A propeller blade retention arrangement having a propeller blade comprising in radial sequence an aerofoil portion, a shank portion and a root portion. The root portion having first cross-sectional area close to the shank portion and second cross-sectional area at the end distal to the aerofoil portion, wherein the second cross-sectional area is greater than the first cross-sectional area. At least two cheeks each having an inner surface arranged to abut the root portion, an outer surface that is threaded and edge surfaces that abut another of the at least two cheeks; wherein the at least two cheeks are arranged to surround the root portion in circumferential abutment. A collar having a threaded inner surface arranged to threadingly engage the outer surfaces of the at least two cheeks.

A driving device includes a body portion, a driving shaft disposed on the body portion and configured to rotate relative to the body portion, a lock portion disposed on the body portion and including a snap-fitting portion configured to snap with the propeller, and an elastic abutting member disposed on the body portion and configured to be pressed down and deformed along a direction parallel to the driving shaft to abut against a propeller in response to the snap-fitting portion being snapped with the propeller.

A driving device includes a body portion, a driving shaft disposed on the body portion and configured to rotate relative to the body portion, a lock portion disposed on the body portion and including a snap-fitting portion configured to snap with the propeller, and an elastic abutting member disposed on the body portion and configured to be pressed down and deformed along a direction parallel to the driving shaft to abut against a propeller in response to the snap-fitting portion being snapped with the propeller.

In some embodiments, a rotorcraft may include a yoke, a blade, a spindle associated with the yoke, and an elastomeric bearing assembly. The center length of the spindle may define a center axis that passes through a center of the elastomeric bearing assembly. The elastomeric bearing assembly may contain a housing coupled to the blade and disposed around the center axis that is configured to rotate in relation to the center axis. The elastomeric bearing assembly may contain an elastomeric shear bearing that has an interior portion coupled to the spindle and an exterior portion coupled to the housing. The elastomeric bearing assembly may contain an elastomeric centrifugal force bearing pressed against the housing. The shear bearing may be configured to counteract a torsional force, and the centrifugal force bearing may be configured to counteract a compression force.

In some embodiments, a rotorcraft may include a yoke, a blade, a spindle associated with the yoke, and an elastomeric bearing assembly. The center length of the spindle may define a center axis that passes through a center of the elastomeric bearing assembly. The elastomeric bearing assembly may contain a housing coupled to the blade and disposed around the center axis that is configured to rotate in relation to the center axis. The elastomeric bearing assembly may contain an elastomeric shear bearing that has an interior portion coupled to the spindle and an exterior portion coupled to the housing. The elastomeric bearing assembly may contain an elastomeric centrifugal force bearing pressed against the housing. The shear bearing may be configured to counteract a torsional force, and the centrifugal force bearing may be configured to counteract a compression force.

An unmanned aerial comprises: a motor and a propeller assembly connected to the motor comprising: a first structure fixed to the motor, having a cylindrical wall defining an inner space, with a helical slit formed through the cylindrical wall; a second structure comprising a cylinder portion, a part of which is rotatably positioned in the inner space, and at least one protruding portion protruding from the outer surface of the cylinder portion to the outside of the cylindrical wall through the helical slit; and a propeller comprising a cylindrical hub engaging with the cylinder portion of the first structure, rotating blades extending from the cylindrical hub, and at least one rib extending from the cylindrical hub toward the motor, the propeller being configured such that at least a part of the rib detachably engages with the first structure by the at least one protruding portion of the second structure.

Disclosed here are systems for detachable airframe components including detachable nose cones, propeller assemblies and motors. In some example embodiments, the assemblies include a nose cone with a connection receiver, a motor assembly with a rotatable section, where the rotatable section includes torque arms configured to secure with the nose cone connection receiver, and a propeller assembly, configured to connect to the nose cone.

Disclosed here are systems for detachable airframe components including detachable nose cones, propeller assemblies and motors. In some example embodiments, the assemblies include a nose cone with a connection receiver, a motor assembly with a rotatable section, where the rotatable section includes torque arms configured to secure with the nose cone connection receiver, and a propeller assembly, configured to connect to the nose cone.

A dual drive hybrid electric power plant to power an aircraft comprises a propulsion assembly, an internal combustion engine having an output shaft configured to drive the propulsion assembly, and an electric motor configured to drive the propulsion assembly and to be selectively coupled to the output shaft. The power plant may be configured such that the electric motor alone drives the propulsion assembly, or such that the internal combustion engine and the electric motor drive the propulsion assembly.

Disclosed here are systems for detachable airframe components including detachable nose cones, propeller assemblies and motors. In some example embodiments, the assemblies include a nose cone with a connection receiver, a motor assembly with a rotatable section, where the rotatable section includes torque arms configured to secure with the nose cone connection receiver, and a propeller assembly, configured to connect to the nose cone.