vmirv8bldr

vmirv8bldr

Well Known Member
I did a search and only found one inconclusive thread regarding this...

Today I began the fun fun task of riveting the bottom skin on the wing. This is my first attempt. I following the directions, to a "T,"...riveted along rear spar between narrow bays first, then half way up those bays, then along the bottom in the next outboard bay, then proceeding up to the main spar. About 9 or 10 holes from the main spar, I clecoed all the way up, to help ensure a good fit. Unfortunately, it isn't a a good fiit. It used to be, but is not anymore. The gap between the tank and the bottom skin is about 1/32nd, surprisingly VERY noticeable.. It is enough to require re-drilling to get the rivet in, and clecos are VERY tight. FWIW, the gap between tank and top sking is 1/64 and barefely noticeable.

Is this a temperature thing? The difference between when I riveted the top skin and now is probably about 25 - 30 degrees. I drilled them all at virtually then same temp.

Here's the thing, all the rib holes line up beautifully. dimples align perfectly, everything is great. It's just the row on the main spar that doesn't align.

I'm not so worried about the gap, I could fill it if necessary. What I am worried about is that the dimples don't align with the c'sunk holes in the spar.

Anyone else have this happen? HELP!

Thanks
 
Wing skin gap

I found the same thing - and in fact the fit at the outboard end was off quite a bit during the early riveting. However as the riveting continued the fit got better and in the end the fit is excellent. A sheet metal structure is inherently flexible (a good thing really) and all the pulling and bending we do in order to buck the rivets makes the interrim fit poor. But as the rivets are installed it is all pulled back into alignment it seems.
Temperature is probably a factor, but just as probably a small one. It was a bit cooler when I did my riveting as well (never paid attention to how much).
When rivet holes don't align perfectly (enough to get the rivet in), I first use a nail set (a convenient tapered rod which is small enough) to align the holes, rather than drill. Sometimes that is not enough and running the drill through the hole is required. Rivets expand to fill the hole (within reason of course) so it's not a huge deal. The impact of riveting aligns things as well.
 
I had the same problem. I think the misalignment might possibly happen when the flap brace is riveted to the rear spar and the top skin. I believe this probably pulls the rear spar slightly aft resulting in a small misalignment. I just kept pulling the skin to the hold with a hole punch and it ended up fine.

Wade
 
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