The above iteration is about as compact as you'll get and could be driven practically straight into the garage... a true flying carriage only seven-foot square.
Ironically it falls foul of the dimensions laid down for the GoFly challenge, which are fixed on radials, upon which basis its maximum diameter exceeds the 102 inches allowable.
The eight-foot square iteration below has a diameter of only 100 inches, meaning that the competitive model may yet be larger than the commercial product.
But I cannot complain, for though it needs tilting to get it out the garage it's altogether easier to build while being more aerodynamically efficient (because its overlapping disks feature only contra-rotating blades).
Although I am going on hunches, it's likely to be more efficient than any of the alternative configurations which feature stacked drones and will thus be submitted as the final draft.
But why is 4.2 the answer?
Because the alloy stockist retails 25 x 25 x 2mm sections in 4.20 metre lengths, and divided four ways (plus allowing for the cutting blade) this provides 41" spars.
Time to cut metal.
