Wing spar mystery rivet hole

[SmittysRV]

I am ready to countersink all the holes in main spar where the skin rivets on. I noticed that here is a rivet hole in the spar over each rib where tank skin overlaps the spar. I assume that this hole will be countersunk and a rivet put into it, holding the rib to the spar, under the tank skin. The plans do not mention this hole (that I can see). Here's a pic:

[jlfernan]

You are correct. Here is a picture showing those holes in my QB wings.

[AntiGravity]

Originally Posted by SmittysRV

I assume that this hole will be countersunk and a rivet put into it, holding the rib to the spar, under the tank skin.

Yep, that's exactly what I did.