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<DIV><FONT face=Arial size=2>To Doug's point re. the long tail moments &
added stability of Pattern designs, this can be overcome pretty well with enough
control throw. Granted, it's not going to be just like a Scale Aerobatic
design, but real snaps can be done and barrel rolls can be avoided. I
remember the angst that was generated by the reverse avalance in Masters in
'05. Fears of bent wing tubes, busted wings etc. Locally at least,
there were several examples where very good pilots had to re-do their setups to
get enough throw to make this maneuver happen properly and not bend their
airplanes. Well, not a single airplane in the district was damaged that I
know about, but I do remember having discussions about upping the elevator and
also rudder throws to get the autorotation to happen properly. Hey, I admit to
having only a short 2.25 year Pattern flying history, but as far as I can tell,
it doesn't seem to be part of the Pattern "DNA" to set airplanes up with enough
throw in alot of cases. Having the deal with a schedule including the
loaded snap in the reverse avalanche has advanced the knowledge because guys had
to figure it out.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ed</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=seefo@san.rr.com href="mailto:seefo@san.rr.com">Doug Cronkhite</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> Saturday, July 08, 2006 8:54
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion]
Snaps</DIV>
<DIV><BR></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">The INBOARD wing
dumps lift as a result of the increases angle of attack AND the rapid
reduction of airspeed (by a sharp yaw moment – rudder input). The outboard
wing’s lift and drag increase rapidly. If the outboard wing dumped lift you’d
get no rotation at all or very little. Some airplanes actually snap much
better with no aileron usage as the changes in angle of attack on the inboard
wing causes it to keep flying and not dump the lift from the yaw
input.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I think the biggest
problem pattern aircraft have with performing proper snaps is the long long
tail moments keep things so stable that it’s very hard to generate the
critical angle of attack required to get the stall to happen. So you see
barrel rolls with VERY high G-loads on the aircraft.
<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">In full scale
aerobatics, there is nearly no G-loading once the stall occurs, except for the
rotational forces of the autorotation of the aircraft. There is some G leading
up to the break, but once that happens, it’s all kind of non-stressful.
<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">-Doug<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> <o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<DIV class=MsoNormal style="TEXT-ALIGN: center" align=center><FONT
face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">
<HR tabIndex=-1 align=center width="100%" SIZE=2>
</SPAN></FONT></DIV>
<P class=MsoNormal><B><FONT face=Tahoma size=2><SPAN
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT
face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org] <B><SPAN
style="FONT-WEIGHT: bold">On Behalf Of
</SPAN></B>Rcmaster199@aol.com<BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Saturday, July 08, 2006 12:45
PM<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B>
nsrca-discussion@lists.nsrca.org<BR><B><SPAN
style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [NSRCA-discussion]
Snaps</SPAN></FONT><o:p></o:p></P></DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">In a message dated 7/8/2006
2:09:25 PM Eastern Standard Time, natpenton@centurytel.net
writes:<o:p></o:p></SPAN></FONT></P></DIV>
<BLOCKQUOTE
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<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Matt<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Regards. Two comments.
<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Snap characteristics are
independent of scale. The only thing that changes is the clock ( due to
changes in moments of inertia ). <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">When the rudder is applied it is
the outboard wing that exceeds the stall AOA and dumps. Actually it is not
much of a lift dump but a huge jump in
drag.<o:p></o:p></SPAN></FONT></P></DIV></BLOCKQUOTE></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Nat true. Moments of inertia are
design parameters. So are several other key parameters that may make or
break a model's ability to perform snaps. That was my
point.<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">I agree in terms of AOA (outboard
aileron low) and drag increase but I am not as sure regards to lift. I know
what you are saying though. <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">One question: how does the
outboard panel lift over the top if its lift has been
dumped?<o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> <o:p></o:p></SPAN></FONT></P></DIV></DIV>
<P>
<HR>
<P></P>_______________________________________________<BR>NSRCA-discussion
mailing
list<BR>NSRCA-discussion@lists.nsrca.org<BR>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</BLOCKQUOTE></BODY></HTML>