Abstract: 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.

Abstract: A computer-implemented method and system for controlling an aircraft based on detecting and mitigating fatiguing conditions and aircraft damage conditions is disclosed. According to one example, a computer-implemented method includes detecting, by a processing system, a health condition of a component of the aircraft. The method further includes determining, by the processing system, whether the health condition is one of a fatigue condition or a damage condition. The method further includes implementing, by the processing system, a first action based at least in part on determining that the health condition is a fatigue condition to mitigate the fatigue condition. The method further includes implementing, by the processing system, a second action based at least in part on determining that the health condition is a damage condition to mitigate the damage condition.

Abstract: A system and method for controlling a rotor of an aircraft is disclosed. A desired rotor speed for the rotor is received and a torque command that generates the received rotor speed is calculated. A fuel adjustment signal is calculated based on the torque command and a dynamic rotor measurement of the aircraft. The fuel adjustment signal is provided to the aircraft to track the rotor speed to the desired rotor speed.

Abstract: A computer-implemented method and system for controlling an aircraft based on detecting and mitigating fatiguing conditions and aircraft damage conditions is disclosed. According to one example, a computer-implemented method includes detecting, by a processing system, a health condition of a component of the aircraft. The method further includes determining, by the processing system, whether the health condition is one of a fatigue condition or a damage condition. The method further includes implementing, by the processing system, a first action based at least in part on determining that the health condition is a fatigue condition to mitigate the fatigue condition. The method further includes implementing, by the processing system, a second action based at least in part on determining that the health condition is a damage condition to mitigate the damage condition.

Abstract: An aircraft and method of flying an aircraft are disclosed. The aircraft includes a cross-feed unit that receives a flight command for the aircraft and determines an amount of fuel for a motor of the aircraft in order to reduce a droop in the aircraft when executing the flight command at the aircraft. A fuel injector or fuel supplier provides the determined amount of fuel to the motor when the flight command is executed at the aircraft.

Abstract: A flight system for an aircraft and method for controlling a clearance between a first rotor disk and a second rotor disk of an aircraft is disclosed. The flight system includes a sensor for measuring an angle of deviation of at least one of a first rotor disk and a second rotor disk of the aircraft to indicate a clearance between the first rotor disk and the second rotor disk as well as sensors for measuring a flight condition of the aircraft. A control allocation module uses the measured angle of deviation and the flight condition of the aircraft to determine an allocation of control settings to axis-controlling devices of the aircraft to attain a selected pitch of the aircraft, wherein the allocation is based at least on the measured angle of deviation and the flight state of the aircraft.

Abstract: A rotary wing aircraft includes an airframe including an extending tail. The airframe includes a longitudinal axis that extends through the extending tail. The rotary wing aircraft also includes a main rotor assembly including at least one rotor hub supporting a plurality of rotor blades configured and disposed to rotate about a main rotor axis, at least one elevator arranged at the extending tail, and a control system operably connected to the main rotor assembly and the at least one elevator. The control system is configured and disposed to adjust each of a pitch rate and an attitude of the airframe by selectively adjusting a position of the at least one elevator.

Abstract: 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.

Abstract: Examples of rotor speed reduction using a feed-forward rotor speed control command are provided. In one example, a computer-implemented method includes: receiving, by a processing device, flight command indicative of a change in a flight characteristic of an aircraft comprising a rotor; generating, by the processing device, a change in load factor based on the flight command; generating, by the processing device, a change in rotor speed based on the change in load factor; generating, by the processing device, a rotor speed command based on the change in rotor speed to a flight controller to cause the aircraft to change a rotor speed of the rotor; and changing, by the processing device, the rotor speed of the rotor responsive to the rotor speed command.

Abstract: A rotary-wing aircraft and system for controlling a flight of the rotary-wing aircraft. The aircraft includes a main rotor, a propeller and a variable speed transmission for transferring power from the main rotor to the propeller. A propeller command module controls operation of the variable speed transmission. The propeller command module varies a transfer of power from the main rotor to the propeller.

Abstract: One aspect is a flight control system for a rotary wing aircraft including a main rotor system and an elevator control system. A flight control computer of the flight control system includes processing circuitry configured to execute control logic. The control logic includes an inverse plant model that produces a main rotor feed forward command based on a pitch rate command, and a load alleviation control filter configured to reduce loads on a main rotor system and produce an elevator command for an elevator control system. A transformed elevator command filter produces a main rotor pitch adjustment command based on the elevator command, and a main rotor command generator generates an augmented main rotor feed forward command for the main rotor system based on the main rotor feed forward command and the main rotor pitch adjustment command.

