A wing distributed electric-duct fan aerodynamic structure

Abstract

The present application relates to a kind of wing distribution type electric duct fan aerodynamic structure, for electric aircraft, by streamlined nose, non-circular section fuselage, the overall layout of wing with T-shaped tail wing using wing integrated distribution type electric duct fan, combined with the integrated design of electric duct fan power group and wing, the acceleration effect of electric duct fan power group to the airflow on the upper surface of wing and the additional thrust effect of high static pressure behind electric duct fan power group nozzle to wing are realized.Electric duct fan power group is integrated on the upper surface of wing using the fusion design form of sinking into airfoil, and wing includes main wing surface and electric duct fan power group located at wing root.The present application effectively improves the lift-drag ratio and propulsion efficiency of the whole machine during cruising and climbing stage, reduces the whole machine resistance and reduces the risk of structural fatigue, considers aerodynamic performance and engineering practicability, ensures the longitudinal static stability margin of aircraft and improves flight quality.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic layout design technology for electric aircraft, specifically to an on-wing distributed electric ducted fan aerodynamic structure. Background Technology

[0002] The mainstream aerodynamic layout of civil aircraft has long followed the classic configuration of "cylindrical fuselage + low-wing + tail-mounted / wing-mounted engines". However, after decades of continuous optimization, the performance improvement of this traditional layout has entered a stage of rapidly diminishing marginal returns. Within the existing framework of aerodynamic, materials, and structural technologies, it is difficult to achieve significant performance improvements from the layout technology itself. At the same time, increasingly stringent environmental protection regulations also pose serious challenges to civil aircraft products with traditional layouts.

[0003] To overcome these bottlenecks, the aviation industry is actively exploring various innovative subsonic civil aircraft layout schemes. Representative examples include: The truss-supported wing layout uses an external truss structure to support the wing, thereby relaxing the structural constraints on the aspect ratio. The blended wing-body configuration reduces the wetted area through a wide, flat, and lift-generating central fuselage. The wing-connected layout employs a spatial rhomboid frame structure to improve structural efficiency.

[0004] These unconventional layouts differ significantly from conventional layouts, and therefore have a substantial impact on downstream industries such as manufacturing, operation, and maintenance in the aviation sector.

[0005] On the other hand, the aviation industry is constantly innovating in the power systems of civil aircraft, with distributed propulsion being a representative example. For instance: CN202411464357.5 discloses a power-assisted lift-enhanced ultra-short takeoff and landing fixed-wing aircraft with a distributed propeller layout. By evenly arranging multiple lift-enhancing propellers under the wing, the wing area covered by the slipstream is increased, effectively improving aerodynamic performance. The lift-enhancing propellers in this layout only operate briefly during takeoff and landing and can be folded during normal cruise to reduce drag. However, this layout is generally used in small-weight, low-altitude, and low-speed aircraft.

[0006] CN202211162442.7 discloses a wing and electric aircraft integrating a distributed ducted fan, illustrating the power configuration of the distributed ducted fan. This design improves the equivalent bypass ratio through multiple small ducts and further enhances the lift-to-drag ratio during climb and cruise phases through deep coupling with the wing. However, the integration of the ducted fan with the wing in this scheme is relatively simple, failing to fully utilize the suction effect of the ducts on the wing's upper boundary layer. Furthermore, the aerodynamic interference between multiple ducts and the flow separation problem behind the ducts are not effectively addressed.

