Abstract: Horizontal control of a toy flying vehicle intended for indoor hovering flight comprises providing the vehicle having a rotor and a separate remote controller for use by a player of the toy. The vehicle is airborne relative to the controller. A signal is sent from a transmitter with the toy to the controller. A variation in intensity of the received signal from the toy being effected in a horizontal plane of the controller. The controller is programmed to transmit a responsive signal to the toy according to the variation of intensity of signal received and thereby to cause the toy with the transmitter in the toy to move horizontally and to thereby retain the received signal in the horizontal direction of the controller at a first predetermined level.

Abstract: An apparatus that includes a first member pivotably connected to a second member that is pivotably connected to a third member. The second member pivots about a first axis with respect to the first member and the third member pivots about a second axis with respect to the second member. The apparatus includes a first encoder configured to determine a first angle of rotation between the first member and the second member and a second encoder configured to determine a second angle of rotation between the second member and the third member. The first and second axes may be transverse to each other. The apparatus may be connected to a rotary aircraft with an object connected to the third member via a cable. The encoders may communicate with a display and/or a processor to display the location and/or movement of the object with respect to the rotary aircraft.

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: Indication of an amount of processing performed in detection and removal of ingress noise may be provided. A frequency domain representation of a narrowband region of a digital input signal may be received. The received frequency domain representation of the narrowband region may be compared with a predetermined threshold. Results from the comparison of the received frequency domain representation of the narrowband region with the predetermined threshold may be aggregated. Based on the aggregated results, an indication of an amount of processing performed by an ingress excizer in removing the ingress noise may be provided.

Abstract: A flight control method and system for a rotary wing aircraft. When the longitudinal speed UX of the aircraft is greater than a first threshold speed Vthresh1, 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 TKsol, a forward speed Va, a flight path angle P, and a heading ?. When the longitudinal speed UX is less than a second threshold speed Vthresh2, a second mode of operation enables flight to be performed while maintaining heading, the flight setpoints being the longitudinal speed UX, a lateral speed VY, a vertical speed WZ, and the heading ?.

Abstract: In an aspect, an apparatus includes a hovering unmanned aerial vehicle (HUAV). The HUAV includes an arm assembly configured to support a propeller in such a way that propeller drag of the propeller is decoupled from yaw torque requirements associated with the hovering unmanned aerial vehicle. In another aspect, an apparatus includes an HUAV that has an arm assembly that is field-foldable relative to the HUAV between a flight-ready state and a folded state. In another aspect, an apparatus includes an HUAV having an arm assembly that is keyed in such a way as to facilitate field-assembly relative to the HUAV.

Abstract: An aircraft is provided and includes a frame, drive elements configured to drive movements of the frame and a computer configured to receive mission planning and manual commands and to control operations of the drive elements to operate in a safe mode in which mission commands are accepted but manual commands are refused, a manual mode in which mission commands are refused but manual commands are accepted and an enroute mode. The computer is further configured to only allow mode transitions between the safe and manual modes and between the safe and enroute modes.

Abstract: A spin stabilized aircraft may include a plurality of wings that passively spin stabilize the aircraft, causing the apparatus to move in a direction opposite that of a wind source. The aircraft may also include two or more propulsive arms that actively stabilize the aircraft in absence of wind or a decrease in altitude.

Abstract: One embodiment of a method of calculating appropriate helicopter rotor adjustments, a method of calculating helicopter rotor adjustment coefficients, a method of producing a set of rotor adjustment coefficients for a specific rotor based on a limited data set, a software application for rotor balance, and a computing system for rotor balance.

Abstract: A blade tracking system for a rotary wing aircraft includes a blade sensor mounted on a blade of the rotary wing aircraft, the blade sensor wirelessly transmitting blade data; a reference sensor mounted to the rotary wing aircraft, the blade driven by the rotor hub, the reference sensor transmitting reference data; and a processor receiving the blade data and the reference data, the processor determining at least one of lead-lag, flap and pitch of the blade in response to the blade data and the reference data.

