Fastback Vertical Stab Mod
Since I ordered the fastback kit and I’m waiting on some elevator parts, I decided to get going on modifying the vertical stab for the fastback kit. This means rotating the lower rib, forward of the forward spar up just 5 degrees. This makes room for the raised turtle deck of the fastback to come back to the tail. Since I knew l was maybe going to make this mod, I never riveted that rib to the skin. This was as some would say, the “see vou play” cause I didn’t have to drill out like 15 rivets.
I did decide to remove the three rivets that held the rib to the spar, so I could remove the rib and modify it slightly to fit better. Since this is such a tight area, I messed up drilling one of the rivets out pretty bad. There’s a pic where you can see there are almost two holes. I determined it was a little to bad to try and salvage so I ended up drilling two more holes on either side of the messed up one. So now there are 4 rivets holding that piece in instead of 3. I plan to fill the messed up hole in later too.
Once I fixed that, I drew the line at 5 degrees and cut it with the die grinder. After cleaning up that edge, I test fit the rib back in to see how it would fit. There were a couple problems. First, the rib seemed pretty big and did not want to fit in this spot very easily. I ended up sanding the nose of the rib down slightly and also fluted the nose to try and make the overall shape a little smaller. This helped. Also, for the 3 most aft holes, the holes in the ribs were too close to the existing holes in the skin to meet the minimum edge distances. I ended up not using two existing holes in the ribs and instead drilled 3 more so I could satisfy the edge distances and still have all the rivets I needed. For the rest of the forward holes, I used an inverted hole finder to match drill holes in the skin off of the rib, which worked pretty well.
Once everything was fit up and drilled, I took it apart, deburred it all, put it back together, and riveted it all. There are two and a half holes in the skin where the old ones used to be that I plan to fill with some micro just for aesthetics and then this will be all ready for the fastback!