[0007] In summary, performance improvements in traditional layouts have reached a stage of rapidly diminishing marginal returns, making it difficult to achieve significant performance gains through layout technology alone, and they also face increasingly stringent environmental regulations. While various innovative layouts each have their specific advantages, unconventional layouts such as truss-supported wings, blended wing-body designs, and coupled wings have a significant impact on downstream industries, and distributed propeller layouts are generally used in low-weight, low-altitude, and low-speed scenarios, still having limitations in terms of applicability and industrialization. How to further improve the aerodynamic performance of civil aircraft while taking into account the impact on existing manufacturing and operating systems has become a direction worthy of exploration in this field. The information disclosed in this background section is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention In view of the shortcomings of the existing technology, the purpose of this invention is to provide an overwing distributed electric ducted fan aerodynamic structure, which aims to solve the problems of limited performance improvement of traditional aircraft aerodynamic layout and the significant impact or limited applicability of existing unconventional layouts on downstream industries, thereby improving the aerodynamic performance and energy utilization efficiency of aircraft.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides an aerodynamic structure for an overwing distributed electric ducted fan, comprising: Streamlined head 10; Non-circular cross-section fuselage 20; The wing 30 adopts an on-wing integrated distributed electric ducted fan. The wing 30 includes a main wing surface 31 and an electric ducted fan power unit 34 located at the wing root. The electric ducted fan power unit 34 includes several single electric ducted fan power units 34D of equal diameter. Each single electric ducted fan power unit 34D is a functional unit, consisting of a fan, a duct nacelle, and an engine. The T-tail 40 consists of a vertical tail 41 connected to the fuselage and a horizontal tail 43 located at the tip of the vertical tail 41 and arranged symmetrically.

[0009] In one specific implementation, the streamlined head 10 includes a nose 11, which is a forward-protruding semi-ellipsoidal shape. The nose 11 transitions to the head body 14 through a curved surface. The head body 14 includes a main windshield 12 and two side windshields 13. The outer curved surface of the nose 11 adopts a non-negative curvature surface, and the outer shape of the head body 14 adopts a non-negative curvature surface.

[0010] In one specific implementation, the cross-section of the non-circular cross-section fuselage 20 includes: an elliptical upper section and a near-square lower section with rounded corners.

[0011] In one specific implementation scheme, the main wing surface 31 adopts a swept-back low-wing form, with a straight leading edge and a two-sweep design for the trailing edge. The sweep angle of the inner trailing edge is smaller than that of the outer trailing edge. The sweep angle of the quarter chord of the main wing surface 31 is between 0° and 20°, the aspect ratio is between 10 and 15, and it adopts a reverse-curving airfoil.

[0012] In one specific implementation, the wing 30 further includes an inner flap 32 located on the inner trailing edge of the main wing surface 31, and is a split flap. The inner flap 32 is located in the trailing edge nacelle of the wing 30 below the electric ducted fan power unit 34, and is connected to a metal rib extending from the main wing rib via three swivel joints.

[0013] In one specific implementation, the wing 30 further includes an outer flap 33, which is located on the outer trailing edge of the integrated area of ​​the electric ducted fan power unit 34 on the main wing surface 31, and does not coincide with the electric ducted fan power unit 34 along the spanwise direction, and adopts the form of a Fuller flap.

[0014] In one specific implementation scheme, the number of individual electric ducted fan power units 34D is 4 to 8 on one side, the leading edges of the electric ducted fan power units 34 are kept in the same heading position, and structural gaps are left between the individual electric ducted fan power units 34D and sealed with hard rubber.

[0015] In one specific implementation scheme, the electric ducted fan power unit 34 is integrated into the upper surface of the wing 30 in a blended design with the airfoil recessed, and the recess of each individual electric ducted fan power unit 34D in the electric ducted fan power unit 34 is between 0% and 50% of the local airfoil thickness.

[0016] In one specific implementation, the wing 30 further includes an upper surface rectification area 34A of the ducted nacelle and a lower surface rectification area 34B of the ducted nacelle, wherein the upper surface rectification area 34A of the ducted nacelle is between 300mm and 600mm, and the lower surface rectification area 34B of the ducted nacelle is between 500mm and 900mm.

[0017] In one specific implementation, the vertical tail 41 adopts a relatively thin symmetrical airfoil and a swept configuration, the horizontal tail 43 adopts a relatively thin symmetrical airfoil and a swept configuration, and the horizontal tail 43 is connected to the vertical tail 41 with a negative mounting angle.

