An unmanned aerial vehicle (UAV) is provided, which includes a main body; a plurality of frames each extending from the main body; and a plurality of thrust generating devices respectively mounted on the plurality of frames, each of the thrust generating devices including a propeller. The propeller includes a hub that provides a rotation axis of the propeller, and rotates according to an operation of the thrust generating device, and a pair of blades, each of which is pivotably mounted on the hub, and generates a thrust or lift while rotating around the rotation axis as the hub is rotated. The blades are pivotably interlocked with each other such that the blades are aligned to a folded position in which the blades are parallel with each other on the hub in a first arrangement or aligned to an expanded position in a diametric direction of a rotating region of the propeller in a second arrangement.

An unmanned aerial vehicle (UAV) is provided, which includes a main body; a plurality of frames each extending from the main body; and a plurality of thrust generating devices respectively mounted on the plurality of frames, each of the thrust generating devices including a propeller. The propeller includes a hub that provides a rotation axis of the propeller, and rotates according to an operation of the thrust generating device, and a pair of blades, each of which is pivotably mounted on the hub, and generates a thrust or lift while rotating around the rotation axis as the hub is rotated. The blades are pivotably interlocked with each other such that the blades are aligned to a folded position in which the blades are parallel with each other on the hub in a first arrangement or aligned to an expanded position in a diametric direction of a rotating region of the propeller in a second arrangement.

A rotor blade disassembly method includes applying spanwise support to a rotor blade body and heating a bond disposed on an end of the rotor blade body. The method also includes removing the spanwise support from the rotor blade body and exerting shear stress on the bond using weight of the rotor blade body. A blade disassembly system is also described.

A rotorcraft main rotor system, including a yoke, a rotor blade, and a grip assembly attaching the rotor blade to the yoke. The grip assembly includes a grip body formed from a contiguous laminated composite and has a substantially constant thickness, where the grip body has an upper extension, a lower extension and a connecting portion connected between an inboard end of the upper extension and an inboard end of the lower extension. An inside surface of the upper extension faces, and is substantially parallel to, an inside surface of the lower extension, and the upper extension has first features and the lower extension has second features that are aligned with the first features, where the first features and second features each include at least one of an edge contour, attachment holes, or first protective elements.

A rotorcraft main rotor system, including a yoke, a rotor blade, and a grip assembly attaching the rotor blade to the yoke. The grip assembly includes a grip body formed from a contiguous laminated composite and has a substantially constant thickness, where the grip body has an upper extension, a lower extension and a connecting portion connected between an inboard end of the upper extension and an inboard end of the lower extension. An inside surface of the upper extension faces, and is substantially parallel to, an inside surface of the lower extension, and the upper extension has first features and the lower extension has second features that are aligned with the first features, where the first features and second features each include at least one of an edge contour, attachment holes, or first protective elements.

A blade attachment (1, 20) for a bearingless main rotor of a helicopter with an airfoil blade (2), a flexbeam (3, 21) including a flexbeam body (16, 17) and a flexbeam head (13) at an end of the flexbeam body (16, 17). A control cuff (4, 22) encloses and extends along at least a predominant portion of the flexbeam (3, 21). A separable junction arrangement between the flexbeam head (13), the control cuff (4, 22) and the root end of the airfoil blade (2) is mechanical with removable fasteners. The removable fasteners comprise a main bolt (7) and at least one supporting bolt (8).

A blade attachment (1, 20) for a bearingless main rotor of a helicopter with an airfoil blade (2), a flexbeam (3, 21) including a flexbeam body (16, 17) and a flexbeam head (13) at an end of the flexbeam body (16, 17). A control cuff (4, 22) encloses and extends along at least a predominant portion of the flexbeam (3, 21). A separable junction arrangement between the flexbeam head (13), the control cuff (4, 22) and the root end of the airfoil blade (2) is mechanical with removable fasteners. The removable fasteners comprise a main bolt (7) and at least one supporting bolt (8).

A rotor system for a rotary wing aircraft includes a rotor hub including a first beam attachment member and a second beam attachment member. A hub arm including a U-shaped beam member is connected to the rotor hub. The U-shaped beam member includes a first end portion, a second end portion and an intermediate section connecting the first and second end portions. The first end portion is connected at the first beam attachment member. The second end portion is connected at the second beam attachment member. A pitch change bearing is mounted between the first and second beam attachment member through the first end portion and the second end portion.

A rotor system for a rotary wing aircraft includes a rotor hub including a first beam attachment member and a second beam attachment member. A hub arm including a U-shaped beam member is connected to the rotor hub. The U-shaped beam member includes a first end portion, a second end portion and an intermediate section connecting the first and second end portions. The first end portion is connected at the first beam attachment member. The second end portion is connected at the second beam attachment member. A pitch change bearing is mounted between the first and second beam attachment member through the first end portion and the second end portion.

A bearing system includes an inboard bearing assembly and an outboard bearing assembly. The inboard bearing assembly includes an inboard fitting and an inboard race. The inboard fitting includes a plate with a convex mating surface and a first aperture formed through the plate for receiving a blade root of a rotor blade. The inboard race comprising a concave mating surface configured to receive the convex mating surface a second aperture formed the inboard race. The outboard bearing assembly includes an outboard bearing assembly comprising an outboard fitting having an aperture formed therethrough for receiving the blade root of the rotor blade.