Section 9


  • Elevator trim tab complete
    Empennage Section 9
    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.

    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!


  • Refolding closeout tab
    Empennage Section 9
    Jun 23, 2017

    To deal with my previously botched fold on the closeout tab on the elevator here, I got a response from Van's that suggested to fabricate a new closeout tab from the same type and thickness of material. After putting some thought into this, I couldn't figure out a way to cleanly fabricate one and get it attached flush with the existing tab. Instead, I decided to try and hammer out the existing fold, and refold the tab in the correct position. If it failed miserably, I would just purchase a new skin from the factory.

    I used a backriveting plate and a flush rivet set to hammer out the crease of the previous fold, then used the edge of the same backriveting plate to make a new fold. It actually turned out a little better than I was expecting, albeit my expectations were fairly low. There's still a noticeable blemish between the two creases, but I think I'll actually keep it and hope it gets hidden by the paint.


  • Starting elevator
    Empennage Section 9
    Jun 20, 2017

    The elevator is a surprisingly long section, so I tried to pull out all the components and get them prepped and primed first. What a pain in the butt this is between cleaning, degreasing, scuffing, priming, and all the resulting cleanup of the HVLP gun. It probably took me a half day for one table of parts.

    For my last attempt at priming, I took the advice of only putting on enough paint to just notice a change in coloration (I'm using SW-P60G2). In the end, I think it was much too thin. This time I put it on much heavier, and I think they came out much better. At least it's a noticeable green, as opposed to the barely tinged silver from before. I also reduced slightly less than 200% to about 175%.

    It was inevitable that I missed a part, however, and it had to be a big one like the trim tab spar. Oh well, I guess I'll collect all the tailcone parts soon and try to prime the whole lot next.

    Everything seemed to be going fairly swimmingly until I got to match drilling the closeout tab on the skins near the trim tab. There's about a 1/4" gap from where the shear clip is and where the skin closeout should be. Doh! Not sure how to compensate for this one, so awaiting some feedback from Van's again.