An anti-torque system for a rotorcraft includes a first tail fan assembly including a plurality of first fan blades and a second tail fan assembly including a plurality of second fan blades. The first tail fan assembly has a larger diameter than the second tail fan assembly. The first fan blades have a larger rotational inertia than the second fan blades such that the second fan blades experience a larger angular acceleration than the first fan blades in response to torque, thereby providing yaw control for the rotorcraft.

According to an example embodiment there is provided an unmanned aerial vehicle (UAV), the UAV including: a first rotor, the first rotor having a diameter and a first number of blades; and a second rotor, the second rotor having a diameter and a second number of blades; wherein the first and second rotor are substantially coaxial; and wherein the first number and the second number are not the same number and are both more than one.

A control circuitry includes a propulsor trim prediction circuitry configured to generate a predicted propulsor collective blade pitch trim value for a target state of an aircraft based on an aircraft velocity and a pitch attitude deviation from a reference. The control circuitry further includes an output circuitry configured to output a propulsor collective blade pitch angle command based on the predicted propulsor collective blade pitch trim value. The propulsor collective blade pitch angle command is configured to cause an adjustment in a blade pitch angle of a propulsor of the aircraft. Additionally or alternatively, the control circuitry includes a pitch attitude trim prediction circuitry configured to generate a predicted pitch attitude trim value. The output circuitry is configured to output an aircraft pitch attitude trim command, configured to cause an adjustment in a pitch angle of the aircraft, based on the predicted pitch attitude trim value.

An anti-torque system (10) for a helicopter (1) is described that comprises: an electric power supply unit (15); at least one first rotor (17), operatively connected to an electric power supply unit (15) and operable by the electric power supply unit (15) so as to rotate with a first variable angular speed; and at least one second rotor (25) operatively connected to electric power supply unit (15) and operable by the electric power supply unit (15) so as to rotate with a second variable angular speed.

Flight control method, flight control device, and multi-rotor unmanned aerial vehicle are provided. The vehicle includes a center frame, a carrier, arms, and a propulsion assembly on each arm. Each propulsion assembly includes a forward-rotating rotor, a counter-rotating rotor, a first driving device, and a second driving device. The method includes: determining a current attitude of the vehicle including a normal flight attitude with the carrier at a lower side of the center frame and an inverted flight attitude with the carrier at an upper side of the center frame; and adjusting vertical arrangement positions of the forward-rotating rotor and the counter-rotating rotor in the direction of the yaw axis according to the current attitude of the vehicle, such that the vertical arrangement positions of the forward-rotating rotor and the counter-rotating rotor remain unchanged, and each rotor maintains a state of pushing down airflow when the rotor rotates.

A differential thrust vectoring system including a first thruster rotation assembly configured to rotate a first thruster relative of an aircraft, a second thruster rotation assembly configured to rotate a second thruster of an aircraft, and an actuator. The system is configured such that actuation of the actuator causes disparate rotation about the tilt axis of the first and second thrusters.

An exemplary tail rotor includes a first blade assembly configured to rotate in a first direction about an axis of rotation and a second blade assembly configured to rotate in a second direction about the axis of rotation.

A pusher rotorcraft is provided in one example embodiment and may include at least one engine in mechanical communication with a drop-down gearbox; a driveshaft in mechanical communication with the drop-down gearbox, a main rotor gearbox, and a tail system gearbox; a main rotor system in mechanical communication with the main rotor gearbox; an anti-torque system in mechanical communication with the tail system gearbox; and a pusher propeller system in mechanical communication with the tail system gearbox.

An electrically distributed yaw control system for a helicopter having a tailboom and a power system includes one or more tail rotors including a motor rotatably coupled to the tailboom and a power distribution unit. The power distribution unit includes a power management monitoring module configured to monitor one or more flight parameters of the helicopter and a power management command module configured to allocate power between the power system and the one or more tail rotor motors based on the one or more flight parameters of the helicopter.

A parking tail rotor for a rotary wing aircraft stops rotating at a high forward aircraft speed when aircraft control surfaces have adequate control authority to balance main rotor torque without the rotating tail rotor. When stopped, the blades of the parking tail rotor move due to the force of the relative wind to a parked position in which the span of the blades extend in the aft direction, reducing air resistance to the forward motion of the aircraft.