A rotor unit is disclosed. The rotor unit includes a hub and a stacked rotor blade. The hub is configured to rotate about an axis in a first rotation direction. The stacked rotor blade is rotatable about the axis and further includes a first blade element and a second blade element. The first blade element has a first leading edge and the second blade element has a second leading edge. The blade elements are arranged in a stacked configuration. A leading edge of the stacked rotor blade is formed by at least a portion of the first leading edge of the first blade element as well as at least as portion of the second leading edge of the second blade element. In some embodiments, the rotor unit is coupled to an unmanned aerial vehicle.

A rotor unit is disclosed. The rotor unit includes a hub and a stacked rotor blade. The hub is configured to rotate about an axis in a first rotation direction. The stacked rotor blade is rotatable about the axis and further includes a first blade element and a second blade element. The first blade element has a first leading edge and the second blade element has a second leading edge. The blade elements are arranged in a stacked configuration. A leading edge of the stacked rotor blade is formed by at least a portion of the first leading edge of the first blade element as well as at least as portion of the second leading edge of the second blade element. In some embodiments, the rotor unit is coupled to an unmanned aerial vehicle.

A propulsor fan array having reduced noise emission is disclosed. The propulsor fan array includes a plurality of propulsor fans that collectively generate thrust. Each of the propulsor fans include a blade fan having a plurality of blades. The plurality of blades are tensioned at tips of the plurality of blade fans such that a pitch of the blades during thrust generation is substantially the same as a pitch of the blades at rest. By tensioning the tips of the blades, an angle of the blades is maintained during operation of the propulsor fan thereby reducing noise that may result from changes in the angle of the blades.

A rotor unit is disclosed. The rotor unit includes a hub and a stacked rotor blade. The hub is configured to rotate about an axis in a first rotation direction. The stacked rotor blade is rotatable about the axis and further includes a first blade element and a second blade element. The first blade element has a first leading edge and the second blade element has a second leading edge. The blade elements are arranged in a stacked configuration. A leading edge of the stacked rotor blade is formed by at least a portion of the first leading edge of the first blade element as well as at least as portion of the second leading edge of the second blade element. In some embodiments, the rotor unit is coupled to an unmanned aerial vehicle.

A rotor unit is disclosed. The rotor unit includes a hub and a stacked rotor blade. The hub is configured to rotate about an axis in a first rotation direction. The stacked rotor blade is rotatable about the axis and further includes a first blade element and a second blade element. The first blade element has a first leading edge and the second blade element has a second leading edge. The blade elements are arranged in a stacked configuration. A leading edge of the stacked rotor blade is formed by at least a portion of the first leading edge of the first blade element as well as at least as portion of the second leading edge of the second blade element. In some embodiments, the rotor unit is coupled to an unmanned aerial vehicle.

A turbocharger impeller is provided with a hub portion with a plurality of vane portions extending outwardly thereof. The hub portion is substantially shaped as a truncated cone with a diameter that gradually increases along a rotation axis. The vane portions are formed on a surface of the hub portion and guide a fluid flowing along the rotation axis radially outward relative to the hub portion. Grooves are formed in and/or on surfaces of the vane portions along a direction of the fluid flowing radially outward during rotation of the impeller. Protruding crest portions are formed between adjacent grooves. Crest portions in a central region near the rotation axis are lower in height than crest portions in an outer region further away from the rotation axis.

A propulsor fan and drive system having reduced noise emission is disclosed. The propulsor fan includes a blade fan having a plurality of blades. The blade fan is tensioned at the tips of the plurality of blades. By tensioning the tips of the blades, an angle of the blades is maintained during operation of the propulsor fan thereby reducing noise that may result from changes in the angle of the blades.

Embodiments of the present application relate to the technical field of propellers, and particularly to a folding propeller, a power component and an unmanned aerial vehicle. The folding propeller includes a hub, at least two blades and at least two connecting pieces, the hub being configured to mount the folding propeller to a driving device. The hub includes a first surface and a second surface disposed oppositely, the first surface facing the driving device, and the second surface facing away from the driving device. Each of the blades is mounted on the second surface by the corresponding connecting piece, and each of the blades is capable of rotating relative to the hub. In the above manner, according to the embodiments of the present application, during mold adjustment in injection molding, a rotary damping between the blade and the hub can be adjusted by only adjusting the friction force of one contact surface, which is convenient for mold adjustment, is beneficial to mass production and reduces the production cost.

Embodiments of the present application relate to the technical field of propellers, and particularly to a folding propeller, a power component and an unmanned aerial vehicle. The folding propeller includes a hub, at least two blades and at least two connecting pieces, the hub being configured to mount the folding propeller to a driving device. The hub includes a first surface and a second surface disposed oppositely, the first surface facing the driving device, and the second surface facing away from the driving device. Each of the blades is mounted on the second surface by the corresponding connecting piece, and each of the blades is capable of rotating relative to the hub. In the above manner, according to the embodiments of the present application, during mold adjustment in injection molding, a rotary damping between the blade and the hub can be adjusted by only adjusting the friction force of one contact surface, which is convenient for mold adjustment, is beneficial to mass production and reduces the production cost.

A propulsor fan and drive system having reduced noise emission is disclosed. The propulsor fan includes a blade fan having a plurality of blades. The blade fan is tensioned at the tips of the plurality of blades. By tensioning the tips of the blades, an angle of the blades is maintained during operation of the propulsor fan thereby reducing noise that may result from changes in the angle of the blades.