Today’s invention is another aerial vehicle (plan view on the right).
It consists of two horizontal drive shafts on each of which are placed a set of rotors (red).
At the rotors turn, their blade pitch is altered (perhaps by a cam on the shaft) so that as they descend on the outer side of the craft, they force air down and provide lift.
On the inner, upward part of their rotation, the blades are feathered so as to cause comparatively little vertical drag (their flat, front-facing blades are shielded from axial drag by being hidden within the body of the vehicle).
Each rotor could be made with numerous blades and each could be rotationally offset from its neighbour causing waves of lift.