Aircraft lifting surface and aircraft comprising such lifting surface

Abstract

An aircraft lifting surface comprising an aerodynamic surface with a first electrode embedded at its surface, and a control surface articulated to the aerodynamic surface, the control surface comprises a second electrode embedded at its surface, and that the first electrode and the second electrode are arranged and adapted to create a plasma in air upon application of a predetermined electrical tension, called ionizing tension, between the first electrode and the second electrode.

Claims

1. An aircraft lifting surface comprising: an aerodynamic surface comprising at least a first electrode embedded at a surface of the aerodynamic surface and, a control surface articulated to the aerodynamic surface, wherein the control surface comprises at least a second electrode embedded at a surface of the control surface, and that the first electrode and the second electrode are arranged and configured to create a plasma in air upon application of a predetermined electrical tension, called ionizing tension, between the first electrode and the second electrode.

2. The aircraft lifting surface according to claim 1, wherein at least one of the first electrode and the second electrode is embedded beneath a dielectric layer.

3. The aircraft lifting surface according to claim 1, wherein the first electrode is arranged in a trailing portion of the aerodynamic surface.

4. The aircraft lifting surface according to claim 1, wherein the first electrode is arranged along an open edge of a trailing edge of the aerodynamic surface.

5. The aircraft lifting surface according to claim 1, wherein the second electrode is arranged in a leading portion of the control surface.

6. The aircraft lifting surface according to claim 1, wherein in a nominal position of the control surface, a leading edge of the control surface is adapted to be housed in a trailing edge of the aerodynamic surface.

7. The aircraft lifting surface according to claim 6, wherein, in the nominal position, the second electrode is arranged on the leading edge of the control surface so as to be housed within the trailing edge of the aerodynamic surface.

8. The aircraft lifting surface according to claim 1, wherein the aerodynamic surface comprises the first electrode on an extrados and a third electrode on an intrados, wherein the control surface comprises the second electrode on an extrados and a fourth electrode on an intrados, and wherein the third electrode and the fourth electrode are configured to create a plasma in air upon application of the ionizing tension between the third electrode and the fourth electrode.

9. The aircraft lifting surface according to claim 8, wherein the third electrode is arranged in a trailing portion of the aerodynamic surface, wherein the fourth electrode is arranged on a leading edge of the control surface so as to be housed within a trailing edge of the aerodynamic surface with the control surface in the nominal position.

10. The aircraft lifting surface according to claim 1, wherein the control surface comprises an array of second electrodes, said second electrodes being separated from each other along a chord of the control surface.

11. An aircraft comprising: the aircraft lifting surface according to claim 1.

12. The aircraft according to claim 11, further comprising: an electrical power source connected to the first electrode and to the second electrode configured to apply the ionizing tension between the first electrode and the second electrode.

13. The aircraft according to claim 11, further comprising: a control device configured to energize the first electrode and the second electrode upon one or more predetermined conditions.

14. The aircraft according to claim 13, wherein the control surface has a nominal position with respect to the aerodynamic surface, and the control device is configured to energize the first electrode and the second electrode when the control surface is deflected from the nominal position of at least a predetermined angle, called deflection angle.

15. The aircraft according to claim 13, wherein the aerodynamic surface comprises the first electrode on an extrados and a third electrode on an intrados, wherein the control surface comprises the second electrode on an extrados and a fourth electrode on an intrados, and wherein the third electrode and the fourth electrode are configured to create a plasma in air upon application of the ionizing tension between the third electrode and the fourth electrode, and, wherein the control device is further configured to energize the third electrode and the fourth electrode when the control surface is deflected from a nominal position below a predetermined angle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Some specific exemplary embodiments and aspects of the invention are described in the following description in reference to the accompanying figures.

(2) FIG. 1 is a schematic representation of a cross-section of a first embodiment of an aircraft lifting surface according to the invention.

(3) FIG. 2 is a schematic representation of a cross-section of a second embodiment of an aircraft lifting surface according to the invention.

(4) FIG. 3 is a schematic representation of a cross-section of a third embodiment of an aircraft lifting surface according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) In FIG. 1 a cross section of part of an aircraft according to the invention is shown. In this figure an aft portion of a lifting surface 10 is represented. This lifting surface 10 may for example be a horizontal tail plane.

