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Minor twist in elevator trim tab

jeffw@sc47

Well Known Member
Elevator trim tab assembled though (09-14, Step 6) to riveting the trim tab hinge onto the tab front spar/top skin and letting tank seal to set on the three foam ribs inside. Has set aside for 24 hours on flat slab with trailing edge aluminum square tube clecoed to TE and weights and flat 1x4 set on top.

Then the next instruction is - 'NOTE: Check for twist before riveting [trailing edge].'

There is a minor twist, about 1/16" to 3/32" across length of EL trim tab: found twist, now how do I correct it?

The TE filler strip is pretty set in with double sided tape strips and I guess the foam blocks are pretty set in their beds of tank-seal.

QUESTION_1: Is there any procedure for mitigating or reversing any of this twist before riveting the TE?

I understand that this twist is minimal, but it's across the very short length of the trim tab. If i have 1/4-3/32 twist in 24", I realize I have to be especially careful with the elevators, ailerons, and flaps to avoid twist in those longer items.

QUESTION_2: What procedures do I follow, besides clecoed angles on TE's and weights to keep things flat/straight, for avoiding twist?

Searched throughout threads for these procedures but haven't found the answers I would like to see; mostly ideas for trying to fix twists already set-in.
 
I have these part laying on my table right now. Kind of interested in the answer if one of you big-brain types could spare a moment. Thanks!
 
i calmed down and riveted on

bhope2505,
i am now just about finished with the elevators >

fixed the trim tab twist >>
with the trailing edge insert inserted inside the tab trailing edge with the double sided adhesive tape (two layers each side) and all but about 6 clecos removed, i didn't want to have the adhesive brake loose. i counter-twisted out the small twist (1/16" to 3/32") diagonally across the length of the trim tab by holding both ends in my hands and applying the counter-twist torque to the trim tab; i think i applied just a little the first application and then a second time just a little more, and when i checked it on a flat surface it was straightened out > no twist.

i carefully riveted the trailing edge by skipping to every fifth rivet starting in the center and flipping the tab over after each run along its length and closing in all the open rivet holes progressively in series top-to-bottom; first run setting the rivets half way and then redoing the series with full press using Avery's slanted hairpin-coupled rivet set using a manual squeezer. when it was done, still no twist. I'll do something similar when i rivet the trailing edges of the elevators. Careful and methodical is the key.
 
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