A rotary blade aircraft includes an airframe, a rotor shaft driven about a rotor axis, and a plurality of rotor blades driven by the rotor shaft about the rotor axis. The rotary blade aircraft includes a swashplate assembly coupled to the plurality of rotor blades. The swashplate assembly is operable to move the plurality of rotor blades about a respective longitudinal axis. The rotary blade aircraft includes a hydraulic control servo coupled between the airframe and the swashplate assembly. The hydraulic control servo is operable to move the swashplate assembly relative to the rotor axis. The rotary blade aircraft includes a harmonic control actuator coupled between the airframe and the swashplate assembly. The harmonic control actuator is operable independently relative to the hydraulic control servo to move the swashplate assembly relative to the rotor axis to reduce vibration at selected frequencies in the airframe.

A rotor blade assembly for a rotary wing aircraft includes a main rotor blade body comprising an upper blade skin, a lower blade skin, an inboard end, an outboard end, and a trailing edge. The rotor blade assembly further includes a trailing edge actuator assembly. The trailing edge actuator assembly includes an upper actuator skin and a lower actuator skin defining a cavity and a trailing edge flap, a control panel disposed in the cavity and coupled to one of the upper actuator skin or the lower actuator skin and one or more actuators disposed in the cavity and configured to apply force to the control panel to cause the trailing edge flap to deflect. The trailing edge actuator assembly is coupled to the trailing edge of the main rotor blade body.

A rotor blade assembly for a rotary wing aircraft includes a main rotor blade body comprising an upper blade skin, a lower blade skin, an inboard end, an outboard end, and a trailing edge. The rotor blade assembly further includes a trailing edge actuator assembly. The trailing edge actuator assembly includes an upper actuator skin and a lower actuator skin defining a cavity and a trailing edge flap, a control panel disposed in the cavity and coupled to one of the upper actuator skin or the lower actuator skin and one or more actuators disposed in the cavity and configured to apply force to the control panel to cause the trailing edge flap to deflect. The trailing edge actuator assembly is coupled to the trailing edge of the main rotor blade body.

A rotary-wing aircraft and system for flying a rotary-wing aircraft. The aircraft includes a servo system for actuating a rotor of the aircraft. A hydraulic system provides hydraulic power to the servo system, and a sensor measures a parameter of the hydraulic system. A processor determines a condition of the hydraulic system from the parameter and enforces an effective flight envelop based on the condition of the hydraulic system in order to fly the aircraft within the effective flight envelope.

A rotary-wing aircraft and system for flying a rotary-wing aircraft. The aircraft includes a servo system for actuating a rotor of the aircraft. A hydraulic system provides hydraulic power to the servo system, and a sensor measures a parameter of the hydraulic system. A processor determines a condition of the hydraulic system from the parameter and enforces an effective flight envelop based on the condition of the hydraulic system in order to fly the aircraft within the effective flight envelope.

A control valve for a multi-stage hydraulic actuator includes a valve body defining a translation axis, a spool disposed within the valve body and movable along the translation axis, and a flange. The flange is fixed relative to the spool and has an aperture disposed externally of the valve body to removably fix the spool to a spool of a redundant control valve independently connected to the multi-stage hydraulic actuator for mitigating force fights between actuators coupled to the control valve.

A control valve for a multi-stage hydraulic actuator includes a valve body defining a translation axis, a spool disposed within the valve body and movable along the translation axis, and a flange. The flange is fixed relative to the spool and has an aperture disposed externally of the valve body to removably fix the spool to a spool of a redundant control valve independently connected to the multi-stage hydraulic actuator for mitigating force fights between actuators coupled to the control valve.

There is provided a control module for a hydraulic system. The module comprises a tank and a plurality of valves. The tank is configured to store hydraulic fluid and is substantially cylindrical. The plurality of valves fluidly connect with the tank and are configured to control distribution of hydraulic fluid from the tank to one or more components of the system. The plurality of valves are spaced around a circumference of the tank. One or more passages fluidly connect the tank with at least one of the plurality of valves and/or a first of the plurality of valves with a second of the plurality of valves.

There is provided a control module for a hydraulic system. The module comprises a tank and a plurality of valves. The tank is configured to store hydraulic fluid and is substantially cylindrical. The plurality of valves fluidly connect with the tank and are configured to control distribution of hydraulic fluid from the tank to one or more components of the system. The plurality of valves are spaced around a circumference of the tank. One or more passages fluidly connect the tank with at least one of the plurality of valves and/or a first of the plurality of valves with a second of the plurality of valves.

A propeller control unit (PCU) for controlling pitch angles of blades of a propeller, has: a pitch angle actuator; a servo valve hydraulically connected to the pitch angle actuator and to a first hydraulic fluid source; and a feather valve having a body movable within a cavity, the feather valve having a first actuation port and a second actuation port both in fluid communication with the cavity, the body between the first actuation port and the second actuation port, the body being movable to selectively hydraulically connect the pitch angle actuator to the servo valve through the feather valve or to hydraulically connect the pitch angle actuator to a drain line through the feather valve, the first actuation port and the second actuation port hydraulically connected to a second hydraulic fluid source independent from the first hydraulic fluid source.