Abstract: According to a first aspect of the present invention there is provided an arrangement comprising, a volitant body comprising at least one actuator; a control unit for controlling said actuator; and a mechanical arrangement for operationally connecting said volitant body to a reference point remote from said volitant body. There is further provided a corresponding method for operating such an arrangement.

Abstract: An unmanned rotorcraft has a lift module having a propulsion system and coaxial rotors driven in rotation by the propulsion system. The rotorcraft includes a payload support system adapted to couple an external payload directly to the lift module. The rotorcraft is devoid of provisions for human passengers.

Abstract: A coaxial, dual rotor system includes a first rotor assembly positioned at a rotor axis. A first rotor quill shaft is operably connected to the first rotor assembly at the rotor axis to drive rotation of the first rotor assembly about the rotor axis. A nonrotating static mast extends along the rotor axis through the first rotor quill shaft. A second rotor assembly is positioned at the rotor axis. A second rotor quill shaft is operably connected to the second rotor assembly to drive rotation of the second rotor assembly about the rotor axis. The second rotor quill shaft is coaxial with the first rotor quill shaft and disposed inside of the static mast. A second rotor bearing is positioned between the second rotor assembly and the static mast to transfer loads from the second rotor assembly to the static mast.

Abstract: One aspect is a flight control system for independent speed and attitude control of a rotary wing aircraft that includes a main rotor system and a translational thrust system. The flight control system includes a flight control computer configured to interface with the main rotor system and the translational thrust system. The flight control computer includes processing circuitry configured to execute control logic. A pitch attitude reference generator provides a pitch attitude reference to a main rotor controller to command the main rotor system based on pilot input. A longitudinal reference generator produces a longitudinal reference as a longitudinal position or longitudinal velocity based on pilot input. An attitude-to-propulsor crossfeed converts the pitch attitude reference into a propulsor trim adjustment. A propeller pitch controller combines the longitudinal reference and the propulsor trim adjustment into a propeller command, and provides the propeller command to the translational thrust system.

Abstract: A method of assisting the piloting of a multi-engined rotorcraft in the event of an engine failure. A main rotor of the rotorcraft is driven at a variable NR speed under the control of a control unit. Calculation means identify an authorized margin of mechanical power usable by the pilot depending on a rating for regulating the operation of each of the engines under the control of a regulator unit. Outside an engine-failure situation, and providing the main rotor is being driven at a low NR speed, the mechanical power margin that is usable by the pilot and that is displayed on a screen, is in fact a limited margin of a value less than the authorized margin. Under such conditions, and in an engine-failure situation, the mechanical power reserve that is actually available enables the pilot to counter rapidly the sudden drop in the NR speed of rotation of the main rotor as induced by the engine failure.

Abstract: Embodiments described herein provide for detecting an angle of a cable attached to a rotorcraft for transporting a hanging payload using a pair of linear displacement sensors that are coupled to both the rotorcraft and the cable. One embodiment is a cable angle detector mounted to an underside of a rotorcraft. A cable has one end coupled to the rotorcraft and another end coupled to a payload. A pair of linear displacement sensors has one end coupled to the underside of the rotorcraft and another end coupled to the cable. The detector measures the displacement of the sensors and calculates an angle of the cable relative to the rotorcraft based on the measurements.

Abstract: A control system (20) for controlling pitching stabilizer means of an aircraft, said system (20) being provided with at least one outlet shaft (21) and with a first actuator (31) and a second actuator (36). The first and second actuators (31 and 36) are different, and the first actuator (31) is a slow actuator having a first driving portion that moves at a first speed, the second actuator (36) being a fast actuator having a second driving portion that moves at a second speed faster than the first speed, said control system (20) comprising a control device (50) connected to the first actuator (31) and to the second actuator (36) in order to cause said outlet shaft (21) to be driven either by the first driving portion (32) and/or by the second driving portion (37).

Abstract: A toy character includes a body, a first propeller assembly, a second propeller assembly, and a motor. The body extends in a longitudinal direction and has a longitudinal axis. The first propeller assembly is mounted to the body to rotate in a first direction about the longitudinal axis and positioned at a mid-portion of the body. The second propeller assembly is mounted to the body to rotate in a second direction about the longitudinal axis and spaced apart from the first propeller assembly. The second propeller assembly is mechanically linked to the first propeller assembly for counter-rotation in the second direction when the first propeller assembly rotates in the first direction. The motor is in communication with the first and second propeller assemblies to drive rotations in the first direction and the second direction.

