The long Zip Dee on my Sovereign
has seen better days. While removing the vista view windows I noticed that both the forward and aft upper brackets were loose. Since the rib and shell area under the brackets were accessible due to the other mods I was doing, I decided to strengthen the mounting area with doublers and a suitable shim on the exterior to match the new vista view window patches. Don't be confused by the photos--they are a combination of the forward and rear brackets, so they may appear reversed if you make them all one installation!
The original bracket mount and damage underneath:
You can see how the skin is pulled away from the rib, here. Two of the new rivets in the vista view patch need to be drilled out to allow the new doublers to lie flat on the inside skin:
Here's the total set of parts. The bracket, the shim under the bracket on the outside, two shims/doublers to equal the thickness of the rib flange, and then the inside doubler with three nut plates. The #10 aircraft screws that fit the existing holes in the bracket have a yield strength exceeding 1,000 lbs (thank you, Kip), so you could pick up the entire Sovereign
on this pair of reinstalled brackets. The inside mounting plate and shims were fit to the existing holes by screwing the bracket in, which held everything in place, then match drilling the rivet holes.
One advantage of the nut plates is that I can remove the brackets and temporarily seal the holes using short screws--the outside shim would protect the skin from the screw heads. The outside shim and inside doublers were installed using Trempro 635 (same as the old Vulkem).
This has been slowing me down for a couple of weeks--very glad to be on the move again!
This same repair can be done fairly easily even if you aren't modifying your vista view windows. It's only requires drilling out about 7-8 pop rivets to peel the skin back far enough to gain access to the inside of the shell (in skins without a vista view) and a few more if you have to release the vista view inside slide cover.