A control horn arrangement includes a control horn body with an inboard end and an opposed outboard end. The control horn body defines a torque tube axis which extends between the inboard and outboard end of the control horn body. An inner flange and an outer flange are disposed on the outboard end of the control horn body. The inner flange and the outer flange extend about the torque tube axis and define between one another a receptacle to fix a torque tube to the outboard end of the control horn body.

A control horn arrangement includes a control horn body with an inboard end and an opposed outboard end. The control horn body defines a torque tube axis which extends between the inboard and outboard end of the control horn body. An inner flange and an outer flange are disposed on the outboard end of the control horn body. The inner flange and the outer flange extend about the torque tube axis and define between one another a receptacle to fix a torque tube to the outboard end of the control horn body.

A vertical take-off or landing (VTOL) aircraft is disclosed that includes a propulsion system comprising at least four tilting propulsion assemblies and two or more lifting propulsion assemblies. Actuation of the tilting mechanisms can convert the aircraft from a hover configuration, in which all propellers produce thrust generally upward to counteract the aircraft's weight, to a forward flight configuration, in which the four or more tilting propellers produce thrust generally in a forward direction parallel to the fuselage to overcome drag in cruise flight and the lifting propellers produce no thrust or a level of thrust generally less than that required in the hover configuration.

A vertical take-off or landing (VTOL) aircraft is disclosed that includes a propulsion system comprising at least four tilting propulsion assemblies and two or more lifting propulsion assemblies. Actuation of the tilting mechanisms can convert the aircraft from a hover configuration, in which all propellers produce thrust generally upward to counteract the aircraft's weight, to a forward flight configuration, in which the four or more tilting propellers produce thrust generally in a forward direction parallel to the fuselage to overcome drag in cruise flight and the lifting propellers produce no thrust or a level of thrust generally less than that required in the hover configuration.

A rotor hub system includes a rotor rotation axis, a flap hinge connected to the rotor rotation axis and enabling flapping motion of a rotor blade, a lead-lag hinge connected to the flap hinge and enabling lead-lag motion of the rotor blade, a first hub to which one end of the rotor blade is fixed, a rotating pitch control actuator connected to the first hub and rotating the first hub to enable pitching motion of the rotor blade, and a second hub equipped with the rotating pitch control actuator and hinged to the lead-lag hinge.

A rotor hub system includes a rotor rotation axis, a flap hinge connected to the rotor rotation axis and enabling flapping motion of a rotor blade, a lead-lag hinge connected to the flap hinge and enabling lead-lag motion of the rotor blade, a first hub to which one end of the rotor blade is fixed, a rotating pitch control actuator connected to the first hub and rotating the first hub to enable pitching motion of the rotor blade, and a second hub equipped with the rotating pitch control actuator and hinged to the lead-lag hinge.

An aircraft includes an airframe having an extending tail, and a counter rotating, coaxial main rotor assembly located at the airframe including an upper rotor assembly and a lower rotor assembly. A translational thrust system is positioned at the extending tail and providing translational thrust to the airframe. An active vibration control (AVC) system is located and the airframe and includes a plurality of AVC actuators configured to generate forces to dampen aircraft component vibration, and an AVC controller configured to transmit control signals to the plurality of AVC actuators thereby triggering force generation by the plurality of AVC actuators. A method of damping vibration of an aircraft includes receiving a vibration signal at an AVC controller, communicating a control signal from the AVC controller to a plurality of AVC actuators, generating a force at the AVC actuators, and damping vibration of the aircraft via the generated force.

A method of controlling noise of an aircraft includes storing a plurality of predefined noise modes; receiving a selection of a selected noise mode from the plurality of predefined noise modes, the selected noise mode identifying at least one operational parameter; and controlling the aircraft in response to the at least one operational parameter.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with an upper blade and a lower rotor assembly with a lower blade. A first antenna in one of upper blade and the lower blade, and a second antenna in the other of the upper blade and the lower blade. An oscillator to apply an excitation signal to the first antenna. A blade proximity monitor to monitor a magnitude of the excitation signal and an output signal from the second antenna to determine a distance between the upper blade and the lower blade.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with an upper blade and a lower rotor assembly with a lower blade. A first antenna in one of upper blade and the lower blade, and a second antenna in the other of the upper blade and the lower blade. An oscillator to apply an excitation signal to the first antenna. A blade proximity monitor to monitor a magnitude of the excitation signal and an output signal from the second antenna to determine a distance between the upper blade and the lower blade.