Aircraft with retractable vortex generators

Abstract

A fixed-wing aircraft (1) comprising at least one vortex generator (6, 7, 8, 11) movable through the outer surface of the aircraft (1) between a retracted condition and a fully extended condition by means of at least one electric motor (12) specifically adapted to actuate the at least one vortex generator (6, 7, 8, 11), and comprising an electronic control unit (13) adapted to control the operation of the at least one electric motor (12) for the actuation of the at least one vortex generator (6, 7, 8, 11).

Description

Technical Field

[0001] This invention relates to a fixed-wing aircraft comprising: at least one vortex generator movable between a retracted state and a fully extended state across the outer surface of the aircraft; and an electronic control unit adapted to control the actuation of the at least one vortex generator. The invention also relates to a method for operating a fixed-wing aircraft comprising at least one vortex generator movable between a retracted state and a fully extended state. The invention is particularly applicable to fixed-wing propeller aircraft, especially those comprising at least three propeller propulsion units per wing, particularly those with electronic propulsion units. Background Technology

[0002] EP 1 896 323B1 discloses a flow control device comprising: a flow control surface on which fluid is designed to flow in a predetermined direction; vortex generators associated with the flow control surface, each respective vortex generator having a pivot axis forming an acute angle with respect to the predetermined direction and being positionable in both an extended state and a retracted state, wherein in the extended state, the respective vortex generator is used to generate a vortex fluid flow, and in the retracted state, the respective vortex generator is pivoted via the pivot axis to be located on top of the overlying flow control surface and in a direction parallel to the overlying flow control surface; and an actuator associated with each of the respective vortex generators, each actuator being adapted to define the associated vortex generator between the extended state and the retracted state.

[0003] US 3,263,945 discloses an aircraft wing comprising: a main section and a drooping nose section having a pivot mount on the main section, the main section and the nose section having respective upper surfaces having a generally continuous common chord when the main section and the nose section are in a first positional relationship, the nose section pivoting relative to the main section on the pivot mount to a second positional relationship in which the upper surfaces are separated by a gap; at least one sealing plate pivotally mounted on the main section, and the at least one sealing plate being pivotally mounted on the main section. When the main section and the nose section are in the first positional relationship, they are in a fully retracted state on the upper surface, meaning that when the main section and the nose section are in the second positional relationship, the sealing plate moves into the gap to close the gap; and a series of blades, the series of blades standing upright on the sealing plate and forming a vortex generator, the blades being fully retracted from the upper surface of the main section and the nose section when the main section and the nose section are in the first positional relationship, and the blades protruding above the upper surface when the main section and the nose section are in the second positional relationship and the sealing plate is in the gap.

[0004] US 4,039,161 discloses vortex generators that are connected to the control surface in front of the hinge line, such that when the control surface deflects, the vortex generator protrudes into the airflow on the side opposite to the deflected control surface. The vortex generators work to keep the airflow attached to the control surface at angles of attack greater than otherwise possible, thus increasing the lift of the airfoil and the control surface.

[0005] US 5,253,828 discloses a concealable flap-actuated vortex generator for generating vortices on a lifting surface assembly and an improved aircraft flight lifting surface having such a concealable flap-actuated vortex generator. The vortex generator is not exposed when the flaps of the lifting surface assembly are in a nominal (unextended or undeflected) state. When the flaps are actuated by flap actuators, the flaps extend or deflect from the nominal state, thereby exposing or exposing the vortex generator to the operational state and enabling it to generate vortices.

[0006] US 8,657,238 B2 discloses an apparatus and method for improving the low-speed performance of a lift surface assembly. At least one eddy current generator is coupled to the lift surface assembly, and the eddy current generator extends through the lift surface assembly by drooping a hinged guide coupled to the lift surface assembly to increase lift. The eddy current generator retracts into the interior of the lift surface assembly to reduce drag.

[0007] US 10,202,187B2 discloses a vortex generator device for an aircraft, comprising: a surface section; a flap element pivotable between a first state and a second state; a biasing device biasing the flap element toward the second state; a holding device holding the flap element in either the first or second state; and a release device releasing the flap element from the first holding device. The biasing device, the first holding device, and the second holding device are configured such that the second holding device automatically holds the flap element in the second state after the flap element has been pivoted from the first state to the second state by the biasing device. Once the torque exceeds a predetermined value, the second holding device automatically releases the flap element, which has pivoted against the force of the biasing device into the first state and is automatically held in the first state by the first holding device.

[0008] US 2013 / 0299643 A1 discloses an vortex generating device including an vortex generator, which is deployed in response to the deployment of a wing leading-edge lift amplification device. The vortex generator is deployed in a state to generate vortices on the upper surface region of the main wing body behind the vortex generator.

[0009] US 2020 / 0391854 A1 discloses a retractable vortex generator system for an aircraft. The system includes: a skin; a slot disposed on the skin; a plate including a profile configured to generate a boundary layer of airflow; and a drive mechanism configured to rotate the plate between a first position and a second position. In the first position, at least a portion of the plate's profile protrudes through the slot, and in the second position, the plate retracts into the slot.

[0010] US 2010 / 0038492 A1 discloses a retractable ridge assembly comprising at least one ridge, which can be articulated onto the surface of an aircraft, such as a wing. The ridge is preferably configured to move between a retracted position and a deployed position. The aircraft may include an engine nacelle mounted on the underside of a wing. The nacelle may generate a nacelle wake that crosses the upper surface of the wing at high angles of attack and causes flow separation. The ridge is preferably configured such that the resulting vortices interact with the nacelle wake to delay flow separation and stall.

