Thread: Tail Wag Cures
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Old 11-11-2015, 07:21 PM   #310 (permalink)
pgoelz
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Join Date: Nov 2008
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Quote:
Originally Posted by Kennihs View Post
The solution for me, was to change the stock tail servo!

i tried everything else in this thread!
FWIW, I have been working on a slowly wagging tail on my Trex 250Pro DFC in a scale Hughes 500 body. It flew fine but the tail had a small wiggle all the time. I initially thought it was linkage slop since there was some. But after I addressed most of the slop, the wag remained.

Turned out that the stock tail servo was absolutely the cause, and it is easy to see why. Simply slowly rotate the body CW and CCW in small increments and watch (and listen to) the tail. The stock servo has appreciable deadband.... for small body movements, there is NO servo reaction at all. I replaced the stock servo with an Eflite DS76T and the servo reaction to small movements is instant and continuous, with no noticeable deadband. In flight, the slow wag is utterly gone. Not a trace left.

I did notice that the stop gain seems to be lower.... I used the same servo horn length, but it may be the the DS76T rotates less than the stock servo for a given signal change. Next time I have it open I'll move the link out one hole.

Paul
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