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<DIV><FONT face=Arial size=2>A test on the tube by itself would not be a
very good way to assess the total load supporting strength of the wing tube
setup in our planes. The wing tubes loading carrying ability is determined
by the distribution along the sleeve and through the bearing surfaces at
the root rib and support rib at the end. The support rib and root
rib then spreads that load through the skin and to the leading edge if the
rib goes that far. The weakest point of the wing tube in the
setup is at the point between the fuse and root rib where it is really not
supported by anything even though this is a very small area.
Ideally to make the tube carry as much load as evenly as possible the
sleeve coming out of the fuse would protrude into the wing root rib and the
end of the tube at the root would also be supported at the same
spot. From some of the posts I have seen the support rib at the end of the
tube can be suspect also. So running the end support rib to the leading
edge for max. load spread. Since I have not been able to bend a wing tube
yet I think that the std method building the sleeve structure to be sufficient
enough. But then.... I have not flown 100 reverse avalanches to
date. If your are using an aluminum tube and have any doubts
by all means get a c.f. tube. Like Gray Fowler once posted if not twice,
the c.f tube will deflect and return its original position from being
stressed up to its failure point then it will just shatter but an aluminum
tube will just bend and stay at the point of deflection or bend to a folded
mess. The point between where the c.f. tube breaks and the aluminum tube
bends is significant enough to warrant using the c.f. tube....plus the c.f tube
is about half as light.... but you'all knew that.</FONT></DIV>
<DIV><FONT face=Arial size=2> Mike Dunphy did some testing on the
c.f tubes a while back and had some pretty interesting stats. Maybe he
would chime in here.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Wayne Galligan</FONT></DIV></DIV>
<BLOCKQUOTE dir=ltr
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=brianyemail-nsrca@yahoo.com
href="mailto:brianyemail-nsrca@yahoo.com">brianyemail-nsrca@yahoo.com</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 1:14
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: RE: Snao G's</DIV>
<DIV><BR></DIV>
<DIV>For the tube itself that load can be approximated by setting your tube
between two chairs resting your hands in the middle and raising yourself off
the floor, for me thats a 180lb load. </DIV>
<DIV> </DIV>
<DIV>I guess you could do the same test with your plane....... </DIV>
<DIV><BR><B><I><A
href="mailto:rcaerobob@cox.net">rcaerobob@cox.net</A></I></B> wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Yeaop.
That works out to about 147 lba (assuming a 10.5lb plane) distributed on
that 7/8" dia wing tube, with complete concentration of the G's likely at
the fuse/wing root intersection, with some load distribution laterally, but
I'd bet not much.<BR><BR>How many of us ever "test" our wing sockets to 150
lbs!!!!<BR>> <BR>> From: "Michael Laggis"
<FISHGOD@POBOX.MTAONLINE.NET><BR>> Date: 2005/01/27 Thu PM 01:51:34
EST<BR>> To: <DISCUSSION@NSRCA.ORG><BR>> Subject: RE: Snao G's<BR>>
<BR>> Very interesting.<BR>> <BR>> Michael Laggis<BR>> <BR>>
_____ <BR>> <BR>> From: discussion-request@nsrca.org
[mailto:discussion-request@nsrca.org] On<BR>> Behalf Of Earl
Haury<BR>> Sent: Thursday, January 27, 2005 9:40 AM<BR>> To:
Discussion List, NSRCA<BR>> Subject: Snao G's<BR>> <BR>> <BR>>
FWIW, I took a quick look at some snap G's yesterday. Equipment was a
Quique<BR>> YAK (140 size) fitted with an Eagle Tree Systems datalogger
with G sensor. I<BR>> only gathered data from one flight - so take that
into consideration.<BR>> <BR>> Flat and level pos snaps @ (nominally)
100mph = 13G, dropping the speed to<BR>> 70mph = 7G. (A normal pull to
vertical @ 100mph = 7G.)<BR>> <BR>> An Avalanche with a neg snap at
the top measured -5G @ 50mph.<BR>> <BR>> A Rev Avalanche with a pos
snap at the bottom measured 13G @ 95mph. (Masters<BR>> maneuver -
intentionally flown fast.)<BR>> <BR>> An Avalanche from the top (push
- F05) with a neg snap and a half at the<BR>> bottom measured -14G @
90mph. <BR>> <BR>> (I normally measure around 5G on upline and
downline snaps with my Partner.)<BR>> <BR>> All snaps were executed
with rapid / high degree elevator lead and %<BR>> reduction of elevator
during rotation.<BR>> <BR>> I may look at this further as the mood
strikes. As expected, controlling<BR>> speed into snaps is easier on your
airplane. None of the observed loads (in<BR>> my opinion) should damage a
well constructed aerobatic model (wouldn't want<BR>> to ride in it
though).<BR>> <BR>> Earl<BR>> <BR>> <BR><BR>Bob Pastorello, El
Reno, OK,
USA<BR>rcaerobob@cox.net<BR>www.rcaerobats.net<BR><BR>=================================================<BR>To
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