[0018] The present invention discloses an overwing distributed electric ducted fan aerodynamic structure for electric aircraft. Through the integrated layout of a streamlined nose 10, a non-circular cross-section fuselage 20, an overwing wing 30 with an integrated distributed electric ducted fan, and a T-tail 40, combined with the integrated design of the electric ducted fan power unit 34 and the wing, the invention achieves the acceleration effect of the electric ducted fan power unit 34 on the airflow on the upper surface of the wing 30 and the additional thrust effect of the high static pressure at the rear of the electric ducted fan power unit 34 nozzle on the wing 30. This effectively improves the aerodynamic performance and energy utilization efficiency of the aircraft, and has the following beneficial effects: 1. This invention employs a wing 30 with an integrated distributed electric ducted fan, enabling coordinated flow between the leading edge of the electric ducted fan power unit 34 and the leading edge of the wing 30. The flow rate entering the electric ducted fan power unit 34 through the upper surface of the wing 30 increases with the fan's work. Due to the presence of the wing 30, this flow rate inevitably increases the flow velocity around the wing 30, thereby creating additional suction between the inlet surface of the electric ducted fan power unit 34 and the leading edge of the wing 30. Simultaneously, the high total pressure airflow discharged after the electric ducted fan power unit 34 performs its work restores a higher static pressure behind the nozzle of the electric ducted fan power unit 34. The high static pressure zone at the trailing edge of the wing 30 and the electric ducted fan power unit 34, together with the additional suction peak at the leading edge of the wing 30 caused by the intake of the electric ducted fan power unit 34, create an additional thrust effect, thereby effectively improving the overall lift-to-drag ratio and propulsion efficiency of the aircraft during cruise and climb phases.

[0019] 2. This invention, through the sinking and integrated design of the ducted nacelle and the setting of the rectifier area behind the electric ducted fan power unit 34, on the one hand, draws more low-energy, low-speed gas from the boundary layer on the upper surface of the wing 30 into the electric ducted fan power unit 34, reducing the average intake velocity of the electric ducted fan power unit 34 and improving its propulsion efficiency. On the other hand, it effectively reduces the overall frontal area of ​​the aircraft (in the front view, the electric ducted fan power unit 34 coincides with the wing 30), and through the "boundary layer suction" effect, effectively improves the near-wall velocity profile of the upper surface of the wing 30 covered by the electric ducted fan power unit 34. Maintaining a laminar boundary layer for an extended period reduces overall aircraft drag. Furthermore, the rectifier design behind the ducted fan power unit 34 prevents flow separation and vortex shedding between adjacent individual ducted fan power units 34D, thus reducing aerodynamic drag and minimizing structural fatigue risks. Simultaneously, the pre-reserved structural gaps and hard rubber seals between the individual ducted fan power units 34D ensure sufficient space for relative position changes when the wing 30 deforms, while also preventing drag increase and noise issues caused by airflow passing through gaps.

[0020] 3. The present invention achieves streamlined optimization of the shape of the engine head by combining the streamlined engine head 10 and the non-circular cross-section body 20, while meeting the requirements of driver's vision and head movement space. At the same time, the non-circular cross-section body 20 increases the vertical internal space, providing sufficient space for the arrangement, installation, disassembly and maintenance of the power battery, thus taking into account both aerodynamic performance and engineering practicality.

[0021] 4. This invention coordinates the layout of the T-tail 40 with the sweep parameters of the wing 30. The vertical tail 41 is swept to increase the longitudinal distance between it and the wing 30, ensuring the longitudinal static stability margin of the aircraft. The horizontal tail 43 is installed at a negative installation angle, further optimizing the pitch trim characteristics of the entire aircraft and improving flight quality. Attached Figure Description

[0022] The present invention includes the following figures: The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein: Figure 1 A schematic diagram of the aerodynamic structure of an overwing distributed electric ducted fan according to the present invention.

[0023] Figure 2 A front view of an overwing distributed electric ducted fan aerodynamic structure according to the present invention.

[0024] Explanation of reference numerals in the attached figures: 10-Streamlined machine head; 11-Nose; 12-Main windshield; 13-Side windshield; 14-Main body of the nose; 20-Non-circular cross-section fuselage; 30-wing; 31-Main wing surface; 32-Inner flap; 33-Outer flap; 34-Electric ducted fan power unit; 34A - Structural nacelle upper surface rectifying area; 34B - Lower surface rectifying area of ​​the duct nacelle; 34C - Outermost single electric ducted fan power unit winglet; 34D - Single electric ducted fan power unit; 40-T tail fin; 41 - Vertical tail fin; 42-Rectified surface; 43 - Horizontal tail fin. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings. This detailed description is an illustration in conjunction with exemplary embodiments of the invention, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0026] This invention proposes an aerodynamic layout for short-range electric aircraft consisting of a streamlined nose 10, a non-circular cross-section fuselage 20, a wing 30 with an on-wing integrated distributed electric ducted fan, and a T-tail 40.

