Drilling the vertical stabilizer3h
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).
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.
So I proceeded with the build and clecoed skin to the skeleton. Surprisingly, this did not require much forcing.
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.
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.
This was the end of the day.