A control circuitry includes a first filter configured to filter a gravity compensated longitudinal acceleration of an aircraft to generate a filtered gravity compensated longitudinal acceleration. The propulsor trim control circuitry also includes a second filter configured to generate a filtered speed of the aircraft based on a speed of the aircraft. The propulsor trim control circuitry includes intermediary circuitry configured to generate a filtered longitudinal control effector error based on the filtered gravity compensated longitudinal acceleration and the speed. The propulsor trim control circuitry also includes a third filter configured to generate a filtered longitudinal thrust effector command value based on a longitudinal thrust effector command value. The propulsor trim control circuitry further includes output circuitry configured to generate a predicted longitudinal thrust effector trim value for a target horizontal state based on the filtered longitudinal control effector error and the filtered longitudinal thrust effector command value.

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.

The present invention includes an anti-torque assembly for a helicopter comprising a plurality of fixed blade pitch motors mounted on one or more pivots on the tail boom of the helicopter, wherein the plurality of fixed blade pitch motors on the one or more pivots are adapted to be oriented substantially in-plane with a tail boom of a helicopter during a first mode of operation that comprises a hover mode and wherein the fixed blade pitch motors are adapted to be oriented substantially off-plane from the tail boom of the helicopter during a second mode of helicopter operation that is different from the first mode.

A rotor system including a hub; a rim configured to rotate about the hub, the rim including an interior surface and an engagement surface; a plurality of rotor blades extending from the hub and coupled to the interior surface of the rim; and one or more outer drive gears disposed adjacent to the engagement surface of the rim; each of the one or more outer drive gears including a plurality of teeth for engaging the engagement surface of the rim; wherein the one or more outer drive gears are configured to rotate the rim such that the plurality of rotor blades rotates about the hub. Other aspects provide an aircraft rotor system and methods of operating an aircraft rotor system.

A propulsion system comprising independent rotor sub-systems producing a thrust force of a desired magnitude in any desired radial direction from the center of the propulsion system, driven from a single driveshaft that may be fixed in its position in the vehicle. When the propulsion system is fitted, for example, to a single-main-rotor helicopter in place of the convention anti-torque tail rotor, the helicopter is thereby equipped with a propulsion system that can produce yaw, pitch, the anti-torque lateral thrust for stability in hover, aft thrust or drag as well as the direct forward thrust that will enable the helicopter to fly at higher speeds. The propulsion system may also be applied in other aeronautical systems as well as to marine and industrial systems to impart energy into a fluid and thereby induce movement in that fluid.

There is provided a rotorcraft, including a body, including a front portion and a tail portion; a main rotor system coupled to the front portion of the body, the main rotor system operable to provide a lifting force on the body; and an anti-torque system coupled to the tail portion of the body, the anti-torque system including a primary tail rotor system and a secondary tail rotor system; wherein the primary tail rotor system and the secondary tail rotor system are operable to provide a first anti-torque force and a second anti-torque force. In other aspects, there are methods of providing anti-torque force in a rotorcraft.

A rotor system including a hub; a rim configured to rotate about the hub, the rim including an interior surface and an engagement surface; a plurality of rotor blades extending from the hub and coupled to the interior surface of the rim; and one or more outer drive gears disposed adjacent to the engagement surface of the rim; each of the one or more outer drive gears including a plurality of teeth for engaging the engagement surface of the rim; wherein the one or more outer drive gears are configured to rotate the rim such that the plurality of rotor blades rotates about the hub. Other aspects provide an aircraft rotor system and methods of operating an aircraft rotor system.

A vertical take-off and landing (VTOL) aircraft (10) comprises a fuselage (24) first and second forward wings (20, 22) and first and second rearward wings (30, 32), each wing having a fixed leading edge (25, 35) and a trailing control surface (50) which is pivotal about a generally horizontal axis. Electric rotors (60) are mounted to the wings (20, 22, 30, 32), the electric rotors (60) being pivotal with the trailing control surface (50) between a first position in which each rotor (60) has a generally vertical axis of rotation, and a second position in which each rotor (60) has a generally horizontal axis of rotation; wherein at least one of the wings (20, 22, 30, 32) has a first and a second electric rotor (60) which are each mounted having non-parallel axes of rotation so that the thrust lines of the first and second electric rotors are different.