bleed-less architecture.
Boeing also is extending the 737's tail
cone and thickening the section above the elevator for the re-engined variant.
Finally, Boeing also could slightly change
the wingtips of the 737 Max, but the company provided no details. A revised
design is being tested in a wind tunnel, Boeing says.
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