Page 46 - World Airnews Magazine May 2021 Edition

COMMERCIAL

CAN RE-WINGED,

RE-ENGINED 737 MAX

COMPETE WITH THE A321XLR?

This article was penned by Aviation Week senior
editor and Western US bureau chief Guy Norris

the 1980s. The nose gear was lengthened After ruling out a costly centre wing box
by 6 in and the main gear strengthened, or side-of-body redesign, Boeing looked

n a word, no. Here’s why: The baseline while the new, bigger engines were can- at several gear options before settling on

I737 confi gurati on has proved to be re- tilevered up and forward of the wing to a new design combining a semi-levered,
markably resilient for a 55-year-old design maintain ground clearance. trailing-link extension with a shrink link.

with 13 major derivatives and more than The launch of the 737 Next Generation The former feature moves the rotation

10,500 deliveries and counting since 1967. in the 1990s saw a major redesign of the point aft, while the latter compresses the

Conceived initially for short-haul routes, wing that widened the main landing gear 9.5-in.-taller gear leg on retraction, allow-

the aircraft was designed with engines track by almost 2 ft. The gear itself re- ing it to fit into the same volume as the

mounted directly beneath the wings rath- ceived few dimensional changes, although standard MAX main-gear wheel well.

er than underslung on a 707-style pylon. tire size increased, and the nose-gear Ingenious though the new gear design

This enabled a shorter, inward-retracting wheel well was extended forward by 3 in. is, the size and position of the wheel well
landing gear and placed the fuselage lower to accommodate fuselage growth. mean that further fuselage extensions are

to the ground—making ground-servicing The baseline gear arrangement was impractical without a major wing redesign.

access easier at regional airports, most again slightly modified for the MAX in the The cost of this -added to the associated

of which at the time lacked skybridges 2010s, and despite the increased size of revisions of the fuselage structure, systems
and other elements of the new jet-age the CFM Leap 1B engine, the design mini- and wing to accept an even larger engine

infrastructure. mized the required change to a mere 8-in. - make this an unattractive option against

Boeing could not have imagined in the extension to the nose-gear leg. the relative benefits of an all-new uncom-
1960s that the short, stocky gear arrange- But more fundamental changes were promised design.

ment would one day prove to be a limit unavoidable when Boeing wanted to After performing beyond all expectations

to its growth, and over the decades, the challenge the Airbus A321neo by stretching as a wellspring of derivatives, the 737 likely

company has worked within the same the 737 beyond the 737-9’s length of 138 will have run its course after the -10 - hence

basic centre wing structure to adapt the ft. 4 in. Boeing’s big challenge was how to Boeing’s pursuit of new options to counter
737 to heavier weights, larger engines and extend the fuselage 66 in. for the 230-seat the Airbus A321XLR. Q

longer fuselages. 737-10 while maintaining aft body clear-

The process began with the launch of the ance on rotation - all without altering the Article courtesy: https://

reengined CFM56-powered 737 Classic in geometry of the wheel well. aviationweek.com/
World Airnews | May 2021
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