Wing assembly for an aircraft

Abstract

The present invention relates to a wing assembly (10) for an aircraft having a fuselage and at least one pair of wings, the wing assembly (10) defining a flow direction (F), with respect to which the wing assembly (10) is configured to generate lift for the aircraft, the wing assembly (10) comprising: a main portion (12) configured to be fixedly attached to the fuselage so as to extend from the fuselage in the direction of extension of the wings; and a plurality of flap portions (14), each having a body portion (16), pivotally attached to the main portion (12) by pivot means (18) so as to be individually pivotable about a pivot axis (A) through a range of angular orientations including a horizontal orientation and a vertical orientation, such that in the horizontal orientation, the body portion (16) of the flap portion (14) is substantially aligned with the main portion (12) to form an elongated, substantially continuous cross-section, and in the vertical orientation, the flap portion (14) is angled downwardly relative to the main portion (12). The invention further relates to an aircraft equipped with at least one pair of such wing assemblies.

Description

Detailed Description of the Invention

[0001] The present invention generally relates to a wing assembly for an aircraft having a fuselage and at least one pair of wings, the wing assembly defining a flow direction relative to which the wing assembly is configured to generate lift for the aircraft. The present invention also relates to an aircraft including a fuselage and at least one pair of such wing assemblies.

[0002] Aircraft that rely on wings to generate lift, in contrast to, for example, helicopters, require control surfaces in addition to the lift-generating surfaces. By utilizing the control surfaces in conjunction with the thrust provided by the aircraft's engines, the aircraft's horizontal velocity, vertical velocity, and attitude can be controlled within the aircraft's certified operating range according to inputs provided by the pilot. To be able to perform the aforementioned control functions, the aircraft requires actuators that can cause changes in forces and moments acting on the aircraft to change the aircraft's velocity or attitude.

[0003] One of the main technical challenges in designing and manufacturing a new type of aircraft is to find the best possible combination of actuators, lift-producing surfaces, control surfaces, and engines to perform these functions. At least some of the criteria, such as the number of actuators, the complexity of the actuators and their control systems, safety margins, mass, etc., may be optimized to find the best possible combination of the parameters of the aforementioned components while keeping in mind the intended performance of the aircraft, such as maximum and cruising speeds, range, maximum payload, fuel or energy consumption, etc.

[0004] While these fundamental considerations must be performed for all types of aircraft, aircraft with vertical take-off and landing (VTOL) capabilities require additional functionality to enable them to be operated in a hovering configuration and to transition between hovering and cruising flight, i.e., between substantially vertical and substantially parallel flight.

[0005] Several different approaches have been taken to provide both VTOL capabilities and controllability for each aircraft in horizontal flight mode. For example, aircraft with two custom thrust systems have been proposed, where one thrust system provides vertical thrust and general lift for hovering, while the second thrust system provides propulsion for cruise flight. However, providing dual thrust systems increases the weight and complexity of each aircraft. Second, VTOL aircraft are known in which the thrust units are rotated between hover and cruise positions without rotating the rest of the wing to which they are attached. While this design overcomes the need and drawbacks of providing two thrust systems, it does not take advantage of the additional lift that could be provided by rotatable lift surfaces integrated with the thrust units. Finally, VTOL aircraft have been proposed in which the entire wing, including the wing-mounted thrust systems, can be rotated between hover and cruise configurations. However, in order to rotate the entire wing, additional control surfaces must be implemented to be able to control the aircraft in cruise flight mode with the wings and thrust units themselves oriented in positions dedicated to cruise flight.

[0006] Therefore, there is still room for improvement in the design of wing assemblies for such aircraft, where lifting surfaces, control surfaces, and thrust-providing engines can be integrated in an optimized manner to provide a reliable, lightweight, and highly accurate integrated lift, control, and propulsion system.

[0007] To this end, according to a first aspect of the present invention, a wing assembly for an aircraft having a fuselage and at least one pair of wings is proposed, the wing assembly defining a flow direction relative to which the wing assembly is configured to generate lift for the aircraft. The wing assembly includes a main section and a plurality of flap sections. The main section is configured to be fixedly attached to the fuselage so as to extend from the fuselage in a direction of extension of the wings. The plurality of flap sections each have a body section and are pivotally attached to the main section by pivot means so as to be individually pivotable about a pivot axis through a range of angular orientations, including horizontal and vertical orientations. In the horizontal orientation, the body sections of the flap sections are substantially aligned with the main section to form an elongated, substantially continuous cross-section. In the vertical orientation, the flap sections are angled downward relative to the main section. Each of the flap sections includes a single ducted fan engine having a cowling, an intake port, and an exhaust port, the ducted fan engine configured to generate thrust within a predetermined range of thrust values ​​during operation. Furthermore, each ducted fan engine is integrally formed with the main body of the corresponding flap section, and the main body constitutes the lower part of the cowling of the ducted fan engine.

