Abstract: A helicopter includes annular rotors surrounding a fuselage. Rotor blades extend radially outwardly from each annular rotor. One or more motors is provided. Each motor rotates a roller, which drives each annular rotor by traction. In an embodiment with two rotors, 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.

Abstract: 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.

Abstract: A helicopter includes a rotor with short blades and tip thrusters. The blades extend from an annular fuel tank that rotates with the blades. Centrifugal force propels fuel from the interior compartment of the annular tank, through conduits extending through the blades from root to tip, to the tip thrusters. Valves (e.g., solenoid valves and/or a flyweight governor) regulate fuel flow to achieve and maintain a determined steady rotational speed. A fuselage covered by a canopy is mounted atop a bearing on the annular fuel tank. The pitch of each blade may be adjusted collectively and cyclically using a swash ring and hydraulic linear actuators.