Boeing today revealed that it has decided to adopt a 20.3cm (8in) nose gear extension for the 737 Max family, in addition to controlling the new twinjet’s spoilers using fly-by-wire.
The company’s announcement clarifies several key design features first discussed by Boeing Commercial Airplanes president and chief executive Jim Albaugh in November.
It had previously been 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. Entry into service for the Max is slated for 2017 with launch customer Southwest Airlines.
Beverly Wyse, vice president and general manager, 737 program, said, “We’ve made several design decisions that support the performance targets for the MAX and evolve the Next-Generation 737’s design within the scope of the 737 MAX program.”
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, which eliminates the need for vortex generators on the tail.