Wing Damage Repair

[sprint27c]

Hi Guys...just starting back up an RV-6 project that had been on hold for 15 years (to build a Rotorway and a few race cars in between ).

Anyway - I dug my wings out of storage and was very disappointed to find some damage on the outboard of one of the wings. Looks like the top side skin took some sort of impact and crinkled the rib below as well.

I'm wondering what the best repair would be here. I'm thinking that replacing the entire skin and rib here may cause more damage than what gets fixed through all of the drilling out of rivets that would occur.

Would it be ok the cut the skin two rib stations back and overlay a new sheet of .024. I think the rib can probably be salvaged/straightened...

Does this seem reasonable or should I bite the bullet and replace the whole skin and rib.??





TIA,

[noelf]

...to replace the outboard rib and work the skin to flatten. The wing tip will need to fit on the outboard wing skin that overhangs the rib.

My second thought would be to cut out the section of rib that is damaged, splice in a matching section, and add a doubler to the repaired section, and again, pound out the skin to flatten. The drawback here is that you may have some difficulty in fitting the wingtip.

[Mel]

It is perfectly acceptable to splice a wing skin, especially this close to the tip. Only negatives will be cosmetic.

[rvbuilder2002]

If I was doing the repair, the first thing I would do is remove the rib. This will allow the skin to no longer be retrained by the rib. You can then evaluate the appearance of the skin and work it back to being flat (not with a hammer, but strategic manipulation).

[Andy_RR]

or shorten the wingspan by a couple of inches.

[MrNomad]

Originally Posted by noelf

...to replace the outboard rib and work the skin to flatten. The wing tip will need to fit on the outboard wing skin that overhangs the rib.

I agree, "work the skin to flatten". Using two hammers, you should be able to get the skin back to its original shape. Then fix or replace the rib.

I work metal with two hammers at once. The first hammer has two flat opposing faces. One flat face of the hammer stays on the crinkled metal which should be laying on a hard piece of particle board or something similar. The second hammer taps the opposite end of the first providing the impact. The lower hammer never leaves the material and is always held perfectly flush to the material. Glide it around while the second hammer provides the "persuasion" thru the first.

Before I do this, I grind the face of the lower hammer perfectly flat so it does not introduce any new problems.

Test the idea on a piece of scrap. We used this idea yesterday to create those alum pieces we need to finish the bottom of the windshield cover pieces. After you buff, try some fill primer to see if the issues are gone.

Another method of persuading crinkles to flatten is to use a rivet gun with low pressure and a wide face. Practice on scrap.

Hope this helps.

[sprint27c]

Originally Posted by MrNomad

Hope this helps.

Yes it certainly does help thank you. To me it looks like the skin was "stretched" quite a bit here. Until I read your posts I was almost sure there was no repair possible with it as it seems once it was stretched it would never lay back down flat without distorting some other area of the skin (ie: oil canning).

I kinda like the idea of splicing the rib also...would there be any downside to this idea?

I guess I'm just trying to avoid drilling out bunches of rivets here - seems like that can be more destructive than the damage itself...

[Andrew M]

I vote to replace the rib, and splice the skin. Once metal is bent, it has stretched and will not go back like it was. On a stressed skin, most airframe manufactures classify creases as a crack. Negligible limits are usually expressed as smooth dents at least a number of diameters away from underling structure. No help there. Ribs are cheap.
AC 43.13-1B para 4-58 (e) and fig 4-16 . Copy the original skin splice that is inboard.
Andrew
RV-9 preview
AP IA
23 years structures

[MrNomad]

Originally Posted by sprint27c

I guess I'm just trying to avoid drilling out bunches of rivets here - seems like that can be more destructive than the damage itself...

Invariably, rivets have to come out so before we embarked on project #1, our local, expert, tech counselor taught us how to remove rivets w/o damaging the pieces. He actually conducted classes in our shop so that we learned how to rivet, remove rivets, work with WEST products, and much more.

You should also find threads on this website as well as threads on the EAA website that deal with this subject. Assuming your local tech counselor is as good as ours, work with him/her and practice before tackling your wing.

From the picture it appeared to be relatively minor bend and fixed by "hammering", but if it's worse, always take the safest route. Nevertheless, use the occasion to expand your metal working skills even if you intend to patch or replace. This won't be the last OOPS!

Best of luck.

[rv6rick]

Not seeing it 'in person'....it appears to be an easy fix. I would remove the rib and repair it on the bench using the hammer/bucking bar/seamer method.

Then, after using the hammer/bucking bar method on the skin......break out the shrinker to pull the excess material back to where it belongs. Use the shrinker gently and it will work wonders. Yes...you'll have to sand and finish the marks left from the shrinker but if you are gentle you should still be able to polish the skin if you want to later on.

If you don't have access to a shrinker Harbor Freight has a cheapo that you can pass on to your buds when you're finished with it. If you need one with deeper jaws they have those as well. If you live near Ohio you are welcome to borrow mine.

I see this kind of stuff at my shop all the time....folks damage stuff in shipping. Try to fix it first....you can always replace the skin. Most important is that it looks and feels like it was never damaged.

Good Luck.