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<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff size=2>Let me
add another two cents worth ...</FONT></SPAN></DIV>
<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff
size=2>Earl,</FONT></SPAN></DIV>
<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff size=2>What
is the sampling rate on your data logger?</FONT></SPAN></DIV>
<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff size=2>Can
you see if the maximum 13-Gs at 100 MPH was sustained for the entire half
second or so that it took to complete the snap,</FONT></SPAN></DIV>
<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff size=2>or was
it a short spike (like 0.1 second) and then sustained at say half of
that value, for the rest of the snap.</FONT></SPAN></DIV>
<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff size=2>Of
course, if the data logger samples once a second, we have almost no way of
knowing.</FONT></SPAN></DIV>
<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=858241016-28012005><FONT face=Arial color=#0000ff
size=2>Later,</FONT></SPAN></DIV>
<DIV><SPAN class=858241016-28012005>
<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>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> discussion-request@nsrca.org
[mailto:discussion-request@nsrca.org]<B>On Behalf Of </B>David
Lockhart<BR><B>Sent:</B> Thursday, January 27, 2005 11:14 PM<BR><B>To:</B>
discussion@nsrca.org<BR><B>Subject:</B> Re: Snao G's<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Ed,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>A couple answers I can think of (and
I'm sure there are more possibilities) -</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>- Flight speed - for F3A at 150 meters, 100
mph is a pretty fast pace. 70-75 mph is on the the slow side. I
know I tend to fly at low 80s with my Vivats.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>- snap wasn't/isn't really a snap.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>- I do know of several planes coming apart on
either the 1.5 snap / 4/8 or the 1.25 snap / 1.25 opp roll in
F3A.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>- Most of the F3A flying I saw did have a reduced
entry speed to the 1.5 snap.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>- Average weight of F3A plane is lighter (but
same spar strength) resulting in less load on the tube/spar structure?
(compared to average weight of planes damaged to date on the Rev
Avalanche).</FONT></DIV><FONT face=Arial size=2>
<DIV><BR>Regards,</DIV>
<DIV> </DIV>
<DIV>Dave</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=divesplat@yahoo.com href="mailto:divesplat@yahoo.com">Ed Deaver</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, January 27, 2005 6:07
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Snao G's</DIV>
<DIV><BR></DIV>
<DIV>So, if I am interpreting these numbers(realize only one day and flight)
correctly. Beings the straight and level pos snap at 100mph(not
unusual speed) was -13G's and the Rev avalance at approximately 95mph was
-13G's, then the forces are about the same. </DIV>
<DIV> </DIV>
<DIV>So, if we can slow the rev avalanche down to 70mph then the G's would
only be -7. </DIV>
<DIV> </DIV>
<DIV>This seems to go along with previous arguments that speed is the
key.</DIV>
<DIV> </DIV>
<DIV>My question is, if the G's on flat and level snaps are approximately
the same, with approx equal speeds, as the rev snap, then why hasn't FAI
pilots been breaking planes with the 1.5snapopp 4/8???? </DIV>
<DIV> </DIV>
<DIV>Before anyone says it, I have seen many of these 1.5 snaps flown with
some speed, so they weren't just puttputt into it.</DIV>
<DIV> </DIV>
<DIV>Thanx Earl. Interesting stuff</DIV>
<DIV> </DIV>
<DIV>ed</DIV>
<DIV><BR><BR><B><I>Earl Haury <ehaury@houston.rr.com></I></B>
wrote:</DIV>
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<DIV><FONT face=Arial size=2>FWIW, I took a quick look at some snap G's
yesterday. Equipment was a Quique YAK (140 size) fitted with an Eagle Tree
Systems datalogger with G sensor. I only gathered data from one flight -
so take that into consideration.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Flat and level pos snaps @ (nominally)
100mph = 13G, dropping the speed to 70mph = 7G. (A normal pull to vertical
@ 100mph = 7G.)</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>An Avalanche with a neg snap at the top
measured -5G @ 50mph.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>A Rev Avalanche with a pos snap at the bottom
measured 13G @ 95mph. (Masters maneuver - intentionally flown
fast.)</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>An Avalanche from the top (push - F05) with a
neg snap and a half at the bottom measured -14G @ 90mph. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>(I normally measure around 5G on upline and
downline snaps with my Partner.)</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>All snaps were executed with rapid / high
degree elevator lead and % reduction of elevator during
rotation.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I may look at this further as the mood
strikes. As expected, controlling speed into snaps is easier on
your airplane. None of the observed loads (in my opinion) should damage a
well constructed aerobatic model (wouldn't want to ride in it
though).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial
size=2>Earl</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>