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<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff size=2>Hi
Bob, </FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff size=2>What
you describe is pretty much what I have done for ages.</FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff size=2>My
real tack, these days is to make a plane that requires less right thrust,
because when the thrust angle is low enough, the plane will fly properly with
the rudder straight.</FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff
size=2>Unfortunately, some designs need all of three degrees and then some more
rudder. Thes airplanes fly funny.</FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff size=2>I
think Nat has the right idea.</FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff size=2>Oh,
your paragraph describing the necessary throttle management ...
BINGO!</FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff size=2>later
compadre,</FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff
size=2>Dean</FONT></SPAN></DIV>
<DIV><SPAN class=960095018-21022006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV> </DIV>
<P><FONT face="Times New Roman">Dean Pappas</FONT> <BR><FONT
face="Times New Roman">Sr. Design Engineer</FONT> <BR><FONT
face="Times New Roman">Kodeos Communications</FONT> <BR><FONT
face="Times New Roman">111 Corporate Blvd.</FONT> <BR><FONT
face="Times New Roman">South Plainfield, N.J. 07080</FONT> <BR><FONT
face="Times New Roman">(908) 222-7817 phone</FONT> <BR><FONT
face="Times New Roman">(908) 222-2392 fax</FONT> <BR><FONT
face="Times New Roman">d.pappas@kodeos.com</FONT> </P>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<B>On Behalf Of </B>Bob
Richards<BR><B>Sent:</B> Tuesday, February 21, 2006 1:37 PM<BR><B>To:</B>
NSRCA Mailing List<BR><B>Subject:</B> Re: [NSRCA-discussion] Rudder mix
instead of right thrust?<BR><BR></FONT></DIV>
<DIV>Dean,</DIV>
<DIV> </DIV>
<DIV>Thanks for that information. I'll have to chew on that for a while.</DIV>
<DIV> </DIV>
<DIV>FWIW, I have always taken a simplistic approach to right thrust and
rudder trim. With the plane properly balanced (laterally) and with the
rudder at neutral, I pull the plane to vertical and see which way, if any, the
plane deviates. This determines the need for thrust change. After the thrust
is adjusted, I fly the plane from horizon-to-horizon with the wings level, and
see that the plane tracks a straight line. Trim the rudder accordingly.</DIV>
<DIV> </DIV>
<DIV>I repeat the above exercise several times, preferably with no wind, and
with the plane in different orientations (left-right, right-left) in case
there is wind.</DIV>
<DIV> </DIV>
<DIV>My viewpoint is that the right/left thrust is most critical when the prop
is heavily loaded, ie: vertical climb. In level flight, the right thrust
alignment has little to do! with yaw trim, except for the slipstream effect
which seems to always be taken care of by the vertical climb test.</DIV>
<DIV> </DIV>
<DIV>The slipstream effect applies whether the plane is upright or inverted.
IMHO, slipstream is best taken care of by engine thrust, NOT rudder trim,
since it will always change with airspeed.</DIV>
<DIV> </DIV>
<DIV>Any other rudder inputs needed are usually (maybe always?) a result of
gyroscopic precession, which is a dynamic situation that can't be trimmed out
by a static control mix. This is why you might need left rudder input on an
inside corner at the top of a square loop. I had a plane that required lots of
right rudder on the outside corners, and slight left rudder on inside corners.
No trim could take care of that, I just had to learn the right stick inputs
(muscle memory).</DIV>
<DIV> </DIV>
<DIV>As for the bias on spin entries, inverted vs upright, this could be
affected much more by tiny differences in the left/right! wing panels,
incidences, etc. Basing a rudder trim setting on this could be risky.</DIV>
<DIV> </DIV>
<DIV>The programmable mix that you incorporated, above 2/3 throttle, is
interesting. It does require learning proper throttle management, as you
suggest. But, again, the airspeed will dictate how much mix you will need. So,
don't give throttle above 2/3 until you have pulled the nose vertical and are
at the vertical terminal velocity, THEN give full throttle. :-)</DIV>
<DIV> </DIV>
<DIV>I'm not in any way disputing your results. I have a tendency sometimes to
play the devil's advocate.</DIV>
<DIV> </DIV>
<DIV>Bob R.</DIV>
<DIV> </DIV>
<DIV><BR><BR><B><I>Dean Pappas <d.pappas@kodeos.com></I></B>
wrote:</DIV>
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<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Hello Vicente,</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>The trimming adjustment procedure for right rudder with throttle
couple I will describe was developed with the Excelleron that I reviewed for
Model Aviation. I synthesized this method, based on the several
different methods I heard described. As Jason said, some of them
did not fly right. The Excelleron is a very good flier, and with a
dependable muffled 120 two-stroke I would use it a low-hassle practice ship.
Like most airplanes, it required about 2-3/4" of right thrust and a small
amount of right rudder to make the plane trim normally. The predictable
unwanted effects in spin entries and loops (especially the outsides) were
present but not unusually bad.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff e="2"
siz!>So what I did was </FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>1)
Set the rudder dead straight and not touch the rudder trim lever
again.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Confirm that this is really the middle with repeated upright and
inverted stalls/spin entries, to make suer the plane does not have a bias to
either side.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>2)
reduce the right thrust to a "guess" setting that is enough for whatever
throttle setting and speed you fly your normal level
lines.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>You test this with shallow climbs at 2/3 throttle, and small
loops at that same throttle. I ended up with about 1-3/4
degrees. </FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>3)
Set up a throttle into rudder curve mix and keep the percentages at zero
from idle up to 2/3 throttle. Then add a slop from there to full
throttle,</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>and adjust those upper coupling ratios to get a straight vertical
line.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=932202016-21022006></SPAN> </DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Limitations: </FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Never fly above 2/3 throttle in level flight.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Never push the throttle up too soon before pulling or pushing to a
vertical.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#00 size=2
000ff>Avoid sudden throttle changes</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>In
other words, this is not appropriate if you have not mastered purposeful
throttle management.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Hope this helps,</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Dean P.</FONT></SPAN></DIV>
<DIV><SPAN class=932202016-21022006></SPAN> </DIV>
<DIV> </DIV>
<DIV><FONT face="Times New Roman">Dean Pappas</FONT> <BR><FONT
face="Times New Roman">Sr. Design Engineer</FONT> <BR><FONT
face="Times New Roman">Kodeos Communications</FONT> <BR><FONT
face="Times New Roman">111 Corporate Blvd.</FONT> <BR><FONT
face="Times New Roman">South Plainfield, N.J. 07080</FONT> <BR><FONT
face="Times New Roman">(908) 222-7817 phone</FONT> <BR><FONT
face="Times New Roman">(908) 222-2392 fax</FONT> <BR><FONT
face="Times New Roman">d.pappas@kodeos.com</FONT> </DIV>
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