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: According to one aspect, a method of initial rotor state compensation for a rotorcraft includes determining a vehicle attitude of the rotorcraft prior to takeoff of the rotorcraft. A rotor state compensation is computed based on the vehicle attitude. A plurality of rotor servos is commanded to an initial rotor state based on a nominal rotor neutral position value in combination with the rotor state compensation to establish a predetermined takeoff trajectory of the rotorcraft.

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: According to one aspect, a method of initial rotor state compensation for a rotorcraft includes determining a vehicle attitude of the rotorcraft prior to takeoff of the rotorcraft. A rotor state compensation is computed based on the vehicle attitude. A plurality of rotor servos is commanded to an initial rotor state based on a nominal rotor neutral position value in combination with the rotor state compensation to establish a predetermined takeoff trajectory of the rotorcraft.

Abstract: A tail sitter aircraft is capable of forward flight and hover operations. The tail sitter aircraft includes a wing and first and second prop-nacelles supportively disposed on the wing. Each of the first and second prop-nacelles includes an articulable rotor, which is rotatable about variable rotational axes and which includes blades that are collectively and cyclically controllable in both forward flight and hover regimes.

Abstract: An aircraft is provided and includes an airframe. The airframe includes first and second rotor apparatuses at upper and tail portions of the aircraft, respectively, to provide for control and navigational drive. The aircraft further includes a stabilizer component disposed at the tail portion in a position displaced from downwash of the first and second rotor apparatuses at airspeed ranges and a control system configured to apply a dither actuation signal to the stabilizer component at the airspeed ranges by which an aircraft response to a stabilizer component input is measurable for airspeed estimation purposes.

Abstract: An aircraft is provided and includes an airframe. The airframe includes first and second rotor apparatuses at upper and tail portions of the aircraft, respectively, to provide for control and navigational drive. The aircraft further includes a stabilizer component disposed at the tail portion in a position displaced from downwash of the first and second rotor apparatuses at airspeed ranges and a control system configured to apply a dither actuation signal to the stabilizer component at the airspeed ranges by which an aircraft response to a stabilizer component input is measurable for airspeed estimation purposes.

Abstract: A flight control system which detects a failure of a flight control surface and performs at least one action in response to the detected failure.

Abstract: A flight control system and method which determines an expected power required data in response to a flight control command of the at least one model following control law and utilizes the expected power required data to perform at least one action to control an engine speed.

Abstract: A flight control system which detects a failure of a flight control surface and performs at least one action in response to the detected failure.

Abstract: A flight control system and method which determines an expected power required data in response to a flight control command of the at least one model following control law and utilizes the expected power required data to perform at least one action to control an engine speed.

Abstract: A system is disclosed for determining the total torque required at the main and tail rotors of a helicopter for use in feed-forward rotor torque anticipation which includes a polynomial neural network adapted and configured to predict the aerodynamic torque at the main and tail rotors with the helicopter in motion based upon a plurality of pilot inputs and airframe inputs, a main rotor load map for determining the torque at the main rotor in hover out of ground effects based upon main rotor speed and collective stick position, a tail rotor load map for determining the torque at the tail rotor with the helicopter stationary based upon main rotor speed and pedal position, and a processor for calculating the required total torque at the main and tail rotors by summing the outputs of the polynomial neural network, and the main and tail rotor load maps.

Abstract: A control system for small unmanned rotorcraft compensates for vehicle pitch control saturation caused by the need for sudden vehicle pitch attitude correction, in turn often caused by wind gusts. The rotorcraft has a pitch-variable rotor system responsive to a vehicle pitch servo command for cyclically controlling rotor pitch and responsive to a collective servo command for collectively controlling rotor pitch. A compensating signal derived from the unlimited vehicle pitch servo command signal is cross-connected to the unlimited collective servo command signal to compensate for pitch control saturation, typically by reducing the magnitude of the resulting collective servo command signal. The compensating signal is derived by passing the unlimited vehicle pitch servo command signal through a dead band which responds as the signal approaches saturation and by preferably also then providing high and low frequency shaping to that signal.

Abstract: A helicopter engine fuel control anticipates sudden changes in engine power demand during yaw inputs to thereby minimize engine and main rotor speed droop and overspeed during yaw maneuvers. The rate (121,123) of yaw control (107) position change generates (110) a yaw component (104) of a helicopter fuel control (52) fuel command signal (70). The magnitude of the yaw component is also dependant upon the rate of yaw control position change (703). The fuel command signal yaw component (104) is overridden (113,115) when rotor decay rate (209,217) has been arrested during a sharp left hover turn (216); when the yaw component is removing fuel (239) during rotor droop (238); and when the yaw component is adding fuel (228) during rotor overspeed (227).

Abstract: A helicopter engine fuel control anticipates changes in main rotor torque in response to lateral cyclic pitch commands, to thereby minimize engine and main rotor speed droop and overspeed during left and right roll maneuvers. A fuel compensation signal (100,101) is summed with a helicopter fuel control (52) fuel command signal (67) in response both to a lateral cyclic pitch command signal (LCP) (107) from a pilot operated cyclic pitch control exceeding a left or right threshold magnitude (201,210) and a total lateral cyclic pitch command signal (TCP) (108) from a lateral cyclic pitch control system exceeding a left or right threshold magnitude (202,207,215,220). The magnitude of the fuel compensation signal is dependant upon the direction of TCP and LCP, e.g., left or right, and helicopter roll acceleration (115). Alternatively, the magnitude and duration of the fuel compensation signal is dependant upon the rate of change in commanded lateral cyclic pitch (107,400,407).