[DragonflyAero]

What have folks be doing where the center fuselage meets the forward bottom skin and at the center section side plates; dimple everything all the way through or countersink somewhere?

Van's said it was OK to dimple the center section bulkhead flanges but it still makes me nervous. I think it is .060, so would be thick enough to countersink. And the center section side plates are also .060. Dimple the side plate and countersink the center section side flange? Dimple everything?

And where the front skin laps over the center bottom skin the front skin would be dimpled, and also the center skin, but what about the bulkhead flange underneath?

The manual is a lot less specific all of a sudden..........

Dimpling would be cleaner, simpler and safer, but that seems like a lot of thick metal to try to dimple.

Thanks for your help!!

 

[YellowJacket RV9]

On the bottom, I countersunk the center bottom skin and bulkhead flange together; which kept from having to countersink the flange too deep. I dimpled the front bottom skin. The intersection turned out very smooth (not that I'll ever see it again, I hope).

On the sides, I countersunk just the doubler plate that is between the bulkhead sides at the side skins.

Just one way to do it, but came out fine for me.

Chris

 

[AlphaCharlieBravo]

The F-704 flange is .040. I dimpled everything on the bottom with the exception of the ribs aft and the floor stiffeners fore. At those spots I countersunk. The center section side plates were countersunk and only the skin dimpled. I countersunk the top of the f-704 for the nut plate rivets although there are other ways to accomplish that.
Hope this helps.