Abstract: An aircraft includes an airframe having an empennage, a counter rotating, coaxial main rotor assembly located at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the empennage and providing translational thrust to the airframe. At least two control surfaces located at the empennage are independently operable via commands from one or more flight control computers. A method of operating an aircraft includes transmitting a first signal from one or more flight control computers to a first control surface located at a first lateral side of a translational thrust system, and actuating the first control surface to a first position via the first signal. A second signal is transmitted to a second control surface located at a second lateral side opposite the first lateral side, and the second control surface is actuated to a second position via the second signal.

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: An aircraft includes an airframe with an upper portion and an extending tail, a counter-rotating, coaxial main rotor assembly disposed at the upper portion of the airframe, a translational thrust system, including a propeller, disposed at the extending tail of the airframe and a flight control system configured to control at least one of revolutions-per-minute (RPM) and pitch of the propeller of the translational thrust system in response to an input speed or acceleration command.

Abstract: An aircraft is provided and includes one or more main rotors, one or more and propellers including blades that are rotatable about a rotational axis, a pitch of each of the blades being controllable, and a flight control computer disposed to control the pitch of each of the blades to reduce propeller blade pitch angles in an event of an engine failure.

Abstract: A method of automating entry of an aircraft into autorotation includes detecting a loss of engine power, analyzing a sensed height and sensed airspeed of the aircraft, determining an adjusted position of one or more control surfaces of the aircraft in response to the sensed height and sensed airspeed, and automatically moving the one or more control surfaces to the adjusted position.

Abstract: A flight control system for an aircraft includes a flight control computer operatively interconnected with a main rotor system and a translational thrust system of the aircraft. A selectively enabled integrated target and flight control system arranged in communication with the flight control computer. The integrated target flight and control system is configured to control pitch attitude and heading of the aircraft. When the integrated target and flight control system is enabled, at least partial operation of the aircraft is controlled in response to a pilot input via the flight control computer.

Abstract: An aircraft includes an airframe having an empennage, a counter rotating, coaxial main rotor assembly located at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the empennage and providing translational thrust to the airframe. At least two control surfaces located at the empennage are independently operable via commands from one or more flight control computers. A method of operating an aircraft includes transmitting a first signal from one or more flight control computers to a first control surface located at a first lateral side of a translational thrust system, and actuating the first control surface to a first position via the first signal.

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: An aircraft composed of an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the extending tail. The translational thrust system provides translational thrust to the airframe. The aircraft includes a turn radius between about (595) feet and about (2440) feet for an airspeed between about (120) knots and about (210) knots at a constant altitude.

Abstract: An aircraft 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 air-frame; and a horizontal stabilizer positioned at the extending tail, the horizontal stabilizer having one or more elevators; wherein the aircraft is configured to mix at least two of the main rotor assembly collective pitch, the main rotor assembly cyclic pitch, the elevator deflection, and the translational thrust system thrust to trim the aircraft attitude.

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 for a rotorcraft includes a controller configured to receive input indicative of ambient conditions, determine a threshold rotor blade tip speed based on the input, and to output rotor control commands to prevent rotor blade tips from exceeding the threshold speed. An aircraft includes an airframe, a main rotor assembly operatively connected to the airframe, and a flight control system as described above. The flight control system is operatively connected to control the main rotor assembly. It is contemplated that the main rotor assembly can be a counter rotating coaxial main rotor assembly including an upper rotor assembly with a plurality of blades and a lower rotor assembly having a plurality of blades, wherein the flight control system is operatively connected to control both upper and lower rotor assemblies to prevent any blade tips of the upper and lower rotor assemblies from exceeding the threshold speed.

Abstract: An aircraft is provided including an airframe, an extending tail, and 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. A horizontal stabilizer with a left elevator and right elevator positioned at the extending tail. A flight control computer to independently control one or more of the main rotor assembly and the elevator through a fly-by-wire control system. The flight control computer is configured to mix a collective pitch of the main rotor assembly and a deflection of the elevator.

Abstract: An aircraft is provided including an airframe, an extending tail, a counter-rotating, coaxial main rotor assembly having an upper rotor assembly and a lower rotor assembly, and a translational thrust system including a propeller positioned at the extending tail. The translational thrust system is configured to provide translational thrust to the airframe when the aircraft is in a non-autorotation state and to generate power when in an autorotation state. A gearbox interconnects the propeller and the main rotor assembly to drive the main rotor assembly and the translational thrust system in the non-autorotation state. When the aircraft is in autorotation, the power generated by the propeller drives rotation of the main rotor assembly via the gearbox.

Abstract: An aircraft is provided including an airframe, an extending tail, and 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. The main rotor assembly and the translational thrust system are configured to provide hover nose down, hover nose up and hover level modes of flight.

Abstract: One aspect is a flight control system for a rotary wing aircraft that includes flight control computer configured to interface with a main rotor system, a translational thrust system, and an engine control system. The flight control computer includes processing circuitry configured to execute control logic. The control logic includes a primary flight control configured to produce flight control commands for the main rotor system and the translational thrust system. Main rotor engine anticipation logic is configured to produce a rotor power demand associated with the main rotor system. Propulsor loads engine anticipation logic is configured to produce an auxiliary propulsor power demand associated with the translational thrust system. The auxiliary propulsor power is combined with the rotor power demand to produce a total power demand anticipation signal for the engine control system.

Abstract: An aircraft is provided and includes an airframe defining a cockpit with first and second control stations configured for co-activation and complementary deactivation, flight control assemblies disposed at multiple locations of the airframe and a flight control computer (FCC). The FCC is configured to control operations of the flight control assemblies in accordance with current flight conditions and commands received at activated ones of the first and second control stations that are inputted by a flight crew. The FCC includes a secondary monitoring system to identify when commands are input at a deactivated one of the first and second control stations, to determine whether the commands are indicative of normal and intentional piloting inputs and to generate control station cues in an event the commands are indicative of normal and intentional piloting inputs to alert the flight crew of a hazardous condition or automatically turn the station back on.

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 flight control system of an aircraft is provided and includes modules configured to shape one or more flight control commands through a flight control system to provide a shaped flight control command and to determine expected power required data for the shaped flight control command. The flight control system further includes an architecture configured to determine enhanced engine load demand anticipation utilizing data reflective of an angle of attack of the aircraft for use in a determination of the expected power required data.