Gusset for fuel line hole?

[TJ_Slice]

When drilling the holes for the aft main tank fuel lines, I got into the stiffening bead a little bit on the inner wing rib hole.

I know this will require a gusset. Is it a gusset or a doubler?

I modeled one up and 3D printed it. I figured it would be a good opportunity to give sendcutsend a try.

While looking at their website, the thinnest 6061 aluminum they have is .040". From my research, I think it needs to be at least as thick as the original wing rib, but is .040" too thick?

I have attached a picture. I welcome any input on the design. I am thinking I could move it 1/4" or so. I am not going to use as many rivets as there are holes, I just wanted to see where everything laid out so that I could come with a good rivet plan.

gussett.jpg

[TLyon]

I'm curious about this - I have the exact same issue on mine. Do you have the same thing on the double rib just inboard from the one it your photo? On that one, scould one be sandwiched in between to avoid dealing with the convex bead that faces out on both sides?

This is a little thread drift, but related...

My lessons learned to pass on to the next guy (and redlines for the new instructions?) is that I should have:
1) Sorted out tank fuel straps and final position before drilling anything in the ribs. The straps I got didn't position the tank quite right - it didn't sit low enough in the wing to clear the top skin stiffeners and it was rubbing around the filler neck. I wasn't comfortable just putting felt on the stiffeners and it was going to take a couple layers if I tried to pad the straps. Didn't like that either...
2) I would have put a slight offset in the tubing, but I followed instructions and can't undrill it now. A related question is on the double rib inboard from this will it take two layers or one that's thicker?

Based on this fit up, I'm curious if your fuel tank straps pull the top of the tank into the top skin stiffeners too? It wasn't by a lot, but I just bought some metal to re-make those and make sure the tank is tightening up against the top strap and not the top skin.

[TJ_Slice]

It's just the outboard rib on mine. The inboard one is fine.

[arborite]

It doesn’t take any special equipment to make a doubler like that. A pair of metal shears and some careful filing can yield a nice patch in the metal thickness of your choice. AC43-13 gives good guidance on rivet spacing and metal choice. Basically as strong as or better for the patch. For added stiffness, you might want to try and roll the edge where it overhangs the lightening hole. I would consider going one size thicker on the metal and forming the rolled edge carefully by hand. It’s not that hard, and you will probably make three or four until you get one you like. Go for it.

[TJ_Slice]

Based on this fit up, I'm curious if your fuel tank straps pull the top of the tank into the top skin stiffeners too? It wasn't by a lot, but I just bought some metal to re-make those and make sure the tank is tightening up against the top strap and not the top skin.

Honestly, I’m not certain about that, but they seem to fit nicely when I tightened the straps.

I think it’s more that it’s very challenging to measure and drill those holes