[0027] The first aspect of the invention proposes a streamlined head 10, see [link to previous document]. Figure 1 As shown. The streamlined nose 10 includes a nose 11, which is a forward-protruding semi-ellipsoidal shape. The nose 11 transitions through a curved surface to the nose body 14, which includes a main windshield 12 and two side windshields 13. The nose body 14 further transitions through a curved surface to the rear straight section of the fuselage.

[0028] The nose 11, which extends forward and is shaped like a semi-ellipsoid, has a non-negative curvature surface. It houses the nose landing gear, weather radar, and other airborne equipment. Preferably, the yaw distance from the leading edge of the nose 11 to the lower edge of the main windshield 12 is selected between 1800mm and 2000mm.

[0029] The nose cone windshield adopts a three-piece layout of "one main and two auxiliary" sections. The main windshield 12 can form a specific angle relative to the horizontal plane, preferably between 35° and 55°, to maximize the streamlined shape of the nose cone. The main windshield 12 is symmetrically arranged in the horizontal direction relative to the plane of symmetry of the entire aircraft and has a relatively wide width, preferably between 1300mm and 1500mm, balancing structural efficiency and the driver's field of vision. The vertical width of the main windshield 12 is relatively small while meeting the requirements of the field of vision, in order to reduce the increase in structural weight caused by the opening, preferably between 500mm and 600mm. The side windshields 13 on both sides use fan-shaped glass.

[0030] The main body 14 of the nose adopts a non-negative curvature surface to ensure process feasibility. The internal space meets the design requirements of the driver's head movement space and minimum clear field of vision. Optimally, the total length of the streamlined nose 10 is the minimum value to meet the internal space requirements.

[0031] For example, the streamlined nose 10 of the present invention may include: a nose 11, which is a forward-extending semi-ellipsoidal shape, a main windshield 12, two side windshields 13, and a nose body 14. The forward-extending semi-ellipsoidal nose 11 has a non-negative curvature surface and houses the nose landing gear, weather radar, and other airborne equipment. Its forward extension (i.e., the yaw distance from the leading edge to the lower edge of the main windshield 12) is set at 1900 mm. The nose windshields adopt a three-piece layout of "one main and two auxiliary," wherein the main windshield 12 can be at a 45° angle to the horizontal plane; the main windshield 12 is symmetrically arranged in the horizontal direction relative to the symmetry plane of the entire aircraft, with a width of 1400 mm; the vertical width of the main windshield 12 is set at 550 mm. The side windshields 13 are fan-shaped glass. The main body of the nose cone 14 adopts a non-negative curvature surface, and the internal space meets the design requirements of the driver's head movement space and minimum clear field of vision. The total length of the nose cone is set at 4500mm.

[0032] A second aspect of the present invention provides a non-circular cross-section fuselage 20. The cross-section of the non-circular cross-section fuselage 20 includes: an elliptical upper part to increase the vertical internal space, and a near-square lower part with rounded corners to provide sufficient space for the arrangement of the power battery and to provide sufficient passage for the installation, removal, and maintenance of the battery. See [reference needed]. Figure 2 As shown.

[0033] For example, the present invention can use a non-circular cross-section body 20, with a maximum cross-section width of 2000mm and a maximum height of 2500mm, to increase the vertical internal space, leave sufficient space for the arrangement of the power battery, and provide sufficient passage for the installation, disassembly, and maintenance of the battery.

[0034] A third aspect of the invention proposes a wing 30 employing an on-wing integrated distributed electric ducted fan. The wing 30 includes a main wing surface 31 and an electric ducted fan power unit 34 located at the wing root. The electric ducted fan power unit 34 includes a plurality of single electric ducted fan power units 34D of equal diameter. Each single electric ducted fan power unit 34D is a functional unit consisting of a fan, a duct nacelle, and an engine.

