Ivan's RV-7

Drilling the vertical stabilizerTimer icon3h

May 4, 2022

So I started working on a vertical stabilizer!

The first thing to do was to assemble a skeleton from two spars, one doubler, and four ribs. Nothing too sophisticated, very similar to how the practice kit is made. I did not fully deburr parts at this point, but just quickly ran them across 7S Scotch-Brite deburring wheel (Aircraft Spruce part number 12-00948). This makes all externalities of parts to be smooth, which is what matters during an initial assembly. I will do proper deburring (including these dreaded rib nooks and crannies).

Assembled spars and ribs into a skeleton

The next thing was to attach the skin. Here I found tiny damage at the rear bottom corner. The damage is a slight dimple as if something poked at the skin. I don't know if it was something I did or if it was damaged during the transportation. Perhaps, the latter since the was another slight indentation close to that spot.

Minor skin damage (dimple, less than 10 thou deep)

So I proceeded with the build and clecoed skin to the skeleton. Surprisingly, this did not require much forcing.

Skin clecoed to the skeleton

Another view

Then I drilled all of the holes. So far I am using a very simple system. I do some row of rivets, then move clecoes into updrilled holes, drill the remaining holes, then repeat on the opposite side. Put a note indicating that the whole row of rivets was updrilled.

I use reamer for updrilling which I like a lot. It is less about "perfect" holes, but more about convenience. First, a straight flute reamer doesn't grab, especially when using an electric drill (cannot use air tools late in the evening!), as it has a much lower RPM. Second, if I accidentally run it into the opposite part, it would leave much less damage. If I need to make a brand new hole, I don't bother with the reamer, I use a regular #30 or #40 drill bit.

After clecoing and re-clecoing, I started to understand why some builders use a pneumatic cleco tool. Even on a small part like the vertical stabilizer, my hand gets tired. So I ordered a pistol grip pneumatic cleco tool. Let's see how well it works!

I noticed that top and bottom rib tips were not ideal in the skin. The bottom one seems to need some bending for better fit. Even though rivets would pull flanges, I might as well bend them just a little bit.

Flanges on the tip of the bottom rib need some adjustment

The top one might need some corner relieving or bending. It might have scratched the skin already. I did deburr the rib so it should not be too bad. I'll see once I disassemble everything.

Top rib might need some minor corners relieving

This was the end of the day.