Trying to think ahead...

I have a question about an upcoming step. I'm thinking about how these holes will be countersunk or dimpled. In this first pic, do these holes get dimpled or countersunk? And how about the holes on the bottom of the spar flanges?



For the holes in the pic below, dimpled or countersunk? I would think the holes with the black arrows would be dimpled, but how about the holes with the red arrows? That area of the bulkhead has a doubler behind it and I wouldn't think I'd be able to dimple two layers of aluminum? Or maybe it's easy and that's how it's done.



I just want to make sure I don't do anything stupid and have to order new center spars or bulkheads!! Thanks!

Mark, I'm going by memory (and it's been a while), but I'm pretty sure that the anodized spar pieces that Van's furnishes all get countersunk. Those pieces are just too thick to easily dimple. As far as that back bulkhead goes, I think you're right. The bottom ones get dimpled and the ones with the doubler get countersunk. If nobody else has chimed in by tomorrow evening, I'll go out and look at how mine were done to make sure. But you'll probably have your answers from somebody by then.

See drawing 11. Your first picture shows only one-half of the 704 (704B) center section assembly. There is also the F-704H center section side plates that will be placed on the outboard side of these anodized pieces. The F-704H is what will be countersunk. Not the anodized center section. And not all of them at that. There are the bottom rivets that are 470 not cs 426's. Be sure to pay attention to rivet callouts on sheet 28 when assembling.

The second picture is the 705. I have to look that one up to be sure.