[0008] According to the first aspect, a wing assembly for an aircraft is provided with a plurality of individually controllable flap sections. The flap sections are pivotable or tiltable with respect to their angle relative to a fixed main section of the wing assembly. A single ducted fan engine is provided for each flap section, providing a highly integrated wing assembly. The variable angle between the flap section, i.e., the propulsion engine, and the fixed main section, i.e., the aircraft fuselage, allows for thrust vectoring. The flap sections also function as control surfaces, contributing to the aircraft's lift, particularly in a horizontal orientation. Note that the flow direction defined for this wing assembly substantially coincides with the corresponding horizontal flight direction of the aircraft. By providing multiple flap sections, each equipped with a single individually controllable ducted fan engine, not only are the control and lift surfaces of the wing assembly involved, but highly precise control of thrust vectoring among the multiple ducted fan engines is possible.

[0009] According to a second aspect, the present invention relates to a wing assembly for an aircraft having a fuselage and at least one pair of wings, the wing assembly defining a flow direction relative to which the wing assembly is configured to generate lift for the aircraft. The wing assembly comprises a main section and at least one flap section. The main section is configured to be fixedly attached to the fuselage so as to extend from the fuselage in the direction of extension of the wings. The at least one flap section has a body section and is pivotally attached to the main section by pivot means so as to be pivotable about a pivot axis through a range of angular orientations including horizontal and vertical orientations. In the horizontal orientation, the body section of the flap section is substantially aligned with the main section to form an elongated, substantially continuous cross-section. In the vertical orientation, the flap section is angled downward relative to the main section. The at least one flap section includes at least one ducted fan engine having a cowling, an intake port, and an exhaust port, the at least one ducted fan engine configured to generate thrust within a predetermined range of thrust values ​​during operation. The at least one ducted fan engine is integrally formed with a main body portion of the flap section, the main body portion forming a lower portion of the cowling of the at least one ducted fan engine. The operating conditions of the wing assembly include a current angular orientation of the at least one flap section and a current thrust generated by the at least one ducted fan engine. The main portion and the at least one flap section are configured such that, within at least a range of operating conditions of the wing assembly, the at least one flap section generates at least about 40% of the lift of the wing assembly. In further embodiments, the at least one flap section may generate at least about 50%, about 60%, or about 70% of the lift of the wing assembly.

[0010] According to a second aspect of the present invention, a wing assembly is proposed in which at least within a certain range of operating conditions, including at least the current angular orientation of at least one flap section and the thrust currently generated by the at least one ducted fan engine, at least one flap unit having at least one integrated ducted fan engine can serve not only as the sole control and propulsion element of the wing assembly, but also as the substantial lift surface, even the primary lift surface. Thus, all necessary forces and moments required for control and maneuverability in a wing assembly according to the present invention can be generated by a combination of propulsion thrust vectoring by dedicated actuators and aerodynamic forces and moments, with the corresponding assemblies also contributing substantial lift, at least within some operating ranges.

[0011] According to both aspects of the present invention, at least one ducted fan is pivotable / tiltable about an axis substantially perpendicular to the axis of rotation of its rotor. This allows the thrust of the ducted fan to be directed and controlled relative to the main portion of the wing assembly, i.e., the aircraft structure, while enhancing the ability to control the aircraft's attitude. When at least one flap portion is tilted about its pivot axis, the aerodynamic lift generated by the flap portion is also modified. Thus, the tilting action affects both the thrust direction and the lift direction, as well as the magnitude of the drag. This, combined with the ability to control and adjust the absolute value of the thrust, significantly enhances the ability to control an aircraft having such an integrated assembly.

[0012] Although it is of course possible to group multiple ducted fan clusters on a single flap section in a wing assembly according to the second aspect of the invention, the general inventive concepts of the first and second aspects of the invention can also be beneficially combined when a wing assembly according to the second aspect is provided with multiple flap sections, each independently pivotable and each comprising only one ducted fan engine.

[0013] It should also be noted that according to both aspects of the invention, the direction of the pivot axis of at least one flap portion may be substantially aligned with the extension direction of the wing.

