Abstract: A tail rotor system for an aircraft includes a tail rotor hub, a tail rotor drive shaft mechanically connected to the tail rotor hub, and an electric motor coupled to the tail rotor drive shaft.

Abstract: An external cargo damping system includes lifting gear and a damping assembly. The lifting gear has a lifting body attachment end and an opposed external cargo end, and defines a load path that extends between the lifting body attachment and external cargo ends of the lifting gear. The damping assembly is connected in series with the lifting gear and is disposed along the load path to damp vibratory force transmitted between the lifting gear lifting body attachment and lifting gear ends.

Abstract: A rotorcraft control system can include a controller configured to receive an input from a pilot or autopilot for controlling at least one of a rotor and/or a performance profile of the rotorcraft and to control a propulsor as a function of the input for controlling the propulsor relative to the rotor and/or for achieving the input performance profile, wherein the controller is configured to fly the aircraft in accordance with the performance profile or to conform manual control inputs to the performance profile.

Abstract: A touchdown control system for a vertical take-off and landing (VTOL) aircraft including a detection controller receptive to aircraft state signals including one or more of an altitude signal, an aircraft attitude signal, an external environment signal, an aircraft velocity signal, an attitude rate signal, and a proximity signal. An enable controller is operatively connected to the detection controller. The enable controller selectively provides a touchdown control signal based on one or more of the altitude signal, the aircraft attitude signal, the external environment signal, the aircraft velocity signal, the attitude rate signal, and the proximity signal. A regulation controller is operatively connected to the enable controller. The regulation controller selectively adjusts aircraft control surfaces based on the touchdown control signal to facilitate final touchdown of the VTOL aircraft.

Abstract: A touchdown control system for a vertical take-off and landing (VTOL) aircraft including a detection controller receptive to aircraft state signals including one or more of an altitude signal, an aircraft attitude signal, an external environment signal, an aircraft velocity signal, an attitude rate signal, and a proximity signal. An enable controller is operatively connected to the detection controller. The enable controller selectively provides a touchdown control signal based on one or more of the altitude signal, the aircraft attitude signal, the external environment signal, the aircraft velocity signal, the attitude rate signal, and the proximity signal. A regulation controller is operatively connected to the enable controller. The regulation controller selectively adjusts aircraft control surfaces based on the touchdown control signal to facilitate final touchdown of the VTOL aircraft.

Abstract: A method of rotorcraft state control includes receiving command input indicative of an intended state change in a rotorcraft. The method also includes issuing command output to a rotor actuation system to carry out the intended state change by varying drag and/or efficiency on one or more rotor blades of the rotorcraft. Issuing command output can include issuing a command output to the rotor actuation system to carry out the intended state change by increasing drag at a substantially constant thrust on one or more rotor blades of the rotorcraft.

Abstract: A method of rotorcraft state control includes receiving command input indicative of an intended state change in a rotorcraft. The method also includes issuing command output to a rotor actuation system to carry out the intended state change by varying drag and/or efficiency on one or more rotor blades of the rotorcraft. Issuing command output can include issuing a command output to the rotor actuation system to carry out the intended state change by increasing drag at a substantially constant thrust on one or more rotor blades of the rotorcraft.

Abstract: A helicopter includes a tail rotor, a primary drive system operatively connected to the tail rotor, and a secondary drive system operative connected to the tail rotor. The secondary drive system is configured to supplement torque provided to the tail rotor by the primary drive system. Related tail rotor drive systems and methods of applying torque to tail rotors are also described.

Abstract: An external cargo damping system includes lifting gear and a damping assembly. The lifting gear has a lifting body attachment end and an opposed external cargo end, and defines a load path that extends between the lifting body attachment and external cargo ends of the lifting gear. The damping assembly is connected in series with the lifting gear and is disposed along the load path to damp vibratory force transmitted between the lifting gear lifting body attachment and lifting gear ends.