Abstract: Provided is a vibration control system for a compound helicopter with a rotor and a fixed wing. The fixed wing includes a movable flap that is mounted on a rear edge of the fixed wing. The vibration control system periodically moves the movable flap so as to periodically change lift of the fixed wing such that vibration aerodynamically generated by the fixed wing is in anti-phase with vibration caused by rotation of the rotor.

Abstract: An arrangement for mechanically changing a surface includes an insulating layer, a pair of electrodes, which is arranged on or in the insulating layer, and a piezo element, which is arranged on or in the insulating layer. The piezo element is separated from the pair of electrodes by the insulating layer. The pair of electrodes is designed to generate in a region of the piezo element an electric field, which causes the piezo element to carry out a mechanical change of shape, in order in this way to mechanically change a surface of the arrangement. The pair of electrodes is also designed to generate the electric field such that the electric field has a minimum field strength in a surrounding area of the arrangement, in order in this way to generate a plasma in the surrounding area of the arrangement.

Abstract: A control system for a wind turbine is provided. The wind turbine includes at least one stationary component. The control system includes at least one mechanical load measurement sensor coupled to the at least one stationary component. The system also includes at least one modeling device configured to generate and transmit at least one wind turbine regulation device command signal to at least one wind turbine regulation device to regulate operation of the wind turbine based upon at least one wind inflow parameter.

Abstract: The invention relates to a method for operating a wind turbine (10) comprising a rotor (12) and a generator (18), connected to said rotor (12), for outputting electrical power to an electrical grid, said rotor (12) comprising rotor blades (14) whose blade pitch angles (?) may be moved during operation in order to control the rotational speed (n) of the rotor (12). Upon reaching a rotational speed (n) higher than a rotational speed limit (nlim) that delimits an operational range (34, 34?, 34?) of said wind turbine (10), the rotor (12) is forcibly braked by increasing the blade pitch angle (?) at a predefined positive blade pitch angle movement rate (?r). According to the invention, the rotational speed limit (nlim) is altered as a function of a blade pitch angle movement rate (?) set by the control. The invention also relates to a corresponding wind turbine (10).

Abstract: According to one embodiment, a flapping measurement system may include a position sensor and a controller. The position sensor may be disposed on the flapping plane of a rotor blade and operable to provide position measurements identifying locations of the position sensor during operation of the rotor blade. The controller may be operable to identify flapping of the rotor blade based on the position measurements.

Abstract: A method for operating a wind turbine is described. The wind turbine includes a tower having a tower axis, and a nacelle being rotatable about the tower axis. The method includes providing a data set of one or more operational parameters of the wind turbine. The one or more operational parameters depend on the angular position of the nacelle with respect to the tower axis. The method further includes determining an angular position of the nacelle with respect to the tower axis; selecting one or more operational parameters from the data set of one or more operational parameters of the wind turbine depending on the determined angular position of the nacelle; and applying the one or more selected operational parameters to the wind turbine. Further, another method of operating a wind turbine and a wind turbine are described.

Abstract: Method and blade monitoring system for monitoring bending moment of a wind turbine blade. The method comprises obtaining a first sensor set signal indicative of a first bending moment at a first sensor position different from the tip end along the longitudinal axis of the wind turbine blade, and estimating a bending moment at a first estimation position along the longitudinal axis based on the first sensor set signal, wherein the first sensor position is different from the first estimation position along the longitudinal axis. The blade monitoring system comprises a processing unit and an interface connected to the processing unit, the processing unit being configured for performing the method.

Abstract: A vertical take-off and landing (VTOL) aircraft according to an aspect of the present invention comprises a fuselage, an empennage having an all-moving horizontal stabilizer located at a tail end of the fuselage, a wing having the fuselage positioned approximately halfway between the distal ends of the wing, wherein the wing is configured to transform between a substantially straight wing configuration and a canted wing configuration using a canted hinge located on each side of the fuselage. The VTOL aircraft may further includes one or more retractable pogo supports, wherein a retractable pogo support is configured to deploy from each of the wing's distal ends.

