Flying wing unmanned aerial vehicle
By adopting laminar flow airfoils, negative torsion wings, and optimized geometric parameters, the design of flying-wing UAVs has solved the problems of low cruise lift coefficient and insufficient directional stability in conventional flying-wing layouts, achieving efficient endurance and improved aerodynamic performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2026-03-10
AI Technical Summary
Conventional flying-wing UAVs have a low cruise lift coefficient, which makes it difficult to meet the requirements of solar-powered UAVs, and their directional stability is insufficient.
It adopts a laminar flow airfoil, a negative twist wing, increases the aspect ratio, adjusts the wing sweep angle and dihedral angle, and applies solar cells to the wing. Combined with the vertical tail and aerodynamic control surface design, the geometric parameters of the wing and fuselage are optimized.
It improves the cruise lift coefficient and lift-to-drag ratio of the flying wing UAV, enhances directional stability, and improves endurance and aerodynamic efficiency.
Smart Images
Figure CN121626474A_ABST
Abstract
Description
Technical Field
[0001] Embodiments of this disclosure relate to the field of aircraft, and more particularly to a flying-wing unmanned aerial vehicle. Background Technology
[0002] Solar-powered unmanned aerial vehicles (UAVs) are near-space flight platforms with ultra-long endurance, capable of performing many functions of low-Earth orbit satellites, such as relay communication, remote sensing, reconnaissance and early warning, and electronic warfare. They can be considered a new type of aircraft similar to satellites. Compared to satellites, solar-powered UAVs have advantages such as mobile deployment and low cost. Compared to aircraft, they have characteristics such as long flight time, long range, and the ability to stay in any specific area for extended periods, making them a promising market prospect.
[0003] Flying wing UAVs have the advantage of high aerodynamic efficiency, but conventional flying wing layouts have large nose-down moments. In order to achieve longitudinal balance, they often use airfoils with small or even negative camber, resulting in a low cruise lift coefficient, which is far from the cruise lift coefficient required by solar-powered UAVs. Summary of the Invention
[0004] This disclosure is made to alleviate or resolve at least one aspect or point of the above-mentioned problems.
[0005] Embodiments of this disclosure provide a flying-wing unmanned aerial vehicle (UAV), comprising: a fuselage and wings disposed on both sides of the fuselage, wherein:
[0006] The airfoil has a laminar flow airfoil section and a negative twist angle, with the negative twist angle ranging from 5° to 10°.
[0007] The aspect ratio of the flying wing UAV is greater than 20; the wing sweep angle is 10° to 30°; and the wing dihedral angle is 0° to 5°.
[0008] In environments with Mach numbers of 0.05 to 0.2 and Reynolds numbers of 200,000 to 600,000, the lift-to-drag ratio K2 of the flying-wing UAV is ≥35 and the cruise lift coefficient CL2 is ≥1.0. Attached Figure Description
[0009] The above and other aspects and features of this disclosure will become clear from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:
[0010] Figure 1 A schematic diagram of the cross-sectional airfoil of a flying-wing unmanned aerial vehicle as an exemplary embodiment of this disclosure;
[0011] Figure 2 A three-dimensional perspective view of a flying-wing unmanned aerial vehicle as an exemplary embodiment of this disclosure;
[0012] Figure 3A schematic diagram of the lift-drag ratio K2 of a flying-wing unmanned aerial vehicle as a function of the lift coefficient CL2, which is an exemplary embodiment of this disclosure.
[0013] Figure 4 A schematic diagram of the pitch moment Cm2 of a flying-wing unmanned aerial vehicle as a function of the lift coefficient CL2, which is an exemplary embodiment of this disclosure.
[0014] Figure 5 A schematic diagram of the lift-to-drag ratio K1 of an airfoil as a function of the lift coefficient CL1, which is an exemplary embodiment of this disclosure;
[0015] Figure 6 A schematic diagram of the pitching moment Cm1 of an airfoil as a function of the lift coefficient CL1, which is an exemplary embodiment of this disclosure;
[0016] Figure 7 This is a schematic diagram of the spanwise cross-sectional twist angle for an exemplary embodiment of the present disclosure.
