Ivan's RV-7

Preparing the left elevatorTimer icon2h

July 6, 2022

Today I prepared the understructure and started match drilling everything together.

When I riveted the right elevator, I put a few scratches on the ribs with my bucking bar. I wanted to see how bad are those, so I used the denatured alcohol to clean the primer. Surprisingly, primer rubbed off. I did tests in the past, and acetone or lacquer thinner would remove primer if rubbed enough. However, I thought that it would resist the alcohol. Well, it does, but it seems like if you make a scratch first, it will easily start to remove the primer starting from the scratched area.

Hopefully, it is not my poor mixing or application. Solvents aside, the primer seems to be sticking quite well, I can only scratch it with some sharp object.

The scratches seem to be blunt, not sharp, so should not be an issue. I am going to re-prime this area.

Denaturated alcohol removes primer!

Going forward with the left elevator, the first step was to deburr and flute the replacement ribs (the previous ones I damaged while drilling when my reamer hit the cleco on the other side).

The replacement ribs fluted and prepared.

Then, I drilled the counterbalance. I used the same technique: mark the location of the holes, drill them on the mini-mill, then upsize the hole with the #12 drill bit (with the lead installed in place).

The counterbalance drilled with #40.

After that, I match-drilled all the understructure holes and all the #30 holes. The remaining holes to match-drill are the holes in the skin.

Also, I need to figure out how to bend the trim tab cutout and the trim tab itself. There are various techniques, including making a small bending brake. However, I don't see how can I attach the bending brake to the cutout given that the elevator has a folded trailing edge (seems like RV-14 elevators are riveted, so you actually have two pieces of skin).

I think I will try the method suggested in the manual: use the hardwood bending blocks and double-sided sticky tape to keep these blocks in place.

The elevator temporarily clecoed for the drilling operation. The opposite side view.