Ps76
Topic Author
Posts: 1015
Joined: Tue Jun 01, 2004 7:52 pm

Main Landing Gear Load For Airliners.

Sun Dec 24, 2006 8:25 am

Hi-Was just wondering how the load is placed on the main landing gear for airliners. At the moment thinking something like:

- There must be very strong members / very strong box for the point where the fuselage attaches to the landing gear.
- The individual gear struts may be attached at more than 1 point to the fuselage to help spread out the load.
- If the load is only transmitted through few points (like 1 per gear strut) the attachment points must be very strong & highly reinforced for the fuselage region.

Mainly wondering if the fuselage is made mainly of light aluminium with the much more soild heavy gear how would the gear not go through the "floor" with landing or parked.

Many thanks for any help/information-P.

[Edited 2006-12-24 00:43:00]
 
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HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Main Landing Gear Load For Airliners.

Sun Dec 24, 2006 10:34 am

Most Commercial Aircraft of today have the MLGs attached via Trunnion joints to the Rear spar & Landing gear support beam,fore & aft respectively.The Trunnion bearings have shear pins that detach if excess loads are experienced to prevent damage to the primary structure.

A reaction link helps the MLG Actuator transmit retraction/Extension loads from the gear to the Fuselage.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Ps76
Topic Author
Posts: 1015
Joined: Tue Jun 01, 2004 7:52 pm

RE: Main Landing Gear Load For Airliners.

Sun Dec 24, 2006 11:43 am

Hi - From the info the internet provided me the following for "Trunnion Bearing":

http://www.ntsb.gov/Recs/letters/1999/A99_4.pdf

It looks like the MLG Aft Beam is spreading the load a lot over the fuselage (maybe wing rear spar too), but it also looks like the Trunnion bearings (which look like ball-&-socket joints(?)) must be strong or if not a great load might rip the ball in the upwards direction from the socket(?).

Maybe the side strut helps reduce the load on the 2 points a little too(?).

Many thanks - P.

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