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Flap Repair Help

mfleming

Well Known Member
Patron
Back on March 14th I put up a post about dropping my wing in the shop :eek:

The aileron has been fixed and I kicked the can down the road on the lower wing skins and end rib.

Talking to Van's tech support, they said re-skinning the flap is doable but take a crack at fixing it first as I have nothing to loose.

I thought I would canvas the best minds in the RV game to see how you would approach this repair.

Here's three photos of the damage.

flap1.jpg


flap2.jpg


flap3.jpg
 
When I messed up my fuel tank, I bought one of these sets... its a must for doing any kind of metal work. Based on what you’re showing, I’d get one of these sets and then go to a hardware store and buy a piece of bar stock to put on the inside to hammer against.

As an alternative, I’d take them to a local EAA chapter meeting. I imagine that there’d be someone there with metalworking expertise...

https://www.eastwood.com/7-pc-econo...F13NQ8_ybG-p3jQz3McSnTps-vNqCWRcaAuRtEALw_wcB

My $0.02
 
When I messed up my fuel tank, I bought one of these sets... its a must for doing any kind of metal work. Based on what you?re showing, I?d get one of these sets and then go to a hardware store and buy a piece of bar stock to put on the inside to hammer against.

As an alternative, I?d take them to a local EAA chapter meeting. I imagine that there?d be someone there with metalworking expertise...

https://www.eastwood.com/7-pc-econo...F13NQ8_ybG-p3jQz3McSnTps-vNqCWRcaAuRtEALw_wcB

My $0.02

Good idea on the body/fender tools...a friend has a set i could borrow. Unfortunately the closest EAA chapter with that kind of expertise is 8 hours away :eek:
 
Repair

I think the best success will come if you drill the skin off. That way you have full access to both inside and out. If you don't succeed, just buy a new skin and replace it.
 
I think the best success will come if you drill the skin off. That way you have full access to both inside and out. If you don't succeed, just buy a new skin and replace it.

If I have to drill the skin off, I'll fit a new skin. I'm contemplating drilling out some of the top skin to bottom skin rivets for access, then resemble with MK-319-BS pull rivets.

I'm reassembling my old flap stand to make it easier to hold the flap steady when I attempt to knock the dent out.
 
You might try taking it to a good, repeat good, auto body shop and asking the manager to put his best sheet metal guy to work fixing it. A good bump artist can work wonders. That's what I did when I was unable to work out a dent I'd put in one of the aft fuselage skins on my project, and when I got it back, there was no sign of a flaw.

They have the tools and the know-how, and are worth whatever they ask. Generally it's modest by airplane standards.

Dave
 
You might try taking it to a good, repeat good, auto body shop and asking the manager to put his best sheet metal guy to work fixing it. A good bump artist can work wonders. That's what I did when I was unable to work out a dent I'd put in one of the aft fuselage skins on my project, and when I got it back, there was no sign of a flaw.

They have the tools and the know-how, and are worth whatever they ask. Generally it's modest by airplane standards.

Dave

Interesting thought. Might have to wait for this Covid19 pandemic to get over before enlisting outside help :eek:
 
Michael, your second picture shows that the damage can be worked out fairly easy if you drilled out the rivet on the end rib and removed it. Then use some wedge shaped dollies/bucking bars and a flat faced hammer to bring back to its original shape. Then just re-rivet the end rib back in place. Follow it up with a small amount of filler if necessary for a smooth appearance.
 
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I too have made some damage when I was building. I think you can fix it. Give it a try!
Just as you have embarked on a building project, a little body building experience will make you the better.
 
I agree that end rib needs to come out. The impact dented the trailing edge and then pushed the skin askew. The skin loaded on that first rivet and the force creased and buckled the skin. Getting the crease out will be the bigger challenge. You have to relieve the stress at that rivet and get room to back it with a bucking bar of some sort. My only concern about the trailing edge is the potential for cracking. 2024 T3 gives you one or two shots before fatigue. Go slow and don?t over work.
As you look at the repair attempt, think about the sequence of events as the flap hit the floor. Try to repair in the same sequence in reverse. Work the crease and buckled top skin and flatten that part of the skin, then progress to the trailing edge. The skin should then start to lay flat as the trailing edge comes into shape.
Have fun. You have nothing to lose. Working metal is both science and black art. Experience is the only teacher.
 
