Abstract: Systems and methods for controlling aircraft obtain at least one of ground-referenced longitudinal movement data of the aircraft and ground-referenced lateral movement data of the aircraft. A round-referenced heading of the aircraft is obtained and a heading error is calculated based on a difference between the ground-referenced heading and a target heading. A lateral movement error value is generated based on at least one of the ground-referenced longitudinal movement data and ground-referenced lateral movement data, and based on the heading error.

Abstract: A method includes determining, by a computing device comprising a processor, a value for at least one parameter related to an operation of a coaxial rotary wing aircraft; processing, by the computing device, the at least one parameter to determine control power available from one or more flight controls comprising a differential cyclic; and establishing, by the computing device, a value for the differential cyclic to create a net yaw moment for the rotary wing aircraft based on the determination of the available control power.

Abstract: A flight control system includes a flight control computer operable in a flight state and a ground state. A high demand trim relief logic is operable by the flight control computer in the ground state. The high demand trim relief logic is configured to automatically modify the neutral position of a rotor when a command input to the flight control computer to control the rotor is near an allowable limit.

Abstract: One aspect is a flight control system for a coaxial rotary wing aircraft including a main rotor system and an active elevator. The flight control system includes a flight control computer with processing circuitry that executes control logic. The control logic includes a gust detector that produces a gust error indicative of a wind gust encountered by the coaxial rotary wing aircraft. The control logic also includes a gust alleviation control that reduces lift on the main rotor system with collective, based on the gust error, and mixes a collective command to a main rotor cyclic and a differential cyclic to reduce an aircraft pitch response and a lift-offset change. The gust alleviation control also reduces a main rotor pitching moment with the main rotor cyclic, based on the gust error, and mixes a main rotor cyclic command to the active elevator to reduce the aircraft pitch response.

Abstract: Embodiments are directed to obtaining data from at least one sensor, processing, by a processor, the data to determine an independent rotor phase lag for each of a plurality of axes associated with a rotorcraft, and issuing, by the processor, at least one command to provide for on-axis moments in accordance with the independent rotor phase lag for each of the axes.

Abstract: A rotorcraft control system can include a controller configured to receive an input from a pilot or autopilot for controlling at least one of a rotor and/or a performance profile of the rotorcraft and to control a propulsor as a function of the input for controlling the propulsor relative to the rotor and/or for achieving the input performance profile, wherein the controller is configured to fly the aircraft in accordance with the performance profile or to conform manual control inputs to the performance profile.

Abstract: A method for controlling a propeller of an aircraft, comprises receiving, with a processor, one or more signals indicative of commanded collective pitch of the propeller; receiving, with the processor, one or more sensed signals indicative of propeller axial speed, propeller rotational speed, and air density; estimating, with the processor, a propeller torque and propeller thrust from one or more of the propeller axial speed, the propeller rotational speed, and the air density; determining, with the processor, information indicative of an error value between a desired torque and a measured torque in the propeller; determining, with the processor, information indicative of a corrected pitch command in response to the determining of the error value; combining, with the processor, the corrected pitch command with the propeller rotational speed into an adjustment solution; providing, with the processor, the propeller with the adjustment solution.

Abstract: A method for controlling a differential rotor roll moment for a coaxial helicopter with rigid rotors, the method including receiving, with a processor, a signal indicative of a displacement command from a controller; receiving, with the processor via a sensor, one or more signals indicative of a longitudinal velocity, an angular velocity of one or more rotors and an air density ratio for the helicopter; determining, with the processor, a ganged collective mixing command in response to the receiving of the displacement command; determining, with the processor, a rotor advance ratio as a function of the longitudinal velocity and the angular velocity; and determining, with the processor, a corrective differential lateral cyclic command for the rigid rotors that controls the differential rotor roll moment to a desired value.

Abstract: A system and method for counteracting a rotor moment of one or more rotors of a coaxial rotor helicopter includes receiving signals with a processor indicative of a displacement command from a controller during a flight maneuver; receiving one or more signals with the processor from a sensor indicative of an airspeed and air density for the helicopter; determining a commanded rate of acceleration for the helicopter during the flight maneuver; and adjusting with one or more control servos a cyclic pitch for the one or more rotors to counteract the rotor moment during the flight maneuver.

Abstract: Two methods of combining multiple response types into a single flexible command model are provided and include receiving a pilot stick input, generating an aircraft response to the pilot stick input that is a continuous blend of response types by including calculable time-varying coefficients set as a function of a magnitude of the pilot stick input and other aircraft states such as airspeed, imposing at least an angular acceleration command limit and using other non-linear elements to optimize the aircraft response to the pilot stick input.

