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prkaye

Well Known Member
I keep going back into the bedroom closet and looking at the completed parts I have in storage up there. One part I haven't been happy with is the trim tab. That jig I made to hold the tab tightly against the foam wedges while the proseal set... well, it pinched a little *too* tightly, and there are now depressions in the trib tab skin at the positions of those two foam wedges. These depressions are quite obvious when light reflects off the skin.

So, two solutions:
1) build a new trim tab
2) use some kind of filler to smooth out the depressions.

Advice on option (2)... what would be the best filler, and how well will it work? I would want the lightest thing possible, since I don't wan the filler to significantly increase the weight of my trim tab. I've heard of epoxy products like "microballons"... is this the way to go? Other options?
 
Is the problem really the trailing edge bend?

I have the same problem, but I don't think it was from the clamps "pinching too tightly". I think what happened was the trailing edge of the trim tab wasn't bent enough.

I bent it as much as I could (see below) but even so, after bending the skin naturally stayed more "open" than the size of the foam ribs. The proseal holds it closed tightly to the foam, but where there is no foam the skin trys to return to it's normal state. That results in the appearance you describe. It is purely cosmetic.

My EAA advisor thinks it could be fixed, by very gently squeezing the trailing edge. I may try this. But I may just make another trim tab since I'll probably switch to electric trim by the end of this project.

How have people bent the trim tabtrailing edge? I used the homemade 2x6 bender from the plans but I couldn't get a good tight bend, even holding the trim tab out (further from the 2x6 hinges). No matter how hard I pressed down, the bend didn't get any tighter.
 
I cut the trim tab skin apart at the trailing edge and used the AEX wedge so that it would match the rest of the elevator. Van's doesn't endorse it and I'll probably fall out of the sky from trim tab flutter, but it was much easier to assemble and looks a lot better than the folded edge.

I agree that unless you squished the foam, that the trailing edge probably just needs to be squeezed a little bit more. (It should be obvious if you squished the foam, because the skin wouldn't sit right on the spar.)

PJ
RV-10 #40032
 
trim tab distortion

This is the only picture I have.... you can see the problem in the skin reflection


I'd love to hear how people get better bends on the trim tab trailing edge.
 
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