Horizontal Stab

Empennage Tips 1

This entry was posted in Elevators Empennage Horizontal Stab on May 27, 2016 by Peter

Previously I began work on the fiberglass tips for the horizontal stabilizer and elevators. The tips for the elevators have very close edge distances in order to not interfere with the end ribs. Here you can see the first two reinforcement strips I made to remedy the problem for the left elevator. I expect the same thing to be required for the right side.

Picking up with the right side, I trimmed the horizontal stab’s tip by inserting it and marking the intersection.

Here is the result after the cut. This is a good point to note that I may need to trim these further after glassing in the elevator tips to ensure I have appropriate clearance and alignment. I bought some foam at home depot to close the back portion of this tip in.

Van’s specifies that you need 1/4 inch of edge distance in the fiberglass for this tip. This can be tricky as there isn’t much room for error. My approach was to mark the 1/4 inch line, and the line at which the fiberglass intersects the horizontal stab. This allows me to measure the line for drilling on the horizontal stab that will provide 1/4 inch of edge distance. There was a little more wiggle room on the left side than there is here on the right. On the left, it was possible to get both the edge distance for the fiberglass and the aluminum. On the right, I will be slightly short of the appropriate edge distance for the aluminum but just fine for the fiberglass. Of the two, I’d rather have the fiberglass OK, and the aluminum a bit short.

Here you can see my approach a little better. 1.5″ between rivets, and I started 0.5″ from the rear.

Came out nicely.

And perfectly within the edge distance guidelines.

Again, the elevator tip needs to be trimmed to 1/2 inch to avoid interference with the end rib. This all but guarantees an edge distance issue.

I made two more backing strips from aluminum and set about drilling and epoxying them to the tips.

Here are a few different pictures. I clamped the strips in place and drilled. After drilling for the rivet holes, I removed the strips and added additional holes. These holes will fill with epoxy and create a stronger bond. I sanded the strips with 100 grit sandpaper to maximize adhesion.

Here is a good demonstration of my thought process. There strip has epoxy underneath and on top. The two are connected by multiple additional holes. In order for these strips to come apart, not only will the aluminum need to separate from the epoxy but the epoxy will need to crack at these points.

Here is the strip in place for curing overnight.

Service Bulletin 14-01-31 (8)

This entry was posted in Empennage Horizontal Stab on March 9, 2016 by Peter

Last night I left off with one rib in progress. Tonight I set up the second rib, using the same method. I then removed the ribs, deburred, trimmed, and riveted to the HS-0002 angles.

Then it was just a matter of riveting. I started with the skin rivets that would not be accessible once the ribs were in place. I then riveted the rib to the spar. Mike was on hand, and we made quick work of it.

Squeezing the remaining rivets to the skin was quick and easy work.

I’m very happy with how this turned out. It wasn’t as much of a horror as people made it out to be, although it certainly was one of the more challenging projects I’ve completed.

Service Bulletin 14-01-31 (7)

This entry was posted in Empennage Horizontal Stab on March 8, 2016 by Peter

Tonight I returned to rivet the spar doublers and reinforcement angles to the front spar. Here are the parts after a quick priming and light paint job. I don’t normally paint interior parts like these, but I’m not a fan of the self-etching primer. It holds moisture too easily, so I figured a light layer of paint wouldn’t hurt.

Everything was clecoed together and then I used the pneumatic squeezer to the best of my ability to set as many rivets as possible.

I was able to get all the top rivets and center rivets. Unfortunately the bottom angle is too wide for my squeezer’s yoke, so I had to buck these rivets.

I had two minor smilies. Both in the same position on each side; three from the inside on the bottom. They are not worth drilling out.

Riveting the remaining rivets was going to be a challenge, so I played around with several different rivet sets with no luck. I was out of ideas, so I grabbed Mike who happened to be working on his annual.

Luckily he had a single offset rivet that was just the right length. Wrapped with electrical tape to prevent rotation and walking, I was able to get the majority of the remaining rivets.

A few of the rivets required a second set of hands, and Mike was nice enough to help out. We made super quick work of finishing it up. Here you can see the results. I’m extremely happy with how this entire project has turned out. A few blemishes here and there, but there is nothing in this service bulletin that I will lose sleep over. Moreover, I will be more comfortable knowing this SB has been complied with in its entirety.

Next it was time to work on the HS-0002 angles. The process described in the service bulletin instructions is rather convoluted. Essentially they have you clamp one side, then the other. Drill one side, clamp again, remove, and finish drilling. I can only surmise that all of that would be necessary without an angle drill or small clamps. I initially clamped the angle in place with the cleco clamps, but I found this to be insufficient. I wound up, and advice you, to use C-Clamps (unfortunately I didn’t take a picture with the c-clamps. I used the c-clamps to clamp the angle to both the rib AND the spar. Then I began drilling the section that mates to the spar and clecoing as I went. After that was completely drilled and clecoed, I repeated the process for the section mating to the HS-405 rib.