Looking for advice to rivet F-811

[tkatc]

The flange tabs do not conform to the contour of the aft bottom skin. At least not perfectly. Any tips to make this work out any nicer? Do I just rivet away and hope for th best? I don't think I can back-rivet this and a squeezer is out of the question.

[flywithme623]

Make little spacers for each rivet where you have space between the flanch and skin. If you don't do that you will see the edges of every flanch through the skin. This technique I can also advice for all the other bulkheads where you see space.

[tkatc]

I reworked/rebent the flanges a bit so the gap is minimzed. I still believe the rivet call out is incorrect depending on how much gap each builder is able to eliminate. It calls for 3.5s but I am thinking at least 4.5s Bucking these rivets will be a bear!

[bird]

The corners of each tab can be bent inboard allowing the center off tab ,where hole, is to be closer to skin. I recall having to use a little longer rivet also -4 I think.

Bird

[bret]

This turned out to be a nightmare to rivet for me, I ended up using -4 rivets, they are a lot stronger rivet for that thick bottom sheet. Shhhh don't tell anyone.......

[Joe Parish]

I am currently working on this on my 9. My print calls for 426 3-4 rivets. The skin is .040 thick. I have had good luck with a small rubber grommet over the rivet and between the bucking bar and tab on the bulkhead. It takes quite a bit of pressure on the bucking bar to squish the grommet. I take it out after a few hits, once the rivet starts to expand and hold the tab.

[aeroaddict]

I'm not building yet but why would you not form the flanges as best you can to match the radii of the skin? The upper flanges look like it would take a lot of forming but I think the gap could still be decreased or eliminated. Any problems with this suggestion? Just curious.