[0011] US 2004 / 0129838 A1 discloses a flow control device, and more particularly relates to a reactive modular flow control device having deployable flow actuators. US 2004 / 0129838 A1 also relates to a method of operating the flow control device. One embodiment includes a method for controlling airflow passing over an aircraft surface under certain flight conditions, the method comprising the steps of: sensing fluid separation from the surface by measuring pressure on the surface; determining a standard deviation of the pressure measurements over a time period; and deploying a flow actuator in response to the standard deviation of the pressure measurements exceeding a predetermined threshold number.

[0012] US 10,137,979B1 discloses a forebody flow control system, and more particularly discloses a flow control system for enhancing maneuverability and stability of an aircraft or missile at high angles of attack. US 10,137,979B1 also relates to a method of operating the flow control system. In one embodiment, it includes: a missile or aircraft comprising a rearbody and a forebody; at least one deployable flow actuator on the missile forebody or aircraft forebody; at least one sensor, each having a signal associated therewith, the at least one sensor for determining or estimating flow separation or lateral forces on the missile forebody; and a closed-loop control system; wherein the closed-loop control system is used to enable and disable at least one deployable flow actuator based at least in part on the signal from at least one sensor.

[0013] US 3,960,345 discloses one or more leading-edge extensions or their streamlined simulations mounted on a typical engine nacelle or similar wing-mounted body to reduce or prevent vortex formation typically found in nacelle-wing assemblies, thereby improving the lift and drag characteristics of the assembly and enhancing aircraft stability by reducing or eliminating variations in undesirable downwash changes on the tail surface.

[0014] DE 10 2015 120 958A1 discloses an actuator module for the controllable generation of turbulence by positioning a turbulent surface along a surface element. The actuator module has an elongated module substrate and a plurality of two-dimensional bending actuators. Each bending actuator includes a fiber composite panel having a shape memory conductor incorporated into the fiber composite material. The fiber composite panel is attached to the module substrate on an attachment side, and the shape memory conductor is designed such that the fiber composite panel extends along the surface of the module substrate in a deactivated state and bends away from the module substrate from the attachment side in an activated state. Furthermore, the actuator module includes a means structure for power lines extending along the module substrate to electrically actuate the bending actuators. Summary of the Invention

[0015] The object of this invention is to at least partially overcome the problems associated with the prior art. Specifically, the object of this invention is to achieve an efficient and flexible manner that enables localized flow separation and aerodynamic stall delay in risk areas on the outer surface of a fixed-wing aircraft, while maintaining a smoother airflow during flight modes where flow separation is not an issue, thereby reducing energy consumption.

[0016] This objective is achieved according to the features of the independent claim. For example, advantageous embodiments can be found in the dependent claims and / or the description.

[0017] This objective is achieved by a fixed-wing aircraft comprising at least one vortex generator capable of moving across the outer surface of the aircraft between a retracted state and a fully extended state via at least one electric motor, the at least one electric motor being specifically adapted to actuate the at least one vortex generator, and the fixed-wing aircraft including an electronic control unit adapted to control the operation of the electric motor for direct actuation of the at least one vortex generator.

[0018] This aircraft offers the following advantages: airflow on the outer surface of a fixed-wing aircraft, particularly on its lifting surface, can be influenced in a particularly flexible manner, thus allowing for a greater degree of flow control. When vortex generators are actuated individually (i.e., independently of other vortex generators) and / or in groups, these vortex generators can be actuated / moved to a desired deployment state (e.g., retracted, partially extended, or fully extended, as described further below), which is particularly suitable for the local position of the vortex generators under the aircraft's current aerodynamic conditions, while other vortex generators at other locations can be deployed differently. This provides an effective delay for local flow separation and aerodynamic stall when the vortex generators are in their extended position, while in other locations, including at least partially retracted vortex generators, airflow can be unrestricted, thus reducing aerodynamic drag and saving energy. Energy is also saved because the vortex generators retract into the aircraft across the surface rather than being in a parallel, overlapping relationship with the flow control surface.

[0019] For example, the aircraft can be a passenger aircraft and / or a cargo aircraft. The aircraft may include at least one fixed left wing and at least one fixed right wing. In particular, the aircraft may not be a helicopter.

[0020] At least one vortex generator extends maximally across the aircraft surface in its fully extended state, thus generating the strongest vortices or turbulence in the airflow. At least one vortex generator, in its retracted state, specifically does not extend from the surface, but rather retracts into or behind it. In one embodiment, the retracted vortex generator is flush with the surface. However, it is generally possible that the vortex generator extends slightly beyond the surface in its retracted state, but less than its extension in the extended state.

[0021] In one embodiment, at least one eddy current generator can be actuated to at least one intermediate state between a fully extended state and a retracted state, i.e., actuated to at least one partially extended state. This partially extended state can be, for example, a deployed state, in which the eddy current generator is extended or deployed to X% of the fully extended state, where X = 0%; 100% (where X = 0% is the fully retracted state, and X = 100% is the fully extended state). In one embodiment, the partially extended state can be a step of the fully extended state, such as 20%, 40%, 60%, or 80%. In one embodiment, the partially extended state can be controlled continuously or quasi-continuously, for example, in a step of 1% of the fully extended state. This capability can also be expressed as enabling the eddy current generator to extend in a differentiated manner.

[0022] The extended state can also be called the deployed state. The retracted state can also be called the withdrawn state.

