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<DIV>It is actually a 1" o-ring. </DIV>
<DIV> </DIV>
<DIV>If you have a slight "pinch" in the pull wires it has the same effect. If
your rudder is very free and the cable-exits offer no friction at all, it can
oscillate. </DIV>
<DIV> </DIV>
<DIV>I also moved the clevises in on the servo arm and it had the effect of
taking away the death-dance, as I call it. (I still think that is what has been
killing Impacts in the air!!!!).</DIV>
<DIV> </DIV>
<DIV>An 8311 does better on the rudder and an 8611 is a no-brainer as Ed
said.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Eric.</DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=js.smith@verizon.net href="mailto:js.smith@verizon.net">Scott
Smith</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 Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, August 24, 2006 7:57
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] DS 8411sa
Servo Oscillation on Rudder</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=440185111-24082006>I believe this may be an issue for you
after 75 flights due to the rudder hinges freeing up. All you need is a
little drag put back into the system. I did this with my last airplane
by putting a small rubber band around both rudder cables about 6"
aft of the servo (per Eric H.) and the problem completely went
away.</SPAN></DIV>
<DIV><SPAN class=440185111-24082006></SPAN> </DIV>
<DIV><SPAN class=440185111-24082006>Try it!</SPAN></DIV>
<DIV><SPAN class=440185111-24082006></SPAN> </DIV>
<DIV><SPAN class=440185111-24082006>Scott </SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT
face=Tahoma>-----Original Message-----<BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<B>On Behalf Of
</B>JonLowe@aol.com<BR><B>Sent:</B> Thursday, August 24, 2006 7:38
AM<BR><B>To:</B> nsrca-discussion@lists.nsrca.org<BR><B>Subject:</B>
[NSRCA-discussion] DS 8411sa Servo Oscillation on
Rudder<BR><BR></FONT></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 PTSIZE="10">Jon Lowe<BR></FONT></DIV></BLOCKQUOTE>
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