[0035] The wing 30 includes a main wing surface 31. The main wing surface 31 adopts a swept low-wing form, with a straight leading edge and a two-sweep design for the trailing edge: the sweep angle of the inner trailing edge is smaller than that of the outer trailing edge, and the two sections are separated near the outermost single electric ducted fan power unit 34D; the sweep angles of the leading and trailing edges must ensure that the 1 / 4 chord sweep angle of the entire main wing surface is within a reasonable range. Preferably, the 1 / 4 chord sweep angle of the main wing surface 31 is selected between 0° and 20°.

[0036] The inner section ends outside the outermost single electric ducted fan power unit 34D on the wing. Since the leading edge of the electric ducted fan power unit 34 does not sweep back (see subsequent description), in order to ensure the intake quality of the electric ducted fan power unit 34 and the intake airflow covering the wing area 30 as large as possible, the sweep angle of the trailing edge of the integrated section of the electric ducted fan power unit 34, i.e. the inner wing section, should not be too large. Preferably, the sweep angle of the trailing edge of the inner section is selected between 0° and 5°, so as to reserve sufficient integration space for the electric ducted fan power unit 34 and the flap actuation mechanism. The outer trailing edge adopts a sweep angle between 0° and 10° to reduce the impact of 30° wing sweep on the aileron aerodynamic and structural efficiency. The inner and outer trailing edges are separated near the outermost single electric duct fan power unit 34D. A circle or near-circular curve can be used to transition between the inner and outer trailing edges. Preferably, the aspect ratio of the main wing surface 31 is between 10 and 15, which relaxes the spanwise arrangement space and improves the aerodynamic performance of the main wing; the airfoil of the main wing surface 31 is a concave airfoil to match the integrated design of the inner section wing and the electric ducted fan power unit 34; preferably, the dihedral angle of the main wing surface is between 0° and 6°.

[0037] The wing 30 includes an inner flap 32 and an outer flap 33. The inner flap 32 is located on the inner trailing edge of the inner section of the main wing surface 31 (close to the fuselage). It is a split flap and is located in the trailing edge nacelle of the wing 30 below the ducted fan power unit 34. The inner flap 32 is connected to the metal rib extending from the main wing rib via three swivel joints. The inner flap 32 must be selected with a thin airfoil according to the space constraints of the trailing edge nacelle to avoid interference with the structure of the ducted fan power unit 34 above. When needed (such as during aircraft landing), it can achieve downward deflection of the trailing edge by pure axial rotation around the common axis of the joints to achieve the purpose of increasing lift / drag. For example, the spanwise arrangement position of the inner flap 32 is between 10% and 40%. For example, based on the half span of the wing, the spanwise arrangement position of the inner flap 32 is between 10% and 40%. The outer flap 33 is located on the outer trailing edge of the integrated area of ​​the electric ducted fan power unit 34 on the main wing surface 31. It does not coincide with the electric ducted fan power unit 34 in the spanwise direction. It adopts the form of a Fuller flap and extends backward and deflects downward when needed (such as in the case of aircraft takeoff) to achieve the purpose of increasing lift. Preferably, the spanwise arrangement position of the outer flap 33 is between 42% and 60%.