[0017] In the picture:
[0018] 1. Fuselage, 2. Wing, 3. Vertical tail, 4. Landing gear, 5. Power plant, 6. Aileron, 7. Elevator, 8. Rudder. Detailed Implementation
[0019] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this disclosure.
[0020] See appendix Figure 1 and Figure 2 This disclosure proposes a flying wing unmanned aerial vehicle, including: a fuselage 1 and wings 2 disposed on both sides of the fuselage 1, wherein: the airfoil of the wing section is a laminar flow airfoil, and the wing twist angle is negative twist, with the negative twist angle ranging from 5° to 10°.
[0021] Optionally, the angle of negative torsion can be 5°, 6°, 7°, 8°, 9°, 10°, etc.
[0022] According to the flying-wing UAV disclosed herein, the aspect ratio of the flying-wing UAV is greater than 20, the wing sweep angle is 10° to 30°, and the wing dihedral angle is 0° to 5°.
[0023] Optionally, the flying wing UAV has an aspect ratio of 21, a wing sweep angle of 10°, and a wing dihedral angle of 1°.
[0024] Optionally, the flying wing UAV has an aspect ratio of 22, a wing sweep angle of 15°, and a wing dihedral angle of 3°.
[0025] Optionally, the flying wing UAV has an aspect ratio of 23, a wing sweep angle of 20°, and a wing dihedral angle of 4°.
[0026] Optionally, the flying wing UAV has an aspect ratio of 25, a wing sweep angle of 25°, and a wing dihedral angle of 5°. The wing aspect ratio directly affects the overall aerodynamic efficiency; increasing the aspect ratio increases the lift-to-drag ratio. Increasing the sweep angle improves longitudinal trim and enhances the efficiency of the elevator and rudder. To increase the solar panel coverage, a wing tip ratio of 1.0 is chosen. Increasing the dihedral angle improves the lateral stability of the aircraft. Increasing the twist angle is also an effective measure to address the longitudinal trim problem in flying wing configurations.
[0027] The disclosed flying-wing UAV has a lift-to-drag ratio K≥35 and a cruise lift coefficient CL≥1.0 in a low Reynolds number environment in near space, which can meet the flight performance requirements of flying-wing UAVs in near space.
[0028] In the embodiments disclosed herein, the flying wing UAV adjusts the airfoil thickness at different locations on the wing and fuselage to meet the design requirements of the fuselage volume and wing structure.
[0029] Optionally, the relative thickness of the airfoil at the fuselage position is ≥18%, the relative thickness of the airfoil at the wing root position is 12%–15%, and the relative thickness of the airfoil at the wingtip position is 8%–10%, and the airfoil shape is as follows: Figure 1 As shown.
[0030] Optionally, the relative thickness of the airfoil at the fuselage position is 18%, the relative thickness of the airfoil at the wing root position is 12%, and the relative thickness of the airfoil at the wingtip position is 8%.
[0031] Optionally, the relative thickness of the airfoil at the fuselage position is 19%, the relative thickness of the airfoil at the wing root position is 13%, and the relative thickness of the airfoil at the wingtip position is 9%.
[0032] Optionally, the relative thickness of the airfoil at the fuselage position is 20%, the relative thickness of the airfoil at the wing root position is 15%, and the relative thickness of the airfoil at the wingtip position is 10%.
[0033] In embodiments of this disclosure, the airfoil has different twist angles at different locations.
[0034] Optionally, the airfoil twist angle at the wing root is greater than the airfoil twist angle at the wing tip.
[0035] Optionally, the airfoil's twist angle gradually decreases from the wing root to the wingtip.
[0036] like Figure 7 As shown, optionally, the installation angle of the airfoil at the middle of the fuselage is 8°, and the installation angle of the airfoil at the wingtip is 2°, then the negative twist angle of the wing of this flying wing UAV is 6°.
