The present invention includes an electric distributed propulsion for anti-torque modules for a helicopter and methods of use comprising: two or more generators connected to a main gearbox transmission; at least a first and a second plurality of variable speed motors connected to one or more fixed pitch blades to provide anti-torque thrust connected to the two or more generators, and at least a first and a second yaw control computer independently connected to each of the at least first and second plurality of variable speed motors, wherein each of the first and second yaw control computer serves as a primary and a backup yaw control computer to provide redundant control to both the first and second plurality of variable speed motors.

A system and method for slowing the rotation of a rotor using, for example, rotor brake system for a rotorcraft comprises: one or more generators connected to a main rotor gearbox; an electric distributed anti-torque system mounted on a tail boom of the rotorcraft comprising two or more electric motors connected to the one or more generators, wherein the two or more electric motors are connected to one or more blades; and wherein a rotation of the rotor is slowed by placing a drive load on the main rotor gearbox with the one or more generators to bleed the mechanical power from rotor into electrical power via the two or more electric motors, wherein the electric distributed anti-torque system generates thrust in opposing directions.

An unmanned aircraft system has a vertical takeoff and landing flight mode and a forward flight mode. The unmanned aircraft system includes an airframe, a rotor assembly rotatably coupled to the airframe and a propeller rotatably coupled to the airframe. The rotor assembly including at least two rotor blades having tip jets that are operably associated with a compressed gas power system. The propeller is operably associated with an electric power system. In the vertical takeoff and landing flight mode, compressed gas from the compressed gas power system is discharged through the tip jets to rotate the rotor assembly and generate vertical lift. In the forward flight mode, the electric power system drives the propeller to generate forward thrust and autorotation of the rotor assembly generates vertical lift.

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.

A rotorcraft capable of a hover mode and a forward cruise mode including a fuselage, a first electric propulsion system, a second electric propulsion system, and an electric power control unit to control power to the first and second electric propulsion systems in the hover and forward cruise modes. The first electric propulsion system is a tip jet cold flow system that imparts rotation on a pair of rotor blades disposed above a top surface of the fuselage, and a first electric motor configured to drive the tip jet cold flow system. The second electric propulsion system includes a propeller disposed in the rear of the fuselage and a second electric motor configured to drive the propeller.

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 vehicle with superior performance and reliability. The vehicle, such as an unmanned aerial vehicle, is capable of vertical takeoff and landing, uses three swashless, variable-pitch vertical lift main rotors with a yaw tail rotor system. Two rear main rotors are optionally tiltrotors, which pivot to increase forward speed without the increased coefficient of drag inherent in tilting the entire vehicle. The three main rotors are positioned in an equilateral triangular configuration, improving balance, increasing load-bearing strength, and making it more compact in size. Movements are controlled through changes in pitch of the rotors, allowing the motors to maintain constant governed rotations per minute, maximizing drivetrain efficiency. Various embodiments allow for smaller vehicle size with greater performance than prior art vehicles.