Embodiments disclosed herein present a spring system for use in a torque dependent rotor assembly designed to operate in resonance, where changes in applied torque controls the blade pitch angle and ultimately the movements of a rotary wing aircraft. More specifically, the present invention relates to a spring system used in such a rotor assembly where the stiffness of an associated spring member is allowed to vary in response to the torque applied from a motor to the assembly.

The present invention includes a safety apparatus and method for protecting users during maintenance operations for a rotorcraft comprising: at least one permanent, semi-permanent, or detachable safety bar, strap, fastener, hook, or loop that is attached or attachable to a rotorcraft, wherein the safety bar, strap, fastener, hook, or loop is positioned in an area or surface between a windshield of the rotorcraft and a tail boom of the rotorcraft and is connectable to a user safety device to provide fall protection from the area or surface.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A cockpit in the airframe, the cockpit including two seats and a single collective control input positioned between the two seats.

An aircraft is provided and includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe, at least one sensor and at least one inertial measurement unit (IMU) to sense current flight conditions of the aircraft, an interface to execute controls of a main rotor assembly in accordance with control commands and at least one flight control computer (FCC) to issue the control commands. The at least one FCC includes a central processing unit (CPU) and a memory having logic and executable instructions stored thereon, which, when executed, cause the CPU to issue the control commands based on the current flight conditions and a result of an execution of the logic for the current flight conditions.

A passive hub flapping lock including: one or more lever arms, each lever arm rotatably coupled to a pivot and comprising a first lever arm end and a second lever arm end; one or more stop wedges; one or more frames coupled to the one or more stop wedges, each frame coupled to the first lever arm end of one of the one or more lever arms; one or more weight sets, each weight set comprising one or more weights coupled to the second lever arm end of one of the one or more lever arms; and one or more pivot torsion springs, each pivot torsion spring positioned at the pivot.

The present invention includes a passive hub flapping lock including stop wedges; frames coupled to the stop wedges; rods coupled to the frames, and each rod comprising a bracket; lever arms, each lever arm rotatably coupled to a pivot and coupled at a first lever arm end to one of the rods at the bracket of the rod; weight sets, each weight set coupled to a second lever arm end; and pivot torsion springs, each pivot torsion spring positioned at a pivot and biased to hold the flapping lock in an engaged position when stationary or at a rotational speed below a specified rotational speed; wherein the flapping lock is in an engaged position below the specified rotational speed and in a disengaged position above the specified rotational speed and the weight sets move outward, rotating the lever arms.

The present embodiments disclose a torque dependent and resonant operating thrust-generating rotor assembly including a cyclic pitch control system for controlling tilting moments about a longitudinal rotor blade axis of one or more rotor blades, in order to control the pitch angle of the rotor blades and thereby also the horizontal movements of a helicopter vehicle or a rotary wing aircraft. A rotor torque assembly of the rotor assembly is further configured to operate in resonance, thereby providing a resonant gain effecting a rotational offset in relation to changes in torque generated by the motor.

A propulsion assembly for a rotorcraft includes a mast and a proprotor hub assembly coupled to the mast and having a gimballing degree of freedom relative to the mast. The proprotor hub assembly includes a hook receiver. The propulsion assembly includes a gimbal lock positioned about the mast. The gimbal lock includes a locking ring and a gimbal lock hook. The gimbal lock is movable between a disengaged position and an engaged position relative to the proprotor hub assembly. The gimbal lock enables the gimballing degree of freedom in the disengaged position and disables the gimballing degree of freedom in the engaged position. The gimbal lock hook is hooked to the hook receiver in the engaged position to secure the locking ring to the proprotor hub assembly.

A propulsion assembly for a rotorcraft includes a mast and a proprotor hub assembly coupled to the mast and having a gimballing degree of freedom relative to the mast. The propulsion assembly includes a gimbal lock assembly positioned about the mast and including a plurality of radially outwardly extending and circumferentially distributed rollers. The gimbal lock assembly is movable between a disengaged position and an engaged position relative to the proprotor hub assembly. In the disengaged position, the gimbal lock assembly enables the gimballing degree of freedom. In the engaged position, the rollers of the gimbal lock assembly contact the proprotor hub assembly to disable the gimballing degree.

A system for driving a tilt rotor between vertical and horizontal using a variable displacement motor controlled in response to a swash angle of the motor measured in a feedback loop.