[0038] The wing 30 integrates an electric ducted fan power unit 34 on its upper surface. Several single electric ducted fan power units 34D of equal diameter are closely arranged on the inner section of the wing 30. Under high thrust, the high-speed airflow in front of the electric ducted fan power unit 34 forms an additional suction peak at the inlet lip and the leading edge of the wing 30, achieving increased lift and reduced drag. At the same time, the total pressure increases after the airflow does work on the electric ducted fan power unit 34, and a higher static pressure can be restored behind the electric ducted fan power unit 34, which acts on the nozzle of the electric ducted fan power unit 34 and the wing 30 behind it, forming an additional thrust effect. According to the above aspects of the present invention, the electric ducted fan power unit 34 includes a plurality of individual electric ducted fan power units 34D, with 4 to 8 individual electric ducted fan power units 34D on one side. The innermost individual electric ducted fan power unit 34D is connected to the fuselage, and the matching duct diameter is between 500 mm and 800 mm. To ensure propulsion efficiency, the direction of the resultant thrust provided by the electric ducted fan power unit 34 should be parallel to the flight direction of the aircraft, i.e., parallel to the plane of symmetry of the aircraft. At the same time, the leading edge of the electric ducted fan power unit 34 must be kept at the same heading position, i.e., there is no sweep angle on the leading edge line of the electric ducted fan power unit 34. Structural gaps are left between the individual electric ducted fan power units 34D and sealed with hard rubber to ensure sufficient space for relative position changes of adjacent individual electric ducted fan power units 34D when the wing 30 deforms, while avoiding problems such as drag increase, noise, and vibration caused by airflow passing through the gaps. Preferably, the gaps are 3 mm to 5 mm. The power unit 34 is integrated into the upper surface of the wing 30 using a recessed airfoil design (i.e., from the frontal view, part of the electric ducted fan power unit 34 is obscured by the wing 30). On the one hand, it draws more low-energy, low-speed gas from the boundary layer of the upper surface of the wing 30 into the electric ducted fan power unit 34, reducing the average intake velocity of the electric ducted fan power unit 34. This allows the electric ducted fan power unit 34 to perform work on the lower-speed airflow, increasing the velocity difference between the intake and exhaust airflow of the electric ducted fan power unit 34, thereby improving the propulsion efficiency of the electric ducted fan power unit 34. On the other hand, it effectively reduces the frontal area of ​​the entire aircraft (in the frontal view, the electric ducted fan power unit 34 coincides with the wing 30), and through the "boundary layer suction" effect, it effectively improves the near-wall velocity profile of the upper surface of the wing 30 covered by the electric ducted fan power unit 34, enhances near-wall fluid momentum, resists adverse pressure gradients, delays the transition from laminar to turbulent flow, maintains the laminar boundary layer for a longer period of time, and thus reduces the overall drag of the aircraft.

[0039] The sinking blended design of the electric ducted fan power unit 34 reduces the effective camber of the wing 30 covered by the electric ducted fan power unit 34, resulting in a loss of lift. This loss is directly related to the sinking amount. Therefore, when determining the specific sinking amount, it is necessary to conduct an optimization trade-off based on CFD (Computational Fluid Dynamics) simulation for the sinking amount of a single electric ducted fan power unit 34D under the typical design conditions of the aircraft involved. Using the design lift-to-drag ratio and the operating angle of attack range as design constraints, the additional thrust benefit brought by the sinking amount of the single electric ducted fan power unit 34D and the lift loss cost of the wing section covered by the unit are calculated and analyzed. The optimal sinking amount applicable to the single electric ducted fan power unit 34D is determined between the benefit and the cost. The sinking amount of the single electric ducted fan power unit 34D may be different in different positions. Preferably, the sinking amount of the single electric ducted fan power unit 34D can be taken between 0% and 50% of the local airfoil (referring to the airfoil of the wing 30) thickness. The ducted fan power unit 34 can be designed with a central cone to prevent the airflow from forming a "dead vortex" (also known as flow separation) between adjacent single ducted fan power units 34D, which would significantly increase aerodynamic drag and structural fatigue caused by vortex shedding. The rectification can be designed as follows: maintain a smooth transition between the flow direction at the nozzle of the single ducted fan power unit 34D and the downstream rectification area. At the same time, the surface of the rectification area expands gradually along the axial direction with the mounting axis of the single ducted fan power unit 34D (i.e., the motor center axis) as the center. The tangent at any point of its circumferential section makes an angle of less than 15° with the mounting axis of the single ducted fan power unit 34D to avoid excessive expansion of the flow channel formed by the rectification area, which would lead to wake separation. Starting from the nozzle of the adjacent single ducted fan power unit 34D, the flow extends downstream through a spline curve until the spline curves intersect, or the spline curve intersects with the extension lines of the upper and lower surfaces of the single ducted fan power unit 34D.

[0040] Based on the above spline curves, the surfaces that intersect at the trailing edges are generated by lofting. The length of the rectifying area 34A on the upper surface of the duct nacelle is between 300mm and 600mm, and the length of the rectifying area 34B on the lower surface of the duct nacelle is between 500mm and 900mm.

