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GRANT ED

Active Member
I am currently building the wing of my RV-7. I have noticed a problem with my ribs. I have clecoed all the ribs to the main spar. Looking at the holes on the top and bottom sides of the rib that joins the skin, spar and rib together I see that they are not lined up. The error is approx half a hole. With a cleco in these holes the rib flange is pulled away from the spar by approx 2mm. Only about 1/4 of the wing ribs have this problem but interestingly the error is the same on all effected ribs.
Has anyone else had this problem. Any ideas on a fix?
 
Yes and I thought I was the only one. Mine also did not align 100% as I have grown accustomed to with the 7's matched holes. I think we are a bit spoiled with the pre match drilled kit. I pulled mine into position with some effort and manage to rivet it fine after ensuring I have a clecko in every single of those holes, taking them out one at a time to rivet, and using a scriber to align it for the rivets. I am waiting in anticipation to hear what others did.
 
Grommet all!

If you are talking about the separated flange "ears" on the wing ribs that have one or two skin rivet holes that go through the spar flange, then yes I had a few that needed persuasion. Just get them into position anyway you can and get a rivet inserted. If the ear wants to pull away from the spar flange before bucking, put a grommet or thick O-ring around the shop end of the rivet so that your bucking bar compresses the rubber and pushes the rib ear into position just before touching the shop end of the rivet. Once you have this all positioned and the mfg head is sitting flush (instead of cocked) on the skin side, give a short shot with the gun, the rivet swells a little and the ear is now held in position against the spar, grommet is removed and the shop head is finished with a few more trigger pulls.
 
I sent back two ribs because the flanges were different sizes from the top to the bottom resulting in an alignment problem. The new ribs lines up perfectly. The ribs that were misformed resulted in about a 1/2 " deviation from a flat plane across the skin surface. Even though I might have been able to force the ribs into place and hold them with rivets, I think it is best to rivet the assembly with as little pre-load as possible. No reason to build tension/stress into the wing.
 
Red said:
I sent back two ribs because the flanges were different sizes from the top to the bottom resulting in an alignment problem. The new ribs lines up perfectly. The ribs that were misformed resulted in about a 1/2 " deviation from a flat plane across the skin surface. Even though I might have been able to force the ribs into place and hold them with rivets, I think it is best to rivet the assembly with as little pre-load as possible. No reason to build tension/stress into the wing.
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Hi Red, I agree 1/2" is a lot, Grant is talking about 2mm = 0.078 of inch. My miss alignment was also very little. If I had 1/2" out I would also send it back, but at 2mm you can make it fit.
 
I have sent an E-mail with pics to Vans and am currently awaiting a response. It seams to me this problem is pretty widespread. I dont really like to idea of forcing the rivets it the holes. All thast will do is stress the rib and pull the radius of the flange away from the spar. When I get an answer from Vans I'll let you know what they say.
 
I had the same problems, but mine got much better once the skins were clecoed on. Even then, I still had a few stuborn "ears" that need to be coaxed into place.
 
Here is my respones from Vans

"Grant: sorry for the delay. We've looked at the photos and think
that with some minor seaming and other persuasion, the holes will
align. We haven't enough information on part numbers etc. to
discern a pattern."

Personally I was hoping for a better fix than just 'make em fit' but there you go.
 
Grommet Trick

Bill,

Thanks for the advice on using the grommet. I've been trying to figure out a way to do this.
 
I've just come across a similar problem - on two of the three W712L ribs supplied in the kit, the rib flange to spar web holes are misaligned vertically by more than 1/2 a hole. No amount of phenangling is going to get them to line up - if I re-bend the ears to repostion the rib vertically then the skin to rib flanges will be way out of line. Has anyone else come across this problem? I'm going to send some pics to Vans in the morning and see what they have to say.
 
GRANT ED said:
...Personally I was hoping for a better fix than just 'make em fit' but there you go.
Click to expand...

Making the ribs is a 2 step process. They are cut out of sheet metal by a computer-guided punch and then the flanges are bent probably on a form. It's highly unlikely that the holes are punched in the wrong location. The flanges are probably just bent slightly out of place. "Make it fit" gets more and more common as you go on through the project.
 
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