• Rudder finished
    Empennage Section 7
    Jun 7, 2017

    Got the lead counterbalance installed in the rudder. Not sure if I'm just being paranoid but I'm totally not touching that with my bare hands!

    I've heard of people using ProSeal to fix the nuts on the interior of the counterbalance since there's no access once everything is riveted together. I actually don't have any ProSeal yet, so used Loctite instead before torquing the bolts down. Fingers crossed they don't back out or that's going to be a mess to fix.

    For the trailing edge, I made sure that everything was perfectly straight when getting everything cleco'd together, and indeed it was almost perfect as-is.

    My perhaps less-than-brilliant scheme to keep it that way was to use a steel square beam I found at the hardware store as a backrivet plate, which was also perfectly straight when I bought it.

    I used a standard flush rivet set on the front face. It turns out the force of backriveting just knocks giant dents into the steel, and leaves the trailing edge with a small indent and a bad rivet that needs to be drilled out. So much for that idea.

    Instead, I used some extra aluminum wedge-stock that was used for the trailing edge as a backing plate such that I had 2 parallel faces to use the squeezer. The aluminum stock definitely took some damage and the manufactured heads ended up slightly rounded, but at least the rivets were consistent and cleanly fastened. I alternated sides between rivets, which is what everyone seems to do for aesthetics, but honestly I think it would be more consistent to have all the shop heads on the same side. The resulting trailing edge wasn't quite as perfectly straight as I hoped, but at least there's no warp in it. I'll attempt to use a tool to get out the wavy sections at some point and hopefully straighten it out some more.

    One thing that I forgot to do was to rivet the flanges on the outside rib before closing up the trailing edge. This left me with basically zero room to get any kind of bucking bar in there. In fact, it was so narrow that the rivet couldn't even be fully inserted without hitting the shop head of the rivet on the other side. I purchased some steel chisels from the hardware store that were angled enough to slip it behind the rivet to serve as a makeshift bucking bar, and it shouldn't be a surprise that it didn't really work. This ended up with a cracked rivet. I'm currently leaving it as-is, because I don't think I can do any better at bucking that rivet. I may drill it out and use a flush blind rivet instead, however, which is what I should have done in the first place.

    In the mean time, I'm a few rivets shy near the corners by the horn where I need to find a specialized bucking bar with a toe, but otherwise I think the rudder is complete. On to finishing the horizontal stabilizer!