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Bird Strike Repair

WingnutWick

Well Known Member
Hello!

I recently suffered a bird strike on the left wing of the 10 and I am looking into the best (least painful/most effective/efficient) way to go about this repair. I have an airframe guy who is going to do it. The three options of now that I am looking at are:

1. Reskin entire panel with solid rivets which would be a massive project considering access is limited to buck rivets. Basically (unless someone knows something I don't) would mean deconstructing most of the wing skin.

2. Splice in a section to cover the damaged part. Seems easy but a little funky and less clean. Obviously the seam could be filled in but it doesn't resonate with my OCD type tendencies.

3. Reskin the entire section using Cherry Max rivets. This to me seems like the best alternative time/cost wise since I'm coming out of pocket and the one I am leaning towards.

Looking for input on all options but my main question is: is there any significant reason why reskinning with cherry max would be a bad thing? Weight difference?

Thank you!

Charles
 

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Couple of thoughts…

1) Have you priced CherryMax rivets? you’re talking about a buck a pop - so count all the rivets!

2) CherryMax rivets are usually found in -4 (1/8”) diameter - I am not sure I have ever actually seen a -3. Most skin to rib rivets on the RV’s are -3 - so the panel will look different. Caveat - I haven’t built a -10….maybe Van’s used -4’s?

3) Another option you didn’t list - call Van’s and talk to them about what they recommend. They designed it - they know how to fix it. I’d give their answer a whole lot more eight than anything you find here (including from me).

Paul
 
There are other threads here on VAF of people documenting repairing dents like this by banging them out from inside. A very good metal working person could make that dent disappear in a few hours. You might need to create an access panel for them, and of course there would be paint work.

I also recall one builder that installed a wing light in the dent location. Not sure if that's an option for you.

And of course I echo Paul's solid advice to call factory.
 
As Paul states, CherryMax are only available in sizes -4/-5/-6/-8.

wing light in the dent location

Is a no-go unless structural integrity can be maintained.

If enough rib distance available, a doubler/patch method could be done. A skilled craftsman could even do the repair in situ… Solid rivets for the doubler, CherryMax for the patch.



And again, Vans is the reference :)
 

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I would cut out an access panel at the spar, just like the other one's vans puts on the wing and make a doubler for the cover, like pictured in the post above. This will give you access to the inside. The form a piece of aluminum that matches the LE contour. Leave it just shorter than the space between the ribs. Cut out the damaged area. Hold the new piece firmly from the inside and match drill, dimple and rivet. Then use poly filler or epoxy to clean up the transition areas on the outside, as well as the rivets. Vans may have some formed LE skins that are damaged and can cut out a piece for you.

The amount of creasing looks bad enough that the average dent guy will not have success getting them out and still maintaining the proper LE shape.

Larry
 
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an opinion

My opinion? It's a $250k aeroplane or thereabouts to replace and the leading edge is a structural element, so why muck around with compromise repairs? In the photo, the damage extends to the leading edge rib, so that would need attention. In replacing the skin, the majority of rivets should be able to be bucked, as we do when we build. For those rivets that can not be reached, Vans should be able to advise what is an acceptable pulled rivet. Good luck with deciding what to do and getting it back in the air, you have had some bad luck to begin with!
 
Just thinking out load for yet another approach.
Perhaps first give the dent guy a chance to see if he can repair it. It maybe a couple of hundred dollars down the drain but I think it may be worth.

If that didn't produce a satisfactory result, replace only a portion of the skin. Cut the skin cleanly right next to the third rib. Get a new rib (for the right wing) and rivet it to the third rib which has the flange to the opposite direction. Then replace only that portion of the skin which should give ample access for bucking. With this you will end up with one more seam but it would be a clean seam much like the one between the tank and leading edge skin. If you don't like that look, you can fill it as part of the painting. But the structure will be sound.

As for the cherry rivet option, beside the cost of it, I think since those come only in -4 and above, you may be compromising the integrity of the spar by upsizing all the holes to the next size hole.

