Abstract: An aircraft is provided and includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe, at least one sensor and at least one inertial measurement unit (IMU) to sense current flight conditions of the aircraft, an interface to execute controls of a main rotor assembly in accordance with control commands and at least one flight control computer (FCC) to issue the control commands. The at least one FCC includes a central processing unit (CPU) and a memory having logic and executable instructions stored thereon, which, when executed, cause the CPU to issue the control commands based on the current flight conditions and a result of an execution of the logic for the current flight conditions.

Abstract: An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly composed of a plurality of blades and a lower rotor assembly composed of a plurality of blades. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A flight control system to control the upper rotor assembly and the lower rotor assembly, wherein the flight control system is configured to control lift offset of the upper rotor assembly and the lower rotor assembly.

Abstract: An aircraft includes an airframe having an extending tail, a counter rotating, coaxial main rotor assembly disposed at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the extending tail and providing translational thrust to the airframe. A fly by wire control system for the aircraft includes a flight control system configured to receive a plurality of inputs and a flight control computer to translate the inputs into commands and issue the commands to one or more controlled elements of the aircraft. A fly by wire control system for a dual coaxial rotor rotorcraft with auxiliary propulsor includes a flight control system configured to receive a plurality of inputs and a flight control computer to translate the inputs into commands and issue the commands to one or more controlled elements of the rotorcraft.

Abstract: An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly composed of a plurality of blades and a lower rotor assembly composed of a plurality of blades. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A flight control system to control the upper rotor assembly and the lower rotor assembly, wherein the flight control system is configured to control lift offset of the upper rotor assembly and the lower rotor assembly.

Abstract: An aircraft is provided and includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe, at least one sensor and at least one inertial measurement unit (IMU) to sense current flight conditions of the aircraft, an interface to execute controls of a main rotor assembly in accordance with control commands and at least one flight control computer (FCC) to issue the control commands. The at least one FCC includes a central processing unit (CPU) and a memory having logic and executable instructions stored thereon, which, when executed, cause the CPU to issue the control commands based on the current flight conditions and a result of an execution of the logic for the current flight conditions.

Abstract: A translational thrust system for a high speed rotary-wing aircraft includes a propeller system driven by a propeller gearbox, a hydraulic system, and a mechanical-hydraulic control system. The mechanical-hydraulic control system utilizes a hydraulic fluid which travels to and from a propeller dome via an oil transfer/position feedback tube which translates with a propeller pitch change piston. Translation of the oil transfer/position feedback tube and the propeller pitch change piston pitches the blades between high (coarse) and low (fine) pitch positions.

Abstract: A translational thrust system for a high speed rotary-wing aircraft includes a propeller system driven by a propeller gearbox, a hydraulic system, and a mechanical-hydraulic control system. The mechanical-hydraulic control system utilizes a hydraulic fluid which travels to and from a propeller dome via an oil transfer/position feedback tube which translates with a propeller pitch change piston. Translation of the oil transfer/position feedback tube and the propeller pitch change piston pitches the blades between high (coarse) and low (fine) pitch positions.

Abstract: In an X-Wing aircraft a dynamic higher harmonic control (HHC) system addresses the vibration which typifies a very rigid rotor and is implemented in two ways--a scheduled HHC and an active HHC. A scheduled HHC is located within the quadruple redundant portion of the flight control computers (FCC). This includes look-up maps for the second through fifth harmonic coefficients of the control equation as a function of airspeed and lift for rotary wing (RW) operation, and as a function of rotor speed for conversion (CV) operation. These are added to the collective and cyclic terms of the control equation and implemented through the pneumatic control valve (PCV) actuators. This flight critical portion of the HHC maintains vibration loads within structural limits. An active HHC, implemented in a dual redundant configuration, is added primarily to enhance vibration control during maneuver conditions and during conversions.

Abstract: The capability of compensating automatically for a failure in an actuator and the associated drive circuit is enhanced by providing a dual channel actuator, each channel having a drive coil and a position sensor tracking the position of the actuator output shaft. A separate circuit is provided for each actuator channel to detect drive loop failures and hydraulic failures. When the drive loop of one channel fails, it is disengaged, and the gain in the remaining drive loop is doubled to maintain authority. In an embodiment, the remaining drive loop cannot disengage when certain criteria, relating to the failure of associated actuators, are met. The invention is particularly useful for aerospace applications.

Abstract: The foldable rotor blades (12) of a helicopter are automatically adjusted to pitch angles where they can be locked as a prerequisite to folding, by commands generated (98, 112) to cause trim actuators (39-41) to drive swash plate servos (17-19) to the correct positions, initially (98) in response to stored trim references (120) and eventually (112) in response to the difference (109) between stored swash plate servo positions (120) and current servo positions (20-22). A claimed embodiment uses values of servo positions (20-22), just before unlocking the blades upon re-spreading them, to store, in nonvolatile memory (138), deviations (131) from nominal positions stored in read only memory, and generates (159) trim references in a subsequent folding operation in response to integrated values (166) to reduce actual position errors (162) toward zero from desired positions indicated by the stored deviations (148).