(6) The lifting surface 10 comprises an aerodynamic surface 11. The aerodynamic surface 11 may for example be the fixed portion of the horizontal tail plane.

(7) The figure also comprises the representation of a control surface 12. This control surface 12 may be an elevator of the horizontal tail plane. The control surface 12 is articulated to the aerodynamic surface 11 in rotation along a rotation axis 15. In this figure, the control surface 12 is represented in a non-nominal position with respect to the aerodynamic surface 11. The angle formed between a medium plane 32 of the control surface 12 and a medium plane 31 of the aerodynamic surface 11 may be defined to have a value of zero when the control surface 12 is in a nominal position with respect to the aerodynamic surface 11.

(8) The medium plane 32 of the control surface 12 may be defined as a plane comprising a leading edge 33 of the control surface 12 and a trailing edge 34 of the control surface 12. The medium plane 32 separates the surface of the control surface 12 between an extrados 25 and an intrados 26. Similarly, a medium plane 31 of the aerodynamic surface 11 may be defined between an extrados 17 and an intrados 18 of the aerodynamic surface 11. The intersections between the medium planes 31, 32 and this cross-section of FIG. 1 represents the chords respectively of the aerodynamic surface 11 and the control surface 12.

(9) In this figure, the angle 35 between the medium plane 31 of the aerodynamic surface 11 and the medium plane 32 of the control surface 12 is different from zero, for examplebetween 20 and 35 degrees.

(10) The aerodynamic surface 11 comprises a first electrode 21 embedded at its surface. The first electrode 21 is embedded at a rear edge 16 of the aerodynamic surface 11, which may be considered as the trailing edge of the aerodynamic surface 11.

(11) The control surface 12 comprises a second electrode 22 embedded at its surface. The second electrode 22 is embedded in a front portion of the control surface 12, which may be considered as a leading edge portion of the control surface 12. In particular in this embodiment the second electrode 22 is placed in the front 25% of the control surface 12 along its chord. In this embodiment, the second electrode 22 may be embedded below a dielectric layer (not represented for clarity of the figure).

(12) As shown in FIG. 2, the rear portion (or trailing edge) of the aerodynamic surface 11 comprises a housing 13 between the trailing edge of its extrados 17 and the trailing edge of its intrados 18. When the control surface 12 is in a nominal position with respect to the aerodynamic surface 11, the leading edge 33 of the control surface 12 is housed within said housing 13.

(13) As show in FIG. 2, particularly, in this embodiment, when the control surface 12 is in a nominal position with respect to the aerodynamic surface 11, the second electrode 22 is housed within said housing 13.

(14) More particularly, in this embodiment, when the control surface 12 is in a nominal position with respect to the aerodynamic surface 11, the second electrode 22 is housed within said housing 13.

(15) As the control surface 12 is rotated with respect to the aerodynamic surface 11, there is an angle, said deflection angle, at which the second electrode 22 emerges from said housing 13 so that it may be exposed to an airflow along the aerodynamic surface 11 and control surface 12. The deflection angle may be of about 15 degrees. When this deflection angle is reached, a voltage may be applied between the first electrode 21 and the second electrode 22 such that a plasma may be formed in the airflow. The formation of the plasma creates an ionic wind 36 represented with lines between the two electrodes 21, 22 on FIG. 1. This ionic wind has proved to delay the separation of the boundary layer along the control surface 12.

(16) The application, between the first electrode 21 and the second electrode 22, of a predefined voltage above a minimum tension value, called ionizing tension, may be triggered automatically depending on the angle between the control surface 12 and the aerodynamic surface 11.

(17) FIG. 2 shows a second embodiment according to the invention. The aerodynamic surface 11 and the control surface 12 are similar to those of FIG. 1.

(18) In this figure, the control surface 12 is represented in a nominal position with respect to the aerodynamic surface 11. The angle between the medium plane 31 of the aerodynamic surface 11 and the medium plane 32 of the control surface 12 is null. As a result, the leading edge portion of the control surface 12 is housed within the housing 13 of the aft portion of the aerodynamic surface 11.

(19) In this embodiment, the aerodynamic surface 11 also comprises a first electrode 21 at a rear edge 16 of its extrados 17 and the control surface 12 comprises a second electrode 22 in a front portion of its extrados 25.

