A device to verify main rotor swashplate positioning includes an inner surface of a first section and a gradient surface of a second section. The gradient surface of the second section may have a plurality of graduation indications. In one implementation, the inner surface of the first section at least partially defines a travel arc that is parallel to and concentric with the inner surface. In such an implementation, the device may be configured to move along the travel arc as it rotates about a collective sleeve to contact a swashplate lug.

A device to verify tail rotor cross-head positioning is disclosed. The device comprises a first portion and a second portion. The second portion may be adjoined to the first portion and comprises maximum and minimum surfaces configured to determine whether a yoke-measuring surface of a tail rotor yoke may be positioned between respective geometric planes of the maximum and minimum surfaces.

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.

Rotary motion sensing systems are well-suited for integration in a bearing system of a rotary aircraft to provide information about the operational state of the rotor blades of the aircraft. In some embodiments, sensors are positioned on lateral sides of an elastomeric bearing system and output signals which may be processed to calculate one or more rotor blade operational states. The operational states include, for example, flap angle, lead-lag angle, and pitch angle. In other embodiments, sensors may be distributed along at least a portion of the length of a rotor blade to detect deflection of the rotor blade or its impact with another object. The operational state of the rotor blades may be transmitted to the pilot and/or the flight control computer of the aircraft in order for corrective action to be taken and/or may be stored within a control box for later review.

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.

A rotor blade deflection sensing system including a rotor blade having a first surface, a second surface, a third surface and a fourth surface. At least two fiber optic sensor arrays are mounted to the rotor blade. At least one of the at least two fiber optic sensor arrays is mounted to one of the first surface, the second surface, the third surface and the fourth surface and another of the at least two fiber optic sensor arrays being mounted to another of the first surface, a second surface, a third surface and a fourth surface. A controller is operatively connected to the at least two fiber optic sensor arrays. The controller determines one or more of a flapwise and an edgewise displacement based on inputs from the at least two fiber optic sensor arrays.

An unmanned aerial vehicle includes a body, a plurality of cantilevers and a plurality of driving components. Each cantilever has a first end and a second end. Each first end is opposite to the corresponding second end. The first ends are connected to the body. The driving components are respectively connected to the second ends of the cantilevers. Each driving component includes a motor and a plurality of paddles. The motor has a shaft. The propeller is connected to the shaft and includes a balance disc and a plurality of paddles. The balance disc is connected to the motor. The paddles are connected to the balance disc. The balance disc has a plurality of counterweight holes. The counterweight holes are used to be disposed with the at least one counterweight block. A propeller is also provided.

This invention provides convenient airframe vibration, tracking, and acoustic improvements of a helicopter rotor blade by use of a profile system. The profile system is designed to minimize acoustic disturbances as air passes the airfoil. The profile may be attached through an adhesive system that allows convenient removal and relocation for use by the helicopter manufacturer or by the helicopter operator in a field environment.

A rotor blade is provided that includes an airfoil extending spanwise from a base to a tip. The airfoil extends longitudinally (e.g., chordwise) from a leading edge to a trailing edge. The airfoil extends laterally between a first side and a second side. The airfoil includes a body and a weight. The body includes a plurality of body layers. Each of the body layers includes fiber reinforcement within a body thermoplastic matrix. The weight includes a weight layer embedded within the body. The weight layer includes metal powder within a weight thermoplastic matrix.