Anonymous wrote:
Glass fibres wet out more easily than do carbon, so itis no doubt easier to saturate the weave that is 'sewn' to link the slats on the inside of the tube. Major structural contribution of the carbon is in the lengthwise/longitudinal direction and the small amountt of added bulk that comes with some glass, is well worth it's practical value over a minor weight penalty.
I think glass is pretty much always a component of a carbon fiber mast. Carbon fiber is incredibly strong in tension and compression for it's weight, but need to be "contained", presumably in a cheaper material. These pultruded sections are unidirectional. I would presume that glass fabric or non-woven bidirectional glass would be laid on a bias to flesh the mast out. and provide some torsional strength as well as hold it's more or less round shape. The mast is not being built in a madrel, so vacuum bagging is not an alternative. Ultimately it would make more sense to build any additional structure inside rather than outside, as the tension / compression members need to be at the extremities, but that's not realistic.
The attraction of the pultruded material they are using is that it is rollable and in long strips. It's not the ideal material.... It's easy to work with obviously.
My idea of how to build a carbon fiber mast is to string a cable between two "dead men"..... Heavy stationary structures. Pieces of XPS foam would be strung on the cable, and glued together, and enough tension applied to hold the works straight. The foam core which is sacrificial, would then be shaped and smoothed, and any inner plies of material applied to it and vacuum bagged forming the permanent core. Carbon fiber in the form of unidirectional material such as roving would be applied with some tension, and held by epoxy compatible spray adhesive. You would apply the full length stuff, and then shorter and shorter material staggering things so there was no abrupt changes. This would then be saturated with resin and vacuum bagged. Once cured a protective outer glass layer on the bias would be applied and also vacuum bagged. At the end of the process, solvent would dissolve the XPS foam out and of course the cable would be removed leaving you with a full length tapered mast.
It would be a time consuming and expensive process, but nothing compared to the cost of buying a factory made mast. I'm not enthusiastic about the telescoping mast being built with straight sections. It's main virtue is that the construction is simple. I'm not sure how one would extend and retract it.... looks complex to me.
H.W.