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How serious is this damage?

J

jwilbur

Well Known Member
I really hate messing things up and even more so I hate advertising the fact to the world in questions like this. But I figure I'd rather swallow my pride and know in the end I've got a solid aircraft.

Firstly, apart from this question, I've finished my VS tonight and I feel really good about the job I did (aside from tonight's question) - thanks in great part to all those who have taken time to help me.

Here's my question. In riveting the bottom inspar rib to the rear spar, my hand drifted and the gun hit a few times at an angle before I realized it. I dented pretty good the bottom flange of the rib causing it to flare out as you get away from the head. Is it safe as is even though it looks pretty bad? Or should it be repaired/replaced? Please see pictures. By the way, the rivet itself set very nicely, though I don't have a picture of it.

n6exhh.jpg

Finished VS

9axwfo.jpg

View of the dented area. Directly around the head, the metal is snug against the spar. It only raises up from the spar as you get away from the head.

ri6zi1.jpg

Second view. Looks bad to me but I don't want to jump through the necessary hoops of replacing this part unless it's an issue of safety.

snzcbm.jpg

View of the head from the top. From directly above, I think it looks OK. It probably hit 4 or 5 times at an angle before I realized. The metal is dented right at the edge of the head - but the head is not deformed.

Thank you,
 
IMO, it's probably fine structurally. I'll defer to someone smarter like Mel.

Cosmetically, if I'm looking at it right, it's going to be under the empennage fairing and you'll never see it (or you can adjust the fairing to glass it under).
 
This is just the beginning

To me it looks bad and in production it would be rejected. There is no way I would live with that in my airplane and you need to set the standard now for what you are going to tolerate in yours. This is not only cosmetic, it is of questionable integrity. You shouldn't have to ask about something like this but since you have, I think it needs to be fixed. When I was on the production line this would be written up by an inspector and a floor engineer would have to disposition the squawk. This would not receive an "acceptable as is" disposition. It would probably require submission to a material review board for salvage. If you don't feel qualified to develop a fix you need to call in someone that is to look at the actual condition of the assembly recommend one - or do it over.

Bob Axsom
 
Consider giving Van's tech department a call on this. This situation may lend itself to drilling out the rivet, redrill to 3/16" and install a AN3-4(5?) and an AN365 nut and washer.
Adds a few grams, not ideal but I think its a viable solution. It is difficult to make a judgment based on several photos
Regads
 
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The fact that the outer part of the flange is curled up off the spar doesn't matter. What matters is whether there is good contact between the parts under the rivet head, the condition of the metal around the rivet, and on the bend of the rib between the rivet and the flat web of the rib. If this were in the middle of a row, I'd be less inclined to worry about it, but since it is at the edge, it feels complicated loads, not just shear.

So, first, if there is any sign of trauma to the rib material right around the rivet - it kind of looks like there is a crease - then the rib should either be replaced, or make a doubler to reinforce all 3 rivets and extend up onto the rib web with a similar number of rivets. That is, drill out the 3 rivets attaching the rib to the spar, make a piece of angle that fits onto the rib (generous bend radius), and re-rivet the 3 holes to the spar, and also 3 rivets into the rib.

If the rib material is not creased or scored, just curled or warped, you may be able to drill out the rivet, tweak the flange of the rib back fairly flat and re-rivet that one hole. You may find it helpful to make some kind of clamp that will hold the flange tight against the spar while you rivet it. A plate with holes in it for the rivet heads, c-clamped in place while you re-set that one rivet will assure that the pieces fit tight around the rivets.
 
A doubler?

You might consider a doubler across the flange. This would require removing all three rivets and installing new, possibly longer, rivets to attach the new thicker assembly. The head is cut on the middle rivet as well so this seems like a difficult area to get into. You might consider a rivet set with offset shank to get in there. Aircraft spruce has some in their catalog.

Bob Axsom
 
Here's what I would do.

1. drill the head off the bad rivet. (I doubt it's lined up with it's shank)
2. try to gently punch the remaining rivet shank through. Otherwise drill it a bit at a time until it will punch through.
3. Use an "off-set" rivet header that Bob mentioned and reshoot the rivet.

Any attempt to straighten the flange will be fruitless IMO. It doesn't look to me like there is any structural problems with that anyway. And besides, it'll last a hundred years if you just leave it alone. Hey let those great, great grand kids fix it.

Those are actually some of the more difficult rivets to shoot on the whole of the project. I too have some ugly, ugly ones and I have shot 10's of thousands of rivets. However, an offset rivet header is a must! Another trick for these is to back drive them. That is, use a good heavy bar (tungsten) on the head and drive the tail. Someone will tell you that you can't do that, but I will tell you that you can. As long as you don't flatten more than 30% of the head thickness you are fine.
 
What I would do.

Joe,
That rib flange would probably last a lifetime as is. But if you are concerned, just drill out the three rivets and add a .032" doubler over the flange. The doubler would "sandwich" the flange holding it flat.
 
I would be inclined to go along with Steve's fix...

using a .032" doubler. Their is about 10 scrap pieces that came in your kit to use as needed so no need to order aluminum. Make an oak block with that radius then clamp up with another oak piece and make your bend with yet another piece using a deadblow hammer or equivalent.

