An aircraft includes a fuselage and a wing assembly that is rotatable between a substantially perpendicular orientation relative to the fuselage in flight modes and a substantially parallel orientation relative to the fuselage in a wing stowage mode. The wing assembly includes a wing that is pivotable between forward flight and VTOL orientations by a pivot angle. A distributed thrust array is coupled to the wing that includes outboard and inboard propulsion assemblies, each propulsion assembly having an axis of rotation that has a fixed angle relative to a chord axis of the wing. In a VTOL flight mode, the axis of rotation of each propulsion assembly is substantially vertical and the wing is in the VTOL orientation. In a forward flight mode, the wing is in the forward flight orientation and the axis of rotation of each propulsion assembly is tilted forward from the vertical by the pivot angle.

An aircraft includes a fuselage and a wing assembly that is rotatable between a substantially perpendicular orientation relative to the fuselage in flight modes and a substantially parallel orientation relative to the fuselage in a wing stowage mode. The wing assembly includes a wing that is pivotable between forward flight and VTOL orientations by a pivot angle. A distributed thrust array is coupled to the wing that includes outboard and inboard propulsion assemblies, each propulsion assembly having an axis of rotation that has a fixed angle relative to a chord axis of the wing. In a VTOL flight mode, the axis of rotation of each propulsion assembly is substantially vertical and the wing is in the VTOL orientation. In a forward flight mode, the wing is in the forward flight orientation and the axis of rotation of each propulsion assembly is tilted forward from the vertical by the pivot angle.

The present disclosure provides a tandem rotor unmanned aerial vehicle, which includes a vehicle body, a flight control system, and a propulsion system. The propulsion system includes a front distributed propulsion system and a rear distributed propulsion system. The front distributed propulsion system is arranged at a front end of the vehicle body. The rear distributed propulsion system is arranged a rear end of the vehicle body. The front distributed propulsion system includes rotor blades, a rotor nose, a main shaft, a speed reducer, a synchronizer, a motor, and a periodic variable pitch mechanism. A polar attitude of the tandem rotor unmanned aerial vehicle of the present disclosure can be adjusted conveniently and stably in the air, and the adjustment efficiency is high. The present disclosure further provides an attitude adjustment control method for the tandem rotor unmanned aerial vehicle.

The present disclosure provides a tandem rotor unmanned aerial vehicle, which includes a vehicle body, a flight control system, and a propulsion system. The propulsion system includes a front distributed propulsion system and a rear distributed propulsion system. The front distributed propulsion system is arranged at a front end of the vehicle body. The rear distributed propulsion system is arranged a rear end of the vehicle body. The front distributed propulsion system includes rotor blades, a rotor nose, a main shaft, a speed reducer, a synchronizer, a motor, and a periodic variable pitch mechanism. A polar attitude of the tandem rotor unmanned aerial vehicle of the present disclosure can be adjusted conveniently and stably in the air, and the adjustment efficiency is high. The present disclosure further provides an attitude adjustment control method for the tandem rotor unmanned aerial vehicle.

A foldable propeller for air mobility includes a link assembly including a plurality of links facilitating blades to be rotated around a hub as a moving portion vertically slides such that the blades are folded to each other or unfolded from each other.

The present invention includes a distributed propulsion system for a craft that comprises a frame, a plurality of hydraulic or electric motors disposed within or attached to the frame in a distributed configuration; a propeller operably connected to each of the hydraulic or electric motors, a source of hydraulic or electric power disposed within or attached to the frame and coupled to each of the disposed within or attached to the frame, wherein the source of hydraulic or electric power provides sufficient energy density for the craft to attain and maintain operations of the craft, a controller coupled to each of the hydraulic or electric motors, and one or more processors communicably coupled to each controller that control an operation and speed of the plurality of hydraulic or electric motors.

The present invention includes a distributed propulsion system for a craft that comprises a frame, a plurality of hydraulic or electric motors disposed within or attached to the frame in a distributed configuration; a propeller operably connected to each of the hydraulic or electric motors, a source of hydraulic or electric power disposed within or attached to the frame and coupled to each of the disposed within or attached to the frame, wherein the source of hydraulic or electric power provides sufficient energy density for the craft to attain and maintain operations of the craft, a controller coupled to each of the hydraulic or electric motors, and one or more processors communicably coupled to each controller that control an operation and speed of the plurality of hydraulic or electric motors.

An aircraft includes a closed wing, a fuselage at least partially disposed within a perimeter of the closed wing, and one or more spokes coupling the closed wing to the fuselage. A source of electric power is disposed within or attached to the closed wing, fuselage or one or more spokes. A plurality of electric motors are disposed within or attached to the one or more spokes in a distributed configuration. Each electric motor is connected to the source of electric power. A propeller is operably connected to each of the electric motors and proximate to a leading edge of the one or more spokes. One or more processors are communicably coupled to the plurality of electric motors. A longitudinal axis of the fuselage is substantially vertical in vertical takeoff and landing and stationary flight, and substantially in a direction of a forward flight in a forward flight mode.

An aircraft includes a closed wing, a fuselage at least partially disposed within a perimeter of the closed wing, and one or more spokes coupling the closed wing to the fuselage. A source of electric power is disposed within or attached to the closed wing, fuselage or one or more spokes. A plurality of electric motors are disposed within or attached to the one or more spokes in a distributed configuration. Each electric motor is connected to the source of electric power. A propeller is operably connected to each of the electric motors and proximate to a leading edge of the one or more spokes. One or more processors are communicably coupled to the plurality of electric motors. A longitudinal axis of the fuselage is substantially vertical in vertical takeoff and landing and stationary flight, and substantially in a direction of a forward flight in a forward flight mode.

An elastomeric bearing assembly has a centrifugal force bearing axially captured relative to a sliding interface. The sliding interface has one or more low friction regions and one or more high friction regions. One or more piezo actuators are configured to force one or more corresponding high friction regions against the centrifugal force bearing when actuated. The sliding interface may have a circular shape, wherein the one or more low friction regions and the one or more high friction regions are alternating concentric segments of the sliding interface. The one or more high friction regions are recessed on the sliding interface relative to the one or more low friction regions.