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Author Topic: Bellcrank position  (Read 2250 times)

Offline Will Moore

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Bellcrank position
« on: July 30, 2017, 04:04:39 PM »
There are some theories about why a bellcrank should be mounted "backwards". I have seen several designs with bellcranks drawn in that way.  I am sure this question has been posted before.  What is the latest thinking on reverse bellcranks, and why is it a bad or good idea?

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Offline Target

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Re: Bellcrank position
« Reply #1 on: July 30, 2017, 05:50:31 PM »
I was told that by pulling on the aft line for down, and forward line for up, it provides more equal line tension by the plane in up and down maneuvers with a traditional turning direction propeller.
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Offline john e. holliday

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Re: Bellcrank position
« Reply #2 on: July 30, 2017, 08:06:00 PM »
I have also been told up line forward but I have planes that has up line in the back.  Some designs have the control horn on top and some on the bottom.  The same with the flap horns.   I put the bell crank pivot behind the spar.   The leadouts should be as close together  at wing tip with out hanging up on each other.  Mine are set at 3/4 inch on adjustable mount.  So far have never had them hang up on each other.  By the way with them that close together I have never felt any difference in the yaw of the planes.   Now in the old days when leadouts were some times as far apart as the bell crank arms, yes I could tell the difference.  In fact the thought just hit me of a design I was going to build in which the leadouts are crossed over coming out to the wing tip.   H^^
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Offline Brett Buck

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Re: Bellcrank position
« Reply #3 on: July 30, 2017, 08:09:52 PM »
There are some theories about why a bellcrank should be mounted "backwards". I have seen several designs with bellcranks drawn in that way.  I am sure this question has been posted before.  What is the latest thinking on reverse bellcranks, and why is it a bad or good idea?\

  Irrelevant, because you don't want to have the leadouts separated far enough to make any difference, to first approximation. I put mine in normally, rear line is "up".

     Brett

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Re: Bellcrank position
« Reply #4 on: July 30, 2017, 08:17:50 PM »
Brett do you offset the clips with different length lead outs and lines, so they cannot touch one another, or do you feel that is never a problem?
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Chris
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