retract mounts
 

hello all i recently had a strut break on my p-51 mustang and it ripped mounts and everything out of the wing. i was wondering if anyone could give me some ideas of how to build stronger mounts and the best way to reinforce them. thanks. heres some pics and it was a ARF. [&o]

RE: retract mounts
 

the mounts I use a c shaped cut from 1/4 birch ply and just epoxied into foam wings or into cut out in the ribs of built up wings that have 1/16 ply doublers on them.i've never landed hard enough to had them rip out.my cutlass patern plane is pushing 30 years old and there are still nice and secure

RE: retract mounts
 

If it is a built-up wing I will use maple only.

RE: retract mounts
 

In the past on L.G. failure, I found it was not so much the design and strength of the model and wood. I tore out, then beefed it up, then next time it tore out a bigger chunk. And bigger after that. I went to more plywood, and more gussets, cords, and bigger fillets on glue joints. Usually up to three rebuilds per problem.

The problem lie in the overall design and strength of the area, and of my touchdown techniques for that A/C. Needs to be softer.

Wm.

RE: retract mounts
 

Ya thats true, but material selection is one of the major issues, U/C getting high spots so we look for something hard and not stiff, Plywood may cracks due to fatigue while maple absorbing shocks much better than plywood.

RE: retract mounts
 

thanks for the reply, would you use the maple for the complete mout and rails and everything or just for the blocks and places the rails mount to? also would something like curly maple work? i have plenty of that for knife handle material. thanks.

RE: retract mounts
 

The maple rails are mounted to plywood ribs (birch or similar), I'm not sure about its type but you may find it in old Malaysian furnatures :).

Attached snapshot of my scratch built PIPER landing gear and another picture of some 12" maple bars.

RE: retract mounts
 

ok, my setup will be sorta like yours but im still not getting why maple would be better than another wood like light ply, can you explain it again and can some 1 tell me if curly maple would work? thanks

RE: retract mounts
 

Let me give a real example. last 2 weeks I crashed my 61" cessna. engine has mounted on maple beams the bolts have bent but the mount holes only got distorted. if light ply is the case it will crack easily. maple has higher density and if you hammer it mostly it will distort

the following pictures (engine mount + engine bolts) may discribes what I'm saying.

RE: retract mounts
 

ok awsome. now that i know this i am ready to make the mounts. I will be using curly maple which is maple that is taken from a fork in the tree. thanks for the info ill post pics when im done.