Wing Spar
 

I dropped a wing the other day and broke the stinking wing spar off that is glued into the wing. It goes into the other wing and is epoxy'd into the wing. Anyone have any great ideas on how to get it out so I can buid a new one and glue it in?

I have tried using a heat gun to soften the epoxy with poor results. I also have a hot knife I am going to try but I haven't yet. I thought maybe someone might have a trick I wasn't aware of. I just hate to buy a new wing or totally destroy the wing if I don't have to. I was even thinking about dremel'ing it out and just building something new to fit it and the other half of the wing, but that is a last resort since I wouldn't actually have the spar to measure so I could make another.

Thanks

RE: Wing Spar
 

Hi panhndi: From your post, I get the thought that your wing is now in two sections. If that is the case. leave the broken spar alone, and splice in a long section of new spar material by making new slots on the ribs for the splice to go up against the original spar. Yes, you will have to remove covering, etc, but this type of repair will work. Let me know if this idea is a good one for you.

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RE: Wing Spar
 

You don't give us particulars.  What model?  Is this a 40" wing or an 80" wing? 

Personally, I'd save the piece.  Dowel it with at least two sections of bamboo skewers and use a 60 minute epoxy to repair the break.

Another option if this is a solid wing when completed is to take a razor saw and slice out the wing to allow a piece of birch plywood to slip against the spar (on both wing halves) and then epoxy that in place when joining the halves - along with the broken piece as filler.  After that hardens use epoxy & fiberglass to reinforce the joint butt where it won't show. 

RE: Wing Spar
 

Sorry. This is a 2 piece wing off of the new Pilot RC 30 cc gas trainer. It has two wing spars and 4 bolts to keep the wing together. It is about 90" wide when all put together.

The short spar is the one that broke. It still has around 1/4 - 1/2 inch sticking out. I would put up a picture but it seems to be not working for me today. Instead, a link to the page

[link=http://pilot-rc.com/Upload/273341048.JPG]wing[/link]

RE: Wing Spar
 

Looks like the shorter spar that broke is more of a locator or anti rotation pin than a structural member. I would use a dowel or bamboo skewers like was said in an earlier response and use epoxy and f'glass to reinforce it. If the use of wing struts is an option, I would use them also. Check the bolts holding the wing to the fuse often for tighteness. Good luck.

RE: Wing Spar
 

That main spar looks awful thin for a plane that size.... You'd think it would be metal...
Easy to fix if you wanted to open it up abit but I doubt you want to do that....
You could sand the remaining bit to a clean end and jusat insert ito the other wing as usual as it's not strucutral and there is enough to assist the bolts in anti-rotation.

What I would do:
ON the remaing bit, clean up the end... cut a slot into it... make a mating piece.... epoxy and be done.

RE: Wing Spar
 

Since I doubt my ability to drill a hole into both the loose and affixed broken wing spar pieces, i think I will use Hysol 9246 instead of plain cheap epoxy since it is stronger, doesn't run, and the spar is sticking out some already. If I feel I need more reinforcement, I will sand it down some and add some additional reinforcement. As far as the rear spar being flimsy or too weak, I don't know. The wing feels very sold when on the plane. Maybe the 4 bolts with two spars are enough. If I am wrong, I will gladly eat crow or possible a pile of rc plane sticks.

RE: Wing Spar
 

I would drill 2 holes into the wing half where the spar has broken.
Insert two pieces of piano wire into those holes.
Glue a piece of wood between the wires
You now have a connecting spar that fits into the spar box...
Have done it on 2 giant scale planes (ten foot wingspan). It really works. And it is a fast and cheap fix.
If you desire, I can send you a picture of it.