Sorry for your troubles.
 
I haven't had any luck with any paintless dent guys thinking they could repair that given the creases in the metal. I will continue to ask around though.

Vans recommends rebuilding the entire leading edge. This seems excessive but I understand that they are going to suggest the most conservative method short of "rebuild the entire wing" due to liability concerns. Even so, it looks like I would have to make an inspection panel between each rid to blind rivet the leading edge on.

Looks like cherry max would require over sizing everything which doesn't sound ideal. Consulting Vans on this aspect of whether blind rivets are an acceptable method for reskinning.

Thanks for the input - gathering more info!
 
Consulting Vans on this aspect of whether blind rivets are an acceptable method for reskinning.

Thanks for the input - gathering more info!

I remember vans stating that the MK319BS is almost as strong as bucked rivet. I believe it is Monel.

Larr
 
Amount of crease, especially in lower one, has me doubting creases can be adequately removed. Not a fan of access panel as you may successfully cut and install access panel and still end up having to replace the skin. If you still wish to pursue this route first check to see that there is a sufficient size lightening hole already be in the main spar web in that area that you can reach through. If there isn't one or one large enough already in the spar web in that bay then the access panel is not an option.

Instead of installing new access panel is to remove the tank and see what you can do with the skin working from that end. Nothing lost here in that if dent cannot be removed sufficiently or you end up damaging the skin you haven't lost much. Tank would have needed to been removed anyway and you don't have an access panel you don't need.

If it was my bird and yes you have a real investment there, I would definitely replace the skin. When done the only evidence will be a logbook entry as looking at the plane nothing will say there ever was damage here. Take it in steps and it is easily manageable.

First thing you have going for you is how well the pre-punched replacement parts from Vans fit. Please don't consider using Cherrymax rivets as stated earlier are very expensive, will up the hole size and will always stand out that a repair was made. Drill and break off heads of rivets holding skin on. Drill only far enough that skin can be pulled from shank of rivet. If you try and drill farther to removed rivet entirely or try and pound out you risk enlarging hole or bending rib flanges underneath. Once the skin is removed you can remove the remainder of rivet in each hole by drilling slightly with say a 1/16" drill bit to relieve pressure of rivet in hole and either using a heavy back stop so flange doesn't bend and punch it out or grab it from the shop head with a small wire nippers and pull it out.
 
Thanks Paul, this is helpful and the route I am likely going to go. What rivet solution would you use for the ones you can't buck rivet? Again, I imagine solid rivets can be used on at least half since the skin can be flexed out of the way enough to get the bar in there, but closing it up would require pop rivets.

Thank you!

Amount of crease, especially in lower one, has me doubting creases can be adequately removed. Not a fan of access panel as you may successfully cut and install access panel and still end up having to replace the skin. If you still wish to pursue this route first check to see that there is a sufficient size lightening hole already be in the main spar web in that area that you can reach through. If there isn't one or one large enough already in the spar web in that bay then the access panel is not an option.

Instead of installing new access panel is to remove the tank and see what you can do with the skin working from that end. Nothing lost here in that if dent cannot be removed sufficiently or you end up damaging the skin you haven't lost much. Tank would have needed to been removed anyway and you don't have an access panel you don't need.

If it was my bird and yes you have a real investment there, I would definitely replace the skin. When done the only evidence will be a logbook entry as looking at the plane nothing will say there ever was damage here. Take it in steps and it is easily manageable.

First thing you have going for you is how well the pre-punched replacement parts from Vans fit. Please don't consider using Cherrymax rivets as stated earlier are very expensive, will up the hole size and will always stand out that a repair was made. Drill and break off heads of rivets holding skin on. Drill only far enough that skin can be pulled from shank of rivet. If you try and drill farther to removed rivet entirely or try and pound out you risk enlarging hole or bending rib flanges underneath. Once the skin is removed you can remove the remainder of rivet in each hole by drilling slightly with say a 1/16" drill bit to relieve pressure of rivet in hole and either using a heavy back stop so flange doesn't bend and punch it out or grab it from the shop head with a small wire nippers and pull it out.
 