Get a CherryMax rivet gauge and an assortment of CherryMax rivets(standard sizes) from ACS. I have oversized rivets I can mail you if you need them. Just check hole size after removal. If you are by yourself and have difficult place to rivet, don't be afraid to use them. They add a little weight but have higher shear/tension numbers than solids. I use a standard manual pop riveter but ACS sells one specifically made for CherryMax rivets. Otherwise try to get some help riveting the tough ones. There are many more to come.

The waviness doesn't bother me. You will see that on rib flanges due to thin metal/shop head combination later on. Just try not to over do it on those rivets. Use masking tape on your rivet sets and you'll need about 15 psi more pressure with your offset rivet set as some of your energy is absorbed by the offset.
 
Don't Ride The Radius!

Joe,

If you put a doubler on there, which is a good idea, make sure that you radius the edge that is common to the radius in the rib. Or just trim the doubler before it get's to the radius.
 
doubler

I'd vote for the doubler. You'll want to be somewhat careful in removing the existing rivets, to avoid enlarging the holes. If you haven't removed rivets from this thickness of material before I suggest practicing on scrap.

The damage looks like the classic "didn't have the rivet set pushing firmly down on the rivet head". An offset rivet set is really needed for spots like this.

Good luck.
 
I'm headed out the door for church so I haven't read all the replies yet. I apologize if this one has been mentioned.

You could also consider putting a liquid-type shim underneath the gap before riveting it. You can use something like epoxy thickened with flox, Metalset A4, or JB Weld.

Drill the rivets and apply enough liquid to the affected area that it oozes out to fill the gap. Then cleco the parts together long enough for the mixture to fully cure. Suddenly all that space that is currently air will be filled with something that is capable of carrying some load.

I agree with Mel that it's probably okay, but using something like JB Weld (since it's available in small quantities) to fill the gap would completely eliminate any concerns that you may have personally.

It's definitely not something you need to reorder parts for.

Phil
 
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Mel said:
Joe,
That rib flange would probably last a lifetime as is. But if you are concerned, just drill out the three rivets and add a .032" doubler over the flange. The doubler would "sandwich" the flange holding it flat.
Click to expand...

This is easy to do and should solve the problem.
 
I really appreciate all the comments (well, except for one). Anyway, the idea of a doubler never crossed my mind. So easy. After removing the rivets I could see there was no damage to the flange other than being bent, but I feel better knowing and it sure looks a lot better this way. Here's the result for those interested.

29xw4f7.jpg


2mesje1.jpg



Thank you once again,
 
jwilbur said:
I really appreciate all the comments (well, except for one). Anyway, the idea of a doubler never crossed my mind. So easy. After removing the rivets I could see there was no damage to the flange other than being bent, but I feel better knowing and it sure looks a lot better this way. Here's the result for those interested.

Thank you once again,
Click to expand...

Joe,

If you use a doubler it needs to be riveted to the rib web, it is essentially "replacing" the original flange. Otherwise it is only a cosmetic change.
 
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Bob Axsom said:
You shouldn't have to ask about something like this but since you have, I think it needs to be fixed.
Click to expand...

Just one thing I wanted to note -- if you have any questions, please ask. It is always better to ask if you are not sure about something (assuming you are not asking folks who give you bad advice) then it is to be unsure if your question is "good enough" for the forum.

I'd personally prefer to answer 100 beginner questions (and see other's insightful answers) then scare one person away from asking and have a bent plane (or worse) result...

Chris
 
Sam Buchanan said:
Joe,

If you use a doubler it needs to be riveted to the rib web, it is essentially "replacing" the original flange. Otherwise it is only a cosmetic change.
Click to expand...

But Sam, in this case it was only reinforcing a single rivet hole that had a bent/distorted flange around it. The doubler is really only forcing the distorted flange flat.

The original flange was not cut off - I don't think....:)
 
az_gila said:
But Sam, in this case it was only reinforcing a single rivet hole that had a bent/distorted flange around it. The doubler is really only forcing the distorted flange flat.

The original flange was not cut off - I don't think....:)
Click to expand...

Maybe I misunderstood the original concern, thought it was about the strength of the flange being compromised by a crease.

That said....I wouldn't have done anything with the slightly bent flange.
 
Correct

az_gila said:
The original flange was not cut off - I don't think....:)
Click to expand...

That is correct. When I got the rivets off, I could see no damage at all aside from the bent flange and chipped primer. I now don't believe it actually needed anything and was safe as it was. I suppose the doubler is in fact only cosmetic. But I'm still glad for the experience of making the doubler and seeing things under the rivets with my own eyes. And the doubler does make it look a lot better which is a small bonus.

I appreciate all the help from everyone very much,
 
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Flange work around

Joe, Welcome to the insane world of kit building. You repair, in my opinion turned out just fine. You will encouter these little gotchas from time to time. Sometimes you have to step back give it some thought, get some opinions then revisit. I am finishing an RV-10 at Manassas. Hope to fly in the next month or two. Anytime you want to visit, let me know.

Here is my site.

http://avee8tor.smugmug.com/Airplanes/Tims-RV-10/2336280_Yo3ae#1131417302_PiCzn

Tim
 
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