[0023] The electric motor can be, but is not limited to, a brushless direct current (BLDC) motor or a stepper motor. The electric motor can be connected to an electrochemical converter (ECC) that generates electricity from hydrogen. The electric motor can be directly connected to the electrochemical converter, or connected to the electrochemical converter via an electrical storage device such as a battery. The electrochemical converter can be connected to a hydrogen tank for supplying hydrogen. The electric motor can be directly connected to at least one eddy current generator, or can be connected via, for example, a linkage system, a gear system, a vertical lifting device, etc. For example, the electrochemical converter can be at least one fuel cell or include at least one fuel cell.

[0024] The electronic control unit is adapted to control the operation of the electric motor, and thus control the actuation of at least one eddy current generator driven or actuated by the electric motor. The electric motor is specifically designed for or adapted to actuate at least one eddy current generator, including electric motors that are not adapted to actuate other types of flow control surfaces (i.e., not eddy current generators), such as leading-edge control surfaces or trailing-edge control surfaces like flaps, ailerons, etc. Therefore, if desired, the eddy current generator can be actuated independently of the actuation or movement of another type of flow control surface.

[0025] One implementation involves at least one vortex generator in the aircraft being actuated exclusively by the operation of an electric motor, while at least one other vortex generator in the aircraft is actuated together with a flow control surface. Thus, it is possible for one subgroup of vortex generators to move independently of the actuation of another type of flow control surface, while another subgroup of vortex generators can only move with the actuation or movement of the flow control surface, for example, because the movement is mechanically coupled / connected to each other, or because one subgroup of vortex generators and at least one control surface are actuated by the same electric motor or mechanically actuated by the pilot.

[0026] If the electronic control unit operates its electric motor accordingly, it can also actuate at least one eddy current generator, which can be actuated independently of but in harmony with another type of control surface. However, this coordinated motion is not mandatory, but rather selectively chosen by the electronic control unit, and may depend, for example, on the operating mode or control law.

[0027] At least one vortex generator may be located, for example, on any side of a lifting surface (e.g., wing / tail), a primary control surface and a secondary control surface (e.g., aileron / rudder / elevator / flaps), a fuselage and / or a propulsion system (e.g., pod / engine cowling).

[0028] As described above, one embodiment includes an aircraft comprising multiple vortex generators, at least one of which is individually actuable, extendable, and retractable. This advantageously provides a particularly flexible method for actuating the vortex generators and allows for a greater degree of flow control than existing solutions in the prior art. In a variation, all vortex generators are individually actuable for enhanced control of flow on the surface having these vortex generators. For individual actuation, the vortex generators can be associated with corresponding electric motors.

[0029] One embodiment is that the aircraft includes multiple vortex generators, and at least one group or subgroup of at least two vortex generators, each originating from these multiple vortex generators, can be actuated or moved in a similar manner, for example, actuated or moved as a group. In this case, a group of vortex generators can be actuated by a common motor. Of course, individually actuable vortex generators can also be actuated so that they move synchronously or in a similar group manner.

[0030] Individual and / or group actuation of eddy current generators includes: if not actuated, at least two eddy current generators can be in different deployment states, such as retracted, partially extended (to different degrees), or fully extended. Furthermore, eddy current generators within the same subgroup can be extended to different deployment states using a linkage system.

[0031] One implementation involves the aircraft including multiple vortex generators on each lifting surface, particularly on the upper side or surface of the wing. Another implementation allows the vortex generators of one wing to be actuated independently of those of the other wing. This is particularly advantageous, for example, during roll control of the aircraft and / or in the presence of shear winds, when airflow conditions are not simultaneous for different wings.

[0032] These vortex generators on each lifting surface can be actuated individually, particularly enabling at least two vortex generators on a single lifting surface to actuate independently of each other. Alternatively or additionally, the vortex generators on each lifting surface can be actuated in subgroups. These implementations are particularly useful when the airflow on the same wing is significantly different relative to the vortex generators. This is especially true when the wing is equipped with a propeller / propeller propulsion unit. Alternatively or additionally, all vortex generators on the wing can be actuated in a similar manner, and, if desired, can be extended or retracted simultaneously, for example.

[0033] The propeller of the propeller propulsion unit can be driven by an electric propulsion device (e.g., an electric propulsion motor / electric engine) and / or a fuel-powered propulsion device (e.g., a fuel-powered engine such as a turboprop aircraft / turbine engine, piston engine, etc.).

[0034] One embodiment involves attaching multiple propeller propulsion units to each wing, with each group / subgroup including at least one vortex generator positioned behind at least two propellers on the wing. Specifically, at least one group or subgroup including at least one vortex generator is positioned behind the first propeller, while another group or subgroup including at least one vortex generator is positioned behind the second propeller on the same wing. In particular, one group of at least one vortex generator is positioned behind each propeller in the propeller propulsion unit. This embodiment offers the advantage that these vortex generators are positioned within the propeller wake (also known as the "propeller slipstream"), and the deployment of these vortex generators therefore has a particularly significant impact on airflow.

[0035] The propeller propulsion unit may include at least one propeller and at least one motor, particularly an electric motor, to drive the at least one propeller. The propeller propulsion unit may also include an electrochemical converter (ECC) that generates electrical energy from hydrogen, or an ECC that can be connected to such an ECC. The propeller propulsion unit may also include a hydrogen tank in fluid connection with at least one electrochemical converter. Therefore, one embodiment is that the aircraft is a hydrogen-fueled, electrically driven aircraft.

[0036] In one embodiment, at least one propeller propulsion unit includes two propellers, for example, one propeller located in front of the wing and one propeller located behind / tail of the wing, or two counter-rotating propellers located in front of the wing. In any case, each propeller propulsion unit generates only one propeller slipstream region, particularly at the wing.