Abstract: A translation layer includes a plurality of first buffers and a controller to assert one or more ready signals corresponding to one or more of the plurality of first buffers in response to the one or more of the plurality of first buffers being less than full. The one or more of the plurality of first buffers receives data or control information from one or more corresponding components in response to the ready signal being asserted concurrently with one or more valid signals asserted by the one or more corresponding components.

Abstract: An aircraft is provided and includes an airframe having main, pylon and tail sections, a rotor disposed at one of the pylon and tail sections and rotatable about a rotational axis to drive the airframe and a primary gearbox disposed within the main section of the airframe and a secondary gearbox disposed within one of the pylon and tail sections. The primary gearbox includes an outer housing rotationally fixed relative to the airframe and a driveshaft extending through the outer housing and coupled to the secondary gearbox to thereby drive rotation of the rotor relative to the airframe via the secondary gearbox. The aircraft further including a sensing system affixed to the outer housing and the driveshaft and configured to sense rotational characteristics of the driveshaft.

Abstract: An aircraft has a main body with a circular shape and a circular outer periphery. One or more rotor blades extend substantially horizontally outward from the main body at or about the circular outer periphery. In addition, one or more counter-rotation blades extend substantially horizontally outward from said main body at or about the circular outer periphery, but vertically offset from the main rotor blades. The main rotor blades are connected to a first annular gear that rotates in a first direction and the counter-rotation blades rotate are connected to a second annular gear that rotates in a second direction that is opposite the first direction for anti-torque. Planetary gears simultaneously drive the first and second annular gear at about the same speed.

Abstract: A remote control device includes an instruction transmitter and a controller which controls a speed of an unmanned helicopter based on an instruction from the instruction transmitter. The instruction transmitter selectively outputs one of a speed change signal that changes the speed of the unmanned helicopter and a speed determination signal that determines the speed of the unmanned helicopter. When an output from the instruction transmitter is changed from the speed change signal to the speed determination signal, the controller determines whether the speed of the unmanned helicopter should be maintained or brought to zero based on a result of comparison between speed information of the unmanned helicopter and a threshold value. Preferably, the speed change signal changes the speed of the unmanned helicopter by changing a tilt angle of a nose of the unmanned helicopter in an up-down direction in accordance with an amount of operation applied to the instruction transmitter.

Abstract: A system for transmitting data from a rotating component of a turbomachine includes a plurality of thermal sensors coupled to corresponding rotatable components within the turbomachine where each thermal sensor generates a discrete analog signal indicative of temperature. A plurality of transmitter assemblies is coupled to an end of a rotor shaft of the turbomachine. The plurality of transmitter assemblies comprises a first transmitter assembly and a second transmitter assembly. The first transmitter assembly is configured to receive the discrete analog signals from the plurality of thermal sensors, multiplex the plurality of discrete analog signals into a single amplifier and an analog-to-digital converter to generate a single stream of digital data therefrom. The system also includes a slip ring assembly having a plurality of conductive rings where at least one of the conductive rings defines a digital signal path between the first transmitter assembly and a data acquisition system.

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 a frame, drive elements configured to drive movements of the frame and a computer configured to receive mission planning and manual commands and to control operations of the drive elements to operate in a safe mode in which mission commands are accepted but manual commands are refused, a manual mode in which mission commands are refused but manual commands are accepted and an enroute mode. The computer is further configured to only allow mode transitions between the safe and manual modes and between the safe and enroute modes.

Abstract: The attitude and speed of the drone are controlled by angular commands applied to a control loop (120) for controlling the engines of the drone according to the pitch and roll axes. A dynamic model of the drone, including, in particular, a Kalman predictive filter, represents the horizontal speed components of the drone on the basis of the drone mass and drag coefficients, the Euler angles of the drone relative to an absolute terrestrial reference, and the rotation of same about a vertical axis. The acceleration of the drone along the three axes and the relative speed of same in relation to the ground are measured and applied to the model as to estimate (128) the horizontal speed components of the cross wind. This estimation can be used to generate corrective commands (126) that are combined with the angular commands applied to the control loop of the drone in terms of pitch and roll.

