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Old Mar 11, 2012, 01:52 AM
dwmumford is offline
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Bountiful, Utah
Joined Dec 2003
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Quote:
Originally Posted by Harjit View Post
Very nice info.

Can you post info. on what carbon fiber material you used in the tail, how you attached it, tips on working with it, etc.?

Also, how are the carbon fiber rod end finished? Do you CA them or?

Thanks,
Harjit
sure...the carbon fiber in the tail is also from CST Composites (CSTsales.com) as well as the carbon fiber push rods.

The carbon fiber in the tail is 1/2 inch by .07 thick. You simply order some and cut off what you need then I use the black rubber flexible CA by Bob Smith Industries that you can get at most hobby stores. It adheres to the carbon fiber very well. I put some weight on it and let it dry over night. Epoxy can also be used, but the rubberized CA seems to adhere the best.
The carbon fiber pushrods come in various diameters. I have used both .07 and .06 diameter rods and they both work well. the .06 is a little more flexible and easier to bend than the .07 but needs to be mechanically held in place more often (about every 4 or 5 inches) to eliminate any flexing or bowing. You can make these up yourself by purchasing the rods and rod ends at the hobby store, but then you don't get those nice teflon tubing that the rods slide in unless you order the rod kit from CST.

On one end of the carbon fiber rod is a 2-56 threaded end which is CA's ( again using the rubberized CA or you can use medium CA, which I did on a previous sailplane and it has also worked without ever coming loose). But CST now recommends using the rubberized CA. Then on the other end you CA the clevis or in my case I used the DuBro ball link. These rods need to be measured very carefully because once the ends are bonded thats it...they cannot be removed and the only adjustment is on the threaded end, so I try to measure the length so that the clevis that is put on the threaded end is about in the middle of the threads. That leaves me plenty of adjustment room. A steel clevis comes in the carbon rod kit, but I opted to use the DuBro ball link. At any rate the carbon fiber rods work very well because they keep the weight light. And any weight saved in the tail saves 4 times as much in the nose. Go to the CST sales web site and you can get lots of good information. the Carbon fiber in the tail (inside the fuse) will strengthen it. Ray Hayes (designer of this Big Bird kit) says go 3 or 4 inches aft of leading edge of Stab and 1 or 2 inches forward with 1/2 inch carbon fiber if you want extra strength. Hope that helps.

Dave
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