Wing building

[Ed Alt]

Hi Anthony:
I have to admit, I don't know it half ribs are commonly being left out now. 
I've only been doing this 2M pattern stuff a short time, so I did make an 
assumption that the common method to secure the socket was just like what I 
have seen in alot of big gas aerobats.  For whatever reason, it's common to 
use just a single light ply plate inside the opening cut in the core, 
nothing else.  I know that some builders do more to build up a better wing 
on those airplanes through various tcehniques, but this is the stock design 
I was used to seeing.  I used the stock design exactly once, almost lost a 
wing on a 35% Cap and never built another wing that way again.

I mentioned something in a followup post on RCU that the half rib or false 
rib is fine.  I didn't want to leave the impression that it's a big problem 
waiting to happen, but there are reasons why the box or "folded rib" is a 
little better.  Better in terms of really long, long service life without 
having to go inside for repairs in the first few hundred flights.  That's 
all I'm trying to get across.

Anyway, if someone wants this in K-Factor, I would be happy to help out. 
It's just one way of doing it.
Ed


----- Original Message ----- 
From: "Anthony Romano" <anthonyr105 at hotmail.com>
To: <discussion at nsrca.org>
Sent: Saturday, January 08, 2005 10:48 AM
Subject: Wing building


>
> Hi Ed,
> Good stuff. When we all flew retracts you used two half ribs that captered 
> the wing socket and based your landing gear mount. Now that we are all 
> flying fixed gear are we leaving this out?
>
> Please send these things in as Kfactor articles. We need to have more in 
> there than contest reports. Also, important to share this to the people 
> who are not connected.
>
> Anthony
>
>>From: "Ed Alt" <Ed_Alt at hotmail.com>
>>Reply-To: discussion at nsrca.org
>>To: <discussion at nsrca.org>
>>Subject: [SPAM] Re: 2005 Masters maneuver #4 - Warning
>>Date: Sat, 8 Jan 2005 00:36:49 -0500
>>
>>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=
>>
>>Regards
>>Ed
>>   ----- Original Message -----
>>   From: Grow Pattern
>>   To: 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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