A propeller, a propeller kit, a power assembly, a power kit and an unmanned aerial vehicle (UAV). The propeller includes a hub and at least two blades connected to the hub. The hub is detachably mounted on a corresponding drive apparatus by a mounting member corresponding to the hub, so that the propeller is mounted on the corresponding drive apparatus. A surface, facing the mounting member, of the hub is provided with a first fitting portion. A surface, facing the hub, of the mounting member is provided with a second fitting portion corresponding to the first fitting portion. The first fitting portion matches the second fitting portion. In the foregoing manner, a user can be prevented from incorrectly mounting a forward propeller and a counter-rotating propeller during the use of a quick-detachable propeller in the embodiments of the present application.

A VTOL aircraft includes a lift propeller configured to provide lift during takeoff, landing and hover operations. The lift propeller is configured to be stowed close to a boom surface when not in use during, e.g., cruise flight, to minimize drag around propeller surfaces. The lift propeller may be displaced vertically with respect to the boom when switching to a lift configuration to provide greater separation from the boom to improve lift efficiency and reduce unwanted vibrations. The lift propeller may have a fail-safe configuration that allows the propeller to move passively between lift and stowed configurations, and to fully rotate even when fully retracted.

A VTOL aircraft includes a lift propeller configured to provide lift during takeoff, landing and hover operations. The lift propeller is configured to be stowed close to a boom surface when not in use during, e.g., cruise flight, to minimize drag around propeller surfaces. The lift propeller may be displaced vertically with respect to the boom when switching to a lift configuration to provide greater separation from the boom to improve lift efficiency and reduce unwanted vibrations. The lift propeller may have a fail-safe configuration that allows the propeller to move passively between lift and stowed configurations, and to fully rotate even when fully retracted.

A propeller, a propeller kit, a power assembly, a power kit and an unmanned aerial vehicle (UAV). The propeller includes a hub and at least two blades connected to the hub. The hub is detachably mounted on a corresponding drive apparatus by a mounting member corresponding to the hub, so that the propeller is mounted on the corresponding drive apparatus. A surface, facing the mounting member, of the hub is provided with a first fitting portion. A surface, facing the hub, of the mounting member is provided with a second fitting portion corresponding to the first fitting portion. The first fitting portion matches the second fitting portion. In the foregoing manner, a user can be prevented from incorrectly mounting a forward propeller and a counter-rotating propeller during the use of a quick-detachable propeller in the embodiments of the present application.

A propeller, a propeller kit, a power assembly, a power kit and an unmanned aerial vehicle (UAV). The propeller includes a hub and at least two blades connected to the hub. The hub is detachably mounted on a corresponding drive apparatus by a mounting member corresponding to the hub, so that the propeller is mounted on the corresponding drive apparatus. A surface, facing the mounting member, of the hub is provided with a first fitting portion. A surface, facing the hub, of the mounting member is provided with a second fitting portion corresponding to the first fitting portion. The first fitting portion matches the second fitting portion. In the foregoing manner, a user can be prevented from incorrectly mounting a forward propeller and a counter-rotating propeller during the use of a quick-detachable propeller in the embodiments of the present application.

A ducted-rotor aircraft may include a fuselage and first and second ducts that are coupled to the fuselage at respective first and second locations. The first location may be on a first side of a fuselage of the aircraft and spaced from a nominal yaw axis of the aircraft. The second location may be on an opposed second side of the fuselage and spaced from the nominal yaw axis. Each duct may include a rotor that is disposed in an opening that extends through the duct. Each rotor may include a plurality of blades. Each duct may further include a control vane that is mounted aft of the plurality of blades and that is pivotable about a vane axis that is oriented toward the nominal yaw axis.

A rotor assembly configured to increase the stiffness of a rotor mast. The rotor assembly includes the rotor mast, a rotor hub, a mast nut, a mast bearing, and a cuff disposed between the mast nut and the mast bearing. The cuff is captured and compressed between the mast nut and the inner race of the mast bearing along an uninterrupted load path that extends between the mast nut and the mast bearing.

An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

A hub assembly for a ducted-rotor aircraft includes a plurality of stator supports, a first integral fitting that attaches to first ends of the stator supports, and a second integral fitting that attaches to second ends of the stator supports. The first fitting includes a plurality of motor attachment portions configured to locate and support a motor of the ducted-rotor aircraft, a plurality of fairing mounts configured to support attachment of an aerodynamic fairing to the hub assembly, and a plurality of stator locators configured to locate respective ones of the plurality of stator supports for attachment to the hub assembly. The first fitting has a body portion with an annular wall that supports the motor attachment portions, the fairing mounts, and the stator locators. The first fitting may be fabricated as a monolith that includes the body portion, motor attachment portions, fairing mounts, and stator locators.

A hub assembly for a ducted-rotor aircraft includes a plurality of stator supports, a first integral fitting that attaches to first ends of the stator supports, and a second integral fitting that attaches to second ends of the stator supports. The first fitting includes a plurality of motor attachment portions configured to locate and support a motor of the ducted-rotor aircraft, a plurality of fairing mounts configured to support attachment of an aerodynamic fairing to the hub assembly, and a plurality of stator locators configured to locate respective ones of the plurality of stator supports for attachment to the hub assembly. The first fitting has a body portion with an annular wall that supports the motor attachment portions, the fairing mounts, and the stator locators. The first fitting may be fabricated as a monolith that includes the body portion, motor attachment portions, fairing mounts, and stator locators.