[0037] The propeller propulsion unit can be specifically mounted on the underside of the wing, the upper side of the wing, or the tip of the wing.

[0038] One implementation involves selectively actuating the vortex generators in these groups, meaning that one group of vortex generators can be actuated or moved in a manner different from that of another group. This selective actuation of the vortex generators in these groups can also be described as enabling a group of vortex generators located in a given propeller slipstream to be actuated or moved in a manner different from other groups located in different propeller slipstreams. This provides the advantage that the deployment state of the vortex generators can be matched to the characteristics of individual propeller propulsion units, such as their throttle settings or rotational speeds (RPM), which may differ between propeller propulsion units.

[0039] One implementation involves aligning at least one of a set of vortex generators located behind (and therefore within) the propeller slipstream volume of the propeller propulsion unit with the alignment offset (e.g., at an angle) relative to the flow direction of the propeller slipstream generated by the preceding propeller / propeller propulsion unit. This provides the advantage that such vortex generators can redirect a portion of the propeller slipstream to a region of the wing near the propeller, i.e., a region not within or outside the propeller slipstream, such as the region between two adjacent propeller propulsion units / propeller slipstreams.

[0040] One embodiment involves at least one set of vortex generators positioned on the wing at a lateral offset / proximity to the propeller propulsion unit and propeller (e.g., in a region not located within the propeller slipstream), wherein these sets of vortex generators can be actuated in a different manner than multiple sets of vortex generators positioned behind the propeller. This embodiment offers the advantage that airflow on the wing can be controlled in a particularly precise manner. In particular, the deployment of vortex generators positioned outside the propeller slipstream can increase the turbulence / turbidity of the flow, thereby delaying flow separation in regions without the increased dynamic pressure from the propeller slipstream.

[0041] In particular, an aircraft can be a distributed electric propulsion (DEP) aircraft in the sense that each wing includes at least three electrically driven propeller propulsion units per wing, especially at least three hydrogen-fueled electrically driven propulsion units. Flexible (individual and / or grouped) actuation of vortex generators is particularly useful in this case because, for example, the airflow along the wing is particularly irregular compared to conventional aircraft with two or fewer propellers / propeller slipstream regions per wing.

[0042] One implementation is that the actuation of at least one vortex generator depends on the flight mode / phase or flight maneuver, such as whether the aircraft is taking off, climbing, cruising, descending, turning and / or landing.

[0043] One implementation involves actuating at least one vortex generator based on the aircraft speed. This offers the advantage that localized flow separation and aerodynamic stall can be delayed at low speeds, while additional energy consumption due to aerodynamic drag is reduced at high speeds.

[0044] One implementation involves actuating at least one vortex generator based on the aircraft's roll angle and / or roll rate. For example, a vortex generator on a downward-moving wing can be actuated in a different manner than one on an upward-moving wing. One use case is to increase control authority of wingtip control surfaces (e.g., ailerons) during roll maneuvers, as one wingtip experiences an increase in angle of attack while the other experiences a decrease, depending on whether the aircraft is ascending or descending.

[0045] One implementation involves actuating at least one vortex generator based on the aircraft's sideslip angle. Sideslip is the aircraft's azimuth angle and occurs when the aircraft moves laterally and forward relative to oncoming airflow. One use case is that if onboard sensors detect a large sideslip angle, at least one vortex generator can be deployed to increase directional (yaw) stability and delay the critical angle of directional instability. At best, exceeding this critical angle significantly increases the pilot's workload in controlling the aircraft, and at worst, the pilot will lose control.

[0046] One implementation involves actuating at least one vortex generator based on the aircraft's angle of attack. The angle of attack is the angle between the oncoming airflow and a reference line passing through the aircraft. As the angle of attack increases, the airflow is more likely to separate from the lifting surface, potentially leading to a stall. One use case is that if onboard sensors detect a large angle of attack, at least one vortex generator can be deployed to re-excite the flow / keep the flow attached and delay stall.

[0047] One implementation involves actuation of at least one vortex generator dependent on at least one operating parameter of at least one propeller propulsion unit. This can include the failure of the propeller propulsion unit. One use case is to deploy at least one vortex generator to reduce the stall risk in the region on the wing located at the tail of the failed propeller propulsion unit.

[0048] One implementation method is that at least one operating parameter includes at least one operating parameter from the following set of operating parameters:

[0049] -Throttle valve setting;

[0050] - Propeller speed (RPM);

[0051] - Propeller rotation direction;

[0052] - Propeller blade pitch angle; and / or

[0053] - Input power supplied to the propeller propulsion unit.

[0054] This also includes situations where the propulsion unit is idle and / or the propulsion unit fails, resulting in a feathered propeller blade. Feathered propeller blades may mean setting the propeller blade pitch angle to close to 90 degrees, making the propeller blades nearly parallel to the airflow to minimize drag and prevent unwanted propeller rotation (known as propeller spin).

[0055] The input power supplied to the propeller propulsion unit specifically includes the input power supplied to the motor / engine that drives the propeller.

[0056] The actuation of at least one vortex generator depends on the rotation direction of the propeller of at least one propeller propulsion unit, and may include, for example, the following: if a propeller rotates counterclockwise when viewed from behind the propeller, a vortex generator located near the boundary of the propeller slipstream (but still within the slipstream) where the blades are moving upward relative to the wing surface can be actuated in a different manner than a vortex generator located near the boundary of the propeller slipstream where the blades are moving downward relative to the wing surface. Then, the actuation of at least one vortex generator depends particularly on the relative motion direction of the blades preceding it (e.g., upward, downward, or lateral relative to the vortex generator).

