Spar repair

[waltermrich]

Re: Spar repair

I would think it would be lot easier to remove 3 or 4 ribs to reach a broken part of a spar than to dissmantel an entire wing to replace a spar, wood when kept dry and in the right climate will last decades and decades .An expericened wood worker would have no problem creating a scarf joint that would be stronger than the spar itself.

[birdlegs]

Re: Spar repair

PS. you're right, NEVER UNDER A FITTING!

John talked me out of a spar splice years ago, after you remove it all (the labor commitment) it's hard to justify not replaceing the whole unit....
As a result I got me two beautiful wings,and zero time on it all.
Just say'n
Birdlegs...

[astjp2]

Re: Spar repair

Very carefully! They need to be installed in a specific order...Tim

One of the things I found challenging in concept was how to fit the ribs over the thicker part of the spar that has the plywood "overlay" (forgot the real term, that was a long time ago). Made a few test splices with resorsinol (sp?) and found the spliced area to be stronger than the main body of the wood, even without the overlay. That was back in the mid 80's. I still have the resorsinol. I've often thought about testing a bit of it to see if it still works. Chuckle.

Darryl

[flyguy]

Re: Spar repair

One of the things I found challenging in concept was how to fit the ribs over the thicker part of the spar that has the plywood "overlay" (forgot the real term, that was a long time ago). Made a few test splices with resorsinol (sp?) and found the spliced area to be stronger than the main body of the wood, even without the overlay. That was back in the mid 80's. I still have the resorsinol. I've often thought about testing a bit of it to see if it still works. Chuckle.

Darryl

[N96337]

Re: Spar repair

So from what Im reading if you found a damaged area near the root attach fitting of a spar you could cut the spar back far enough and splice anew piece in place reglue doublers and that would be permissible.

No.... What I'm saying is I'd just replace the spar. It's going to be at least as much work to mess around splicing. Like Hank says, if it was at the tip or maybe the last couple bays outboard, I'd consider a splice....but why is it broken? I always worry about a shock load being transferred down the length of the spar and showing up somewhere else. I've done a few splices, and to do them totally correct, to me it's easier, less work and more comfortable to just replace the whole spar. It's not easy to CORRECTLY do a spar splice, line everything up correctly, fit the splice correctly, glue correctly (with approved glue) etc when it's still in the wing. It's not that tough to just get it done without it being totally correct in every aspect, but then it's not really legal is it? Also, if it's not done to the exact specs spelled out, how strong is it? How do you know? My past experience doing spar splices has shown me that my time is better utilized just replacing it, especially if it's in the area between the root and the strut attach, and my reluctance to even mess with it goes up exponentially as it nears the root..... but that's just MY opinion.

[waltermrich]

Re: Spar repair

Finding some one who has experience with repairing wood spars will be a great resource for me , calling EAA and talking with some of there members at the vintage group might give me some help.

Re: Spar repair

Im seeking information on the repair of spruce spars, It is permissible to splice a spar according to AC 43.13 but not under an attach fitting, what Im not sure about is does that mean the splice joint cannot be under the attach fitting or can the splice be made away from the attach fitting. Some one in this group will know ?

Hi Walt,

I don't see the difference between these two options. What did I miss?

Can you find a good experienced restorer in your area and consult with him or her?

Spar fixing is an old problem that has been solved many times in the past they will walk you through it.

Dave

[Hank Jarrett]

Re: Spar repair

There are lots of things you "can" do, but there are also a lot of them you can fix a better way. If I had a spar with a break in the last two feet at the tip I wouldn't hesitate to splice it. If I had one broken in the first two feet at the ROOT, I would make a clip wing spar out of it or replace it. You "can" splice it, but I wouldn't without some static testing after I did it, and it would be cheaper to just make a new spar with the testing I would do.

Hank

[stearman3]

Re: Spar repair

You really should have a look at AC43.13-1B. the repair criteria your going to use is spelled out very well.

So from what Im reading if you found a damaged area near the root attach fitting of a spar you could cut the spar back far enough and splice anew piece in place reglue doublers and that would be permissible.

[waltermrich]

Re: Spar repair

I've found through past experience, that it's more economical to just replace the spar than going through all the work of a splice...especially if you have to pay someone to do it. I'm sure there are many that will disagree, but that's my preference. To get the splice exactly right is quite a bit of fitting and work.... just sayin'.
John

So from what Im reading if you found a damaged area near the root attach fitting of a spar you could cut the spar back far enough and splice anew piece in place reglue doublers and that would be permissible.

[N96337]

Re: Spar repair

I've found through past experience, that it's more economical to just replace the spar than going through all the work of a splice...especially if you have to pay someone to do it. I'm sure there are many that will disagree, but that's my preference. To get the splice exactly right is quite a bit of fitting and work.... just sayin'.
John

[stearman3]

Re: Spar repair

PS. you're right, NEVER UNDER A FITTING!

[stearman3]

Re: Spar repair

As long as the splice and reinf. plates don't interfere with a fitting your ok. There may be min distance from a fittng as well, I'd have to look that up again.

Im seeking information on the repair of spruce spars, It is permissible to splice a spar according to AC 43.13 but not under an attach fitting, what Im not sure about is does that mean the splice joint cannot be under the attach fitting or can the splice be made away from the attach fitting . Some one in this group will know ?

[waltermrich]

Im seeking information on the repair of spruce spars, It is permissible to splice a spar according to AC 43.13 but not under an attach fitting, what Im not sure about is does that mean the splice joint cannot be under the attach fitting or can the splice be made away from the attach fitting . Some one in this group will know ?