Abstract: Described herein is an aircraft that includes a fuselage with a higher portion and a lower portion. The aircraft also includes two fixed wings that are coupled to and extend from opposing sides of the lower portion of the fuselage. Additionally, the aircraft includes a tilt-rotor assembly that is coupled to each of the two fixed wings.

Abstract: An aerial vehicle including self-autonomous deployable arms and methods of deploying the vehicle are disclosed. The arms may include patterns located thereon that allow the arms to transition between wrapped, flat, and deployed configurations autonomously without the need for direct intervention by a user.

Abstract: An unmanned aerial vehicle (UAV) including a winch system, wherein the winch system includes a winch line having a first end that is secured to the payload, and wherein the winch system is controllable to vary the rate of descent of the payload, an inertial measurement unit positioned on the payload or on the first end of the winch line, wherein the inertial measurement unit is configured to measure oscillations of the payload, and a control system configured to (a) receive data from the IMU, (b) determine oscillations of the payload based on the data received from the IMU, and (c) operate the winch system to vary the deployment rate of the winch line so to damp oscillations of the payload.

Abstract: A method for monitoring a process plant having a fieldbus of process automation technology, via which a number of field devices exchange with a process control unit PLC telegrams in regular data traffic for process control. The following method steps are executed: telegrams transmitted via the fieldbus to the process control are tapped by a monitoring application, which performs a testing of the telegrams for data relevant for the monitoring application; data relevant for the monitoring application are processed as actual values in a process modeling application, which is part of the monitoring application; and when a significant deviation is determined between desired and actual values, an error signal is generated.

Abstract: The invention relates to a method for adjusting parameters in a stabilizing device (4) for stabilizing a flying attitude of a remote-controlled fixed-wing aircraft. To adjust a first parameter for a first axis, a first adjustment signal is transmitted from the transmitter (1) to the stabilizing device (4). The first parameter (P1) is stored during the flight as a result of a first memory signal transmitted from the transmitter (1). A second parameter (P2) for a second axis is then adjusted and stored in a similar manner.

Abstract: A helicopter autopilot system includes an inner loop for attitude hold for the flight of the helicopter including a given level of redundancy applied to the inner loop. An outer loop is configured for providing a navigation function with respect to the flight of the helicopter including a different level of redundancy than the inner loop. An actuator provides a braking force on a linkage that serves to stabilize the flight of the helicopter during a power failure. The actuator is electromechanical and receives electrical drive signals to provide automatic flight control of the helicopter without requiring a hydraulic assistance system in the helicopter. The autopilot can operate the helicopter in a failed mode of the hydraulic assistance system. A number of flight modes are described with associated sensor inputs including rate based and true attitude modes.

Abstract: An apparatus and method for controlling a haptic actuator. A haptic actuator controller can includes driver input amplifier, an actuator feedback amplifier, an actuator driver, and a gain controller. The actuator driver is configured to drive a haptic actuator based on a difference of output of the input amplifier and output of the actuator feedback amplifier. The gain controller is configured to determine a boost interval for initiating motion of the haptic actuator, the boost interval based on a boost threshold back-electromotive-force (BEMF) voltage value exceeding a BEMF voltage generated by the haptic actuator. The gain controller is also configured to apply boost gains in the input amplifier and the feedback amplifier during the boost interval. The boost gains are higher than gains applied subsequent to the boost interval to maintain motion of the haptic actuator.

Abstract: A rotorcraft engine starting system includes a starting system controller in communication with a flight control computer; an electric engine starter; an electronic engine controller in communication with the electric engine starter; an electrical power distributor; and a plurality of power sources coupled to the electrical power distributor; the starting system controller selecting at least one of the plurality of power sources and instructing the electrical power distributor to use the at least one of the plurality of power sources to power the electric engine starter.

