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cubdriver2
11-26-2013, 04:40 PM
Carbon Cubs have had some broken tail wires. All the airplanes designs from the 1920s, 30s and 40s that had an adjustable tail for trim had the load attach point for the wires on the center of the stabilizer rear spar, which is the center hinge line for the stab. So that when the front of the stab is going up and down with trim changes it does not move the location of the wire attach point. The Carbon Cub moved the wire attach point to the stab/elevator hinge pin. That looked like a simple solution when I first looked at it but now I think it's going to be a problem area thats going to have to be redesigned by CC. I'm no engineer, what do you think?

http://i774.photobucket.com/albums/yy21/cubdriver2/005_zps14c052ca.jpg (http://s774.photobucket.com/user/cubdriver2/media/005_zps14c052ca.jpg.html)





This is what the brackets look like on the one with the broken wire.




http://www.j3-cub.com/forum/images/statusicon/wol_error.gif




http://i774.photobucket.com/albums/yy21/cubdriver2/002_zpsc27fa86c.jpg (http://www.j3-cub.com/forum/redirect-to/?redirect=http%3A%2F%2Fs774.photobucket.com%2Fuser %2Fcubdriver2%2Fmedia%2F002_zpsc27fa86c.jpg.html)






Just thinking, looking at this photo above, the hinge line for the elevator is just aft or off center of the rear spar for the stablizer. And the rear spar is the center line hinge point when the stab goes up and down when you trim. So as you trim the stab up the rear spar rotates CCW and the wire/elevator pin goes down pulling harder on the top wire and vise versa when the stab goes down.



http://www.j3-cub.com/forum/images/statusicon/wol_error.gif




http://i774.photobucket.com/albums/yy21/cubdriver2/004_zpsf5d807eb.jpg (http://www.j3-cub.com/forum/redirect-to/?redirect=http%3A%2F%2Fs774.photobucket.com%2Fuser %2Fcubdriver2%2Fmedia%2F004_zpsf5d807eb.jpg.html)

Glenn

pzinck
11-26-2013, 06:13 PM
This wasn't broken on a looping carbon cub ?

PerryB
11-26-2013, 08:36 PM
I'd like to know the official reasoning behind this design, because to my feeble mind it seems inferior to the original.

M1
11-26-2013, 09:10 PM
What is breaking? the wire, fitting or?

Den
11-26-2013, 09:27 PM
Haven't seen either broken yet, even with impacts. I would think the fitting would give first though.

8GCBC
11-26-2013, 09:41 PM
Nobody sent a SDR into FAA.

Query perform on my iPAD using "Chrome " 26-NOV;

Selected Unique Control # Operator
Designator Difficulty
Date N-Number Aircraft Make Aircraft Model JASC
Code
2009FA0000468 5/13/2009 866MM CUBCFT CC18180 7820
2007FA0000890 9/11/2007 787AK CUBCFT CC11100 8530
2007FA0000889 9/11/2007 787AK CUBCFT CC11100 8530
2011FA0000668 9/26/2011 907CF CUBCFT CC18180 2562
2011FA0000131 2/10/2011 907CF CUBCFT CC18180 7322
2013FA0000413 7/17/2013 527CC CUBCFT CC18180 2730
2013FA0000414 6/26/2013 618CC CUBCFT CC18180 2720

Den
11-26-2013, 10:01 PM
Nobody sent a SDR into FAA.

Query perform on my iPAD using "Chrome " 26-NOV;

Selected Unique Control # Operator
Designator Difficulty
Date N-Number Aircraft Make Aircraft Model JASC
Code
2009FA0000468 5/13/2009 866MM CUBCFT CC18180 7820
2007FA0000890 9/11/2007 787AK CUBCFT CC11100 8530
2007FA0000889 9/11/2007 787AK CUBCFT CC11100 8530
2011FA0000668 9/26/2011 907CF CUBCFT CC18180 2562
2011FA0000131 2/10/2011 907CF CUBCFT CC18180 7322
2013FA0000413 7/17/2013 527CC CUBCFT CC18180 2730
2013FA0000414 6/26/2013 618CC CUBCFT CC18180 2720


I just checked the SDR and the query format doesn't even have the carbon cub as an option. The carbon cub is CC11-160. The CC18-180 is for the Top cub, the only certified aircraft. I am guessing that SLSAs are not part of the SDR program, Are we talking about top cubs or carbon cubs having broken wires????

8GCBC
11-26-2013, 10:18 PM
All Cubcrafters SDRs. Experimental/LSA included. I thought.

cubdriver2
11-26-2013, 10:49 PM
www.cubcrafters.com/pdfs/sc/sa0009.pdf

Glenn

bob turner
11-26-2013, 11:00 PM
How does it fly with a broken wire? I assume good enough to get back home?

8GCBC
11-26-2013, 11:17 PM
The SB is only 3 days old. Replacement Part TBD.

Steve Pierce
11-27-2013, 09:16 AM
I'd like to know the official reasoning behind this design, because to my feeble mind it seems inferior to the original.

Less parts count, easier to build, lighter?

randylervold
11-28-2013, 10:04 AM
Yes indeed, we just issued a Safety Alert for our CC11 (Sport Cub, Carbon Cub) tail wires. For anyone interested the full story can be found here (http://www.cubcraftersforums.com/showthread.php/1554-SA0009-Release). For those curious for more of the technical go to post #21 from our director of engineering.

Bill Rusk
11-28-2013, 10:35 AM
Once again I am favorably impressed by Cub Crafters.

Bill

evroosevelt
11-28-2013, 10:07 PM
The Carbon Cub EX kit planes are not affected by this problem as our wires are installed just like a Super Cub.
EV