Bottom Fuse skins to Bottom Wing Skins... A little Buckling

Wicked Stick · Post by **Wicked Stick** » Wed Nov 05, 2008 5:11 pm

Hi,

Getting a lot done with the wings mounted, but ran into a snag.
When I mounted the wings for the first time, we noticed that when all the spar bolts were in, that the bottom fuselage skins sat about 1/4" lower than the bottom wing skins did.

So, when you try and flex them up to meet the wing skins and drill pilot holes, you end up with a few minor buckles in the fuse skin.

Anyone else encounter this on any of the side by sides ? (this is RV8 shown in pic)
If you have encountered this, what did you do to resolve ?
(I was thinking I could add an extra strip of aluminum between them as a "fix", but will wait on others suggestions/expriences to consider first.

Post by **bullojm1** » Wed Nov 05, 2008 6:39 pm

Hi Dave-

I didn't run into that problem, but here are some suggestions for what you can do to fix them. When you final size these holes, there is a chance they will fit a little better and have some more "float". In drilling the holes, you might want to start from the worst spot and see if you can't work the kink out to either side.

If that doesn't work, you might try using an edge roller to put a slight upward curvature in the bottom fuse skin. This slight bend will probably cause the skin to look more flush, if not give the skin enough reinforcement to stay proper. Please note you should edge roll before you dimple, and you might have to grind down the female dimple die so it doesn't crush the rolled edge.

Good Luck!
Mike Bullock

Post by **Spike** » Thu Nov 06, 2008 9:36 am

The slight flanging idea might help.

Wicked Stick · Post by **Wicked Stick** » Thu Nov 06, 2008 11:10 am

Thanks,

I'm leaning towards trying one of those metal stretcher/shrinker tools.
I do plan to edge roll the skin, and yes, I've been down that road before with regards to rolling first then dimpling it.

I'd like to get it a "little" better before I dimple and move on with the build.

weezbad · Post by **weezbad** » Thu Nov 06, 2008 11:40 am

If it takes very little, to no pressure to push them down, I would try edge rolling but if it takes more pressure I would go the shrinker route possibly. The shrinker puts tiny scribe marks in the metal as it
compresses / stretchesâ€™ it. I am not crazy about that. Thatâ€™s why I would try the rolling idea if possible. YMMV

Post by **Spike** » Thu Nov 06, 2008 1:44 pm

One thing to mention is that I have read, and I don't know where, that those skins are most definitely load bearing. That might warrant a call to Vans if you plan on doing anything very mechanical to them.

John

Wicked Stick · Post by **Wicked Stick** » Thu Nov 06, 2008 2:18 pm

Spike wrote:One thing to mention is that I have read, and I don't know where, that those skins are most definitely load bearing. That might warrant a call to Vans if you plan on doing anything very mechanical to them.

John

What load/forces do they bear ? The wing is held in place by the main and aft spars, as well as a little from the front attach angle.

Post by **Spike** » Thu Nov 06, 2008 2:31 pm

I was under the impression that there were some support of the wings under positive G. Its like a strap running under the fuse from one wing to another. I could be wrong though.

Wicked Stick · Post by **Wicked Stick** » Thu Nov 06, 2008 5:19 pm

I'm sure that it does help a little.

RobDob · Post by **RobDob** » Sat Mar 21, 2009 7:18 am

How did you resolve this issue in the end? Curious in case I have the same situation!

Cheers

Wicked Stick · Post by **Wicked Stick** » Mon Mar 23, 2009 7:59 pm

I edge rolled the fuse skins and that helped some.. I also plan to shim between them when I get ready to re-hang the wings for good.

A metal Shrinker may also become an option, but will report back when the time comes.

RobDob · Post by **RobDob** » Tue Mar 24, 2009 6:40 am

Thanks Dave