New Main Gear for the 737-10X

[Guest]

Boeing Outlines 737-10X Gear Test Plan

May 2, 2017 Guy Norris | Aviation Daily

 

As Boeing works towards the expected launch of the 737-10X around midyear the company has offered more details of the design and test plan for the extended main gear which is pivotal to the configuration of the stretched twin.

The -10X will incorporate a 66-inch fuselage stretch, taking overall length to 143 ft. and increasing two-class capacity to 189 passengers, compared to 193 for its arch-rival, a similarly configured Airbus A321neo. In a single class the -10X could seat up to 230. However, the extension means Boeing has to incorporate a modified main landing gear design to enable adequate clearance of the longer body for rotation on take-off and landing, and to ensure the aircraft remains stall – rather than pitch - limited.

Boeing has already introduced an 8-inch nose leg extension into the MAX family to increase ground clearance for the larger diameter CFM Leap-1B, but has wrestled with several options for the main gear changes for the -10X – including various forms of telescoping configurations. The company later revealed it was focusing on a solution that used a version of the semi-levered design developed for its larger, multi-axle widebody gear systems, to pivot the axle further aft in a design that resembled a trailing link gear.

While precise details of the finalized gear arrangement are not yet being disclosed, Boeing is offering new insights into both the overall configuration and the way it will be evaluated during 2017.  The design focus is on “the upper portion of the gear as it integrates with the actuator,” says 737 MAX vice president and general manager Keith Leverkuhn.  In this area, within the tight confines of the existing wheel well, Boeing’s new design will do some “clever folding using a link mechanism at the top,” he adds.

The lower section of the leg is also modified with “an additional shock strut that fits inside the same forging. This moves the contact point aft a little bit. That’s fundamentally what we are doing and yes, it will look like a trailing link gear. We want to make it maintainable, reliable, and we are going to need that gear to get the performance we want out of the -10 but I’m confident in the solution set,” Leverkuhn says.

Boeing is constructing two types of rig to test the new gear, one to evaluate functionality and the other its robustness.  “The kinematics are tricky,” says Leverkuhn.  “How do we take this fundamentally longer gear and make sure it folds up nicely in the gear well. So we do drop tests to understand the structure we have sized is appropriate and another rig test around the function of the new gear.  We will spend most of the year doing that, but we are really zeroing in on it,” he says.

Boeing has been actively marketing the 737-10X which, if sufficient launch orders are taken to ensure go-ahead this year, is targeted at entry-into-service in 2020.

[deicer]

When are they going to realise there is only so much modification you can do to an old design?