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Does this look right?: elevator trim cable position

mcencula

Well Known Member
Calling folks who are knowledgeable... (three questions)

  1. Today, I setup the trim cable to achieve 25 degrees of up trim tab travel and 35 degrees of down travel. Here's the position of the cable in the anchor nut weldment. Does this look right? Seems a bit close to the end to me, but I can't really conceive of a way that it could come unscrewed.
    Hi res image
    20200902-13-tn.jpg

  2. As for the clevis end, the exposed thread in this photo was all screwed into the clevis end. The remainder of the threads is covered by tape, but the position of the last thread is marked on the tape. So, it was screwed a bit more than 2/3 of the way on. Thoughts / comments?
    Hi res image
    20200902-14-tn.jpg

  3. Lastly, is there supposed to be a locknut tightened up against the anchor nut weldment? Don't see it on the plans, but it not having one seems different than what we do with, say, rod end bearings.

Thanks!
 
Hi Mike,

1. that looks ok to me. i was wondering the same... you can unscrew/turn the entire thing around the trim cable if you bend the cable slightly down.

2. the thread engagement looks also ok to me. 2/3 just sounds right, a bit more is even better. i do not recall if the thread of the trim cable could rotate, if it can you just put a small stop nut on the clevis end with a little bit of blue loctite.

3. the trim cable is not able to turn in the anchor nut weldment, therefor no further locknut or so is required.

Disclaimer: that's my very personal point of view.
 
And from real world experience, you will NEVER need more than ~10° of deflection of the trim tab relative to the elevator (about 3/4" up or down...)

A little goes a long way.
 
And from real world experience, you will NEVER need more than ~10° of deflection of the trim tab relative to the elevator (about 3/4" up or down...)

A little goes a long way.

I think it must depend on CG position. My bird tends forward CG and as a result it uses more trim throw for the speed range than you describe from your experience.
 
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