High-lift-drag-ratio low-speed airfoil profile and Evtol aircraft with high-lift-drag-ratio low-speed airfoil profile
By designing a high lift-to-drag ratio low-speed airfoil, especially by setting a concave section on the lower surface of the airfoil body and adjusting the position of the maximum camber and thickness, the problem of insufficient lift-to-drag ratio of existing airfoils has been solved, achieving a higher lift-to-drag ratio and better takeoff performance.
Patent Information
- Application Number
- CN202520648865.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2035-04-08
AI Technical Summary
The existing Evtol aircraft has an insufficient lift-to-drag ratio, resulting in poor takeoff performance. It is necessary to improve the lift-to-drag characteristics of the airfoil to reduce frictional drag and improve takeoff performance.
A high lift-to-drag ratio low-speed airfoil is designed by setting a concave section that bends toward the upper surface on the lower surface of the airfoil body near the trailing edge, adjusting the maximum camber, thickness, and thickness position, and using a cubic parabolic concave section to enhance boundary layer stability and flow acceleration, thereby improving the lift-to-drag ratio.
It significantly improved the lift-to-drag ratio of the airfoil, reduced frictional drag, expanded the laminar flow region, and enhanced the takeoff performance of the Evtol aircraft.
Smart Images
Figure CN223850802U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to wing type relates to technical field, especially a kind of high lift-drag ratio low-speed airfoil and the Evtol aircraft with it. BACKGROUND
[0002] The basic airfoil (low-speed airfoil) generally used by Evtol aircraft has a maximum thickness of 15-19%, a maximum thickness position of 25-40%, a maximum camber of 4-6% and a maximum camber position of 30-50%. Such a basic airfoil with a large leading edge radius has the characteristics of large lift-drag ratio, high maximum lift coefficient, low minimum drag coefficient, wide low-drag range and gentle stall process. The above performance coefficients of the low-speed airfoil determine the take-off performance of the Evtol aircraft. In order to improve the take-off performance of the Evtol aircraft, the lift-drag characteristics of the airfoil need to be improved to ensure a larger laminar flow region, thereby reducing the frictional drag of the airfoil and improving the lift-drag ratio, so as to further improve the take-off performance of the Evtol aircraft. SUMMARY
[0003] Therefore, the utility model aims to provide a high lift-drag ratio low-speed airfoil and an Evtol aircraft with the same, which has high take-off performance.
[0004] The utility model provides a high lift-drag ratio low-speed airfoil, which comprises an airfoil body, the maximum camber of the airfoil body is 4-4.5%, the maximum camber position is 45-50%, the maximum thickness is 15-17%, and the maximum thickness position is 30-35%.
[0005] Optionally, the lower surface of the region near the trailing edge of the airfoil body is provided with an inverse bend section that curves towards the upper surface of the airfoil body.
[0006] Optionally, the inverse bend section comprises a front section and a rear section, the front section gradually inclines towards the direction close to the upper surface of the airfoil body in the direction of extending from the leading edge to the trailing edge on the lower surface of the airfoil body, and the rear section is connected with the front section, the rear section gradually inclines away from the upper surface of the airfoil body in the direction of extending from the leading edge to the trailing edge on the lower surface of the airfoil body.
[0007] Optionally, the front section of the inverse bend section extends in the shape of a cubic parabola, the rear section is symmetrically distributed with the front section, and the curvature of the connection between the front section and the rear section is continuous.
[0008] Optionally, the angle between the cubic parabola presented by the shape of the front section and the rear section of the inverse bend section and the chord of the airfoil body is 1-5°.
[0009] Optionally, the reverse bend segment position is 85%-100%.
[0010] The utility model also provides an Evtol aircraft, including high lift drag ratio low speed airfoil as described above.
[0011] The utility model discloses the beneficial effect lies in: through the maximum camber of airfoil body, maximum camber position, maximum thickness and maximum thickness position are designed, make airfoil body have greater lift drag ratio. BRIEF DESCRIPTION OF DRAWINGS
[0012] In order to more clearly illustrate the technical scheme of the embodiment of the utility model, the following will be to the drawing needed in the embodiment used briefly introduces, should understand, the following drawing only shows some certain embodiment of the utility model, therefore should not be regarded as the limited scope, for the ordinary skilled person in the art, under the premise of not paying creative labor, still can obtain other related drawings according to these drawings.
[0013] Figure 1 It is the structural schematic diagram of the prior basic airfoil.
[0014] Figure 2 It is the structural schematic diagram of the high lift drag ratio low speed airfoil of the utility model.
[0015] Figure 3 It is the airfoil CFD grid topology and boundary layer grid schematic view of the high lift drag ratio low speed airfoil of the utility model.
[0016] Figure 4 It is the resistance coefficient curve contrastive view of the high lift drag ratio low speed airfoil provided by the utility model and the prior basic airfoil.
[0017] Figure 5 It is the lift coefficient curve contrastive view of the high lift drag ratio low speed airfoil provided by the utility model and the prior basic airfoil.
[0018] Figure 6 It is the lift drag ratio curve contrastive view of the high lift drag ratio low speed airfoil provided by the utility model and the prior basic airfoil.
