Rib repair help needed

[sekps]

Hi,

I had this paint booth collapse a while ago - and back then I thought there were no damages at all. Now when I finally have my new hangar completed and a new paint booth built, I discovered that one rib actually is broken...

A bit boring on a recently covered wing but the good thing is that I have just brushed the first coat of nitrate.

I can look into the wing and it's the lower capstrip (is it called that on aluminium ribs?) that's bent about 1/2". The diagonal members (truss) are intact. It's behind the rear spar and I can't reach it through any of the inspection holes (not yet cut).

What's the best way to cut the fabric to reach the damaged section? I was planning to lift the finishing tape and reinforcing tape and cut the fabric over the damaged section and try to reach it that way. The some baseball stitches and back with the tapes.

Or should I glue an inspection ring and cut a hole? Use a curved needle and pull a satefy wire under the rib, pull and pretend that nothing happened?...

/Mattias

 

[mike mcs repair]

if its just bowed and not cracked or kinked...

the simple way..

pop a small hole on TOP of wing above it just big enough for flat screwdriver tip and reach through to bent section and tap it strait....

put a patch over the small hole... done

usually you are doing this from the bottom to push up ribs that someone has broomed down removing snow, or been on its back....

 

[Steve Pierce]

If you have rib stitched that will help hold the fabric tight. Like Mike said if it is bent go from the top and tap it down with something heavy underneath to tap against. If it is broken I would go outboard one rib and inboard one rib and cut the fabric just outside of your finish tape. Then use the Piper repair material available from Univair and form it over the broken section. You could also put an inspection ring around the damage to keep the fabric tight if that would give you enough room the make the repair. With the proper glued patch overlap you won't need to sew anything except to rib stitch the rib.

 

[sekps]

Thanks! The rib is "just" bowed so I'll start with the "tap method". Hopefully that will do.

/Mattias

 

[bob turner]

The Stits process allows glued seams - I think 2" is enough overlap. Same glue, but they have not yet approved it for Ceconite. Nevertheless . . .

I think I would cut a small slit, patch the rib, pull the fabric back together and put a small patch over the slit, then re-shrink to remove wrinkles. New surface tape, extra silver over the repair and a lot of wet 320 sanding, and you will hardly ever notice it. It won't completely go away, but who stares at the underside of the wing? Don't forget; you can get away with sanding on the underside - the top of the wing is what really needs the silver protection.

 

[Steve Pierce]

Bob, You need to update your Ceconite manual by a couple of revisions. 8) Glued seams have been approved on Ceconite for quite some time.

 

[bob turner]

This is rumor, of course. If you want to, say, paint automotive enamel on top of Ceconite or Stits, you need the older revision, which, according to some, remains approved by the FAA.

And yes - I do need to update. Goldberg said the 2" open glued joint was approved for Stits, but not Ceconite, in a phone call two years ago. And he said Poly Tak was now the same stuff as Super Seam Cement. 43-13 has apparently always allowed a wider glued seam in open areas.

Another subject: I have started noticing problems with patches in highly stressed areas, like landing gear vees and those pesky transverse floor braces on the Decathlon where the fabric is pop-riveted. Seems that in these places you absolutely have to go all the way to the fabric, and maybe even stitch, for a glued patch to hold.