[0041] For example, the present invention can employ a wing 30 with an integrated distributed electric ducted fan. Its main wing surface 31 is a swept-back low-wing monoplane, divided into inner and outer sections. The inner section has a 1 / 4 chord sweep angle of 15° and integrates a distributed electric ducted fan power unit 34 thereon. Simultaneously, a split inner flap 32 is arranged at the trailing edge within a spanwise range of 10% to 40%, with a trailing edge sweep angle of 0°. The outer section can have a 1 / 4 chord sweep angle of 16°, and a Fuller outer flap 33 is arranged at the trailing edge within a spanwise range of 42% to 60%, with a trailing edge sweep angle of 5° when the flap is retracted. The wing 30 of the present invention can preferably be designed with an aspect ratio of 12 and employ an anti-curve airfoil and a 3° dihedral angle.

[0042] The upper inner surface of the single-sided wing 30 of this invention can integrate five distributed single electric ducted fan power units 34D with a duct diameter of 700mm. The electric ducted fan power units 34D are integrated into the upper surface of the wing 30 through a recessed fusion design, with the recess amount set at 10% of the local airfoil thickness. Correspondingly, the height of the rear spars web of the integrated section wing 30 should be reduced according to the engine integration space requirements. The engine and the wing 30 can be connected by a double lug or other form of mounting structure. At the same time, to ensure the integrity of the power transmission path, the upper wall skin of the integrated section wing 30 should be retained, and holes should be opened at the mounting structure. A 3mm structural gap can be maintained between the single electric ducted fan power units 34D to avoid structural interference caused by deformation. The design of the D-shaped conical rectification area maintains a smooth transition between the nozzle of the single ducted fan power unit 34D and the downstream rectification area. At the same time, the angle between the curved surface of the rectification area and the jet of the single ducted fan power unit 34D is less than 15° (confirmed by CFD calculation results). The flow channels after the nozzles of adjacent single ducted fan power units 34D extend backward sequentially until they intersect. The rectification area 34A on the upper surface of the duct nacelle is set at 450mm, and the rectification area 34B on the lower surface of the duct nacelle is set at 700mm. The outermost single ducted fan power unit 34D is equipped with an outermost single ducted fan power unit winglet 34C, which makes the shape near the ducted fan power unit 34 more streamlined, visually increasing lightness and speed, and taking into account the requirements of industrial design aesthetics and aerodynamics.

[0043] A fourth aspect of the invention provides a T-tail 40. The T-tail 40 consists of a vertical tail 41 connected to the fuselage and a horizontal tail 43 located at the tip of the vertical tail 41 and arranged symmetrically.

[0044] The vertical tail 41 can adopt a relatively thin symmetrical airfoil to avoid the yaw moment caused by the vertical tail 41 itself; the vertical tail 41 adopts a swept-back configuration, which increases the distance between the horizontal tail 43 and the wing 30 to a certain extent, ensuring the longitudinal static stability margin of the aircraft; the vertical tail 41 includes a smoothing surface 42 at the junction of the wing root leading edge and the fuselage, which improves the airflow quality at the junction to a certain extent, while also accommodating the necessary internal connecting structures.

[0045] The horizontal tail 43 includes left and right horizontal tail 43s arranged symmetrically relative to the vertical tail 41. The horizontal tail 43 may adopt a relatively thin symmetrical airfoil; the horizontal tail 43 may adopt a certain degree of swept-back configuration; the horizontal tail 43 may connect with the vertical tail 41 with a certain negative installation angle (upward deflection of the trailing edge), for example, the installation angle is between 0° and -5°.

[0046] For example, the present invention may employ a T-tail 40, and the vertical tail 41 may employ a relatively thin symmetrical airfoil with a certain swept-back configuration, with its quarter-chord sweep angle set at 50°; a flow-straightening surface 42 is provided at the junction of the leading edge of the vertical tail 41 and the fuselage, which improves the airflow quality at the junction to a certain extent, while also accommodating necessary internal connecting structures. The horizontal tail 43 may employ a relatively thin symmetrical airfoil with a certain degree of swept-back configuration, its quarter-chord sweep angle set at 25°, and may be mounted at a -2° installation angle at the tip of the vertical tail 41.

