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wing spar web - I need some opinions

H

HayesRV7

I'm New Here
First I want to thank Doug for building this wonderful resource and all the members of these forums for the advice I have received while lurking.

Now that I am an official builder, I need some help. (and probably a little confidence boost:confused:) We are working on the wings for our RV 7 and ran into an issue while riveting the leading edge ribs to the spar over the weekend. This turned out to be a challenge for us. In addition to not being able to really see well inside the leading edge to buck the rivets, getting the rivet gun set on the head of the rivet perfectly correct, due to the main ribs being in the way, seemed to be next to impossible. I have a few concerns I needed opinions on before moving on with riveting the leading edge skins to the spar.

1) The way I understand it, one should always try to put the manufactured head of the rivet on the same side as the thinner of the two materials being riveted. As I understand this is to help minimize “scalloping” or “pillowing” between the bucket rivets. This is not possible when riveting the leading edge ribs to the spar – the manufactured head goes on the spar side of the joint – the thicker of the two materials. As we riveted the thinner material of the leading edge ribs “pillowed” between rivets and the outboard edge of the rib flange lifted off the surface of the spar. This “lifting” appears to have only occurred at the edge of the flange. The middle of the flange where the rivets are installed appears to be tight against the main spar. How concerned with this do I need to be?

2) As mentioned in my opening paragraph, getting the rivet set squarely on the shop head of the rivets was very difficult. In a few cases we have slight “smiley's” in the spar web right next to the rivet where the rivet set hit against the spar slightly. Also, we had one case where the rivet set slid completely off the rivet head onto the spar leaving a mark on the spar. These marks/dings appear to be slight and barley a finger nail catches in them. My thought is to lightly buff the scratches/dings smooth and then either put a little primer on them or touch up with an alodine pen. Again, how concerned due I need to be with these marks in the spar? Will buffing them out and the putting a little alodine or primer over them be a proper and airworthy repair.


Thank you all very much in advance for any help and guidance.
 
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use rivet snaps

rivet snaps are very good at holding the set in place when you have restricted access to keeping the gun perfectly straight.

i got mine from avery... they come in a 10 pack that will last a while.

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Thank you for the responses. Great information. I also received some feedback from another builder after showing the picture and the comment was to lightly smooth out the dings, put a little primer on the spots where alodine was removed and move on. Any alternate opinions to that comment?

I really want to move on with riveting the leading edge skin to the spar but certainly wanted to make sure all this was all okay first.

Again, thank you for any information.
 
Offset rivet set can be seen here http://www.aircraftspruce.com/menus/ha/rivets.html?pg=2

I Wouldn't do too much with those smileys. You can make things worse. Most importantly is never try to shoot a rivet unless you on on the head squarely. Just prime them. You could "burnish" them with a burnishing tool or use a blue scotchbrite wheel and polish them smooth. Try not to use anything too abrasive, you don't want to remove any excess material.

Offset rivet sets are the only way to go. You need 2. 3/32 and 1/8. Try to get them 6" long. The double offsets work well also.
 
Van's has approved the use of pulled rivets in these locations in the past. I was told directly by Van's that LP-4 or LP-3 rivets were perfectly OK, and I know I am not the only one. I used them where the chances of a well-set solid rivet were questionable. Hope this helps.
 
Again, thank you all for the information. I polished the smiley /ding with scotchbright tonight and it basically is gone now. As I look at the picture I posted, the ding/smiley appears worse than it really looks - I think the camera flash caused this.

This is the first major error (and from what people tell me it will not be the last) and I will admit it got me very nervous. I couldn't bear the thought of ruining my spar and having to start all over. I was looking for help to solve the problem and learn for going forward.

Thank you all for your help. This has sure helped so far.
 
I did one rib like that and put similar smileys in my spar web. Even with the offset rivet set I wasn't able to get the results I wanted. I buffed them smooth with scotchbrite and primed them. I went with the LP-3 and LP-4 rivets for the rest of them. For the small areas where the anodizing was removed I sprayed some napa 7220 spray primer into the cap from the spray can and brushed it on with an acid brush.
 
I can confirm that Van's approved LP4-4 and/or LP4-3 pulled rivets in this area. I contacted Gus a few months ago asking for this and his answer was that those rivets are ok for that purpouse. I'm riveting solo so I went straight with this solution.
 
Given the difficulty of riveting in that area, the significant possibility of spar damage, and the acceptability of LP4 blind rivets, I would think Van's would simply specify them to be the baseline design for those ribs.
John
 
Hi Eric,

If you haven't finished yet, here are a couple of old-school ideas. The snapsoc things probably work better, but the old-school technique was to put a spot of 'hockey tape' (fabric athletic tape) on the nose of the rivet set. That did help me a bit, even in normal locations.

For the rib rivets, I was working alone & found the offset sets to be unmanageable. I ended up using the longest 1/8" set that I had in my collection, which reduced the angle quite a bit. It was still a pretty messy process; if I'd known it was ok to use 'pops' I'd have probably done it.

Charlie
 
Hello all,

Thank you everybody for all of the hints and advice. I did finally get all of the rivets set successfully. Also learned some things that I will do differently on the right wing. Also got some new rivet sets and snap socs as suggested and that helped a lot as well. My technical counselor stopped by and gave some great advice. I polished out the marks and smileys and primed as suggested. Glad to be moving forward again.

Thanks again everyone.
 
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