Abstract: An aircraft is provided and includes an airframe, first and second main rotors rotatably supported on the airframe to rotate about a rotational axis in opposite directions, first and second emitters disposed on an emitter blade of the second main rotor, each of the first and second emitters being configured to emit an emission toward a detector blade of the first main rotor, a detector disposed on the detector blade of the first main rotor, the detector being configured to detect the emissions of the first and second emitters and a flight computer which determines a clearance between the first and second main rotors in accordance with detections of the emissions by the detector.

Abstract: A method of controlling a helicopter having a rotor with blades is provided. The method includes receiving, by a computing device comprising a processor, at least one input associated with the helicopter; generating, by the computing device, control signals configured to counteract blade bending associated with the rotors based on the received at least one input; measuring, by the computing device, blade signals using sensors for the blades; extracting, by the computing device, harmonic loads from the measured blade signals; adapting, by the computing device, the control signals based on the harmonic loads; and controlling, by the computing device, servos connected to the blades to adjust the blades according to the adapted control signals to reduce vibratory loads on the blades.

Abstract: An example method may include determining a drag force of an apparent wind on an aircraft that is coupled to a ground station via a tether. The method also includes determining a trajectory of the aircraft to a point downwind of the ground station such that the aircraft travelling the trajectory causes the tether to unfurl along a catenary path above ground. The method further includes determining an orientation of the aircraft to travel the trajectory in the apparent wind so that an actuator of the aircraft is configured to provide a vertical thrust in a direction substantially perpendicular to the ground. The method also includes determining a vertical thrust for the aircraft at the orientation to travel the trajectory in the apparent wind. The method also includes providing instructions to cause the actuator of the aircraft to provide the vertical thrust to move the aircraft along the trajectory.

Abstract: A pitch stabilizer [10] equipped with an upper stabilizer surface [15] and a lower stabilizer surface [20], with the upper stabilizer surface [15] being located in an upper plane [P1] and with the lower stabilizer surface [20] being located in a lower plane [P2], with the upper plane [P1] overhanging the lower plane [P2]. The upper stabilizer surface [15] is rotatable about an upper axis of rotation [AX1], with the said lower stabilizer surface [20] being rotatable about a lower axis of rotation [AX2], with the stabilizer means [10] having linking means [30] whereby a rotary movement of one stabilizer surface causes an equal rotary movement of the other stabilizer surface.

Abstract: A rotary wing aircraft includes a rotor assembly includes a rotor sensor generating a rotor sensor time domain signal; a rotor transform module converting the rotor sensor time domain signal to a rotor sensor frequency domain signal; and a rotor transceiver for transmitting the rotor sensor frequency domain signal over a transfer medium; an airframe assembly including: an airframe transceiver receiving the rotor sensor frequency domain signal; and an airframe transform module converting the rotor sensor frequency domain signal to the rotor sensor time domain signal. Signals from the airframe assembly may also be converted to the frequency domain prior to transfer over the transfer medium to the rotor assembly.

Abstract: A method of driving a rotorcraft rotor (1, 2) at variable controlled speeds. Starting from a required speed (Nr), a setpoint for total power (Pt) is calculated while taking account of an anticipated power (Pf) to be delivered by the power plant (3) for driving the main rotor (1) at the required speed (Nr), and while taking account of a power surplus (S) relating to progressive power needs to be delivered from a current power (Pc) for driving the main rotor (1) at a current speed (V) of rotation to an anticipated power (Pf) for driving the main rotor (1) at the required speed (Nr). By way of example, account may be taken at least of the acceleration or conversely of the deceleration of the main rotor (1) between the current speed (V) and the required speed (Nr), or indeed account may be taken of the flight circumstance of the rotorcraft determining the calculated required speed (Nr).

Abstract: Embodiments are directed to causing, by a computing device comprising a processor, a rotating tail rotor to operate in a tail rotor mode when an aircraft is operating at a speed less than a rudder control power threshold, receiving, by the computing device, a command that indicates a request to transition the aircraft, determining, by the computing device, that a rudder of the aircraft has control power in an amount greater than a second threshold based on receiving the command, and causing, by the computing device, the rotating tail rotor to operate in a pusher propeller mode based on determining that the rudder has control power in the amount greater than the second threshold.