Abstract: A control system is provided and includes a servo control system configured to control aerodynamic element pitching, an optical sensor system disposed along rotor blades to generate an optical response reflective of rotor feedback states of the rotor blades and a processing unit operably coupled between the servo control and optical sensor systems, the processing unit being configured to calculate strain in the rotor blades from the optical response, convert the calculated strain into readings of the rotor feedback states and issue a servo command to the servo control system as an instruction for controlling the aerodynamic element pitching.

Abstract: Examples of rotor speed reduction using a feed-forward rotor speed control command are provided. In one example, a computer-implemented method includes: receiving, by a processing device, flight command indicative of a change in a flight characteristic of an aircraft comprising a rotor; generating, by the processing device, a change in load factor based on the flight command; generating, by the processing device, a change in rotor speed based on the change in load factor; generating, by the processing device, a rotor speed command based on the change in rotor speed to a flight controller to cause the aircraft to change a rotor speed of the rotor; and changing, by the processing device, the rotor speed of the rotor responsive to the rotor speed command.

Abstract: A system and method for controlling a rotor of an aircraft is disclosed. A desired rotor speed for the rotor is received and a torque command that generates the received rotor speed is calculated. A fuel adjustment signal is calculated based on the torque command and a dynamic rotor measurement of the aircraft. The fuel adjustment signal is provided to the aircraft to track the rotor speed to the desired rotor speed.

Abstract: An aircraft and method of flying an aircraft are disclosed. The aircraft includes a cross-feed unit that receives a flight command for the aircraft and determines an amount of fuel for a motor of the aircraft in order to reduce a droop in the aircraft when executing the flight command at the aircraft. A fuel injector or fuel supplier provides the determined amount of fuel to the motor when the flight command is executed at the aircraft.

Abstract: A flight system for an aircraft and method for controlling a clearance between a first rotor disk and a second rotor disk of an aircraft is disclosed. The flight system includes a sensor for measuring an angle of deviation of at least one of a first rotor disk and a second rotor disk of the aircraft to indicate a clearance between the first rotor disk and the second rotor disk as well as sensors for measuring a flight condition of the aircraft. A control allocation module uses the measured angle of deviation and the flight condition of the aircraft to determine an allocation of control settings to axis-controlling devices of the aircraft to attain a selected pitch of the aircraft, wherein the allocation is based at least on the measured angle of deviation and the flight state of the aircraft.

Abstract: A rotary wing aircraft includes an airframe including an extending tail. The airframe includes a longitudinal axis that extends through the extending tail. The rotary wing aircraft also includes a main rotor assembly including at least one rotor hub supporting a plurality of rotor blades configured and disposed to rotate about a main rotor axis, at least one elevator arranged at the extending tail, and a control system operably connected to the main rotor assembly and the at least one elevator. The control system is configured and disposed to adjust each of a pitch rate and an attitude of the airframe by selectively adjusting a position of the at least one elevator.

Abstract: Lift offset management and control systems are provided for a rotorcraft including main rotor and auxiliary propulsor assemblies, the main rotor assembly including first and second rotors disposed to oppositely rotate relative to an airframe about a same rotational axis, and sensors disposed to generate hub moment, tip clearance and lift offset data of the main rotor assembly.

Abstract: One aspect is a flight control system for a rotary wing aircraft including a main rotor system and an elevator control system. A flight control computer of the flight control system includes processing circuitry configured to execute control logic. The control logic includes an inverse plant model that produces a main rotor feed forward command based on a pitch rate command, and a load alleviation control filter configured to reduce loads on a main rotor system and produce an elevator command for an elevator control system. A transformed elevator command filter produces a main rotor pitch adjustment command based on the elevator command, and a main rotor command generator generates an augmented main rotor feed forward command for the main rotor system based on the main rotor feed forward command and the main rotor pitch adjustment command.

Abstract: Disclosed is a rotorcraft including a plurality of blades, and a control computer configured to obtain a blade bending measurement from a sensor associated with a one of the plurality of blades, process, by a device comprising a processor, the blade bending measurement to obtain moment data for the rotorcraft, obtain data from an inertial measurement unit (IMU), wherein the data obtained from the IMU pertains to at least one of a pitch of the aircraft and an angular rate, and process, by the device, the moment data and the data from the IMU to generate a command configured to stabilize the aircraft, wherein the command is based on a reference input, and wherein the reference input is based on at least one input provided by a pilot of the aircraft.