Wing Skin Fitting

[Kenneth]

Hey everybody,

I'm in the process of fitting the skins to the wing skeleton on my RV-8 wings. I had no problems when I did the left wing, but I am having issues with the right wing bottom skins.

I have the wing skeleton hung in a jig and made sure there is no twist or sag in the spar. I fit the top skins with little problem, but for some reason the bottom inboard skin will not line up with both the ribs and the main spar. I have a couple clecos holding the skin to the ribs and the spar-to-skin holes are out of alignment by about 1/2 diameter of the hole. No way I can get a cleco in 'em.

Click Here for a picture.

I've emailed Vans, but I'm wondering if this has happened to anyone else and what you did to pull them into alignment.

Thanks,
--Ken

[bullojm1]

Ken-
I just did this a few weeks ago with little problem. I think the problem you are having is by clecoing the skin to the ribs, the ribs are pulled downward away from the spar ever so slightly by gravity. When I did mine, I clecoed the skin to the main spar first - every 4th hole with a cleco. Then I worked myself down the ribs. I think this way it is easy to bring the ribs into position one by one. The way you have it now, you are trying to raise all of the ribs concurrently to meet the spar.

[Kenneth]

Hi Mike,

The picture is misleading a bit, and is the last of many attempts to get it to fit. I initially cleco'd the skin to the spar and had the same fit issue.

Thanks for the idea, however!

--Ken

[bullojm1]

Ken-
When you look at the front flange of the ribs against the spar is it reasonably tight? From looking at your pic a little closer, the top most hole in the rib is about 1/2 hole distance below the top hole it is supposed to line up with on the spar. You need to somehow squeeze those ribs tight. Have you tried clecoing the skin to the main spar and rear spar to compress the ribs? Or, cleco the skin to the top spar and then start clecoing the ribs 1/2 way down and work yourself to the spar? Just trying to give you some ideas. I just did this less than a month ago and I don't recall any specific problems.

Good Luck!

[briand]

Recheck the straightness of all your ribs.

[MTBehnke]

You might try using a 36" long clamp from the front to rear spar to see if it closes the gap rather than trying to force it using clecos which may cause oblong holes. I'd think a little light pressure would do the trick.

[William Slaughter]

I had a similar issue when skinning my wings recently - when I first put the skin on attached to the main spar, I was half a hole off at the rear spar. I clecoed the skin to the main spar (every rivet hole), then used a small bottle jack (with a wood block on the rear spar) to apply a bit of upward pressure to the rear spar, then clecoed the ribs on starting at the main spar and working back towards the trailing edge. Everything pulled into place nicely.

[LettersFromFlyoverCountry]

I had the same problem with mine. Oddly -- and I don't know why -- it worked much better if I clecoed along the main spar first, and then clecoed down the ribs evenly... that is, go down one hole and go laterally (as it hangs in the jig) outboard...down a hole....outboard...etc.