Here's the modified airframe out in the sunshine with a vastly simplified seat support to which an office chair is clipped using conduit clamps. Note the removable stubs at each corner, which form hard-points for suspending the air vehicle from museum ceilings, for example, or indeed for fitting longer legs so that it can be transported on a flat deck inverted.
Also a feature now are the carry-handles at each corner, which also allow the airframe to be stood upright against the garage wall for storage without damaging the motor or propeller nearest the floor. Note too the 'lunar-landing' feet, which are easily swapped out for either skids or floats.
This five-foot frame weighs under thirty pounds, and soon we can estimate the basic weight of the vehicle fitted with U15 motors, ESCs, 40" propellers and battery packs. Its 1/16th inch alloy tubing supports my hundred-sixty pounds too, albeit with a degree of flexure that could be expected at this gauge.
Three ways of improving the stiffness of the airframe would be to sub a thicker tubing, switch to carbon-fibre or to reduce the outline from 60" to nearer 50" by choosing 36" propellers over 40". I reject all of these at this stage because:
(a) adds to weight and does not allow the snuggest fit of tube-connectors
(b) is inordinately expensive and does not allow for rapid prototyping
(c) worsens both ergonomics and aerodynamics (and thus endurance).
Beside this, a five-foot frame is also 1.50 metres, which suits US and global needs.
