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<DIV><FONT face=Arial size=2><EM>This is a sort of public service announcement,
or at least please regard it as a "Heads-up".</EM></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>For all of you who are flying or will be flying the
Reverse Avalanche you might want to check your wing tubes and phenolic tube wing
supports.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>It seems that if you go into the snap a bit hard
you can bend your wing tube or, in the worst case scenario break, your wing. The
plane is pulling some G's at the bottom of the loop and then you add
more by putting in a lot of elevator to get a good break for the
snap.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Last year I had several incidents reported to me
and my initial reaction was to say that they were probably not flying the
maneuver correctly. <EM>"You need to slow the plane down at the bottom of the
loop",</EM> I said. I must add that what I said did not impress an FAI
and pilot and District masters champion very much. :-(</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>So strapping on my asbestos underwear I decided to
do some testing of my own. </FONT><FONT face=Arial size=2>At the end of
November 2004 it was nice here in NJ. I took the Focus-2 and the Temptation
out for a day of Masters 2005. Both planes were inspected for tube tightness and
the wing covering touched up with the glove-iron.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Twelve flights later and an average of 10 reverse
avalanches in each flight I went home thinking all was well. (It got cold and a
bit dark too).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Back in the shop the first thing that I
noticed was new wrinkles in the covering on the Temptation wings. Nothing
was loose. To test this I put the wing-tube in the wing and leaned on it a
little. All was well but I was beginning to think that the wing must
have flexed to cause the covering to loosen up. A bit like what the
covering sometimes does around the aileron horns. It this case it was at the
roots above the tubes - both sides.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Then I turned to the Focus-2 wings. Not good! The
wing-tube could now be moved up and down and I could hear foamy crunches in both
of the wings. </FONT><FONT face=Arial size=2>Both wings have Carbon tube wing
tubes and it dawned on me that they could not bend (much) or stay bent. That is
why I had not seen this before. The forces were applying themselves to the
ends of the wing tubes. I opened up both panels and added epoxy and micro
balloons to stabilize the sub ribs. It was an easy repair but could have been a
lot worse if I was not looking for it.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I am advised that stress damage is cumulative
and that it does not show up initially. It certainly had not revealed
itself while I had been demonstrating the 2005 schedule over the late summer of
2004. So where does this leave me? I think we have a potential problem
that requires frequent preventative equipment inspection depending upon the
planes that you fly. If you can slow down your plane and it is at around 10 lb
you may never see this happening.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG><U>I would strongly advise checking your
wing with the wing tube in place to look for tube movement. Also look for
straightness if you have an ali-wing-tube.</U></STRONG></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>This situation is a bit unique for me. It is the
first time I have been involved with a maneuver that you don't know you are
doing it wrong unless you fly it that way too many times. And then only if the
wing shows damage or even worse it breaks in the air.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV><FONT face=Arial size=2>
<DIV><BR>Eric Henderson.</DIV>
<DIV> </DIV>
<DIV>P.S. The only time I remember seeing a reverse avalanche before is in
the hardly flown? current FAI Finals
schedule.</FONT></DIV></BODY></HTML>