[0047] Accordingly, compared with the traditional conventional layout, this invention, while meeting the basic design constraints of traditional civil aircraft, adopts an overall layout of "streamlined nose 10 + non-circular cross-section fuselage 20 + wing 30 with wing-integrated distributed electric ducted fans + T-tail 40". On the one hand, the electric ducted fan power unit 34 integrated on the upper surface of the wing 30 can increase the airflow velocity on the upper surface of the wing 30 in front of the duct, thereby improving the aerodynamic performance of the entire aircraft. On the other hand, the distribution of multiple electric ducted fans and the high static pressure behind the duct can increase the thrust of the entire aircraft, thereby improving the energy utilization efficiency of the aircraft during flight.

[0048] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0049] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included in the scope of protection set forth in the claims.

Claims

1. An aerodynamic structure for an overwing distributed electric ducted fan, characterized in that, include: Streamlined head (10); Non-circular cross-section fuselage (20); The wing (30) adopts an overwing integrated distributed electric ducted fan. The wing (30) includes a main wing surface (31) and an electric ducted fan power unit (34) located at the root of the wing. The electric ducted fan power unit (34) includes several single electric ducted fan power units (34D) of equal diameter. Each single electric ducted fan power unit (34D) is a functional unit consisting of a fan, a duct nacelle, and an engine. The T-tail (40) consists of a vertical tail (41) connected to the fuselage and a horizontal tail (43) located at the tip of the vertical tail (41) and arranged symmetrically.

2. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 1, characterized in that, The streamlined head (10) includes a nose (11), which is a forward-protruding semi-ellipsoidal shape. The nose (11) transitions to the head body (14) through a curved surface. The head body (14) includes a main windshield (12) and two side windshields (13). The nose (11) has a non-negative curvature surface, and the head body (14) has a non-negative curvature surface.

3. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 1, characterized in that, The cross-section of the non-circular cross-section fuselage (20) includes: the upper part of the cross-section is elliptical, and the lower part of the cross-section is a near-square shape with rounded corners.

4. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 1, characterized in that, The main wing surface (31) adopts a swept-back low-wing form, with a straight leading edge and a two-sweep design for the trailing edge. The sweep angle of the inner trailing edge is smaller than that of the outer trailing edge. The sweep angle of the 1 / 4 chord of the main wing surface (31) is between 0° and 20°, the aspect ratio is between 10 and 15, and it adopts a reverse-curving airfoil.

5. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 4, characterized in that, The wing (30) also includes an inner flap (32), which is located on the inner trailing edge of the inner section of the main wing surface (31). It is a split flap and is located in the trailing edge compartment of the wing (30) below the electric ducted fan power unit (34). The inner flap (32) is connected to a metal rib extending from the main wing rib via (3) rotating joints.

6. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 4, characterized in that, The wing (30) also includes an outer flap (33), which is located on the outer trailing edge of the integrated area of ​​the electric ducted fan power unit (34) on the main wing surface (31), and does not coincide with the electric ducted fan power unit (34) along the spanwise direction, and adopts the form of a Fuller flap.

7. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 1, characterized in that, The number of individual electric ducted fan power units (34D) is 4 to 8 on one side. The leading edges of the electric ducted fan power units (34) are kept in the same heading position. Structural gaps are left between the individual electric ducted fan power units (34D) and hard rubber is used for sealing.

8. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 7, characterized in that, The electric ducted fan power unit (34) is integrated into the upper surface of the wing (30) in a blended design with the airfoil recessed. The recess of each individual electric ducted fan power unit (34D) in the electric ducted fan power unit (34) is between 0% and 50% of the local airfoil thickness.

9. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 8, characterized in that, The wing (30) also includes an upper surface rectification area (34A) of the duct nacelle and a lower surface rectification area (34B) of the duct nacelle, the upper surface rectification area (34A) being between 300mm and 600mm, and the lower surface rectification area (34B) being between 500mm and 900mm.

10. The aerodynamic structure of an overwing distributed electric ducted fan as described in claim 1, characterized in that, The vertical tail fin (41) adopts a relatively thin symmetrical airfoil and a swept-back layout. The horizontal tail fin (43) adopts a relatively thin symmetrical airfoil and a swept-back layout. The horizontal tail fin (43) is connected to the vertical tail fin (41) with a negative mounting angle.

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