Abstract: The adaptive control method for an unmanned vehicle with a slung load utilizes a feedback linearization controller (FLC) to perform vertical take off, hovering and landing of an unmanned aerial vehicle with a slung load, such as a quadrotor drone or the like. The controller includes a double loop architecture, where the overall controller includes an inner loop having an inner controller which is responsible for controlling the attitude angles and the altitude, and an outer loop having an outer controller responsible for providing the inner loop inner controller with the desired angle values. States, such as including roll, pitch, yaw and/or altitude, are selected as outputs and the feedback linearization technique is used.

Abstract: A method of operating an aircraft system includes receiving flight information and trajectory intent information other than current values by an engine control system associated with an engine of the aircraft system from a flight control system associated with the aircraft system; and operating an engine associated with the engine control system using the received non-current information. An aircraft includes an engine positioned on the aircraft; a full authority digital engine controller (FADEC) communicatively coupled to the engine; and a flight control system positioned on the aircraft and communicatively coupled to the FADEC, the flight control system configured to transmit other than current values of flight information and trajectory intent information to the FADEC and to receive other than current values of at least one of engine health and parameters used to estimate engine health from at least one of the FADEC and a separate flight control center positioned offboard the aircraft.

Abstract: A rotary wing aircraft including a vehicle vibration control system.

Abstract: The system for adaptively governing a speed of a rotor assembly in an aircraft can include a processor configured for comparing receivable data to limit data in an algorithm and subsequently making one or more commands that affect the speed of the rotor assembly, the algorithm being configured for analyzing power available during operation of the aircraft. The method can include calculating a first power available by comparing an actual transmission torque to a transmission torque limit; calculating a second power available by comparing an actual engine exhaust temperature to an engine exhaust temperature limit; and comparing the first power available to the second power available.

Abstract: A method, apparatus, and computer program product for managing movement of a flight control surface on an aircraft. A control signal is received to move the flight control surface to a position. Travel in a number of actuators in a plurality of actuators coupled to the flight control surface is limited to an amount that reduces a load on the number of actuators in the plurality of actuators in response to receiving the control signal while the aircraft is on the ground and the speed of the aircraft is less than a threshold.

Abstract: A method of controlling a group (2) of engines developing a necessary power (Wnec) for driving a rotor (3), said group (2) of engines having at least one electrical member (4), electrical energy storage means (5), and a first number n of engines (6) that is greater than or equal to two. A processor unit (10) executes instructions for evaluating a main condition as to whether the group of engines can develop the necessary power while resting one engine, and if so for resting one engine and accelerating a second number engines not at rest, and for causing the electrical member to operate in motor mode, if necessary, the electrical member operating temporarily in electricity generator mode when the storage means are discharged.

Abstract: The adaptive reference model algorithm uses a gain scheduling feature combined with a customized Least-Squares routine as an adaptive method for adjusting feedback control so as to account for variations in Transfer Function (G), thereby optimizing the effectiveness of the Active Vibration Control (AVC) System. The Least-Squares routine identifies the transfer function in a background process without interruption of closed loop vibration control. This identification approach is accomplished without intentional interrogation of the AVC actuators and without intentional vibration level changes. For this adaptive control logic, the dynamic relationship between AVC actuators and AVC sensors is represented by a mathematical model of Transfer Function (G). The mathematical model of Transfer Function (G) is continuously updated by the Least-Squares routine.

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 method for controlling rotor blades of a co-axial rotor assembly of an aircraft including a first rotor co-axial with a second rotor includes identifying a first zone of rotor rotation angles of the co-axial rotor assembly. The first zone defines a range of rotor rotation angles corresponding to an up-flow of air to the coaxial rotor assembly, and the remainder of the rotor rotation angles other than the first zone of rotation angles is defined as a second zone. The method includes receiving a yaw command to adjust a yaw moment of the aircraft and applying a different rotor blade angle change to rotor blades in the first zone than a rotor blade angle change applied to rotor blades in the second zone to adjust the yaw moment of the aircraft according to the yaw command.