(20) Contrary to the embodiment of FIG. 1, in this embodiment of FIG. 2, the aerodynamic surface 11 also comprises a third electrode 23 at a rear edge of its intrados 18. Also, the control surface 12 comprises a fourth electrode 24 in a front portion of its intrados 26. Thereby, when the control surface 12 is rotated clockwise around the rotation axis 15 in this representation of FIG. 2, the second electrode emerges from the housing 13 when the angle 35 is above a first deflection angle. Similarly, when the control surface 12 is rotated anti-clockwise from its nominal position, below a second deflection angle, the third electrode emerges from the housing 13. With the angle 35 taking the value zero in the nominal position, the first deflection angle and the second deflection angle have opposite signs.

(21) Thereby in such embodiment, a plasma may be formed on the extrados when the control surface is deflected so as to increase the path of air on the extrados of the lifting surface 10, and a plasma may be formed on the intrados when the control surface in deflected so as to increase the path of air on the intrados of the lifting surface 10.

(22) FIG. 3 shows a third embodiment according to the invention. The aerodynamic surface 11 and the control surface 12 are similar to those of FIG. 1. As in FIG. 2, the aerodynamic surface 11 comprises a first electrode 21 on its extrados and a third electrode 23 on its intrados.

(23) Contrary to the embodiment of FIG. 2, the control surface 12 comprises an extrados group of electrodes comprising a plurality of second electrodes 22 in a front portion of its extrados 25. The control surface 12 also comprises an intrados group of electrodes comprising a plurality of fourth electrodes 24 in a front portion of its intrados 26.

(24) The second electrodes 22 are separated from each other along the chord of the control surface 12. Thereby a rotation of the control surface 12 around its rotation axis 15 in a clockwise direction will make the second electrodes 22 emerge one after the other from the housing 13. The chord distance between two successive second electrodes 22 may be adapted such that when the distance between the first electrode 21 and the closest exposed second electrodes becomes two large for a plasma to be effectively created in the airflow, a new second electrode emerges from the housing 13 so as to be exposed to air.

(25) The ionizing tension may be applied successively between the first electrode 21 and each of the second electrodes 22 successively emerging from the housing 13. Thereby, the higher the number of second electrodes in the extrados group of electrodes, the wider the range of angles at which a plasma may be created between the first electrode 21 and one of the second electrodes 22.

(26) A controller may determine which of the second electrodes 22 to apply a voltage to based on the rotation angle 35 between the control surface 12 and the aerodynamic surface 11.

(27) Similarly the fourth electrodes 24 are separated from each other along the chord of the control surface 12 and may be energized successively as they appear on the exposed portion of the intrados of the lifting surface 10.

(28) In any of the three embodiments presented, the first and fourth electrodes may be isolated from the air by an electrically isolating layer, while the second and fourth electrodes may be exposed to air.

(29) The invention is not limited to the specific embodiments herein disclosed as examples. The invention also encompasses other embodiments, covered by the claims, but not herein explicitly described, which may comprise various combinations of the features herein described.

(30) The systems and devices described herein may include a controller or a computing device comprising a processing and a memory which has stored therein computer-executable instructions for implementing the processes described herein. The processing unit may comprise any suitable devices configured to cause a series of steps to be performed so as to implement the method such that instructions, when executed by the computing device or other programmable apparatus, may cause the functions/acts/steps specified in the methods described herein to be executed. The processing unit may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

(31) The memory may be any suitable known or other machine-readable storage medium. The memory may comprise non-transitory computer readable storage medium such as, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory may include a suitable combination of any type of computer memory that is located either internally or externally to the device such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. The memory may comprise any storage means (e.g., devices) suitable for retrievably storing the computer-executable instructions executable by processing unit.

(32) The methods and systems described herein may be implemented in a high-level procedural or object-oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of the controller or computing device. Alternatively, the methods and systems described herein may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems described herein may be stored on the storage media or the device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein.

(33) Computer-executable instructions may be in many forms, including modules, executed by one or more computers or other devices. Generally, modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically, the functionality of the modules may be combined or distributed as desired in various embodiments.

(34) It will be appreciated that the systems and devices and components thereof may utilize communication through any of various network protocols such as TCP/IP, Ethernet, FTP, HTTP and the like, and/or through various wireless communication technologies such as GSM, CDMA, Wi-Fi, and WiMAX, is and the various computing devices described herein may be configured to communicate using any of these network protocols or technologies.

(35) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.