[0014] At least one flap section, having a body section that functions as an extension of the cross section of the main section of the wing assembly in a specific orientation, generates lift in all cases in horizontal flight of an aircraft equipped with the wing assembly of the invention. To further enhance the lift performance of the integrated flap section, the upper and / or side panels of the cowling of at least one ducted fan engine may be formed with a cross section in the streamwise direction of the aircraft such that, together with the at least one flap section in a horizontal orientation, said portion of the flap / engine assembly also generates lift during engine operation. Therefore, designing an additional structural element associated with the ducted fan engine to generate lift in addition to the body section of the corresponding flap section may allow at least one flap section to contribute to generating at least about 40% of the lift of the wing assembly in a specific range of operating conditions.

[0015] In particular, in a streamwise cross section of the wing assembly, the upper portion of the cowling may be formed to have a predominantly (i.e., primarily) convex curvature, preferably comprising half of a cambered airfoil cross section. Such cross section may be inverted or non-inverted. Such a shape is optimized for minimum inlet distortion in hover conditions and maximum lift in cruise conditions.

[0016] Additionally or alternatively, the cowling upper leading edge nose radius, normalized to the cowling chord length, is between 1.8% and 5%, preferably about 2%. Such selection of the cowling upper leading edge nose radius contributes to minimizing inlet distortion in hover conditions. Also, the chord length may typically range from 600 mm to 900 mm, and preferably about 780 mm.

[0017] Alternatively or additionally, in plan view of a wing assembly having at least one flap section in a horizontal orientation, the at least one flap section may form at least about 40% of the total lifting surface, wherein a wing planform associated with the wing assembly may be defined to extend to the transition between the wing assembly and the aircraft fuselage or further to the centerline of the aircraft.

[0018] Furthermore, the present invention relates to an aircraft comprising a fuselage, at least one pair of wings according to the first and / or second aspects of the present invention, and a flight control unit for controlling the angular orientation of the flap sections and the thrust output of the ducted fan engine. Such an aircraft may in particular have the above-mentioned VTOL capability.

[0019] In particular, an aircraft according to the invention may comprise at least two pairs of wing assemblies, wherein the main section and at least one flap section of at least one pair of wings according to the first and / or second aspects of the invention are configured such that, within at least a range of operating conditions of the wing assemblies, the flap section of a pair of wing assemblies generates at least about 40% of the total lift of the entire wing of the aircraft.

[0020] In one embodiment, an aircraft may comprise two pairs of wing assemblies according to the first and / or second aspect of the invention, with two different wing lengths, preferably with the pair of wings with the shorter wing length mounted in front of the other pair of wings in the aircraft's direction of horizontal flight, so that the aircraft has a main pair of wings and a canard pair.

[0021] In the above embodiment, the wing flap portion may, for example, constitute between 30% and 50%, particularly about 35%, of the total lifting surface of the wing, and the canard flap portion may constitute between 50% and 70%, particularly about 61%, of the total lifting surface of the canard. Alternatively or additionally, under normal trimmed cruise conditions of the aircraft, due to the additional lift provided by integrating additional lifting surfaces in the flap / engine assemblies described above, the wing flap portion may contribute between about 45% and 60%, particularly about 49%, of the total lifting surface of the wing, and / or the canard flap portion may contribute between 65% and 85%, particularly about 77%, of the total lifting surface of the canard. [Brief explanation of the drawings]

[0022] Further features and advantages of the present invention will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings, in which: [Figure 1] 1 is a cross-sectional view of a wing assembly according to the present invention; [Figure 2] FIG. 2 is an isometric view of a single integrated flap unit of a wing assembly according to the present invention. [Figure 3] Front view of three such integrated flap units. [Figure 4] 1 is a plan view of an aircraft according to the present invention having two pairs of wings; [Figure 5] FIG. 1 is a front view of a wing assembly having multiple flap units at different angular orientations. [Figure 6] 2 is a schematic cross-sectional view of the upper cowling of the ducted fan engine of FIG. 1; DETAILED DESCRIPTION OF THE INVENTION

[0023] In Figure 1, a wing assembly according to the present invention is shown in cross section and generally designated by the reference numeral 10. The wing assembly comprises a main section 12 configured to be fixedly attached to a fuselage of an aircraft so as to extend from the fuselage in a direction of extension W of the wing assembly 10, for example as shown in Figure 4. The wing assembly 10 defines a flow direction F with respect to which the wing assembly 10 is configured to generate lift for an aircraft in level flight.

[0024] The wing assembly 10 further comprises a flap portion 14 having a body portion 16. The flap portion 14 is pivotally mounted to the main portion 12 of the wing assembly 10 so as to be pivotable about a pivot axis A by pivot means 18, which is shown only diagrammatically in Figure 1 and may be embodied, for example, by a servo motor.