Abstract: A rotor assembly for a rotary wing aircraft includes a plurality of rotor blades operably connected to a rotor shaft. Two or more active adaptive devices are located at one or more rotor blades of the plurality of rotor blades. The one or more active adaptive devices are operably connected to an aircraft flight control system such that, when activated, the one or more active adaptive devices change one or more operational characteristics of the rotor assembly. A method of operating a rotor assembly of a rotary wing aircraft includes rotating a plurality of rotor blades about a rotor shaft. Two or more active adaptive devices located at one or more rotor blades of the plurality of rotor blades are activated and change one or more operational characteristics of the rotor assembly.

Abstract: Disclosed are a rotor for wind power generation which converts wind power into electric energy, and a wind power generation apparatus having the same. The rotor for wind power generation includes a vertically or horizontally oriented rotating shaft, a plurality of main blades conically installed to the rotating shaft so as to be equidistantly spaced apart from one another, and an auxiliary blade coupled to each of the main blades, the auxiliary blade being configured to be bent according to the direction of wind. Through this configuration, it is possible to reduce an initial starting wind velocity and achieve increased lift and drag force, resulting in an enhancement in power generation efficiency.

Abstract: In accordance with one embodiment of the present application, an actuation system is configured for actuation of an airfoil member with a flap mechanism. The actuation system can include an upper drive tape and a lower drive tape, each partially wrapped around a first bearing and second bearing. An inboard frame can be actuated by at least one linear actuator. Similarly, an outboard frame can be actuated by at least one linear actuator. The inboard frame is coupled to the upper drive tape, while the outboard frame is coupled to the lower drive tape. An actuation of the inboard frame and outboard frame in a reciprocal manner acts move a flap input lever reciprocally upward and downward. A flap mechanism is configured to convert the movement of the flap input lever into rotational movements of the airfoil member.

Abstract: In accordance with one embodiment of the present application, an actuation system is configured for actuation of an airfoil member with a flap mechanism. The actuation system can include an upper drive tape and a lower drive tape, each partially wrapped around a first bearing and second bearing. An inboard frame can be actuated by at least one linear actuator. Similarly, an outboard frame can be actuated by at least one linear actuator. The inboard frame is coupled to the upper drive tape, while the outboard frame is coupled to the lower drive tape. An actuation of the inboard frame and outboard frame in a reciprocal manner acts move a flap input lever reciprocally upward and downward. A flap mechanism is configured to convert the movement of the flap input lever into rotational movements of the airfoil member.

Abstract: A rotor assembly for helicopter vehicles for providing an easy way of controlling pitch, roll and lift of the aircraft by respective servo actuators. The rotor assembly has a rotor shaft, at least two rotor blades, a rotor head, and a non-rotating swash plate. The rotor assembly also includes a pitch hinge for each rotor blade connecting each rotor blade to the rotor head. The rotor assembly also includes a guide member for each rotor blade. As the rotor assembly rotates, the guide members are in substantial contact with an upper surface of the non-rotating swash plate. Forces such as magnetic and/or an aerodynamic forces are applied on the rotor blades and are sufficiently strong to create a valve effect on the pitch hinge, which in turn maintains contact between the guide members and the non-rotating swash plate.

Abstract: A rotor hub assembly and method for controlling movement of a rotor blade relative to a swashplate. The hub assembly having an attachment device operably associated with the rotor blade and the swashplate. The attachment device provides pivot and rotational blade movement relative to the swashplate. A dual spring-rate damper is operably associated with the attachment device. The damper switches between a first spring rate and a second spring rate during flight to control movement of the rotor blade. The method includes the process of switching the damper between the first spring rate and the second spring rate during flight.

Abstract: A rotorcraft may include an airframe and a rotor connected to the airframe. The rotor may include a plurality of blades defining ducts along the length thereof and vents in fluid communication with the ducts. Flow from through the vents may be controlled by valves with piezoelectric actuators. The valves may be adjusted to achieve a lift profile suited for an operational mode such as vertical, autorotative, or unloaded flight. The lift profile may vary along the length of the blade and may vary cyclically with rotation of the blade. The lift profile may be chosen to approximate a figure of merit for the rotor suitable for a given operational mode.

Abstract: A device for controlling the pitch of a helicopter's rotor blade, the device having a BLDC motor based actuator; and at least one control surface operatively connected to the BLDC motor based actuator. The actuator and the control surface are preferably fully integrated into the interior profile of the rotor blade and are capable of controlling the PFC of the helicopter and improving HHC during operation by reducing noise and vibration. The motor is preferably a high power density motor incorporating rare earth permanent magnets connected to a roller/ball screw or planetary gear set to provide the right combination of force/torque, stroke and frequency.

