Horizontal Stabilizer Complete!
We finally have a part that looks like it goes on an airplane. Dan and I finished the horizontal stabilizer today around 1700! We made a lot of progress yesterday and got as far as attaching the right HS to the skeleton (framework). We started today after Dan got back from football practice and hoped we would finish the HS by the end of the day. Assembly is starting to come together pretty well as we gain confidence in our metalworking skills. Dan and I are beginning to work very well together – it’s a learning process for both of us and we are having a blast.
The pneumatic squeezer is a great time saver for all the rivets used along the edges of the empennage. Dan got a good bit of practice today attaching the skin.
Close up of squeezer. Once it is set, you can accurately place a lot of rivets in a very short amount of time.
There are a lot of rivets that you can’t use the squeezer on. In such cases, you have to use the rivet gun and a bucking bar. I’ll cover that process in another post.
Lessons Learned
Like I said earlier, we are learning as we go… Here are a few lessons learned from the last two days of work.
Lesson #1: Double check the rivet schedule before staring a line of rivets. While squeezing the rivets that attach the skin to the front spar assembly, I noticed that one rivet was not right. It happened to be where the skin attaches to spar and middle rib. The schedule specifies AN426AD3-4 rivets instead of the “usual” AN426AD3-3.5 in order to compensate for the additional layer of metal from the rib. If I had read the schedule a little more closely, I would have clearly seen and noted this:
(The highlighter is mine of course).
Lesson #2: Be very careful drilling out rivets and using the punch to force the rivet out. As a result of Lesson #1, we had to drill out the rivet. Dan took a couple of good whacks on a punch to dislodge a rivet used to attach the skin to a rib and spar. The rivet went through 3 pieces of metal. After he hit the hammer a couple of times, I heard him say “Oops” — it’s never good to hear that expression in the shop… The punch had pushed the rivet out of the skin, BUT bent the flange from the rib on the bottom. We were able to get the rivet shank out of the flange and then bend the flange back to the proper fit without much trouble, but a little extra care removing rivets should reduce the need to do things like that. (Reading the plans a little better might have even allowed us to avoid drilling out the rivet in the first place).
Lesson #3: Always check your previously constructed parts for complete assembly before attaching them to another part. When assembling the final parts on the HS I got so excited that I forgot that I had left out 2 rivets on the end of the rear spar reinforcement bars. I can’t exactly remember why the rear spar was missing a couple of rivets – but there they were – two holes at the very end of the reinforcement bars. The real problem was that I noticed they were missing AFTER we had completely attached the top skin and ribs on both sides. There was now no way to get behind the spar now with a bucking bar. Thank goodness for blind rivets. I’ll call Van’s builder support tomorrow to get their suggestion, but for now I’m thinking a couple of blind rivets similar to the ones I used to attach the rear spar to the middle ribs will do the trick.
Total time: 5.9 hrs, Hobbs: 57.7
Next up – completion of the vertical stabilizer.
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