Rib repair at fabric clips

[mark munro]

Does anyone know proper method to repair elongated fabric clip holes? Off set with new holes? Backing plates doubler? Rivits?

[lktiller]

Shift the clip wire down (or up) a quarter of an inch and drill new holes.

Put in a screw and washer.

Wrap a 2 inch wide piece of aluminum over the rib cap and rivet to the vertical web. 43:13 gives the rivit size and spacing.
Assuming this is stamped ribs.

If a bridge-work rib (pre-war), no corrosion, only one or two elongated holes, find a scrap piece of cap strip material. Open it up enough to fit over the rib cap and rivet to the vertical member. Min. 4 rivits per inch.

Or Rib Stitch.... (use correct edge protection on stamped ribs)

backing doubler to the rib cap is not suitable. No rivits through the cap.

[Robert Lees]

...of course, Larry, you know that wires should not be used on truss ribs anyway...

Rob

[lktiller]

Yeah, but that didn't stop the previous three or four people that covered the 1941 wing I'm rebuilding!!!!!
So many redrilled holes the cap was cracked in places. After repairs I rib stitched.

[mark munro]

Thanks for info.

The redrill or double with 2 inch aluminum
seem to be the most appropriate method.

These are stamped ribs and I do not want to try for a field approval which I believe I would need to do if stitching or screwing or riveting. Waiting on new spars from the factory.

[Robert Lees]

Check out AC43 (available free on-line here ) which will tell you what repairs are permitted.

I think a repair approval (i.e. a signature that the repair has been inspected and found to be airworthy) from your IA/whatever will be needed anyway.

Rob