Abstract: A wind turbine comprising a drive shaft; at least one vane connected to the drive shaft; and a torque converter attached to the vane, the torque converter comprising an airfoil, the torque converter being adapted to capture air for use in aiding the vane to rotate. Certain embodiments include the vane comprising a first surface and a second surface positioned opposite to the first surface, the first surface comprising a plurality of wind disrupters. Certain embodiments include a plurality of vanes rotatably connected to the drive shaft, the plurality of vanes comprising a plurality of strakes adapted to capture air and direct air to the drive shaft. Yet certain embodiments include a first air scoop connected to the vane, the first air scoop comprising a first air scoop portion at an angle relative to the vane.

Abstract: A hinged connection apparatus is described for securing a first wind turbine component to a second. The first wind turbine component may be a wind turbine blade (10) and the second wind turbine component may be a control surface such as an aileron (11). The first or second wind turbine component comprises at least one hinge housing in which a hinge pin (16, 26) is retained. The hinge pin (16, 26) may be extended from a retracted position into an extended position in which it engages with a hinge recess on the other wind turbine component to form a connection. A locking mechanism is provided for securing the hinge pin in place. The hinge pin may be extended manually or automatically by an actuator.

Abstract: A vertical axis omni-wind turbine having a wind sail centrally mounted to a turbine drive shaft, the wind sail consisting of three generally identical vanes paced 120 degrees apart. The vanes each have a generally concave surface for capturing impinging wind thrust with an opposite generally convex surface to provide minimal wind resistance. The resulting disparate wind resistance causes a stronger reaction on the concave side of a vane which in turn provides rotation about the vertical oriented drive shaft. The turbine has omni-wind characteristics in that regardless of the wind direction an adequate portion of the concave surface of a rotor blade will always be exposed to impinging wind. The subsequent drive shaft rotation is transmitted to an electrical turbine.

Abstract: A rotor blade includes an active flap and an airflow disturber configured to selectively alter airflow across the active flap.

Abstract: A wind turbine blade extending in a longitudinal direction from a root end to a tip end and defining an aerodynamic airfoil cross-section between a leading edge and a trailing edge in a chordwise direction transverse to the longitudinal direction, the aerodynamic airfoil cross-section having an effective camber in the chordwise direction; the wind turbine blade comprising: blade body; first device for modifying the aerodynamic surface or shape of the blade, the position and/or movement of the first device relative to the blade body being controlled by a first actuation mechanism; second device for modifying the effective camber of the airfoil cross section; herein, in use, the first device modifies the aerodynamic surface or shape of the blade at a frequency up to a first maximum frequency and the second device modifies the effective camber of the airfoil cross section at a frequency up to a second maximum frequency, the second maximum frequency being higher than the first maximum frequency.

Abstract: A system for actively controlling the span-wise rotational twist of a hollow beam along its longitudinal axis, including a hollow beam structure having a leading edge and a trailing edge region, the beam being split along its length, an actuator arranged between split surfaces of the beam, the actuator adapted to move the split surfaces in a longitudinal direction relative to each other, inducing a twist in the beam. The hollow beam is affixed to an external structure at one or both ends, with only the zero warping displacement points of the beam being attached to the external structure, material or device. In one embodiment, the actuator is a plurality of solid blocks with high thermal expansion coefficients arranged between frames of the split surfaces of the beam, with alternating blocks being heated by resistance heaters to cause expansion in the spanwise longitudinal direction.

Abstract: The current invention provides significant performance improvements or significant energy savings for fans used in these applications: personal, industrial and automotive cooling, ventilation, vacuuming and dust removal, inflating, computer component cooling, propulsors for unmanned and manned air vehicles, propulsors for airboats, air-cushion vehicles, airships and model aircraft. Additionally, the invention provides higher performance such as higher lift and higher lift efficiency to small air vehicles. These advantages are achieved by using plasma actuators to provide active flow control effectors into thin fan blades and wing.

Abstract: The present invention relates to a device and method for capturing the kinetic energy of a fluid and converting it to rotational, electrical or mechanical energy, the device including a rotating bar mechanism for enabling rotation of a flow-capturing blade around a central axis of the device while retaining the flow-capturing blade in an orientation perpendicular to the fluid flow direction throughout the rotation cycle.