[0037] According to the airfoil of the flying-wing UAV disclosed herein, the design lift coefficient CL1 of the airfoil is in the range of 1.2≤CL1≤1.4, the lift-to-drag ratio K1≥60, and the zero lift moment |C m0 |≤0.14.
[0038] Among them, the design lift coefficient is the airfoil lift coefficient used in the aircraft's cruise state, and it is the airfoil lift coefficient when the aircraft is in the state of optimal lift-to-drag ratio.
[0039] Optionally, the airfoil can be designed with a lift coefficient CL1 of 1.2, a lift-to-drag ratio K1 of 60, and a zero lift moment of 0.14.
[0040] Optionally, the airfoil is designed with a lift coefficient CL1 of 1.3, a lift-to-drag ratio K1 of 62, and a zero lift moment of 0.13.
[0041] Optionally, the airfoil is designed with a lift coefficient CL1 of 1.4, a lift-to-drag ratio K1 of 65, and a zero lift moment of 0.12.
[0042] Optionally, if the maximum lift coefficient of the airfoil disclosed herein is ≥1.7, then the maximum lift coefficient of the flying-wing UAV disclosed herein is ≥1.5.
[0043] The disclosed flying-wing UAV has a lift-to-drag ratio K2≥35 and a cruise lift coefficient CL2≥1.0 under the conditions of Mach number range of 0.05 to 0.2 and Reynolds number range of 200,000 to 600,000.
[0044] Optionally, the flying-wing UAV disclosed herein has a lift-to-drag ratio K2 of 35 and a cruise lift coefficient CL2 of 1.0.
[0045] Optionally, the flying-wing UAV disclosed herein has a lift-to-drag ratio K2 of 38 and a cruise lift coefficient CL2 of 1.1.
[0046] Optionally, the flying-wing UAV disclosed herein has a lift-to-drag ratio K2 of 40 and a cruise lift coefficient CL2 of 1.2.
[0047] This disclosure adopts a high-lift, high-lift-drag ratio laminar flow airfoil, which improves the overall aerodynamic performance and has a lift-drag ratio greater than that of conventional solar-powered UAVs; and significantly improves the cruise lift coefficient of the flying wing layout, greatly enhancing the endurance performance of low-speed flying wing UAVs.
[0048] The fuselage and wings in this disclosure are important components of the UAV. Optionally, the airfoil of each section of the wing can be determined first, and then created using mathematical methods such as quadratic curves through CAD software such as CATIA.
[0049] Airfoil optimization design requires consideration of many factors. First, it must meet the requirements of a cruise lift coefficient CL2 ≥ 1.0 and K2 ≥ 35 for flying-wing UAVs with Mach numbers of 0.05–0.2 and Reynolds numbers of 200,000–600,000. This necessitates an airfoil design with a lift coefficient of 1.2 ≤ CL1 ≤ 1.4 and a lift-to-drag ratio of K1 ≥ 60. Second, it must meet the longitudinal trim requirements of the flying-wing layout, requiring an airfoil design with zero lift moment |C. m0 |≤0.14; Third, to meet the requirement that the maximum usable lift coefficient CLmax2 of the flying wing UAV is ≥1.5, the maximum lift coefficient CLmax1 of the airfoil needs to be ≥1.7; Fourth, to meet the requirements of fuselage volume and wing structure design, the relative thickness of the airfoil at the fuselage position needs to be ≥18%, the relative thickness of the airfoil at the wing root needs to be 12% to 15%, and the relative thickness of the airfoil at the wingtip needs to be 8% to 10%. This results in the design of high lift and high lift-to-drag ratio airfoils, such as... Figure 1 As shown.
[0050] The wing design disclosed herein needs to consider geometric parameters such as aspect ratio, sweep angle, dihedral angle, and torsion angle to determine the relative positional relationship between the wing and the fuselage.
[0051] In one embodiment, the wing reference area of the flying wing UAV is taken as S = 60m². 2 With a wingspan of 44 meters, the wing geometric parameters are obtained from the optimized design based on the wing geometric parameters, as shown in the table below.