[0057] This provides the advantage of better flow control across the wing, and its main benefit is increased control over vortex recovery. Vortex recovery refers to the reduction of rotational induced velocity from the propeller, where the aim is to reduce propeller-induced losses. Vortex distribution depends on the propeller rotation direction and can be controlled by actuating individual vortex generators in different ways relative to the propeller rotation direction within the propeller slipstream. This is particularly useful when the propeller rotation direction differs between adjacent propeller propulsion units.

[0058] One implementation involves actuation of at least one vortex generator depending on the degree of deflection (e.g., rotation and / or extension) of control surfaces such as flaps, ailerons, rudders, etc. The degree of deflection can be detected by a sensor connected to the electronic control unit, or it can be determined from commands used to move the control surfaces.

[0059] One embodiment is that an electronic control unit is connected to at least one sensor and is adapted to operate at least one electric motor based on sensor readings from the at least one sensor to actuate at least one eddy current generator. The at least one sensor may be, for example, a gyroscope for measuring roll and yaw angles, or a pitot tube hydrostatic probe for determining aircraft airspeed, etc.

[0060] One implementation involves actuation of at least one vortex generator dependent on control commands from the pilot or the flight computer. This offers the advantage that the pilot or flight computer can exercise overriding control of the electronic control unit based on flight phase / manipulation or operating mode. The pilot can also select the operating mode of the vortex generator from within the cockpit.

[0061] In one embodiment, actuation can be managed by actuation logic or actuation scheme, wherein at least some, or possibly all, of the parameters are assigned specific weights and / or hierarchies to determine their impact on the actuation of at least one eddy current generator, or possibly on the actuation of at least one subgroup or all eddy current generators.

[0062] However, the actuation of at least one vortex generator in the vortex generator is not limited to or constrained by these parameters. For example, actuation can also depend on the location of the vortex generator on the aircraft surface: for instance, a subgroup of vortex generators near the wingtip may have a higher sensitivity to roll angles compared to a subgroup of vortex generators near the fuselage.

[0063] This objective is also achieved by a method for operating a fixed-wing aircraft, the fixed-wing aircraft including at least one vortex generator capable of moving directly between a retracted state and an extended state via at least one electric motor, wherein the electric motor is controlled to selectively actuate the at least one vortex generator. This method can be implemented in a manner similar to that of an aircraft and provides the same advantages. Attached Figure Description

[0064] The above-described features and advantages of the invention, and how they are implemented, will now be illustrated in more detail with reference to at least one embodiment in the context of one or more accompanying drawings.

[0065] Figure 1 A schematic diagram of the aircraft according to the first embodiment is shown in top view;

[0066] Figure 2 A schematic cross-sectional side view of a wing with an extended vortex generator is shown.

[0067] Figure 3 A retractable eddy current generator is shown. Figure 2 A side view of the cross-section of the wing;

[0068] Figure 4 An oblique view of a wing section with two sets of protruding vortex generators and one set of retracted vortex generators is shown.

[0069] Figure 5 A cross-sectional side view of the wing is shown with the vortex generator extending together with the trailing edge control surface;

[0070] Figure 6 This illustrates the case where the eddy current generator retracts together with the trailing edge control surface. Figure 5 A cross-sectional side view of the wing;

[0071] Figure 7 A schematic diagram of a section of the left wing of the aircraft according to the second embodiment is shown in top view;

[0072] Figure 8 A top view schematic diagram of a section of the left wing of the aircraft according to the third embodiment is shown;

[0073] Figure 9 A top-view schematic diagram of a section of the left wing of the aircraft according to the fourth embodiment is shown; and

[0074] Figure 10 A front cross-sectional view of the fuselage or fairing of an aircraft with asymmetrically distributed retractable and extended vortex generators is shown. Detailed Implementation

[0075] Figure 1 A schematic diagram of an aircraft 1 is shown, which has a left wing 2l and a right wing 2r (partially shown) fixed to a fuselage 3. Each of the wings 2l and 2r is equipped with a plurality of propeller propulsion units 4, each of which includes a propeller 5 at its forward portion. Each wing 2l and 2r is also equipped with a selectively extendable and retractable vortex generator 6, particularly at different locations along the wings 2l and 2r (not shown for the right wing 2r). In particular, the left wing 21 and the right wing 2r, and especially the vortex generators 6 and their positions, can be mirror-symmetrical with respect to the wings 2l and 2r.

[0076] As illustrated by the example via the left wing 21, some of the vortex generators 6 can be positioned in regions A1 to A5 on the upper surface of the wing 21 behind the corresponding propeller 5, thus exposing them to the corresponding propeller slipstream. Here, other vortex generators 6 can be positioned in regions B1 to B4 near the propeller 5: and in regions B1 to B4 positioned between the propellers 5.

[0077] The aircraft 1 also includes one or more other selectively extendable and retractable vortex generators, such as vortex generators (not shown) located on the underside of the wings 2l and 2r, vortex generators 7 and 8 located on the tail 9 of the aircraft, vortex generator 11 located on the fuselage 3 or fairing, vortex generator (not shown) located on the propeller propulsion unit 4, etc.