Abstract: A helicopter rotor blade having a blade body that defines a confined space and a control flap that is secured to the blade body that moves through a range of motion. An electric machine is secured inside of the rotor blade body that rotates a motor shaft. A transmission device is secured to the motor shaft and the control flap that transfers rotary motion of the motor shaft to the control flap to generate movement of the control flap through its range of motion. The transmission device remains substantially within the confined space throughout the range of motion.

Abstract: A vertical axis wind and hydraulic turbine with flow control including a regular hexagonal structure of radius R, parallelepiped-shaped, inside which a rotor rotates with three or more vanes on a vertical axis which is located in the center of the hexagon as seen from above, wherein the vanes when rotating generate a circle of radius Rt, further including six articulated deflector vanes that grab and concentrate the flow of air or liquid entering the rotor vanes, from the wind or liquid current entry side to the turbine and diffuse the flow of air or liquid exiting from the rotor vanes, from the side opposite to the wind or liquid entry side to the turbine.

Abstract: A vertical axis wind turbine having a plurality of upright airfoils pivotally engaged. A continuous adjustment of the angle of attack of the airfoils to oncoming wind is provided by rotation of a control plate connected to the vanes which are mounted upon a rotating drive plate. A vane can be employed to rotate the control plate to affect the continuous adjustment of the airfoils.

Abstract: The computer programmable system and program product include first program instructions for actively driving a first imbalance mass concentration rotor and a second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a rotating net force vector to inhibit periodic vibrations. The program product includes second program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a starting stopping rotation speed less than the vibration canceling rotation frequency. The system includes a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating assembly vibration control system.

Abstract: The invention relates to a method for controlling a rotary wing aircraft with at least one main rotor, comprising a rotor head and rotor blades (12), arranged such that each rotor blade (12) is supported to be able to pivot or twist around the lengthwise axis of its blade on the rotor head and has at least one control flap (14) that can be deflected. According to the invention, the rotary wing aircraft is controlled solely by changing the respective blade pitch angle (X) by means of changing the flap control angle (Y) of the assigned control flaps (14) by the resulting blade pitch angle (X3) being set by applying the resulting flap angle (Y4) to the control flap (14), and the flap angle (Y4) being computed using an algorithm, the input quantities comprising the flap control angle (Y1) depending on the pilot primary control and the flap correction angle (Y2) depending on the secondary control.

Abstract: A wind turbine having at least a blade comprising a first component having an aerodynamic profile with a leading edge, a trailing edge, and suction and pressure sides between the leading edge and the trailing edge, and a second component, attached to the trailing edge and/or to the leading edge of the first component in at least a part of the blade, comprising one or several upwards and/or downwards deflectable flaps that allow changing the flow over the blade, in which a device for deflecting each of the flaps comprises an actuating force or torque provided by scaling devices connected to a predetermined location in the outer surface of the blade, through a duct, so that the changes in the wind pressure at this location can be scaled to the actuating force or torque.

Abstract: An actuation system includes a pump assembly configured to form a pump chamber, an actuator having first and second chambers and a movable member and configured to convert pressures applied to the first and second chambers into a movement of the movable member, and a valve section. The valve section has a plurality of positions set by a controller, and the plurality of positions includes a first position in which the valve section opens the first flow path and closes the second flow path, a second position in which the valve section closes the first flow path and opens the second flow path, and a neutral position in which the valve section closes the first and second flow paths.

Abstract: The present disclosure is directed to a rotary wing rotor comprising one or more blades. Each blade has a torsion frequency around its span being substantially equal to a rotation frequency (?) of the rotor; torsion means twist to the rotation frequency of the rotor, in synchronization with said rotation; and comprising a material configured to dampen the torsion resonance, so as to avoid the resonance divergence.

Abstract: A blade system and method of use for a wind turbine to produce electrical power. The system has a vertical rotor shaft coupled to an anchor pad and supports a horizontal blade arm. A blade assembly having a rotatable flap is coupled to the blade arm. The flap captures the wind which causes the rotor shaft to rotate and generates electrical power from an electrical generator.

