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<DIV dir=ltr align=left><SPAN class=312335122-10012007><FONT face=Arial>I agree,
very good summary Wanye....where did you find the article?
;-)</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=312335122-10012007><FONT
face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=312335122-10012007><FONT
face=Arial>Amir</FONT></SPAN></DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org] <B>On Behalf Of </B>Keith
Black<BR><B>Sent:</B> Wednesday, January 10, 2007 9:11 AM<BR><B>To:</B> NSRCA
Mailing List<BR><B>Subject:</B> Re: [NSRCA-discussion]
Pull-Pull<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><FONT face=Arial size=2>Good summary Wayne. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>This topic is like religion or politics. I know
several top level FAI pilots that swear the DEPS (or similar) system is the most
accurate for exact elevator matching and they'd not use anything else. I also
know some FAI pilots that have made the finals of NATS (even won) with dual
elevator servos (of course, these guys could probably kick butt with only one
elevator half).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I don't recall many, if any, top guys in the NATS
FAI finals flying with pull-pull recently.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>My observation is that my rudder pull-pull tension
varies over time and I think the same would occur with the elevator. If it did
then it seems like an opportunity for the two halves to get out of unison.
</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>There's also the constant debate about what the
best cable is based on weight and how much each stretches. Some will tell you
that fishing leader doesn't stretch, others say Kevlar doesn't stretch, and on
and on.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Well I've tested multiple types and sizes of
cables, fishing leader and Kevlar, under controlled tests with weight hanging on
them for a day or so and they all stretch. Maybe the stress we put on them isn't
enough to cause stretch, but I think it is. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I personally prefer either dual elevator servos or
DEPS, that's my religion ;-).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Keith</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </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=wgalligan@goodsonacura.com
href="mailto:wgalligan@goodsonacura.com">wgalligan</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> Wednesday, January 10, 2007 10:17
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion]
Pull-Pull</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>I have tried all these methods of elevator
setup. Pushrod with Y at the end, pushrod to MK bellcrank, dual
servo's, pull/pull steel line and Kevlar, and DEPS(dual
pushrods.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>FWIW... All these setups work
good and are personal preference based on your building abilities and the type
of airframe your using. One thing I have found is its paramount to have
a fuse that does not flex or twist under load. If it does have any
movement I would think the dual servo's or DEPS may have an advantage
over the pull/pull. </FONT><FONT face=Arial size=2>But I have been wrong
before.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>1. Pushrod with Y... worked good only
if it had a bearing at the front and tail to support pushrod.</FONT></DIV>
<DIV><FONT face=Arial size=2>2. Pushrod to MK bellcrank... was very solid with
nary any blow back. But a little heavier then some setups. Pushrod needs
support in middle of rod with foam to prevent oscillation of the rod.
Has to many points of possible failure and requires more hardware, although I
put over 800 flights on one setup.</FONT></DIV>
<DIV><FONT face=Arial size=2>3. Dual servo's... Very redundant and with
the right transmitter can be setup precisely. Slightly heavier then
pushrod setup with servo's and wire leads.</FONT></DIV>
<DIV><FONT face=Arial size=2>4.Pull/pull... Very light and most
adjustable of the setups, Requires more time to set up properly and is a
little less ahhh... aesthetic with all the lines protruding from
fuse. Wire lines require good crimps and straight exit holes in line
with servo and control surface. Kevlar(my choice) requires Teflon or
nylon exits to prevent chafing of the line but does not have to be a perfect
line to the control surface when using this type of exit. I went
gun shy on pull/pull my setup(wire) broke on the down elevator on the
10th flight causing a mishap. One other plane with Kevlar had
hundreds of flights before a radio failure retired it and it was still in good
condition on inspection after the crash. BTW I have found a spool
of Kevlar control line works good and will last for many setups and cost about
8 bucks.</FONT></DIV>
<DIV><FONT face=Arial size=2>5. DEPs ... dual elevator rods (.07 c.fiber with
Teflon sleeves) has been in the last two planes I have built.
Requires a little time setting up in a straight line through exit to assure
smooth operation. Very light and positive control to elevator halves.
When exited below stab looks cleaner.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Wayne Galligan</FONT></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=bob@toprudder.com href="mailto:bob@toprudder.com">Bob Richards</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> Wednesday, January 10, 2007 7:38
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion]
Pull-Pull</DIV>
<DIV><BR></DIV>
<DIV>Not all planes have push-pull elevators. I've had planes with all
pull-pull tail surfaces.</DIV>
<DIV> </DIV>
<DIV>But, there are a few reasons why elevators would be setup with
push-pull. Seperate servos (much smaller ones) can easily be mounted in the
tail. Having seperate servos allows easy travel adjustment (travel matching)
through the radio programming, and also allows redundancy on this critical
control.</DIV>
<DIV> </DIV>
<DIV>The rudder requires more torque -- heavier servo -- and it might be a
design consideration (balance) to keep the weight of the heavier servo
closer to the CG.</DIV>
<DIV> </DIV>
<DIV>Personally, I like pull-pull and would prefer it in my models.</DIV>
<DIV> </DIV>
<DIV>JMHO.</DIV>
<DIV> </DIV>
<DIV>Bob R.</DIV>
<DIV><BR><BR><B><I>Jay Marshall <lightfoot@sc.rr.com></I></B>
wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Why
are rudder controls pull-pull and elevator controls push-pull?<BR><BR>Jay
Marshall<BR><BR>_______________________________________________<BR>NSRCA-discussion
mailing
list<BR>NSRCA-discussion@lists.nsrca.org<BR>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</BLOCKQUOTE><BR>
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