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.

Embodiments are directed to a double Hooke's joint gimbal in a rotor system. An upper Hooke's joint has four arms extending radially outward to define first and second axes, and a lower Hooke's joint has four arms extending radially outward to define third and fourth axes. A pair of connectors couple the upper Hooke's joint and the lower Hooke's joint. A first set of bearings are positioned between arms on the upper and lower Hooke's joints and the connectors. The first set of bearings comprise an elastomer, such as elastomeric journal bearings. The upper Hooke's joint is coupled to a yoke and rotor blades by a driver assembly that allows rotor blade flapping. The lower Hooke's joint is coupled to and driven by a mast. A spherical bearing allows the upper Hooke's joint to move laterally along the mast.

A rotor hub assembly that includes a yoke configured to attach blades thereto, a universal joint configured to attach to, and transmit forces between, a mast and the yoke, and an elastomeric member configured to attenuate vibrations transmitted from the universal joint to the mast.

A rotor hub assembly that includes a yoke configured to attach blades thereto, a universal joint configured to attach to, and transmit forces between, a mast and the yoke, and an elastomeric member configured to attenuate vibrations transmitted from the universal joint to the mast.

Provided is a flight vehicle and in particular a flight vehicle in which a main module equipped with a device capable of carrying cargo, photographing, etc. may freely switch directions during flight while applying a posture independent of a thrust module because the thrust module is configured to freely perform roll and pitch motions with respect to the main module.

Provided is a flight vehicle and in particular a flight vehicle in which a main module equipped with a device capable of carrying cargo, photographing, etc. may freely switch directions during flight while applying a posture independent of a thrust module because the thrust module is configured to freely perform roll and pitch motions with respect to the main module.

A rotor hub assembly that includes a yoke configured to attach blades thereto, a universal joint configured to attach to, and transmit forces between, a mast and the yoke, and an elastomeric member configured to attenuate vibrations transmitted from the universal joint to the mast.

A rotor hub assembly that includes a yoke configured to attach blades thereto, a universal joint configured to attach to, and transmit forces between, a mast and the yoke, and an elastomeric member configured to attenuate vibrations transmitted from the universal joint to the mast.

Systems and methods related to passive variable pitch propellers are described. For example, an aerial vehicle may include one or more passive variable pitch propellers, and such propellers may include one or more passively movable propeller blades having respective hinges, flexible joints, or torsionally flexible joints. Based at least in part on current flight configurations, required thrust, and/or desired advance ratios, the passively movable propeller blades may modify their coning angles and/or pitches, such that the passive variable pitch propellers may operate with improved efficiency in two or more flight configurations. For example, in a VTOL flight configuration, the passive variable pitch propellers may have increased coning angles and decreased pitches, whereas in a horizontal flight configuration, the passive variable pitch propellers may have decreased coning angles and increased pitches.

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.