[SPAM] Re: 2005 Masters maneuver #4 - Warning

[Bill Glaze]

Ed:
Very clear, coherent article.  Thanks.  Bill Glaze

Ed Alt wrote:

> OK, here's the link to a thread I just started on RCU re. the little 
> tube socket box I mentioned earlier.  Use it if you like the idea, I 
> find that it helps.
>  
> http://www.rcuniverse.com/forum/m.asp?m=2514871&mpage=1&key 
> <http://www.rcuniverse.com/forum/m.asp?m=2514871&mpage=1&key>=
>  
> Regards
> Ed
>
>     ----- Original Message -----
>     From: Grow Pattern <mailto:pattern4u at comcast.net>
>     To: discussion at nsrca.org <mailto:discussion at nsrca.org>
>     Sent: Friday, January 07, 2005 7:40 PM
>     Subject: 2005 Masters maneuver #4 - Warning
>
>     This is a sort of public service announcement, or at least please
>     regard it as a "Heads-up".
>      
>     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.
>      
>     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.
>      
>     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. "You need to slow the plane down at the bottom
>     of the loop", I said. I must add that what I said did not
>     impress an FAI and pilot and District masters champion very much. :-(
>      
>     So strapping on my asbestos underwear I decided to do some testing
>     of my own. 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.
>      
>     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).
>      
>     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.
>      
>     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. 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.
>      
>     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.
>      
>     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.
>      
>     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.
>      
>     Regards,
>
>     Eric Henderson.
>      
>     P.S. The only time I remember seeing a reverse avalanche before is
>     in the hardly flown? current FAI Finals schedule.
>
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