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 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.

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.

This disclosure relates to various multi-rotor aircrafts including at least one passively tiltable rotor group which may be tilted, typically in a direction of their movement. More importantly, the passively tiltable rotor group can tilt on its own, without having to include any additional electric motor or other power generating devices. This disclosure relates to various multi-rotor aircrafts including various load sharing units capable of taking up at least a portion of a weight load of the aircraft to itself, thereby diverting that portion of the weight load from a tilting unit. Therefore, the tilting units may be tilted more easily under the reduced weight load and friction. This disclosure further relates to various methods of fabricating or operating such passively tiltable rotor groups, tilting units, or load sharing units, and various methods of incorporating such into the multi-rotor aircraft.

This disclosure relates to various multi-rotor aircrafts including at least one passively tiltable rotor group which may be tilted, typically in a direction of their movement. More importantly, the passively tiltable rotor group can tilt on its own, without having to include any additional electric motor or other power generating devices. This disclosure relates to various multi-rotor aircrafts including various load sharing units capable of taking up at least a portion of a weight load of the aircraft to itself, thereby diverting that portion of the weight load from a tilting unit. Therefore, the tilting units may be tilted more easily under the reduced weight load and friction. This disclosure further relates to various methods of fabricating or operating such passively tiltable rotor groups, tilting units, or load sharing units, and various methods of incorporating such into the multi-rotor aircraft.

A flight control method and system for a rotary wing aircraft. When the longitudinal speed U.sub.X of the aircraft is greater than a first threshold speed V.sub.thresh1, a first mode of operation of the method enables flight to be performed while maintaining track relative to the ground, the flight setpoints of an autopilot being a ground course angle TK.sub.sol, a forward speed Va, a flight path angle P, and a heading Ψ. When the longitudinal speed U.sub.X is less than a second threshold speed V.sub.thresh2, a second mode of operation enables flight to be performed while maintaining heading, the flight setpoints being the longitudinal speed U.sub.X, a lateral speed V.sub.Y, a vertical speed W.sub.Z, and the heading Ψ.

A flight control method and system for a rotary wing aircraft. When the longitudinal speed U.sub.X of the aircraft is greater than a first threshold speed V.sub.thresh1, a first mode of operation of the method enables flight to be performed while maintaining track relative to the ground, the flight setpoints of an autopilot being a ground course angle TK.sub.sol, a forward speed Va, a flight path angle P, and a heading Ψ. When the longitudinal speed U.sub.X is less than a second threshold speed V.sub.thresh2, a second mode of operation enables flight to be performed while maintaining heading, the flight setpoints being the longitudinal speed U.sub.X, a lateral speed V.sub.Y, a vertical speed W.sub.Z, and the heading Ψ.

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.

A system and method for providing feedback for an aircraft-bladed rotor about a longitudinal axis and having an adjustable blade pitch angle. At least one position marker is provided at the rotor, extends along an axial direction, from a first end to a second end, and has varying magnetic permeability from the first end to the second end. At least one sensor is coupled to the rotor and configured for producing, as the rotor rotates about the longitudinal axis, at least one sensor signal in response to detecting passage of the at least one position marker. A control unit is communicatively coupled to the at least one sensor and configured to generate a feedback signal indicative of the blade pitch angle in response to the at least one sensor signal received from the at least one sensor.

A system for receiving feedback in a flight plan of a vehicle includes a haptic-enabled device comprising a crew seat with an inceptor mounted thereto; and a processor with memory having instructions stored thereon that, when executed by the processor, cause the system to: receive signals indicative of the flight plan for the vehicle; receive deviation signals indicative of a proposed deviation in a trajectory for the flight plan; and transmit signals to the haptic-enabled device representing trajectory constraints in the proposed deviation in response to the receiving of the deviation signals.