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<DIV>Jon</DIV>
<DIV>Read this about pull-pull.</DIV>
<DIV>This will also happen if your cable ends slip. If you put the cable through
the ferrule just one time it may be slipping. Bad geometry will cause this
also.</DIV>
<DIV> </DIV>
<DIV>Jim Ivey</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV><A
href="http://members.cox.net/bdfelice/Ackerman/ackerman.htm">http://members.cox.net/bdfelice/Ackerman/ackerman.htm</A></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=JonLowe@aol.com href="mailto:JonLowe@aol.com">JonLowe@aol.com</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, August 24, 2006 7:38
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [NSRCA-discussion] DS 8411sa
Servo Oscillation on Rudder</DIV>
<DIV><BR></DIV>
<DIV>I'm running a JR 8411sa on rudder on my Aggressor, pull-pull, using the
setup that Troy Newman recommends (ss control line cable, NMP links at the
servo end, and MK links at the rudder, etc.). For the first 75 or so flights,
I had no issues. Then, the servo started self oscillating around
neutral, even with the engine not running, on the ground if the rudder stick
was bumped. The surface buzzes back and forth about 1/4", until damped
out by grabbing the surface. Thinking it was a servo pot going bad, I
changed out the servo. After two or three flights, same problem
appeared. Then thinking it must be a natural frequency issue in the
linkage exciting the feedback loop in the servo, I tightened up on the
pull-pull somewhat. It wasn't loose before (these cables, as Troy says,
don't stretch at all), but I increased tension somewhat. That
helped for about 3 flights, then the problem reappeared. These servos
are new 8411's, self converted to SA with a new plastic gear package.
I've gone thru the linkage completely, and find no evidence of anything
amiss. I've changed nothing in the setup from the
first flight. </DIV>
<DIV> </DIV>
<DIV>I believe I read somewhere in the past, about some 8411's doing this
because the feedback loop in the servo was too tight, and could be corrected
by sending them back to Horizon. Can anyone shed some light on
this? I'm about to install an 8611 on rudder, but would like to track
down this issue with the 8411s.</DIV>
<DIV> </DIV>
<DIV>Thanks.</DIV>
<DIV> </DIV>
<DIV><FONT size=2 PTSIZE="10">Jon Lowe<BR></FONT></DIV>
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