[0052]
[0053]
[0054] like Figure 2 As shown, the flying wing UAV disclosed herein adopts a flying wing aerodynamic layout design. The wings 2 are installed on both sides of the fuselage 1, and the wingtips of the wings 2 are provided with vertical tails 3. The landing gear 4 is installed under the wings 2 and the fuselage 1. The power unit 5 is arranged on the leading edge of the wings 2, and the power unit includes a motor and a propeller.
[0055] The vertical tail of the UAV is located on the wingtip, which effectively solves the problem of insufficient directional stability of the flying wing layout. At the same time, it can also act as a winglet, improving the aerodynamic efficiency of the entire aircraft.
[0056] Optionally, solar cells can be installed on the upper surface of wing 2.
[0057] The flying-wing UAV includes aerodynamic control surfaces, which include: ailerons 6, elevators 7, and rudders 8.
[0058] Among them, the aileron 6 is arranged on the trailing edge of the wing 2 near the fuselage 1, and is mainly used to control the roll and yaw of the UAV.
[0059] The elevator 7 is located on the trailing edge of the wing 2 on the side away from the fuselage 1, and is mainly used to control the pitch and ascent of the UAV.
[0060] The rudder 8 is located at the trailing edge of the vertical tail 3 and is mainly used to control the yaw of the UAV.
[0061] Optionally, space is reserved inside fuselage 1 for installing radar, sensors, and various avionics equipment.
[0062] Optionally, the landing gear 4 is a tricycle landing gear, with the nose landing gear located on the underside of the fuselage 1, and the pair of main landing gears located on the underside of the left and right wings 2 respectively.
[0063] like Figure 3 As shown, the flying-wing UAV disclosed herein has a lift-to-drag ratio of close to 36 when the cruise lift coefficient CL2 = 1.0, which is a significant improvement over the lift-to-drag ratio of conventional solar-powered UAVs of the same size.
[0064] like Figure 4 As shown, the pitch moment of the disclosed flying-wing UAV is close to self-trimming when the cruise lift coefficient CL2 = 1.0, which is a significant improvement in cruise lift coefficient compared with traditional flying-wing aircraft, greatly improving the aircraft's endurance.
[0065] like Figure 5 As shown, when the lift coefficient CL1 of the airfoil of the flying-wing UAV disclosed herein is 1.2, the lift-to-drag ratio is greater than 60.
[0066] like Figure 6 As shown, when the lift coefficient CL1 = 0 of the airfoil of the flying-wing UAV disclosed herein, the zero lift moment |C m0 | < 0.14.
[0067] The flying-wing UAV disclosed herein improves overall aerodynamic performance, with a lift-to-drag ratio greater than that of conventional solar-powered UAVs; and significantly increases the cruise lift coefficient of the flying-wing configuration, greatly enhancing the endurance of low-speed flying-wing UAVs.
[0068] Based on the above, this disclosure proposes the following technical solution:
[0069] 1. A flying-wing unmanned aerial vehicle (UAV), comprising: a fuselage and wings disposed on both sides of the fuselage, wherein:
[0070] The airfoil has a laminar flow airfoil section and a negative twist angle, with the negative twist angle ranging from 5° to 10°.
[0071] 2. The flying-wing UAV according to 1, wherein:
[0072] The flying-wing UAV has an aspect ratio greater than 20, a wing sweep angle of 10° to 30°, and a wing dihedral angle of 0° to 5°.
[0073] 3. The flying-wing UAV according to 1, wherein:
[0074] The airfoil's design lift coefficient CL1 ranges from 1.2 to 1.4, the lift-to-drag ratio K1 is greater than or equal to 60, and the zero lift moment is |C m0 |≤0.14.
[0075] 4. The flying-wing UAV according to claim 1, wherein:
[0076] The maximum lift coefficient of the airfoil is ≥1.7, and the maximum lift coefficient of the flying wing UAV is ≥1.5.
