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<DIV><SPAN class=781054719-30012006><FONT face=Arial color=#0000ff size=2>Hey
Bob,</FONT></SPAN></DIV>
<DIV><SPAN class=781054719-30012006><FONT face=Arial color=#0000ff size=2>I like
your story ... NYAHHH!</FONT></SPAN></DIV>
<DIV><SPAN class=781054719-30012006><FONT face=Arial color=#0000ff
size=2>Dean</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>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<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> Monday, January 30, 2006 2:41 PM<BR><B>To:</B> NSRCA
Mailing List<BR><B>Subject:</B> Re: [NSRCA-discussion] Trimming
question<BR><BR></FONT></DIV>
<DIV>I don't like to get involved with knife-edge trim discussions since I
don't feel that I am an expert on the subject. However, I developed a theory
about it years ago that seemed to fit most problems I have seen.</DIV>
<DIV> </DIV>
<DIV>The vertical placement of the wing and stab on the fuselage has a lot to
do with it. With a top-wing and a bottom stab (such as the Ultrasticks) the
tendency would be to pitch nose-up during knife edge. OTOH, a Cap 21 has a
bottom wing and a top mounted stab, and I know only too well that this pitches
severely to the belly in knife edge - my old Cap21 took 35% mix to fly
straight.</DIV>
<DIV> </DIV>
<DIV>My theory is that, when the fuselage is presented to the relative wind at
a given angle of attack, there is pressure built up on the side of the
fuselage (has to be, to fly knife edge). This pressure will naturally wrap
around the fuselage, so there will be a separation line along the fuselage
where the air separates, just l! ike at the leading edge of a wing -- some
goes over, some goes under. The stab should be placed near this natural
separation line. If it is far below this line, the plane will pitch to the
canopy, if far above, it will pitch to the belly. This is due to the stab
trapping some of the pressure.</DIV>
<DIV> </DIV>
<DIV>I don't think the wing incidence change can correct anything other than a
very minor pitch coupling problem. For really bad situations, a change in the
stab location is probably what is needed.</DIV>
<DIV> </DIV>
<DIV>Anyway, that is my story and I am sticking to it. :-)</DIV>
<DIV> </DIV>
<DIV>Bob R.</DIV>
<DIV><BR><BR><B><I>John Ferrell <johnferrell@earthlink.net></I></B>
wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">My
Guess:<BR>The sum of the drag vectors is well above the vertical CG. You
MIGHT be able <BR>to help the condition with really big wheels generating
some dr! ag down low. <BR>Its anybody's guess what the turbulance might
trigger.<BR><BR>The wing is not lifting in knife edge, but it is still
draggin'.<BR><BR>John Ferrell<BR>http://DixieNC.US<BR><BR>----- Original
Message ----- <BR>From: "John Pavlick" <JPAVLICK@IDSENG.COM><BR>To: "NSRCA
Discussion" <NSRCA-DISCUSSION@LISTS.NSRCA.ORG><BR>Sent: Friday, January 27,
2006 11:31 PM<BR>Subject: [NSRCA-discussion] Trimming
question<BR><BR><BR>> Ok here's a good one. The owner of the L.H.S. asked
me what I thought <BR>> about<BR>> this and I couldn't come up with a
good answer. He has a Hangar 9 Ugly<BR>> Stik - the real big one. I can't
remember exactly what it's called. Guess <BR>> it<BR>> has a gas motor
in it. It's big. He says he has it trimmed so it will fly<BR>> inverted
with just a very slight bit of down elevator (almost none). Ok, <BR>>
so<BR>> it's not nose heavy, maybe even a little tail heavy. Now, when he
flies it<BR>> knife edge (either side) it pulls s! everely to the canopy.
I mean like it<BR>> will fly a complete circle. It needs almost 3/4 down
elevator to fly<BR>> straight. It's beyond a mix - fix. He also says that
it has a bit of roll<BR>> couple when flying level (not knife edge) but
it doesn't pitch severely up<BR>> or down under these conditions. Any
thoughts? I guess you can rule out <BR>> C.G.<BR>> because if anything
it should pull to the belly considering how it's <BR>> trimmed<BR>> to
fly level upright and inverted. I haven't flown it so I can't add
too<BR>> much more. He builds OK so I don't think there's anything way
out of<BR>> alignment, but again I haven't seen it yet so maybe there is.
What should <BR>> I<BR>> look for if I get my hands on it to try and
help him?<BR>><BR>> John Pavlick<BR>>
http://www.idseng.com<BR>><BR>> --<BR>> No virus found in this
outgoing message.<BR>> Checked by AVG Free Edition.<BR>> Version:
7.1.375 / Virus Database: 267.14.23! /243 - Release Date:
1/27/06<BR>><BR>>
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