[0078] In one embodiment, all vortex generators 6 of the left wing 2l and the right wing 2r are individually movable across the upper surfaces (i.e., through the corresponding openings) of the respective wings 2l, 2r between a retracted state and a fully extended state, which may include an intermediate / partially extended state. Actuation of the vortex generators 6 is performed by corresponding electric motors 12 adapted specifically for actuating the vortex generators 6 (see [link to relevant documentation]). Figure 2 and Figure 3 This is caused by the operation of the electric motor 12. The operation of the electric motor 12 is controlled by the electronic control unit 13 of the aircraft 1.

[0079] Alternatively, at least one group or subgroup of at least two eddy current generators 6 can be actuated in a similar manner. For example, multiple groups of eddy current generators 6 in each of regions A1 to A5 can be actuated in a similar / grouped manner, wherein the actuation can be different in different groups and in regions A1 to A5. In one embodiment, the eddy current generators 6 in each of regions A1 to A5 can be actuated together by the same electric motor 12, for example, the eddy current generators 6 in region A1 are actuated by a specific common electric motor, the eddy current generators 6 in region A2 are actuated by another electric motor 12, and so on.

[0080] Furthermore, the eddy current generators 6 in regions B1 to B4 can be actuated in the same or different ways compared to the eddy current generators 6 in regions A1 to A5 and / or the eddy current generators 6 in other regions B1 to B4.

[0081] In one embodiment, at least one of the vortex generators 6 in regions A1 to A5 is angled relative to the direction of the propeller slipstream, such that a portion of the airflow is partially redirected to regions B1 to B4.

[0082] Typically, the vortex generator 6 of one wing 2l, 2r can be actuated independently of the vortex generator 6 of the other wing 2r, 2l, such that the vortex generator 6 of region A1 of the left wing 2l and the vortex generator 6 of the mirror-symmetric region A1 of the right wing 2r can extend simultaneously to different degrees, for example, or the vortex generator 6 of region A1 of the left wing 2l can retract, while the vortex generator 6 of region A1 of the right wing 2r can extend at least partially, and so on.

[0083] Figure 2 A cross-sectional side view of a wing 2l with an extended vortex generator 6 is shown. The vortex generator 6 is mechanically connected to an electric motor 12 via cable 13, in this example via a lift enhancer in the form of a rod 14 and a cylindrical member 15, or alternatively via a linkage mechanism (not shown). The extended state can be the "normal" state in which the vortex generator 6 moves without external force. This can be achieved by means of a spring or the like (not shown). The electric motor 12 actuates only at least one vortex generator 6.

[0084] Figure 3 A cross-sectional side view of a wing 2l with a retracted vortex generator 6 is shown. To actuate the vortex generator 6 to its retracted state, an electric motor 12 moves a lever 14, which in turn pulls a cable 13, which in turn pulls the vortex generator 6 into the wing 2l. The retracted vortex generator 6 may be flush with the surrounding surface of the wing 2l, or it may still protrude from the surrounding surface, but less than when it is fully extended.

[0085] Figure 2 and Figure 3 The eddy current generator 6 shown can operate independently of other flow control surfaces 16 or 17 (see...). Figures 4 to 6 (e.g., the movement and / or positional state of leading-edge control surfaces and / or trailing-edge control surfaces such as slats, flaps, ailerons, etc.) can cause actuation.

[0086] In one exemplary embodiment, one or more (but not all) of the vortex generators 6 of the wings 2l and 2r are actuated together with the flow control surface: Figure 4 A perspective view of a portion of the wing 2l with three sets of vortex generators 6 is shown. The three sets of vortex generators 6 are: four vortex generators 6 in the first set S1 located in region A1 behind the propellers 5; two vortex generators 6 in the second set S2 located in region B1 between the two propellers 5; and three vortex generators 6 in the third set S3 located in region A2 behind the propellers 5. As an exemplary embodiment only, the vortex generators 6 in each set S1, S2, and S3 are each capable of being actuated or moved in the same manner.

[0087] As shown, the vortex generator 6 of group S1 is mechanically connected and thus actuated together with the corresponding trailing edge control surface (e.g., aileron) 16.

[0088] In one embodiment, the eddy current generator 6 of group S3 is mechanically connected and thus actuated together with the corresponding trailing edge control surface 17.

[0089] In another embodiment, the vortex generator 6 of group S3 is not mechanically connected to the trailing edge control surface (e.g., aileron) 17, and therefore does not necessarily (but may) engage with the corresponding control surface 17, for example, with Figure 2 and Figure 3 The manner shown is actuated in which the eddy current generators 6 of groups S1 and S3 are moved by actuation of a dedicated electric motor 12, depending on the position (extension / rotation angle) of the trailing edge control surfaces 16 and 17, as sensed or detected by at least one sensor (not shown), or based on control commands for the trailing edge control surfaces 16 and 17.

[0090] In another embodiment (not shown), the eddy current generators 6 of groups S1 and S3 are not mechanically connected to the corresponding trailing edge control surfaces 16 and 17, respectively. This provides the advantage that the eddy current generators 6 of groups S1 and S3 can be similar to those in... Figures 4 to 6 The mechanism can move as shown in the mechanical linkage, but it can also be actuated independently of the trailing edge control surfaces 16 and 17. In this case, the eddy current generator 6 of groups S1 and S3 can be actuated by an electric motor that is different from the trailing edge control surfaces 16 and 17.

[0091] In any case, when the trailing edge control surfaces 16 and 17 deflect by different deflection angles (e.g., different angles), the eddy current generators 6 of the corresponding groups S1 and / or S3 can also extend to different states.

[0092] Return to reference Figure 4 The vortex generator 6 of group S2 can be actuated independently of the trailing edge control surfaces 16 and 17, and can extend in a different manner (as shown) for example, independently of the retraction extension of the vortex generator 6 of groups S1 and S3, or can be fully extended or fully retracted, depending, for example, on the maneuvering of aircraft 1.

