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.
I suppose you could even steer this like a helicopter: reduce the pitch of the front blades to lean forwards, lift, and you’ll move forwards. Reduce the pitch on the left and you’ll lean left. Fun.
Yes, thanks for the suggestion. One of the other problems with this, that only just occurred to me, is the intense dust storm which would get sucked up between the central blades when near the ground. Blade life might be a problem. If they were all stubbier and/or turning more slowly to protect them, you could compensate with a (much) longer vehicle…but then steering and stability might be impaired.
I just discovered this, which looks strangely familiar…
http://www.theengineer.co.uk/1009179.article?cmpid=TE01&cmptype=newsletter&cmpdate=010711&email=true