Abstract: An apparatus and system for counteracting wind gusts and other high load situations in a wind turbine includes the use of one or more gust counteracting devices configured to extend an air deflector outwardly from a surface of a turbine rotor blade. The air deflector may subsequently be retracted into the rotor blade once the wind gust has subsided or once the load falls below a certain threshold. Mechanisms for extending and retracting the air deflector may include pneumatic or hydraulic systems and/or electromechanical devices. Air deflectors are generally configured to normalize air flow around the rotor blade so that the risk of potential damage to components of the wind turbine is minimized. In one arrangement, the gust counteracting device may be located at a leading section of the turbine blade. Additionally or alternatively, the device may be modular in nature to facilitate the removal and replacement of the device.

Abstract: Wind turbine, yaw system controller and yaw system for a wind turbine and method of reducing the loads on such a yaw system. A method for reducing the loads acting on a wind turbine yaw system (19) due to yawing moments which are induced to the yaw system (19) by a rotor which comprises at least one rotor blade with a pitch control system is provided. In the method, the yawing moment which is induced to the yaw system (19) by the rotor is determined and the pitch of the at least one rotor blade is set based on the detected yawing moment such that the determined yawing moment is reduced.

Abstract: A wind turbine having at least a blade comprising a first component having an aerodynamic profile with a leading edge, a trailing edge, and suction and pressure sides between the leading edge and the trailing edge, and a second component, attached to the trailing edge and/or to the leading edge of the first component in at least a part of the blade. An upwards and/or downwards deflectable flap allows changing the flow over the blade, in which the unit for deflecting the flap is a fluid inflatable unit placed in a flap inner chamber close to the first component and in which the wind turbine comprises a unit for controlling the inflatable unit depending on the wind situation and/or the blade loads.

Abstract: Gas turbine engine systems involving mechanically alterable vane throat areas are provided. In this regard, a representative vane for a gas turbine engine includes: a leading edge; a trailing edge; a suction side surface extending between the leading edge and the trailing edge; a cavity having an aperture located in the suction side surface; and a barrel located within the cavity and being moveable therein such that movement of the barrel alters an extent to which the barrel protrudes through the aperture.

Abstract: A trim tab assembly includes first and second shape memory alloy (SMA) actuators and a trim tab substrate which provide elastic/plastic locking in response to an induced strain actuation.

Abstract: Power generation apparatus includes a wing-shaped blade having opposite sides, opposite ends and leading and trailing edges extending between those ends. A lift differential producing device in the blade produces a lift differential at the opposite sides of the blade and that device is switched so that one blade side or the other produces the greater lift. A blade shaft extends along an axis in the blade that is in close parallel relation to the leading edge of the blade and that shaft is fixed to move with the blade. Supports support the blade shaft so that the blade can be positioned in a fluid stream with the leading edge facing upstream and swing about the axis between first and second extreme positions on opposite sides of a neutral position, the blade shaft oscillating with the blade. A coordinating device coordinates the switching of the lift differential producing device with the swinging of the blade so that the switching occurs at the extreme positions of the blade.

Abstract: Helicopter rotating hub mounted vibration control system for a rotary wing hub having periodic vibrations while rotating at an operational rotation frequency. The vibration control system includes a housing attachable to the rotary wing hub and rotating with the hub at the operational frequency. The housing is centered about the rotary wing hub axis of rotation and has an electronics housing cavity subsystem and an adjacent rotor housing cavity subsystem. The rotor housing cavity contains a first coaxial ring motor with a first rotor and imbalance mass and a second coaxial ring motor with a second rotor and imbalance mass.

Abstract: An articulated rotor system with a servo-flap rotor control system locates the focal point of a blade retention spherical elastomeric bearing inboard of a joint in the servo-flap pitch control tube which separates the flap hinge and supports the servo-flap pitch control tube on a single pivot bearing within a blade retention spindle. Rotor blade flapping produces relative movements between the servo-flap pitch control tube and the blade retention spindle which is converted through a servo-flap drive linkage into servo-flap pitch motions to provide flap/pitch coupling which reduces steady and transient blade flapping.

Abstract: A rotor blade 1 includes a main blade section 10, and an extension flap 20. The extension flap 20 is moveable relative to the main blade section 10. At least the main blade section 10 and the extension flap 20 form an airfoil lifting surface of the blade. A dimension of the airfoil lifting surface is variable by moving the extension flap 20 relative to the main blade section 10.