As others mentioned, nothing to loose at this point, so worth a bit of experimenting on. I'd start with slipping a Philips screw driver (same or slightly larger radius that trailing edge) and gently tapping backwards to re-establish the trailing edge. Than get the end rib out of the way & use seamer to get majority of bend flattened. After that, light body hammering to flatten the surfaces before riveting it back together. Some Feather Light will make the owie fade into history at the cost of not much more than a couple of hours.
 
Wow, Great suggestions...

So far I have removed the end rib, fashioned a brass dowel to match the trailing edge radius and removed the ugly inverted dent. Then I started using hand seamers to give the train edge the proper shape and follow the rest of the trailing edge.

Today I will see if there is someway to fit a tapered block inside the flap and use the spoon method to work out the wavy skin.

Photos and videos when I've got this puppy finished.
 
The problem with doing the trailing edge first, is now there is no place for the ?wavy skin? to move too. If there wasn?t too much stretching, you?re still ok, but always try to work backwards from last point of damage to first point.
Fortunately aluminum is pretty malleable, but 2024 T3 has a memory and it can start to get ?noodley?, then your done,l...
I am still betting you can get this in decent enough shape to move on.
 
The problem with doing the trailing edge first, is now there is no place for the ?wavy skin? to move too. If there wasn?t too much stretching, you?re still ok, but always try to work backwards from last point of damage to first point.
Fortunately aluminum is pretty malleable, but 2024 T3 has a memory and it can start to get ?noodley?, then your done,l...
I am still betting you can get this in decent enough shape to move on.

Yes, I was a bit backward on the sequence. I'll find out soon how this will come out.
 
I would drill out a couple rivets so I could lift it. Try to gently rub it back into the proper shape like the paintless dent removal place do for cars (or even pay then to do it since they are magicians at it. Then make an inside doubler, re-rivet, and build on.
 
Make a wooden V block the shape of the flap. Make a wooden plug that matches the V block. Line both pieces with one or two layers of electrical tape.
Remove rib, lubricate tape and carefully press/ tap the plug inside the flap into the V block.
It may take a few tries to get it to shape. It will never be perfect but you should be able to get it close enough that a bit of glass cloth and final final prime and paint.
Carefully insect for cracks when finished

No guarantees, but it will be good practice for hangar rash!
 
Repair Completed

So, Thanks to all the great advice. I wish I would have listened to some of it earlier ;)

The flap repair came out serviceable so I won't have to reskin the flap :D
The advice I wish I had payed attention to earlier is working from the outside of the dent inward.

Anyway, here is how it was repaired. I had an old brass rod that I rounded the end to match the radius of the flap trailing edge. If you look at the beginning photos, the trailing edge had an ugly inverted dent. The rod worked well to massage the inversion back out.

It became clear the end rib would have to be removed and so it was. This provided much more access to the damaged area. I made a hardwood wedge that fit into the training edge but it was only marginally useful as the dent was a inny and the wedge would work best for an outty.

One thing that did work pretty well was using a wooden dowel hot glued to the skin and pulling the dent out. I watched some body work pros using similar technique with a putty glue and a slide hammer on YouTube. This was done several times.

Once I had the general shape of the trailing edge worked out, I used a spoon and some mineral oil to push down the high spots.

The repair isn't perfect but there are no cracks and the trailing edge shape is aerodynamic.

When the flap gets prepped for paint I'll use some filler and it will invisible.

Here's a short video of using the wooden dowel hot glued to the skin :eek:

Click reload if the images don't load right away.

The brass dowel shaped like the trailing edge radius.
fix1.jpg



Working out the inverted trailing edge dent.
fix2.jpg


Using some hardwood blocks to smooth the train edge dent.
fix3.jpg


After a little persuading :rolleyes:
fix4.jpg


Ready for the end rib to be re-riveted.
fix5.jpg


All back together
fix6.jpg
 
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Using a Spoon to Work Out a Dent

Here's a video of using a spoon mentioned in my above post for working out dents. This was several years ago when I had a mishap with an edge roller on an aileron skin.
 
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