• Elevator trim tab complete
    Jul 13, 2017

    The elevator trim tab took surprisingly long to complete, given its size and apparent complexity. First was a fair bit of countersinking through material that is right on the threshold of too thin in my opinion. When countersinking the spar with the hinge cleco'd to the backside, the countersink essentially went completely through the spar and just touches the hinge. A new element I haven't used in the build so far was the use of foam ribs that had to be adhered to the aluminum skin with ProSeal, which is a bit of a mess to work with. First the contact surfaces need to be scuffed and cleaned.

    You mix the ProSeal at a ratio of 10:1 by weight, which was actually a bit challenging given the goopyness of both the accelerator and the base. I hear this stuff doesn't have that long of a shelf life, and I'd like to use it for the wing when I get to it, so now it's sitting in my fridge. Then I clamped it all together and riveted the spar, skin, and hinge together.

    The rivets along the hinge were the hardest part, as a squeezer could barely fit in there, and the rivets were so long that it was extremely hard to get them to compress straight. I probably ended up drilling out half of the rivets due to this. I've found one of the side effects of drilling out rivets through sandwiched material is that it's easy to start creating space between the layers that you can't compress back down. I ended up with a few small pockets of space underneath the hinge that I'm not too happy about. I've flagged it to show to a tech councilor, and may have to redo it. Furthermore, despite doing most of the riveting clamped to a steel beam that I know is perfectly straight, the tab ended up with a very slight bow, but no twist. I'll have to see how well it attaches to the elevator afterwards, but it annoys me slightly.

    In the mean time, onward to working on the rest of the elevator!