The TeTra Mk. 5 is obviously not the first of its kind. A little history shows its origins in the Boeing GoFly completion – in which the team won a $100,000 “Disruptor” prize from Pratt & Whitney, the long-time engine makers. As stunning, and confusing, the appearance of their GoFly entry was, it did not prepare your editor for the 32-rotor (plus pusher propeller) single-seater shown flying in California recently. They flew SN2 of the Mk. 5 model in unpiloted mode, and will begin sales with serial number 3 at a yet unannounced price. One can speculate, though. Model aircraft motors such as the Hacker Q-100 cost 999 euros (about $1,163.00) each. (The makers have cleverly taped over the maker’s name on close-ups of the Oshkosh display model.) Even a lower-budget Chinese motor will cost around $500 each. An appropriate electronic speed controller (ESC) will be about half that of the motor. The 32-inch diameter carbon-fiber propellers would cost …