Abstract: Embodiments of systems and methods for enhancing the performance of rotary wing aircraft through reduced torque, noise and vibration are disclosed. In one embodiment, a method includes configuring the rotorcraft in a selected flight condition, communicating input signals to a control system operable to position sails coupled to tips of blades of a rotor assembly, processing the input signals according to a constraint condition to generate sail positional information, and transferring the sail positional information to the sail. Alternately, input signals may be communicated to a control system operable to position a plurality of sails, each sail having an aerodynamic shape and positioned proximate to a tip portion of the rotor blade. The input signals may be configured to rotate each sail about a longitudinal axis into a corresponding pitch angle independently of the other sails.

Abstract: In a blade vortex interaction (BVI) noise reduction system for a helicopter a rotor blade, a tab is movable via an actuator from a first position, wherein the tab is within the blade, to a second position, wherein the tab extends outwardly from a trailing edge of the rotor blade. The actuator is operated so that the tab advances and retreats in response to rotating timing of the rotor blade, to reduce the BVI noise of the rotor blade.

Abstract: An airborne mobile platform generally includes a plurality of rotating rotor blades operating in an airflow that forms a boundary layer on each of the rotor blades. At least one of the rotor blades includes a section that encounters the airflow that includes an unsteady subsonic airflow having at least a varying angle of attack. At least one of the rotor blades also includes one or more vortex generators on the at least one of the rotor blades that generate a vortex that interacts with the boundary layer to at least delay an onset of separation of the boundary layer, to increase a value of an unsteady maximum lift coefficient and to reduce a value of an unsteady pitching moment coefficient for the section.

Abstract: The computer programmable system and program product include first program instructions for actively driving a first imbalance mass concentration rotor and a second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a rotating net force vector to inhibit periodic vibrations. The program product includes second program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a starting stopping rotation speed less than the vibration canceling rotation frequency. The system includes a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating assembly vibration control system.

Abstract: The present method is characterized by providing the rotor blade with a tab 3, which can advance and retreat with respect to rear of rotating direction of the rotor blade between a position where the tab protrudes from a trailing edge of the rotor blade and a position where the tab does not, and providing an actuator 4, which advances and retreats the tab 3, and operating the actuator 4 so that the tab advances and retreats in response to rotating timing of the rotor blade 2, when reducing the BVI noise of the rotor blade of a helicopter. Thus, the BVI noise of a helicopter can be reduced effectively.

Abstract: The present invention relates to a rotorcraft rotor blade (1) that comprises at least one tiltable trailing-edge flap (5), said flap (5) being suitable for pivoting about a virtual hinge axis (Y?) extending substantially in the span direction of said blade (1) and of said flap (5). The blade (1) is remarkable in that the flap (5) is provided with at least two fastener ball joints (30), each provided with an inner cage (32) together with an outer cage (33) and a first pin (31) that is also secured to said flap (5), the first pins (31) of the fastener ball joints (30) being perpendicular to the virtual pivot axis (Y?) of the flap (5). In addition, the blade (1) is provided at its trailing edge (BF) with a fastener tongue (20) provided with ball-receiving sockets (21), the outer cages (33) of the fastener ball joints (30) being secured to the ball-receiving sockets (21).

Abstract: The present invention relates to a rotorcraft rotor blade (1) having at least one trailing edge flap (5) that is tiltable, the flap (5) being suitable for pivoting about a virtual hinge axis (Y?) extending substantially along the span of the blade (1) and of the flap (5). The blade (1) is remarkable in that the flap (5) is provided with at least one main ball joint (30) having an inner cage (32) and an outer cage (33), and a first shaft (31) secured to the flap (5), the front portion (33?) of the outer cage (33) of the main ball joint (30) being connected to a linear actuator (10) which is arranged in the blade (1) and which enables the flap (5) to be pivoted, the first shaft (31) of the main ball joint (30) extending substantially perpendicularly to the virtual hinge axis (Y?) about which the flap (5) pivots.

Abstract: A helicopter is fitted with a main rotor (1) having at least two blades (10, 20), each blade (10, 20) being provided with attachment elements (11, 21) for attaching it to a hub (2) of the rotor (1). The rotor is also fitted with one lift element (12, 22) per blade (10, 20), each lift element (12, 22) being mechanically linked to a single blade (10, 20) to vary the pitch of the single blade (10, 20) with which the lift element (12, 22) is linked.