[0093] For example Figure 5 As shown, the vortex generator 6 can extend as the trailing edge control surfaces 16 and 17 move away from the wing 2l. This is particularly suitable for low-speed situations, such as takeoff and landing, where localized flow separation and aerodynamic stall that may occur on the lift surface of the wing 2l are delayed due to the larger angle of attack. By doing so, the stall speed of the aircraft 1 will be reduced, thereby improving the low-speed performance characteristics of the aircraft 1. This provides a simpler, lighter, and smoother leading-edge solution compared to heavier and more complex leading-edge high-lift devices, such as slats or slots that also introduce surface discontinuities.

[0094] During the cruise phase, trailing edge control surfaces 16 and 17 move into wing 2l, and vortex generator 6 retracts, as... Figure 6 As shown in the diagram. Therefore, the wing surface will have a smooth, low-drag flow without the interference of the deployed vortex generator 6, which would otherwise convert the flow into turbulence. For normal cruise conditions, it is undesirable to force the airflow into turbulence, as the aircraft 1 does not operate at high angles of attack where flow separation is a problem. Therefore, energy is saved.

[0095] Figure 7 A top view of a section of the left wing 2l of an aircraft 1 according to a second exemplary embodiment, having regions A1, A2, and B1, is shown. In this embodiment, control surfaces in the form of, for example, ailerons 16 or 17, are shown. Furthermore, one of the vortex generators 6 is shown positioned near the wingtip, close to region A1.

[0096] If the control surface (e.g., aileron) 16 or 17 deflects, the vortex generator 6 in front of the control surface also extends. These vortex generators 6 extend according to the deflection of the aileron 16 or 17, but are not mechanically connected to the aileron 16, 17, for example, as in combination Figure 2 and Figure 3 As described. Alternatively, these vortex generators 6 can, for example, be mechanically connected to the ailerons 16, 17, as in combination. Figures 4 to 6 As described.

[0097] Figure 8 A top view of a portion of the left wing 2l of the aircraft 1 according to a third embodiment, having regions A1 to A3 and B1 to B2, is shown. In this embodiment, vortex generators 6 are arranged in front of and behind each other, at least in regions A1 to A3.

[0098] In this situation, the propeller 5 or propeller propulsion unit 4 associated with region A2 has failed. Therefore, the vortex generator 6 of region A2, and possibly also the vortex generator 6 of regions B1 and / or B2, extends to control the airflow in that region in order to delay the initiation of flow separation. Other vortex generators 6, such as those of regions A1 and A3, remain in their deployed state, for example, retracted state.

[0099] Figure 9 A top view of a portion of the left wing 2l of the aircraft 1 according to a fourth embodiment is shown. The vortex generator 6 shown in at least regions A1 to A3 is angled relative to the axial direction of the propeller slipstream. When extended, the vortex generator 6 widens the propeller slipstream, which then covers the increased area of ​​the wing 2l. This advantageously minimizes the risk of stall in this region, which would otherwise not experience any propeller slipstream.

[0100] The different actuations of the vortex generator are not limited to vortex generators 6 and 7 located on lifting surfaces, such as the horizontal elevators of the wings 2l, 2r or the tail 9, but can also be applied, for example, to the surface of the fuselage 3 or the fairing, such as vortex generator 11. Figure 10 As shown, the eddy current generator 11 on the left side is retracted and the eddy current generator 11 on the right side is extended. The same applies to the eddy current generator 8.

[0101] The actuation of at least one of the eddy current generators 6, 7, 8 and / or 11 can depend on at least one of the parameters from the following set of parameters:

[0102] - The flight mode / phase and / or control of aircraft 1;

[0103] -Airspeed of aircraft 1;

[0104] - The roll angle of aircraft 1;

[0105] -Slip angle of aircraft 1;

[0106] - Angle of attack of aircraft 1;

[0107] - Throttle setting of at least one propulsion unit 4;

[0108] - The propeller speed (RPM) of at least one propulsion unit 4;

[0109] - The rotation direction of the propeller of at least one propulsion unit 4;

[0110] - The propeller blade pitch angle of at least one propulsion unit 4;

[0111] - Input power supplied to at least one propulsion unit 4;

[0112] - At least one control surface 16, 17 to the degree of deflection;

[0113] - Control commands from the pilot or flight computer, but not limited to or limited by these parameters. In one embodiment, actuation can be managed by logic or scheme in which at least some, possibly all, and other possible influencing factors, such as the position of the vortex generator on the aircraft, are assigned specific weights and / or hierarchies to determine their impact on the actuation of at least one vortex generator, or possibly on the actuation of at least one subgroup or all vortex generators.

[0114] Of course, the present invention is not limited to the embodiments described.

[0115] For example, the number, location, and orientation of the vortex generators are generally unrestricted. In particular, any of the vortex generators 6 shown in the above figures can be present on the same wing 2l, 2r. For example, any of regions A1 to A5 and / or B1 to B4 may include one or more rows of vortex generators 6, wherein no vortex generator is angled relative to the direction of the propeller slipstream, or one or more of the vortex generators 6 are angled relative to the direction of the propeller slipstream. If angled vortex generators 6 are provided, they can be actuated independently of non-angled vortex generators 6, and vice versa, and so on.

