Wing spar repair

[Tree top pilot 13]

This may need to be in the technical dept. but wanted to post here first. I have sent this idea to an A&P / IA to speculate on. I want you guys to let me know your thoughts.

 

The rear wing spar root ribs were removed with an unknown amount of heat...just to get them off the spar tube. Hysol 9460 was used to bond. I know that a weldment will age itself to somewhere near 30% of it's original strength....but here is my idea. What do you think about it? All cheers and jeers welcomed.

[wypaul 448]

When you say an unknown amount of heat was used, do you know what the heat source was?  If you do repair it, will you trust it or will you be flying around waiting for the wings to fold.  I guess if it were me I would just rebuild the wings so I wasn't worrying about it.  The problem with the sleeve is that it adds a stress riser at the end of the sleeve but what I don't know is, would that be a problem or not.

[EDMO 1078]

It doesn't take too much heat to soften/melt the 9460 - But you need to know how and how much heat was applied.

To prevent the stress riser at the end of the insert, it should have a large rounded "V" cut out on two sides.

If it was mine, I would replace the spar, rather than worry about the unknown, unless you can verify that the heat used was not excessive, and then epoxy the insert repair if that makes you feel safer.

EDMO

Edited 26 May 2014 by Ed In Missouri

[Tree top pilot 13]

It was done by a helper with a propane torch...while I was absent. I would hate to scrap what I have....but it is critical. I am at a loss here. He told me it was heated from the inside enough to wiggle the rib off. So who knows...it was more than a year ago. As for replacing the spar...you know how much work that would be. Better off to start all new again. I am trying to figure a way out of doing just that. I agree with a fish-mouth to prevent a stress point. I am just trying to rationalize this as some other aircraft have a welded headrack tube made from T-6....and they are not falling out of the sky. My MTOW will be under 650lds. But .........I will be in touch with a person at Alcoa soon. Hopefully they will help in some capacity. Thanks for the suggestions......a lot to swallow at this point. Just now being able to get back to work on it a bit before the next round of health issues retards my activities.

[akflyer 1427]

I don't see the heat being a big issue. If he didn't smoke the glue, only enough to soften it up, I wouldn't loose too much sleep.

(:

[1avidflyer 1983]

If it helps any, I was told that the front spar carries more weight on a plane than the rear one.  Don't take my word for it, but look it up if you can.  If it's true, that might alleviate  some of the worry.  Jim Chuk

[EDMO 1078]

Jim,

      You really got my attention on that - I always thought the opposite:  That the rear spar carried more weight - and wings have failed in a DOWN direction at the front -

Dang, got to get out the books on this one - back to school again!   

      Too bad the guy with the torch didn't just hit the glue on the outside - that would have taken a lot less heat than trying to get the tube hot from the inside!    I wouldn't fly it "as is" - an insert or new spar would make me more comfortable.

      It is not too hard to replace one spar - just cut chunks of spar tube out between ribs and use a heat gun to melt glue and slide the short pieces out.

EDMO

Edited 27 May 2014 by Ed In Missouri

[akflyer 1427]

Ed, do you have a story on an avid or a kitfox that has had an inflight wing failure?