[0019] In the drawing:
[0020] Airfoil body 10, reverse bend segment 11, front section 111, rear section 112, leading edge 12, trailing edge 13. DETAILED DESCRIPTION
[0021] The specific embodiments of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and are not all the embodiments. Based on the description of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.
[0022] Unless otherwise explicitly specified and limited, the terms "arranged", "mounted", "connected" and the like should be broadly understood, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to the specific circumstances.
[0023] The terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the present application is used, and are only for the convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.
[0024] The terms "first", "second", "third" and the like are only for distinguishing similar attributes of elements, and do not indicate or imply relative importance or a particular order.
[0025] The terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, in addition to including the listed elements, other elements not explicitly listed can also be included.
[0026] As shown in Figure 1 , the present embodiment provides a high-lift low-speed airfoil, which comprises an airfoil body 10, the maximum camber of the airfoil body 10 is 4%, the maximum camber position is 45%, the maximum thickness is 15%, and the maximum thickness position is 30%. Figure 1
[0027] Embodiment one: as shown in Figure 2 , the present embodiment provides a high-lift low-speed airfoil, which comprises an airfoil body 10, the maximum camber of the airfoil body 10 is 4%, the maximum camber position is 45%, the maximum thickness is 15%, and the maximum thickness position is 30%.
[0028] Compared with the existing basic airfoil, the maximum camber of the airfoil body 10 is 4%, which can improve the maximum lift coefficient of the airfoil body 10, the maximum camber position of the airfoil body 10 is 45%, which is conducive to enhancing the stability of the boundary layer of the part of the airfoil body 10 close to the trailing edge 13, the maximum lift coefficient is slightly reduced, but a relatively gentle speed characteristic can be obtained. And the maximum thickness of the airfoil body 10 is 15%, which can reduce the resistance of the airfoil body 10, at the same time, the maximum thickness position of the airfoil body 10 is 30%, which can make the minimum pressure position of the airfoil body 10 later, further make the pressure distribution of the upper surface of the airfoil body 10 tend to be flat, thereby shorten the range of action of the adverse pressure gradient, finally in the range of about 40% of the chord length of the airfoil body 10 has obvious positive pressure gradient, the flow is accelerating all the time, the laminar flow area is wide.
[0029] The lower surface of the area close to the trailing edge 13 of the airfoil body 10 is provided with a reverse bending section 11 bending towards the upper surface of the airfoil body 10. By setting the reverse bending section 11 on the lower surface of the airfoil body 10 close to the trailing edge 13, a greater positive pressure than the existing basic airfoil can be generated, the lift of the rear part of the airfoil body 10 is increased, thereby generating a greater forward component, reducing the pressure difference resistance, and improving the lift-drag ratio of the airfoil body 10. The reverse bending section position is 85%, that is, the distance between the reverse bending section 11 and the leading edge of the airfoil body 10 is 85% of the chord length.
[0030] Specifically, the reverse bending section 11 includes a front section 111 and a rear section 112. The front section 111 gradually inclines towards the upper surface of the airfoil body 10 in the direction extending from the leading edge 12 to the trailing edge 13 on the lower surface of the airfoil body 10. The rear section 112 is connected with the front section 111, and gradually inclines away from the upper surface of the airfoil body 10 in the direction extending from the leading edge 12 to the trailing edge 13 on the lower surface of the airfoil body 10. The front section 111 and the rear section 112 are symmetrically distributed. The position of the reverse bending section 11 is defined by the farthest point of the rear section 111 from the upper surface of the airfoil body 10.
[0031] The front section 111 of the reverse bending section 11 extends in the shape of a cubic parabola, the rear section 112 is symmetrically distributed with the front section 111, and the connection between the front section 111 and the rear section 112 has continuous curvature. The angle between the cubic parabola shape of the front section 111 and the rear section 112 of the reverse bending section 11 and the airfoil chord of the airfoil body 10 is 1°.
[0032] Embodiment two: as shown in the figure, the airfoil body 10 provided in the embodiment has a maximum camber of 4.2%, a maximum camber position of 47%, a maximum thickness of 16%, and a maximum thickness position of 32%. Figure 2
[0033] Compared to existing basic airfoils, the airfoil body 10 provided in this embodiment has a maximum camber of 4.2%, which improves the maximum lift coefficient. The maximum camber position of the airfoil body 10 is 47%, which helps enhance the stability of the boundary layer near the trailing edge 13. While the maximum lift coefficient is slightly reduced, a more moderate speed characteristic is achieved. Furthermore, the maximum thickness of the airfoil body 10 is 16%, which reduces drag. Simultaneously, the maximum thickness position of the airfoil body 10 is 32%, which positions the minimum pressure position further aft, making the pressure distribution on the upper surface of the airfoil body 10 flatter. This shortens the range of the adverse pressure gradient, resulting in a significant compressive pressure gradient within approximately 40% of the chord length of the airfoil body 10. The flow continuously accelerates, and the laminar flow region is wide. The inflection point 11 is located at 92%, which is the ratio of the distance of the inflection point 11 from the leading edge of the airfoil body 10 to the chord length. The shape of the front section 111 and the rear section 112 of the concave section 11 forms a cubic parabola, and the angle between the parabola and the chord of the airfoil body 10 is 3°. The other parts of this embodiment are the same as those in Embodiment 1, and will not be described again here.