[0116] List of reference numerals

[0117] 1. Aircraft

[0118] 21 Left Wing

[0119] 2r Right Wing

[0120] 3. Fuselage

[0121] 4 Propeller Propulsion Unit

[0122] 5 propellers

[0123] 6. Eddy Current Generator

[0124] 7. Eddy Current Generator

[0125] 8. Eddy Current Generator

[0126] 9. Tail wing

[0127] 11 Eddy Current Generator

[0128] 12 Electric motors

[0129] 13 Cables

[0130] 14 strokes

[0131] 15 Cylindrical parts

[0132] 16 Trailing edge control surfaces

[0133] 17 Trailing edge control surface

[0134] The area on the upper surface of the A1-A5 wings located behind the corresponding propellers.

[0135] The area on the upper surface of the B1-B4 wings located between the propellers

Claims

1. A fixed-wing aircraft (1), comprising at least: At least one vortex generator (6, 7, 8, 11), said at least one vortex generator (6, 7, 8, 11) being movable across the outer surface of the aircraft (1) between a retracted state and a fully extended state by at least one electric motor (12), said at least one electric motor (12) being specifically adapted to actuate said at least one vortex generator (6, 7, 8, 11); and said aircraft (1) comprising: An electronic control unit (13) is adapted to control the operation of the at least one electric motor (12) for actuation of the at least one eddy current generator (6, 7, 8, 11). The aircraft (1) includes multiple vortex generators on each wing (2l, 2r). in, Multiple propeller propulsion units (4) are attached to each wing (2l, 2r). Multiple groups, each having at least one vortex generator, are each positioned on the wing (2l, 2r) behind at least two propellers (5), and A set of vortex generators located in a given propeller slipstream can be actuated in a different manner than multiple sets of vortex generators located in different propeller slipstreams.

2. The aircraft (1) according to claim 1, wherein, The aircraft (1) includes a plurality of vortex generators (6, 7, 8, 11), and at least one of the plurality of vortex generators (6, 7, 8, 11) can be actuated individually.

3. The aircraft (1) according to claim 1 or 2, wherein, The aircraft (1) includes a plurality of vortex generators (6, 7, 8, 11) and has at least one set of at least two vortex generators (6, 7, 8, 11) that are each capable of being actuated in a similar manner.

4. The aircraft (1) according to claim 1, wherein, The vortex generator of one wing (2l, 2r) can be actuated independently of the vortex generator of the other wing (2r, 2l).

5. The aircraft (1) according to any one of claims 1, 2, and 4, wherein, At least two vortex generators of a wing (2l, 2r) can be actuated independently of each other.

6. The aircraft (1) according to any one of claims 1, 2, and 4, wherein, The alignment of at least one of the at least one set of vortex generators positioned behind the propeller (5) is offset relative to the flow direction of the propeller slipstream generated by the preceding propeller (5).

7. The aircraft (1) according to claim 6, wherein, The alignment of at least one of the at least one set of vortex generators located behind the propeller (5) is angled relative to the flow direction of the propeller slipstream generated by the preceding propeller (5).

8. The aircraft (1) according to any one of claims 1, 2, and 4, comprising at least one group of at least one vortex generator, each positioned on the wing (2l, 2r) close to the propeller (5), wherein, The vortex generator in the group can be actuated in a different manner than the vortex generators in the multiple groups located behind the propeller (5).

9. The aircraft (1) according to any one of claims 1, 2, and 4, comprising at least three propeller propulsion units (4) per wing (2r, 2l).

10. A fixed-wing aircraft (1), comprising at least: At least one vortex generator (6, 7, 8, 11), said at least one vortex generator (6, 7, 8, 11) being movable across the outer surface of the aircraft (1) between a retracted state and a fully extended state by at least one electric motor (12), said at least one electric motor (12) being specifically adapted to actuate said at least one vortex generator (6, 7, 8, 11); and said aircraft (1) comprising: An electronic control unit (13) is adapted to control the operation of the at least one electric motor (12) for actuation of the at least one eddy current generator (6, 7, 8, 11). The actuation of the at least one vortex generator (6, 7, 8, 11) depends on at least one operating parameter of at least one propeller propulsion unit (4).

11. The aircraft (1) according to claim 10, wherein, The actuation of the at least one eddy current generator (6, 7, 8, 11) depends on at least one of the following set of operating parameters: The flight mode and / or operation of the aircraft (1); The speed of the aircraft (1); The roll angle and / or roll rate of the aircraft (1); The sideslip angle of the aircraft (1); The angle of attack of the aircraft (1); Control the degree of deflection of surfaces (16, 17); Control commands from the pilot or flight computer.

12. The aircraft (1) according to claim 10 or 11, wherein, The at least one operating parameter includes at least one operating parameter from the following set of operating parameters: Throttling valve setting; Propeller speed; Propeller rotation direction; Propeller blade pitch angle; Input power supplied to the propeller propulsion unit (4).

13. A method for operating a fixed-wing aircraft (1), the aircraft (1) comprising at least one vortex generator (6, 7, 8, 11), the at least one vortex generator (6, 7, 8, 11) being directly actuated between a retracted state and a fully extended state by at least one electric motor (12), wherein, The electric motor (12) is specifically controlled for selective actuation of at least one eddy current generator (6, 7, 8, 11). The aircraft (1) includes multiple vortex generators on each wing (2l, 2r). in, Multiple propeller propulsion units (4) are attached to each wing (2l, 2r). Multiple groups, each having at least one vortex generator, are each positioned on the wing (2l, 2r) behind at least two propellers (5), and A set of vortex generators located in a given propeller slipstream can be actuated in a different manner than multiple sets of vortex generators located in different propeller slipstreams.

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