vertical stab skin fitment question

[dwollen89]

I'm working on the vertical stab and just clecoed on the skin. I'm having a hard time with the point of the lower nose rib fitting into the wedge of the skin (if that makes sense). It's very tight and the flange doesn't want to lay flat against the skin. I took it apart and bent the flange back a few degrees, which helped, but still not stellar. There is one hole that needs to be match drilled at the very point of the rib, so I'm sure that'll help. I think I can clamp it flat, but I don't know if that will be too much pressure on the rivet. This is my first skin, so I'm not sure what is normal.

Thoughts?

Here's a pic https://photos.app.goo.gl/Co4nbAdUHDcUPvzN8

[nohoflyer]

Clamp it flat, drill, rivet, move on.

Caveat..

As long as you are bringing the flange to the skin and not the skin down to the flange I think you’ll be fine.

[CT Brietigam]

Just flare the nose rib flange outboard a bit to better conform with the skin. And then if you're not satisfied with the fit apply some Scotch Weld 2216A/B or similar structural epoxy between the nose rib and the skin. Cleco in place, let dry for 24 hours, clean up any excess epoxy in the dimple and rivet away! This process known at "Boeing" is called liquid shimming.

Chuck Brietigam
RV-6XXL

[dwollen89]

Thanks for taking the time to reply. I’ll try to bend the flange a little more and see if I can tighten up the gap before riveting. Looking at the picture again, I’m wondering if the flutes on the last tab are partly to blame. Maybe I’ll take those flutes out and see if that helps.

[swift12]

I doubt it’s your flutes…just flex the flange out a little…clamp….drill rivet….bear in mind that is covered by the fibreglass fairing….the skin is rather thick compared to the rib flange….mine looked the same….I have that issue on the centre hs nose centre ribs.

[nohoflyer]

One more option would be to make a small “doubler” to sit between the flange and the skin. Upsize rivet to accommodate. But even that is overkill imo.