Rudder trailing edge holes

In the process of countersinking the rudder trailing edge holes, three or four of them came out mis-shaped, as shown. Should I build on or order a new edge? If you say start over, please give a reason. Thanks

3 or 4 out of 50 I would leave it. Proseal or epoxy the perpetrators

It is normal for these holes to get slightly enlarged, but yours definitely look ragged, like the countersink bit was chattering. Were you using an air-drill? I do all my countersinking with a cordless drill at low speed for much better control.

If you do use it, I would at least try to clean up those holes a bit. I'm sure it would be fine. Personally, I would make another one, because AEX is cheap, and I'd want every possible chance for getting that trailing edge as straight as possible. Enlarged rivet holes may allow for some waviness. That's all speculation, but like I said, the wedge is cheap, and if you're like most of us, won't be the first replacement part you'll be ordering from Vans soon!

Just my thoughts. But seeing since Vlad is flying (a lot, or so I hear), and I am sitting in my garage making airplane noises, his thoughts get more weight! Edit: I forgot that I pro-sealed mine as well. Do that, and I doubt you'll have any issues!

Chris

Rudder Trailing Edge Holes

Three or four should be ok. Next time try drill the holes into a piece of wood or a scrap piece of metal under the rudder wedge. This will give your countersink pilot a deeper hole to go in, this will keep things straight and stop chatter.

Brian Davis
Building RV-7A
Peachtree City, GA

One aspect of the holes that I wonder about is that the inner edge of every hole is knife edge-like. Is this normal, or did I over-countersink? I feel like I sunk them as deep as I needed to in order to fully seat the skin dimples, but maybe not.

It's normal for the wedges to be knife-edged if you go deep enough.

Chris

You don't want knife-edge holes for your binding sections, on the grip areas of the external sides of the rivet. In this case with the AEX wedge, the knife-edge holes are still non-desirable but less critical - the AEX will be clamped between the two skins and as long as the skins do not have knife-edge rivet holes (should be dimpled, not countersunk) you'll be OK. The knife edges produce concentrated stress on a very small area and don't hold well, but on an interior layer this is less of a consideration. The primary purpose of the AEX wedge in this case is to produce the desired angle of the two sides approaching the zero AOA on the trailing edge.