[0034] Example 3: Figure 2 As shown, the airfoil body 10 provided in this embodiment has a maximum camber of 4.5%, a maximum camber position of 50%, a maximum thickness of 17%, and a maximum thickness position of 35%.
[0035] Compared to existing basic airfoils, the airfoil body 10 provided in this embodiment has a maximum camber of 4.5%, which can improve the maximum lift coefficient. The maximum camber position of the airfoil body 10 is 50%, which helps to enhance the stability of the boundary layer near the trailing edge 13 of the airfoil body 10. The maximum lift coefficient is slightly reduced, but a more moderate speed characteristic is obtained. Furthermore, the maximum thickness of the airfoil body 10 is 17%, which can reduce the drag of the airfoil body 10. At the same time, the maximum thickness position of the airfoil body 10 is 35%, which allows the minimum pressure position of the airfoil body 10 to be located further rearward, further making the pressure distribution on the upper surface of the airfoil body 10 more flat, thereby shortening the range of the adverse pressure gradient. Finally, there is a significant compressive pressure gradient within about 40% of the chord length of the airfoil body 10, the flow is continuously accelerated, and the laminar flow region is wide. The position of the inflection section 11 is 100%, that is, the ratio of the distance of the inflection section 11 from the leading edge of the airfoil body 10 to the chord length. The shape of the front section 111 and the rear section 112 of the concave section 11 forms a cubic parabola, and the angle between the parabola and the chord of the airfoil body 10 is 5°. The other parts of this embodiment are the same as those in Embodiment 1, and will not be described again here.
[0036] In summary, the high-lift-drag ratio low-speed airfoil provided in the embodiment has a high lift-drag ratio.
[0037] As shown in Figure 3 , Figure 3 , the wing profile CFD grid topology and boundary layer grid of the high-lift-drag ratio low-speed airfoil provided in the application are shown in the figure. In the figure, the total amount of grid is about 120,000, the height of the first layer of grid is 0.001mm, the grid growth rate is 1.15, the boundary layer layer number N=76, and the grid topology is O topology.
[0038] As shown in Figures 4 to 6 , Figure 4 , Figure 5 and Figure 6 are respectively the resistance coefficient curve, the lift coefficient curve and the lift-drag ratio curve comparison diagram of the high-lift-drag ratio low-speed airfoil and the basic airfoil provided in the application. As can be seen from the figure, under the same angle of attack, the resistance coefficient of the high-lift-drag ratio low-speed airfoil provided in the application is lower than that of the basic airfoil, the lift coefficient is higher than that of the basic airfoil, and the lift-drag ratio is higher than that of the basic airfoil. Therefore, the lift-drag ratio of the high-lift-drag ratio low-speed airfoil provided in the application is greatly improved compared with the basic airfoil.
[0039] The embodiment further provides an Evtol aircraft comprising the high-lift-drag ratio low-speed airfoil as described above. In the case that the high-lift-drag ratio low-speed airfoil described above has a high lift-drag ratio, the take-off performance of the Evtol aircraft can be sufficiently improved.
[0040] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the application, which should be covered within the protection scope of the application.
Claims
1. A high-lift low-drag ratio airfoil characterized by: The airfoil body (10) has a maximum camber of 4%-4.5%, a maximum camber position of 45%-50%, a maximum thickness of 15%-17%, and a maximum thickness position of 30%-35%.
2. The high-lift low-drag ratio low-speed airfoil of claim 1, wherein: The lower surface of the airfoil body (10) is provided with a reverse bending section (11) which is curved towards the upper surface of the airfoil body (10).
3. The high-lift low-drag ratio low-speed airfoil of claim 2, wherein: The reverse bending section (11) comprises a front section (111) and a rear section (112), the front section (111) gradually inclines towards the upper surface of the airfoil body (10) from the leading edge (12) to the trailing edge (13) of the airfoil body (10), and the rear section (112) gradually inclines away from the upper surface of the airfoil body (10) from the leading edge (12) to the trailing edge (13) of the airfoil body (10).
4. The high-lift low-drag ratio airfoil of claim 3, wherein: The front section (111) of the reverse bending section (11) extends in the shape of a cubic parabola, the rear section (112) is symmetrically distributed with the front section (111), and the connection between the front section (111) and the rear section (112) has continuous curvature.
5. The high-lift low-speed airfoil of claim 4, wherein: The angle between the cubic parabola presented by the shape of the front section (111) and the rear section (112) of the reverse bending section (11) and the chord of the airfoil body (10) is 1°-5°.
6. The high-lift low-speed airfoil of claim 2, wherein: The reverse bending section position is 85%-100%.
7. An Evtol aircraft characterized by: The high-lift-drag ratio low-speed airfoil comprises the high-lift-drag ratio low-speed airfoil according to any one of claims 1-6.