This disclosure describes a configuration of an unmanned aerial vehicle (UAV) that includes a frame that provides structural support for the UAV, protection from foreign objects that may come into contact with the UAV, and protection from precipitation so that the UAV can be used in a wide range of weather conditions. The UAV may have any number of lifting motors. For example, the UAV may include four lifting motors (also known as a quad-copter).

The vibration suppression system includes a vibration isolator located in each corner in a four corner pylon mount structural assembly. The combination of four vibration isolators, two being forward of the transmission, and two being aft of the transmission, collectively are effective at isolating main rotor vertical shear, pitch moment, as well as roll moment induced vibrations. Each opposing pair of vibration isolators can efficiently react against the moment oscillations because the moment can be decomposed into two antagonistic vertical oscillations at each vibration isolator. A pylon structure extends between a pair of vibration isolators thereby allowing the vibration isolators to be spaced a away from a vibrating body to provide increased control.

An aircraft includes a wing positioned below a vertical rotor, the wing extending in a transverse direction to a wingtip having an outboard face, and a turbulence feature located on the wingtip and oriented to induce turbulence in the rotor downwash flowing across the outboard face in a direction from a top surface of the wing to a bottom surface of the wing.

An oscillating pump system includes a pump operable to circulate a fluid. The pump has a first port stage including an inlet port and an outlet port and a second port stage including a first oscillating port and a second oscillating port. An oscillator disk is disposed between the first port stage and the second port stage. The oscillator disk is rotatable relative to the inlet port, the outlet port, the first oscillating port and the second oscillating port. During rotation, the oscillator disk alternatingly routes the fluid to the inlet port from the first and second oscillating ports and alternatingly routes the fluid from the outlet port to the first and second oscillating ports, thereby generating oscillating fluid flow.

A piston for use in a liquid inertia vibration elimination (LIVE) system. The piston includes a port that extends from a first end of the piston to an opposite second end of the piston, wherein a length of the port is longer than a length between the first and second ends of the piston.

One example of a mount for a rotorcraft comprises a structural support member, a bracket, and an elastomer. The bracket is configured to attach to a component of the rotorcraft. The component of the rotorcraft produces vibrations at a first frequency. The structural support member configured to transfer a weight of the component of a rotorcraft to an airframe of the rotorcraft. A rotor system of the aircraft vibrates the airframe of the rotorcraft at a second frequency. The elastomer is located between a structural support member and a bracket. The elastomer is configured to attenuate noise caused by the vibrations at the first frequency by isolating the vibrations at the first frequency from reaching the airframe of the rotorcraft while the airframe vibrates at the second frequency.

A compound helicopter includes a fuselage including a fuselage airframe, a translational thrust system coupled to the fuselage airframe and a pylon assembly subject to vibration. The pylon assembly includes a transmission and a rotor system having a main rotor assembly. The compound helicopter also includes a main rotor vibration isolation system including a plurality of augmented liquid inertia vibration eliminator units each having an isolation frequency and each coupled between the fuselage airframe and the pylon assembly to reduce transmission of the pylon assembly vibration to the fuselage airframe at the isolation frequency. Each augmented liquid inertia vibration eliminator unit includes at least one active tuning element movable to tune the isolation frequency thereof.

A resonator provided with a heavy member comprising a casing fastened a spring blade. The heavy member comprises a set of masses that is movable in translation in said casing along a longitudinal direction. A wormscrew driven by drive means is engaged in a slider nut of said set of masses. The set of masses comprises two masses that are slidable respectively in two cylindrical spaces of the casing. Each mass presents at least two presser means interposed between the mass and the casing, each presser means comprising a groove formed in a circumference of a mass, each presser means comprising at least one resilient member arranged in said groove and a split ring pressed against the casing by said at least one resilient member of the presser means.

A rotary wing aircraft includes a rotor system rotatable about an axis relative to an airframe. A plurality of blade assemblies is mounted to the rotor system. A higher harmonic control system is operable to generate a harmonic load at the rotor system according to a higher harmonic control signal. An active vibration control system is operable to generate vibration forces about the aircraft according to an active vibration control signal. A controller is operable to issue the higher harmonic control signal and the active vibration control signal to coordinate the higher harmonic control system and the active vibration control system to reduce vibration within the airframe.

A vibration isolating device that is adapted for an elastic coupling of a first component to a second component and for vibration isolation in predetermined frequency ranges between the first and second components, the vibration isolating device comprising at least a first and a second elastically deformable plate that are attached to each other in at least two separate connecting points, the first elastically deformable plate comprising a first curvature and the second elastically deformable plate comprising a second curvature, wherein the first and second curvatures are respectively located in a region between the at least two separate connecting points and arranged such that a gap is defined between the first and second elastically deformable plates.