A method of assisting in rotor speed control in a rotorcraft can include measuring a rotor speed with a sensor; detecting a droop in the rotor speed beyond a lower droop limit; and commanding a decrease in collective in response to the rotor speed drooping beyond the lower droop limit. A system of assisting in rotor speed control in a rotorcraft, the system can include: a computer having a control law, the control law operable to generate a decrease collective command to an actuator in response to a rotor speed decreasing below a lower droop limit; wherein the lower droop limit is below a normal lower rotor speed range.

A main rotor blade assembly for a rotary wing aircraft is provided including a main rotor blade root region, a main rotor blade inboard region arranged outboard of said main rotor blade root region, a main rotor blade main region arranged outboard of said main rotor blade inboard region, and a main rotor blade tip region arranged outboard of said main rotor blade main region. At least one of chord, twist, sweep, airfoil shape, and thickness/chord of the main rotor blade assembly has been optimized to achieve balanced high speed forward flight and hover relative to both efficiency and high thrust capability.

A main rotor blade assembly is provided including a spar which comprises a main section. A main core is positioned adjacent a trailing side of the main section of the spar. A tip assembly includes a main tip core and a tip end pocket core. The tip assembly is positioned adjacent an outboard end of the main core and the spar such that the main tip core is substantially aligned with a longitudinal axis of the main core and the tip end pocket core is substantially aligned with a longitudinal axis of the spar. At least a portion of both the main tip core and the tip end pocket core comprises a high density core. An upper composite skin and a lower composite skin extend over the spar, the main core, the main tip core, and the tip end pocket core. A portion of the upper composite skin and the lower composite skin has a thickness sufficient to be load bearing.

A method of mounting a replacement tip section to an exposed end of a rotor blade includes removing an existing tip section from the rotor blade to create the exposed end of the rotor blade, installing the rotor blade having the exposed end onto a holding fixture, assembling the replacement tip section about the exposed end of the rotor blade, positioning a bonding fixture about the replacement tip section, and curing the replacement tip section to the exposed end of the rotor blade.

Systems and methods are provided for decoupling movable control surfaces. Such systems may detect that a movable control surface is in a non-responsive state, such as a hard-over, and decouple the movable control surface from the main, fixed, control surface. The control surfaces may be coupled to an aircraft. A controller of the aircraft may detect the nonresponsive movable control surface, provide instructions to decouple the movable control surface, and compensate for the decoupling of the movable control surface in instructions provided to flight systems of the aircraft.

Systems and methods are provided for decoupling movable control surfaces. Such systems may detect that a movable control surface is in a non-responsive state, such as a hard-over, and decouple the movable control surface from the main, fixed, control surface. The control surfaces may be coupled to an aircraft. A controller of the aircraft may detect the nonresponsive movable control surface, provide instructions to decouple the movable control surface, and compensate for the decoupling of the movable control surface in instructions provided to flight systems of the aircraft.

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 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 rotor assembly for a rotary wing aircraft includes a rotor hub having a central axis. The rotor hub is rotatable about the central axis. A plurality of flexible structural members extend radially outwardly from the rotor hub. Each flexible structural member is substantially U-shaped having a first arm extending from the hub, a second arm extending from the hub, and an end portion connecting the first arm to the second arm at a radially outboard end of the flexible structural member. The first arm, the second arm and/or the end portion have a cross section with a height along the central axis greater than a thickness of the cross section to increase stiffness of the rotor assembly along the central axis. The rotor assembly further includes a plurality of rotor blades, each rotor blade being secured to each flexible structural member of the plurality of flexible structural members.

A rotor assembly for a rotary wing aircraft includes a rotor hub having a central axis. The rotor hub is rotatable about the central axis. A plurality of flexible structural members extend radially outwardly from the rotor hub. Each flexible structural member is substantially U-shaped having a first arm extending from the hub, a second arm extending from the hub, and an end portion connecting the first arm to the second arm at a radially outboard end of the flexible structural member. The first arm, the second arm and/or the end portion have a cross section with a height along the central axis greater than a thickness of the cross section to increase stiffness of the rotor assembly along the central axis. The rotor assembly further includes a plurality of rotor blades, each rotor blade being secured to each flexible structural member of the plurality of flexible structural members.