[0025] 1 shows the flap section 14 in a horizontal orientation. In the horizontal orientation, the body section 16 of the flap section 14 is substantially aligned with the main section 12 of the wing assembly 10 to form an elongated, substantially continuous cross-section. The flap section 14 may be pivotable about pivot axis A, for example, through a 90° angle, or the flap section 14 may be angled downward to achieve a vertical orientation. In the vertical orientation, the main section 12 and the body section 16 of the flap section 14 are substantially perpendicular to each other.

[0026] The flap section 14 further includes a ducted fan engine 20 having a cowling 22, a leading edge nose 23, an air intake 24, an exhaust 26, a rotatable rotor 28, and a fixed stator 30. During operation, the ducted fan engine 20 generates thrust along a thrust axis T due to rotation of the rotor 28.

[0027] It should further be noted that the ducted fan engine 20 is integrally formed with the main body 16 of the flap section 14, said main body 16 forming the lower part of the cowling 22 of the ducted fan 20, the upper part 22a of which forms the cross section of the wing assembly 10 in the flow direction F that also contributes to the lift provided by the flap section 14.

[0028] By tilting the flap section 14 about pivot axis A relative to the main section 12, the flap section 14 may serve as a control surface for the wing assembly 10, while simultaneously rotating the thrust trajectory T and varying the lift provided by the flap section 14. Thus, by integrating the pivotable flap section 14 with the ducted fan engine 20, said flap section 14 can simultaneously serve as an aerodynamic control surface and vector thrust, thereby providing two degrees of freedom within a single unit. The flap section 14 also contributes a substantial proportion of the lifting surface of the wing assembly 10, thereby greatly improving maneuverability and enabling higher flight speeds compared to conventional designs.

[0029] As a result, the flap section 14 generates a significant percentage of the total aircraft lift in addition to providing independently variable thrust magnitude and thrust vectoring. Therefore, the aforementioned flap section 14 is utilized during all flight phases to reduce engine thrust demands at slower flight speeds or to increase payload. As further seen in Figures 2 and 3 below, the design of the inlet 24 of the ducted fan engine 20, combined with the geometric characteristics of the remaining elements of the flap section 14, allows for clean intake conditions at all flap section angles.

[0030] 2 and 3, an isometric view of a single flap section 14 with an integrated ducted fan engine 20 and a front view of three such flap sections 14 are shown, respectively. While it can be seen that each of the flap sections 14 carries only one ducted fan engine 20, in other modifications of the illustrated embodiment, multiple ducted fan engines may be integrated in a single flap section. FIGS. 2 and 3 further illustrate, in cross section, how the cowling 22 of the ducted fan engine 20 is aerodynamically shaped at its top 22a and at portions of the side panels 22b of the ducted fan engine 20. The cross section, together with the flap section 14, may also contribute to generating lift during engine 20 operation.

[0031] 4 shows a plan view of an aircraft 100 having a fuselage 102 and two pairs of wings 10a and 10b, each of which is equipped with a flap portion as described above, with a first pair of wings 10a functioning as the main wings and a second pair of wings 10b having a shorter wingspan functioning as canards located in front of the main wings 10a.

[0032] The overall wing planform of the wing 10a is selected such that the flap portion contributes approximately 35% of the overall wing planform, as indicated by box 104, while the flap portion of the canard 10b contributes approximately 61% of the total wing planform surface of the canard 10b, as indicated by box 106. Each wing planform is defined to extend toward the centerline C of the aircraft 100.

[0033] Due to the additional lift contributed by the aforementioned unique design of the flap sections 14 on wings 10a and 10b, the flap sections on wing 10a will contribute approximately 49% of the aforementioned total lift of the wing 10a, and the flap sections on canard 10b will contribute approximately 77% of the total lift generated by the canard 10b, at the nominal, trimmed cruise condition of aircraft 100. Thus, under the aforementioned conditions, the combination of the flap sections on wing 10a and canard 10b will generate over 50% of the total lift of aircraft 100.

[0034] Additionally, FIG. 5 shows a front view of one of the main wings 10a with its multiple flap units 14 all at different angular orientations to demonstrate the ability of the multiple flap units 14 to be independently pivoted over a range of angular orientations.

[0035] Finally, FIG. 6 shows a schematic cross-section of the upper portion 22a of the cowling 22 of the ducted fan engine 20 of FIG. 1 in the flow direction F. This cross-section minimizes inlet distortion of the air drawn into the engine 20 in the hover configuration and maximizes lift for each flap unit 14 in the cruise configuration. In particular, the upper portion 22a of the cowling 22 is formed with a predominantly convex curvature as half of a cambered airfoil profile with a camber line CA. The dashed line in FIG. 6 indicates the theoretical lower half of this cross-section.

