Really curious how that thing generates torque since it doesn't have asymmetric props.

edit: I'm dumb, it has gimbaled props. That makes OP's link much more impressive, since that thing doesn't require gimballing which is expensive.

yea there is another top level comment by gtirloni which links to a different example which does it without a gimbal, by applying a sinusoidal current with variable amplitude and phase to the motors. They have symmetric rotors though, so your question applies there! I wonder if maybe the rotors are in fact slightly asymmetric and just look symmetrical.

edit: I got it, this is super neat: The blades are hinged at a 45 degree angle, but in opposite directions. See Figure 1 and 2 here

http://www.modlabupenn.org/wp-content/uploads/paulos_an_unde...

Yeah, that still requires moving parts on the rotor. OPs design requires no additional moving parts. I like it.

> Seems more sensible to me to do it that way,

The interesting part to me of the OP's design is it has only two identical moving parts.

Adding 2 * 2 DOF gimbals is four more actuators to go wrong, for a total of 6. That flight demo is pretty nice, though.

Opposing rotors is a proven helicopter design, https://en.wikipedia.org/wiki/Coaxial_rotors

By placing the rotor under the vehicle you remove the mechanical complexity of the rotor but you don't have any way to land... Unless your landing gear is as wide as the rotor and extending around it, or some kind of arm catching the whole vehicle from the side.

Interesting. Watching it move, I wonder if copters like this would be better suited for things like navigating through trees and forests. Small quads can do it too but these should be able to do it while carrying larger payloads.