If I was doing this repair, I would remove the skin and then remove all of the nose ribs from the spar.

Prep a new skin and any new ribs that needed to be replaced.

Rivet the ribs into the L.E. skin as was done during original construction.

Then rivet the L.E. section back onto the wing using blind rivets to attach the ribs to the spar, and conventional rivets to attach the skin.
It will require some long reaches and contorting for some areas but it should be possible via the existing access hole and inward from the outboard end with the wing tip removed.
 
I built my nine and the wings I think are roughly the same as the ten. If you remove the wing tip, the existing wing access panels and the tank I think you should be able to do it with solids entirely. I believe the rivets you feel may be a problem are the ones on the aft side of the spar on the flange inboard closer to the fuselage. Maybe you will need to add one access panel but not sure without seeing a ten. Maybe one of the guys with one at my airport will let me take a look at there's. If blind rivets are really necessary in a specific location to do this repair Vans will confirm that and have a recommendation. On a side note length and size of arms can be the difference so possibly getting help from someone with long skinny arms just might do it.
 
If you suffer from the short arm syndrome, you could consider installing an access panel in the bottom wing skin, third most outboard bay, just behind the spar. This would give you bucking bar access to the most difficult spot while riveting the leading edge section back on. Vans sells a great Access Panel Kit that could be used for this...
 
If you suffer from the short arm syndrome, you could consider installing an access panel in the bottom wing skin, third most outboard bay, just behind the spar. This would give you bucking bar access to the most difficult spot while riveting the leading edge section back on. Vans sells a great Access Panel Kit that could be used for this...

That or find a flexible rivet bucker with long arms. I meant to stick my arm in the RV-10's wing today to see how difficult of a job this would be, and forgot until I'd already left the airport. Tomorrow... I hope.
 
If I was doing this repair, I would remove the skin and then remove all of the nose ribs from the spar.

Prep a new skin and any new ribs that needed to be replaced.

Rivet the ribs into the L.E. skin as was done during original construction.

Then rivet the L.E. section back onto the wing using blind rivets to attach the ribs to the spar, and conventional rivets to attach the skin.
It will require some long reaches and contorting for some areas but it should be possible via the existing access hole and inward from the outboard end with the wing tip removed.

I have no dog in this fight, but this post is: Concise, clear and complete. Thanks.
 
I have no dog in this fight, but this post is: Concise, clear and complete. Thanks.
I agree with the exception of I can not see how one can buck the rivets to the spare flange three ribs away. I don't know anyone with that long of an arm.
 
I agree with the exception of I can not see how one can buck the rivets to the spare flange three ribs away. I don't know anyone with that long of an arm.

There are 6 bays. You should be able to reach (and rivet) the three outboard bays from the wingtip. The next two ribs create the aileron bellcrank bay, so those are "easy" <ahem> through the bellcrank access panel.

The next bay inboard can be reached from the aileron bay, as well, so 5 bays down, one to go.

The most inboard bay of the leading edge is equidistant from the aileron bellcrank access panel and the "middle" access panel. So pick the access point that is least agonizing and make it happen. If necessary, you might resort to a few -319BS rivets, but a flexible person could probably buck all of 'em, properly motivated. I've still got a wing sitting on a stand at the airport, and will check access tomorrow.
 
I think an access hole can be cut into the bottom of the LE just like the access for the stall warner tab. This will provide access to rivet the inner ribs. For the long wing RV10, maybe 2 access holes.
 
There are 6 bays. You should be able to reach (and rivet) the three outboard bays from the wingtip. The next two ribs create the aileron bellcrank bay, so those are "easy" <ahem> through the bellcrank access panel.

The next bay inboard can be reached from the aileron bay, as well, so 5 bays down, one to go.

The most inboard bay of the leading edge is equidistant from the aileron bellcrank access panel and the "middle" access panel. So pick the access point that is least agonizing and make it happen. If necessary, you might resort to a few -319BS rivets, but a flexible person could probably buck all of 'em, properly motivated. I've still got a wing sitting on a stand at the airport, and will check access tomorrow.

