An exemplary anti-torque system for a helicopter includes two or more electric fans rotatably mounted on a tail boom, the two or more electric fans rotatable about a longitudinal axis of the tail boom.

An exemplary electric distributed propulsion system includes two or more rotors that are individually controlled by the rotational speed of associated motors, an input control connected to the associated motors to provide rotational speed control to the two or more rotors to produce a desired net thrust, and a logic connected to the input control and the associated motors, the logic for controlling speed and direction of the two or more rotors to achieve the desired net thrust and to avoid a motor speed condition.

A hybrid rotor propulsion system includes a motor having a rotational output connected to a rotor and a prime mover connected to the motor through a rotational input, the prime mover configured to apply a rotational input speed to the motor.

An aircraft includes an airframe; an extending tail; a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly; and a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe; wherein a ratio of (i) the hub separation between the hub of the upper rotor assembly and the hub of the lower rotor assembly to (ii) a radius of the upper rotor assembly is between about 0.1 and about 0.135.

The present invention includes an a plurality of first variable speed motors arranged in a first matrix pattern and mounted on a tail boom of the helicopter; one or more fixed pitch blades attached to each of the plurality of first variable speed motors; and wherein a speed of one or more of the plurality of first variable speed motors is varied to provide an anti-torque thrust.

An aircraft is provided including an airframe, an extending tail, a counter-rotating, coaxial main rotor assembly having an upper rotor assembly and a lower rotor assembly, and a translational thrust system including a propeller positioned at the extending tail. The translational thrust system is configured to provide translational thrust to the airframe when the aircraft is in a non-autorotation state and to generate power when in an autorotation state. A gearbox interconnects the propeller and the main rotor assembly to drive the main rotor assembly and the translational thrust system in the non-autorotation state. When the aircraft is in autorotation, the power generated by the propeller drives rotation of the main rotor assembly via the gearbox.

An anti-torque system for a rotorcraft includes a first tail fan assembly including a plurality of first fan blades, a second tail fan assembly including a plurality of second fan blades and a motor adapted to provide torque to the first and second fan blades. The first fan blades have a larger rotational inertia than the second fan blades. The second fan blades are adapted to experience a larger angular acceleration than the first fan blades in response to torque from the motor, thereby providing responsive yaw control for the rotorcraft.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A horizontal stabilizer with a left elevator and right elevator positioned at the extending tail. A flight control computer to independently control one or more of the main rotor assembly and the elevator through a fly-by-wire control system. The flight control computer is configured to mix a collective pitch of the main rotor assembly and a deflection of the elevator.

A bidirectional aircraft rotor for a rotorcraft tail rotor. The rotorcraft tail rotor uses a hub and a first tail rotor blade affixed to the hub. A pitch of the first tail rotor blade is fixed, and a profile of a leading edge of the first tail rotor blade is identical to a profile of a trailing edge of the first tail rotor blade. The tail rotor is driven by a torque source, such as an electric motor or an engine. The tail rotor uses variable RPM and reversible rotational direction to provide rotorcraft with yaw control.

An aircraft includes an airframe having an extending tail, a counter rotating, coaxial main rotor assembly disposed at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the extending tail and providing translational thrust to the airframe, the translational thrust system including a propeller. A gearbox system is operably connected to the main rotor assembly and the propeller to drive rotation of the main rotor assembly and the propeller. The gearbox is configured to maintain a main rotor assembly tip speed below Mach 0.9 and a propeller helical tip speed below Mach 0.88.