[0036] Furthermore, the radius R23 of the leading edge nose 23 of the upper portion 22a of the cowling 22, normalized to the chord length CL, is between 1.8% and 5%, preferably about 2%, and typically the chord length CL of such an engine 20 ranges between 600 mm and 900 mm, and in particular may be about 780 mm.

Claims

1. 1. A wing assembly for an aircraft having a fuselage and at least one pair of wings, the wing assembly defining a flow direction (F), the wing assembly being configured with respect to the flow direction (F) to generate lift for the aircraft; a main section configured to be fixedly attached to the fuselage so as to extend from the fuselage in a direction of extension (W) of the wing; at least one flap portion having a main body portion pivotally attached to said main body portion by pivot means for pivotal movement about a pivot axis (A) through a range of angular orientations including horizontal and vertical orientations; in the horizontal orientation, the body portion of the flap portion is substantially aligned with the main portion to form an elongated, substantially continuous cross-section; In the vertical orientation, the flap portion is angled downward relative to the main portion. at least one flap portion; the at least one flap portion includes a plurality of ducted fan engines, each ducted fan engine having a cowling, an air intake, and an exhaust, each ducted fan engine configured to generate thrust within a predetermined range of thrust values ​​during operation; each ducted fan engine is integrally formed with the main body of the flap portion, and the main body constitutes a lower portion of the cowling of each ducted fan engine; an operating condition of the wing assembly including an angular orientation of the at least one flap section from the range of angular orientations and a thrust value generated by each ducted fan engine from the predetermined range of thrust values; the main section and the at least one flap section are configured such that, within at least a range of operating conditions of the wing assembly, the at least one flap section generates at least 40% of the lift of the wing assembly; when the at least one flap portion is in a horizontal orientation, the cowling top and / or side panel of each ducted fan engine is configured such that a cross section of the wing assembly in the flow direction (F) is a cross section that generates lift during operation of the engine; the upper portion of the cowling having the cross section in the flow direction (F) of the wing assembly is formed with a predominantly convex curvature and includes half of a cambered airfoil profile; each said ducted fan engine has a vertical centerline, an outer surface of the upper part of the cowling peaks at the vertical centerline of each said ducted fan engine and descends horizontally away from each side panel of the ducted fan engine, and the outer surface of the upper part of the cowling of each said ducted fan engine is symmetrical about the vertical centerline of each said ducted fan engine; a radius (R23) of the leading edge nose of the upper part of the cowling normalized to a chord length (CL) of the upper part of the cowling is between 1.8% and 5%, and / or the chord length (CL) is between 600 mm and 900 mm.

2. 10. The wing assembly of claim 1, comprising a plurality of flap sections, each of said plurality of flap sections being independently pivotable, each comprising a single ducted fan engine.

3. A wing assembly as described in claim 1, wherein the direction of the pivot axis (A) of at least one flap portion substantially coincides with the extension direction (W) of the wing.

4. A wing assembly as described in claim 1, wherein in a plan view of the wing assembly having at least one flap portion oriented horizontally, the at least one flap portion forms at least 40% of the total lifting surface.

5. 10. An aircraft comprising: a fuselage; at least one pair of wing assemblies according to claim 1; and a flight control unit for controlling the angular orientation of the flap section and the thrust output of the ducted fan engine.

6. 6. An aircraft according to claim 5, 1. An aircraft comprising at least two pairs of wing assemblies, wherein the main section and the at least one flap section of the at least one pair of wing assemblies are configured such that, within at least a range of operating conditions of the wing assemblies, the flap section of the pair of wing assemblies generates at least 40% of the total lift of all of the wings of the aircraft.

7. 6. An aircraft according to claim 5, comprising two pairs of wing assemblies having different wing spans, the pair of wings having the shorter wing span being mounted in front of the other pair of wings in the direction of horizontal flight of the aircraft.

8. 6. The aircraft of claim 5, wherein the flap sections of a first pair of wings comprise between 30% and 50% of the total lifting surface of the first pair of wings and the flap sections of a second pair of wings comprise between 50% and 70% of the total lifting surface of the second pair of wings; and / or wherein, under normal trimmed cruise conditions of the aircraft, the flap sections of the first pair of wings contribute between approximately 45% and 60% of the total lift of the first pair of wings and / or the flap sections of the second pair of wings contribute between 65% and 85% of the total lift of the second pair of wings.

9. An aircraft as described in claim 8, wherein the first pair of wings includes main wings and the second pair of wings includes canards.

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