Carbon Fiber tube spar?

[Redster]

I'm building a new 2M sailplane and going to do glass on foam.I was wondering if I can use Carbon tube for spar coupled with the usual sparcap.In a way I'm trying to do a quick build and use the carbon tube spar to plug in the outer section(3 pc wings)Will this be strong enough for winch launch?Thank you for any advice on this mater...

Redster

[BMatthews]

If you're talking about using the usual caps on top and bottom such that the carbon tube is acting more as a web then I suppose it would work great. But why use carbon then? The caps would give you all the strength. You might as well go for a cheaper and possibly lighter glassfiber tube.

There's in between scenarios where the caps taper out to nothing and the tube could be the entire spar at the tips but basically yeah, it would work.

[flyfalcons]

CF Tubes are very strong for their weight. Just remember, though, that when you overstress an aluminum tube it will bend. A CF tube will snap clean in half.

[Shakey Jake]

Try carbon golf club shafts. Light, won't break under high stress, and are tapered. Even old used shafts are OK. Wrap a little glass at the butt end where you plug them in. If you break these you arn't flying a sail plane. You can get cheep ones from Golf Smith in Dallas TX if you look at the component parts for club builders. Usually around $7 or $8 ea.