[0077] 5. The flying-wing UAV according to claim 1, wherein:
[0078] The relative thickness of the airfoil at the fuselage position is ≥18%, the relative thickness of the airfoil at the wing root position is 12% to 15%, and the relative thickness of the airfoil at the wingtip position is 8% to 10%.
[0079] 6. The flying-wing UAV according to any one of 1 to 5, wherein:
[0080] In environments with Mach numbers of 0.05 to 0.2 and Reynolds numbers of 200,000 to 600,000, the lift-to-drag ratio K2 of the flying-wing UAV is ≥35 and the cruise lift coefficient CL2 is ≥1.0.
[0081] 7. The flying-wing UAV according to 6, wherein:
[0082] The upper surface of the wing is covered with solar cells, and the wingtip is provided with a vertical tail.
[0083] 8. The flying-wing UAV according to 7, wherein:
[0084] The flying-wing UAV includes aerodynamic control surfaces, which include: ailerons, elevators, and rudders.
[0085] 9. The flying-wing UAV according to 8, wherein:
[0086] The aileron is located on the trailing edge of the wing near the fuselage, the elevator is located on the trailing edge of the wing away from the fuselage, and the rudder is located on the trailing edge of the vertical tail.
[0087] 10. The flying-wing UAV according to claim 1, wherein:
[0088] It also includes the power unit;
[0089] The power unit is located on the leading edge of the wing, and the power unit includes an electric motor and a propeller.
[0090] It should be noted that the above technical solutions can be combined arbitrarily where logically possible, and all are within the scope of protection of this disclosure. In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0091] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.
[0092] Although embodiments of the present disclosure have been shown and described, it will be understood by those skilled in the art that variations and combinations of elements may be made to these embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A flying wing drone comprising: A fuselage and wings arranged on both sides of the fuselage, wherein: The cross-sectional airfoil of the wing is a laminar flow airfoil, and the twist angle of the wing is a negative twist, and the angle range of the negative twist is 5°-10°.
2. The flying wing UAV of claim 1, wherein: The aspect ratio of the flying wing UAV is greater than 20, the wing sweepback angle is 10°-30°, and the wing dihedral angle is 0°-5°.
3. The flying wing UAV of claim 1, wherein: The wing profile is designed with a lift coefficient CL1 in the range 1.2 ≤ CL1 ≤ 1.4, a lift-drag ratio K1 ≥ 60, a zero-lift moment |C m0 | ≤ 0.
14.
4. The flying wing UAV of claim 1, wherein: The maximum lift coefficient of the airfoil is greater than or equal to 1.7, and the maximum lift coefficient of the flying wing UAV is greater than or equal to 1.
5.
5. The flying wing UAV of claim 1, wherein: The relative thickness of the airfoil at the fuselage position is greater than or equal to 18%, the relative thickness of the airfoil at the wing root position is 12%-15%, and the relative thickness of the airfoil at the wing tip position is 8%-10%.
6. The flying wing UAV of any one of claims 1-5, wherein: In an environment with a Mach number of 0.05-0.2 and a Reynolds number of 200,000-600,000, the lift-drag ratio K2 of the entire flying wing UAV is greater than or equal to 35, and the cruising lift coefficient CL2 is greater than or equal to 1.
0.
7. The flying wing UAV of claim 6, wherein: The upper surface of the wing is coated with solar cell pieces, and the wing tip of the wing is provided with a vertical tail.
8. The flying wing UAV of claim 7, wherein: The flying wing UAV includes aerodynamic control surfaces, and the aerodynamic control surfaces include ailerons, elevators, and rudders.
9. The flying wing UAV of claim 8, wherein: The ailerons are arranged on the trailing edge of the wing near the fuselage side, the elevators are arranged on the trailing edge of the wing away from the fuselage side, and the rudders are arranged on the trailing edge of the vertical tail.
10. The flying wing UAV of claim 1, wherein: Further comprising a power device; The power device is arranged on the leading edge of the wing, and the power device includes a motor and a propeller.