wood spar questions

[sibbeston]

Im just in the process of disassembling my wings and the plywood on the rear spar root is delaminated. The wood looks sound and other than dark areas looks rot free. A few questions
-On the UK BREY restoration aluminium plates are used instead of wood. Any comments on this?
-what material are the bushings for bolt holes made of? Where can i find this? Im a long way from aircraft supply.
-What plywood is OK that i can get from a local supplier (basic hardware outlet) and what glue is best?
thinking of ordering metal spars from D&E, but undecided.
Thanks for any input.

[N96337]

Re: wood spar questions

Check the rest of the spars very closely for any splices...if they're there, you've got a really good chance that they are having, or are about to have a glue problem as well. When I pulled my Tcraft spars, they were delaminated at more than a few glue joints...good for patterns only.
As far as plywood, I always went with aircraft grade plywood. The bushings are of phenolic. Glue is a no-brainer... resorcinol is the only approved stuff that I know of. DO NOT let someone talk you into T88...it loses over 70% of it's strength very quickly with temperature increases that are normally seen in a wing....and it's not legal.
All that may not be the case up there, but down here it is. Your MOT is light years ahead of the FAA in some aspects.
John

[Hank Jarrett]

Re: wood spar questions

I found a good source of really fine aircraft grade plywood is your local hobby shop. SIG manufacturing is supposed to distribute thin aircraft ply for models.
Hank

[Larry Lyons]

Re: wood spar questions

Maybe it is just the pic, but I see what look like cracks through two of the bolt holes, with the top one going to the inboard end?
L

[crispy critter]

Re: wood spar questions

I see the cracks as well but if you look closely they are directly in the grain line.

[Larry Lyons]

Re: wood spar questions

Yep I agree and I am not even close to knowing what I am talking about, but my spars were cracked along the grain too. However a crack is crack, although it may be just the photo showing a color change there and not a crack at all. L

[crispy critter]

Re: wood spar questions

You are correct Larry,they are certinly cracked in the grain lines around two or three of the bolt holes. If they were mine I would replace them without question. However with the doubler that glues overtop on this area I think that would be considered a proper splice. Personally I would still replace them but that is up to the builder and the A&P/AI.

[sibbeston]

Re: wood spar questions

I dont think there are cracks, but i dont like the mildew and for a grand i think ill replace with wag aero spars. I feels wrong to rebuild it without new spars.
Thanks for the comments.

[Larry Lyons]

Re: wood spar questions

I have my new spars laying next to the old and "My, they do look nice"! But the $1,000 I payed for $20 worth of lumber still hurts.