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<DIV><FONT face=Arial size=2>Dean</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Presently I've the sample rate set to 10/sec so as
to log an entire P05 (speed, altitude, volts, aileron, G). Snap duration
is on the order of 0.6sec and there's typically only one data point at the max,
before mid-snap, it appears that the "spike" ramp up-down is on the order of
0.2sec, and yes - the remainder is half or less. We shouldn't read too much into
this quick look. For the next session I plan to increase the sample rate (40/sec
available) so that the load profile is more quantifiable during a snap. Keep the
thinking cap on - I welcome the brain storming.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Earl</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=d.pappas@kodeos.com href="mailto:d.pappas@kodeos.com">Dean Pappas</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> Friday, January 28, 2005 10:23
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: Snao G's</DIV>
<DIV><BR></DIV>
<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></BLOCKQUOTE></BODY></HTML>