In reality, that truss is not much (if at all) lighter than a larger truss spread out from the fuselage sides and triangulated. Structurally, the wider you can spread your material, the stronger and stiffer it is going to be. since we are needing a framework for the cloth covering anyway, it might as well be with the aluminum tubing.The two dimensional truss (like on the afford-a-plane), filled out w/lightweight formers/fabric seems like a relatively quick and simple way to build a fuselage as well as potentially light.
I am already looking for options for CNC tube cutting, possibly building our own. I like what Cartesian does Cartesian Tube Profiling â€“ Aircraft Kit Library but we need to be able to do it ourselves. Of course, if we use aluminum, we could always use oversized tube templates and simply use a spindle sander to get the proper profile shapes on both ends. Jig fixtures should be able to take care of everything else.
It's really hard for me to resist my infatuation with composites, and thus introduce design creep... "if only we did a composite tube... what about a composite empennage?... what do you mean it's too heavy?!?"