why isn't there composite tube fuselage design?

Shin Gou wrote:
I am just wondering...if composite materials are stronger and lighter
than steel, why composites tubes aren't glued together to form the
fuselage frame just like the traditional 4103 steel tubes being
welded
together? Any reasons?

Shin Gou
Rans S-9
Warrenton, VA

The better question would be why would you want to use carbon fiber to
build a tubular type framework? The real secret is to utilize the best
strengths of your material and design to that strength. There is no
technical limitation that would prevent using carbon fiber composite
tubes to create a tubular framework. The only limitation I can think
of is the joints for replacing the welded joints of the steel. That
could easily be solved by custom bondable carbon fiber joints. Clamps
could substitute for welded tabs and so on. One thing for certain, you
would never have to be concerned with rust.

One thing though, due to the very limited amount of composite vs steel
involved, you would not be saving a lot on weight.