I am not sure how you are suggesting it, if you mean thru the access panel of the aileron bay, that is aft of the spare and there is no access thru the spar. Besides if one can reach three bays from the wing tip, then s/he can access it the other three bay from the tank side as well. But that requires some really long arm.
 
The skin to spar rivets are on the back side of the spar web.
All the riveting to attach the new leading edge skin to spar needs to be done through the aileron bellcrank access panel and through the end rib (not nose ribs). Not great access but not too bad.
A tungsten bar using the spar web to help align by feel should be doable. I’d suggest it’s a 2 (experienced) man rivet job.

The blind rivets to hold the nose ribs to the spar can be done from either side.
Probably best if possible from the front as it will put the shop head in the thicker spar so as to not pucker the thinner rear flanges of the nose ribs.
 
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I am not sure how you are suggesting it, if you mean thru the access panel of the aileron bay, that is aft of the spare and there is no access thru the spar. Besides if one can reach three bays from the wing tip, then s/he can access it the other three bay from the tank side as well. But that requires some really long arm.

The suggestion I was building on was that you rivet the ribs and stiffener to the skin in a cradle. The perceived challenge of that approach was how to rivet the flanges of the assembled leading edge to the spar. For that, you need access aft of the spar.
 
Sam Buchanan posted a bird strike dent repair thread about a year ago.
Went from a nasty/impossible looking mess to virtually not detectable.
There were great photos in the thread.

1" plywood LE contour mandrels can be CNC milled and drilled, then passed into a section through rib holes into the bay you are working on. Then bolt them together and place carefully cut blocking on the spar face to support a stubby hyd. cyl. ( make sure the end pieces of the stack have a nice radius from the airfoil nose profile to the end face , not a sharp edge) The blocking to the spar needs to fit the top and bottom thick sections, not the middle.

Find the thread or PM Sam for his photos and show your PDR guys.

Not sure it is an option for everybody or your 10. But it might be.
 
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Here are some photos of the above referenced repair in my thread. However, my bird strike didn't have as many sharp creases in the skin so don't know if this repair would be as effective on your wing. But it might be worth a try before disassembling the wing. I used all-thread as a jack to force the dolly into the damaged area. The final adjustment was via manually persuading the dents with hand pressure to relieve the tension on the skin. I ended up with a 90% repair.
 

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I looked at this on one mounted wing and one unmounted wing yesterday.

The skin to spar rivets on the outboard 5 bays are doable from the end of the wing and through the aileron bellcrank access panel. The most inboard bay will be really tough through any of the existing access points.

The other thing I can't figure out is how to rivet all of the ribs to the spar if the leading edge D structure is built as an assembly and then attached. Some of them appear reasonably accessible, others, not so much.
 
Bird strike repair

It was built with bucked rivets, just order the skin and ribs, drill rivets out on bottom aft skin, drill ribs and leading edge skin. Make a go no gauge for upsize oops rivets, probably need 4’s and 6’s. Just did this on my 7 wing. Takes two to buck and drive rivets back but it has been done once. Send any ribs back to vans that you didn’t need to replace.
 
Whatever repair scheme you choose, if you find there are one or two MS20426AD3 solid rivets you really can't buck successfully, Cherrymax CR3214-4 rivets are the blind equivalent of NAS1097AD3 "oops" rivets.

They are not cheap, but can meet the structural requirements and won't be obvious from outside.
 
CherryMax 3214 series has -4 shank and flush -3 head. About .65 apiece. I've used them frequently when my riveting skills were seriously challenged (doesn't take much). Built 8A using them. Currently building 14A and still using them. Drill out to #30, use CherryMax measuring tool to determine length and go for it. Most skin rivets are -2 or -3 in Cherry system. You can use ATS pneumatic or dedicated Cherry puller. I prefer the latter, but circumstance may dictate otherwise. Monroe Aerospace is my current source.
 
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