US Patent 11292588 Helicopter with coaxial counter-rotating annular electric motor rotors

A helicopter includes annular electric motors surrounding a fuselage. Each annular electric motor includes an annular stator and an annular rotor. Rotor blades extend radially outwardly from each annular rotor. In an embodiment with two electric motors, one rotor rotates in one direction and the other rotor rotates in the opposite direction. A swash device with a grooved outer cylindrical surface engages the free end of a crank arm of each rotor blade to provide collective and cyclic pitch control. Actuators, which may be electromechanical or hydraulic, control positioning and movement of the swash device. Batteries, an electric generator and/or a hydrogen fuel cell may supply electric power.