Category: Rudder

Feb 20, 2010 – Woohoo! The rudder is complete! Some of the fun stuff I’ve read about that are challenges are now behind me.

I started by riveting the trailing edge that I had assembled a week or so ago using the L-angle to keep it all straight. Riveting was interesting, because the rivets are double-flush, meaning that they have to be flat on both sides. It’s also necessary to keep the trailing edge straight. Riveting incorrectly could result in the trailing edge bowing. During the process, I had a very slight bow in the center of the edge, but it worked itself out nicely. I’m kinda not fond of the “acorn-in-a-dimple” look that Van’s describes. I may fill these with sealant, or just wait until the airplane gets painted and fill them then to make it smooth.

The next thing I had to deal with was a few rivets that were in the trailing edge of the top and bottom ribs for the rudder. Since the rudder tapers to a very thin edge, the ribs also are very thin at that point, so I couldn’t get a bucking bar in there to rivet the aft two rivets on each side, top and bottom. So I back-riveted them indirectly, using a long, thin bar with the rudder sandwiched in between the bar and a bucking plate. Shot the top of the bar with the rivet gun. Works great.

Then it was time for the fun. I had to roll the leading edges of the skins to produce the airfoil shape. I had an extension for a ceiling fan lying around (Now I know why I don’t throw things away). I taped it to the skin, and turned the tube using a screwdriver on one end, and vise-grips in the rudder hing cutout areas. The challenge is to keep the skin from creasing at the spar.

The rolls came out OK. Had to manually finesse the skins a little bit, but I got them to cleco together. This was really hard at the lower end of the rudder, because the rudder is wider there, and the material has to roll farther to mate up.

I then removed the clecos, ran a bead of sealant along the mating surface, and clecoed them back together again. THAT was hard. If I was doing this again, I wonder if I wouldn’t make a thin narrow strip of aluminum to go on the inside of the leading edge, just to reinforce the skin where it is riveted.

The leading edge then gets riveted with pop-rivets. Looks great.

I used some leftover sealant to fillet seal the balance skin that I talked about earlier.

Time : 4:15

Feb 11, 2010 – Over the course of two days, I’ve gotten a lot done. To begin with, I fit and installed the rudder counterbalance weight. This is just a block of lead that I needed to trim to fit past the rivets in the balance skin.

In the first picture below, you can see where I’m notching the weight where it interferes with rivets and structure. The second picture shows the weight installed.

I then clecoed the skins to the structure. The first picture is a nice shot of the skeleton and the skin with the stiffeners. I then had an issue about whether the balance skin should go inside or outside the main rudder skin. Per the drawing, it goes inside the skin, but that would have the rudder skin edge facing the windstream. I opted to place the balance skin on the outside. I beveled the edge and will run a bead of sealant there as an aerodynamic seal.

My next problem was installing rivets in the side of the rudder horn brace.These were very difficult to get to. So to handle the rudder, I set it up on blocks to protect the leading edge of the skins, then supported it with safety wire to keep it standing. I was able to get on the upper 3 rivets with the squeezer, but I caved and put in pop rivets on the very bottom ones on each side.

Then it was time to install the wedge in the trailing edge of the rudder. This wedge is very thin, and ties the skins together. The challenge with this part of the project is keeping the trailing edge straight.

I bought a 6′ section of 1/8″ L-angle at Lowe’s. I attached it to the edge of the table so the top of the angle is flush with the top of the table. Using the wedge as a drill guide, I drilled the holes through the L-angle.

I mixed up some sealant, slathered it on the wedge and the inside edges of the rudder skins, and clecoed the mess together, attaching it to the L-angle.

After the sealant sets up, the trailing edge gets riveted. These are double-flush rivets, set in a certain order so that the trailing edge stays straight.

On another note, Van’s called yesterday to let me know that my servo for the electric trim is back-ordered, so I’ll have to wait until the first of the month before I can work on the left elevator. It’s just as well. I need to try to slow down since I’m not ready to order the wings yet, and I’m running out of work to do on the tail. Pretty soon I’ll start on the elevators, and that will be it.

Time : 4:20

Feb 9, 2010 – Began the assembly of the rudder structure today. It was nice to be able to use the squeezer on much of the rivets, except for the four rivets connecting the horn to the horn brace. I was able to put solids in there. I put a small tungsten bar in the hole, and held it with a finger while I shot the rivets. Worked great. I’ll probably continue with by attaching the skins tomorrow.

I did have to order some LP4-3 blind rivets from Van’s. I got ahead of myself back in the horizontal stab, so I ran out. I’ll need them to attach the top rib in the rudder. Ordered 20, they’re cheap enough.

I also finally went out on a limb and ordered the electric elevator trim kit. I’ve been going back and forth about this; I finally decided that if it came down to it, it would help with resale. Still trying to save for the wings, but I’d rather install the electric trim while building the elevator, than try to retrofit later.

Time : 1:45