Disclosed is a blade lock assembly, which may include a drag brace coupled to a fold crank assembly and to a rotary wing blade and may further include an actuator assembly configured to be coupled to a rotary wing cuff. The actuator assembly may include an actuator pin housing, an actuation pin at least partially sheathed by the actuator pin housing, and an actuator configured to extend and retract the actuation pin away from and toward the actuator pin housing.

Methods for performing maintenance operations using unmanned aerial vehicles (UAVs). The methods are enabled by equipping a UAV with a maintenance tool capable of performing a desired maintenance operation (e.g., nondestructive inspection) on a limited-access surface of a large structure or object (e.g., a wind turbine blade). The UAV uses re-orientation of lifting means (e.g., vertical rotors) to move the maintenance tool continuously or intermittently across the surface of the structure while maintaining contact with the surface of the structure undergoing maintenance.

Methods for performing maintenance operations using unmanned aerial vehicles (UAVs). The methods are enabled by equipping a UAV with a maintenance tool capable of performing a desired maintenance operation (e.g., nondestructive inspection) on a limited-access surface of a large structure or object (e.g., a wind turbine blade). The UAV uses re-orientation of lifting means (e.g., vertical rotors) to move the maintenance tool continuously or intermittently across the surface of the structure while maintaining contact with the surface of the structure undergoing maintenance.

An adjustable length crank arm includes a first component having a longitudinal length, a second component coupled to the first component, the second component having a longitudinal length. A total length of the crank arm can be adjusted by changing an amount of longitudinal overlap that exists between the first component and the second component. The adjustable length crank arm can include a first wedge and a second wedge and at least a portion of each of the first wedge and the second wedge is longitudinally captured between the first component and the second component.

An adjustable length crank arm includes a first component having a longitudinal length, a second component coupled to the first component, the second component having a longitudinal length. A total length of the crank arm can be adjusted by changing an amount of longitudinal overlap that exists between the first component and the second component. The adjustable length crank arm can include a first wedge and a second wedge and at least a portion of each of the first wedge and the second wedge is longitudinally captured between the first component and the second component.

A rotorcraft having a rotor system including a yoke, a plurality of grip assemblies, each of which is hingedly attach a rotor blade to the yoke, a plurality of flap stops, each flap stop attached to a respective grip assembly, a channel bounded by an upper and lower retaining surfaces, and a droop ring slideably disposed in the channel of the droop limiting system. The droop ring has a body with an inner surface, an outer surface, and a first end surface between the inner surface and the outer surface. The droop ring further has a first wear element removably disposed at the first end surface and extending above the first end surface and spaces the first end surface apart from the channel. Each flap stop is arranged to contact the outer surface of the droop ring and limit a downward droop of the respective rotor blade.

The ‘Air Wheel’ rotor is a rotor with blades of variable pitch and variable twist. The ‘Air Wheel’ rotor comprises one or more hubs connected to the closed axisymmetric wing via flexible blades. There is provided a wide range of combinations of the wing relative width and coning angle typical for a lifting rotor with a thin planar wing attached to the tips of long blades, for a shrouded fan in a wide annular wing, or an impeller in a rotating cylindrical wing is provided.

The ‘Air Wheel’ rotor combines and enhances the advantages of a rotor and a wing. The ‘Air Wheel’ rotor has high aerodynamic properties, and eliminates limitations of the rotor size and flight speed. The ‘Air Wheel’ rotor can be used for designing vertical take-off and landing aircraft.

The ‘Air Wheel’ rotor is a rotor with blades of variable pitch and variable twist. The ‘Air Wheel’ rotor comprises one or more hubs connected to the closed axisymmetric wing via flexible blades. There is provided a wide range of combinations of the wing relative width and coning angle typical for a lifting rotor with a thin planar wing attached to the tips of long blades, for a shrouded fan in a wide annular wing, or an impeller in a rotating cylindrical wing is provided.

The ‘Air Wheel’ rotor combines and enhances the advantages of a rotor and a wing. The ‘Air Wheel’ rotor has high aerodynamic properties, and eliminates limitations of the rotor size and flight speed. The ‘Air Wheel’ rotor can be used for designing vertical take-off and landing aircraft.

A rotor system includes a rotor assembly and a duct system. The rotor assembly includes rotor blades extending from a mast axis and configured to rotate about the mast axis. The duct assembly includes a moveable duct portion and a stationary duct portion. In a first duct configuration, the moveable duct portion surrounds a first portion of the rotor assembly, the stationary duct portion surrounds a second portion of the rotor assembly, and the moveable duct portion and the stationary duct portion enclose the rotor assembly. In a second duct configuration, the stationary duct portion surrounds the second portion of the rotor assembly, and the moveable duct portion is moved away from the first portion of the rotor assembly, such that the rotor assembly is not enclosed.

A rotor system includes a rotor assembly and a duct system. The rotor assembly includes rotor blades extending from a mast axis and configured to rotate about the mast axis. The duct assembly includes a moveable duct portion and a stationary duct portion. In a first duct configuration, the moveable duct portion surrounds a first portion of the rotor assembly, the stationary duct portion surrounds a second portion of the rotor assembly, and the moveable duct portion and the stationary duct portion enclose the rotor assembly. In a second duct configuration, the stationary duct portion surrounds the second portion of the rotor assembly, and the moveable duct portion is moved away from the first portion of the rotor assembly, such that the rotor assembly is not enclosed.