Originally Posted by
old,not bold
Very clever, but is it any better than a traditional rotor driven by an electric motor and battery? I would have thought that the energy needed to keep the ship airborne would be the same, whether delivered through multiple rotors or just the one?
I cannot answer your question regarding efficiency (other might be able to do so).
The key advantage of a multicopter is that the rotor system can use fix pitch propellers. So no need for any articulation. No collective pitch change, let alone cyclic pitch change.
Control about the roll and pitch axes are produced by differential variation of motor speeds across the propeller plane, while yaw control is via appropriate combinations of motor torques.
https://vtol.org/files/dmfile/08Evolo2.pdf
Presumably also no need to accommodate for lead, lag or dragging or hunting. That makes the whole system much less complex.