Abstract: Systems and methods for controlling aircraft obtain at least one of ground-referenced longitudinal movement data of the aircraft and ground-referenced lateral movement data of the aircraft. A round-referenced heading of the aircraft is obtained and a heading error is calculated based on a difference between the ground-referenced heading and a target heading. A lateral movement error value is generated based on at least one of the ground-referenced longitudinal movement data and ground-referenced lateral movement data, and based on the heading error.

Abstract: Systems and methods for controlling aircraft obtain at least one of ground-referenced longitudinal movement data of the aircraft and ground-referenced lateral movement data of the aircraft. A round-referenced heading of the aircraft is obtained and a heading error is calculated based on a difference between the ground-referenced heading and a target heading. A lateral movement error value is generated based on at least one of the ground-referenced longitudinal movement data and ground-referenced lateral movement data, and based on the heading error.

Abstract: One aspect is a flight control system for a coaxial rotary wing aircraft including a main rotor system and an active elevator. The flight control system includes a flight control computer with processing circuitry that executes control logic. The control logic includes a gust detector that produces a gust error indicative of a wind gust encountered by the coaxial rotary wing aircraft. The control logic also includes a gust alleviation control that reduces lift on the main rotor system with collective, based on the gust error, and mixes a collective command to a main rotor cyclic and a differential cyclic to reduce an aircraft pitch response and a lift-offset change. The gust alleviation control also reduces a main rotor pitching moment with the main rotor cyclic, based on the gust error, and mixes a main rotor cyclic command to the active elevator to reduce the aircraft pitch response.

Abstract: A method for controlling a differential rotor roll moment for a coaxial helicopter with rigid rotors, the method including receiving, with a processor, a signal indicative of a displacement command from a controller; receiving, with the processor via a sensor, one or more signals indicative of a longitudinal velocity, an angular velocity of one or more rotors and an air density ratio for the helicopter; determining, with the processor, a ganged collective mixing command in response to the receiving of the displacement command; determining, with the processor, a rotor advance ratio as a function of the longitudinal velocity and the angular velocity; and determining, with the processor, a corrective differential lateral cyclic command for the rigid rotors that controls the differential rotor roll moment to a desired value.

Abstract: Two methods of combining multiple response types into a single flexible command model are provided and include receiving a pilot stick input, generating an aircraft response to the pilot stick input that is a continuous blend of response types by including calculable time-varying coefficients set as a function of a magnitude of the pilot stick input and other aircraft states such as airspeed, imposing at least an angular acceleration command limit and using other non-linear elements to optimize the aircraft response to the pilot stick input.

Abstract: A system and method for estimating rotor mixing commands for an aircraft includes receiving signals indicative of reference commands from one or more controllers; receiving signals indicative of airspeed and sideslip angle for the aircraft, the sideslip angle being indicative of a direction of flight for the aircraft; calculating a sine and cosine of the sideslip angle; determining gains for roll and pitch as a function of the airspeed, the determining including referencing a look-up table that indexes the gain constants with the airspeed; and determining the one or more rotor mixing commands from the determined gains, the one or more rotor mixing commands being applied synchronously to the rotors in the aircraft.

Abstract: A system and method for counteracting a rotor moment of one or more rotors of a coaxial rotor helicopter includes receiving signals with a processor indicative of a displacement command from a controller during a flight maneuver; receiving one or more signals with the processor from a sensor indicative of an airspeed and air density for the helicopter; determining a commanded rate of acceleration for the helicopter during the flight maneuver; and adjusting with one or more control servos a cyclic pitch for the one or more rotors to counteract the rotor moment during the flight maneuver.

Abstract: A flight control system includes a flight control computer operable in a flight state and a ground state. A high demand trim relief logic is operable by the flight control computer in the ground state. The high demand trim relief logic is configured to automatically modify the neutral position of a rotor when a command input to the flight control computer to control the rotor is near an allowable limit.

Abstract: A method for controlling a propeller of an aircraft, comprises receiving, with a processor, one or more signals indicative of commanded collective pitch of the propeller; receiving, with the processor, one or more sensed signals indicative of propeller axial speed, propeller rotational speed, and air density; estimating, with the processor, a propeller torque and propeller thrust from one or more of the propeller axial speed, the propeller rotational speed, and the air density; determining, with the processor, information indicative of an error value between a desired torque and a measured torque in the propeller; determining, with the processor, information indicative of a corrected pitch command in response to the determining of the error value; combining, with the processor, the corrected pitch command with the propeller rotational speed into an adjustment solution; providing, with the processor, the propeller with the adjustment solution.

Abstract: Embodiments are directed to obtaining data from at least one sensor, processing, by a processor, the data to determine an independent rotor phase lag for each of a plurality of axes associated with a rotorcraft, and issuing, by the processor, at least one command to provide for on-axis moments in accordance with the independent rotor phase lag for each of the axes.