An unmanned aerial vehicle of a close-coupled tandem wing configuration

Abstract

The application relates to the technical field of unmanned aerial vehicles, and particularly discloses an unmanned aerial vehicle with a near-distance coupling tandem wing layout, which comprises a holder, a front normal lift wing, a rear normal lift wing, a flight controller, a propeller and an energy management system; the front normal lift wing is fixedly arranged on the holder; the rear normal lift wing is fixedly arranged on the holder, is located below and behind the front normal lift wing, and forms a tandem wing layout with the front normal lift wing; the propeller is located in front of the front normal lift wing; the rear normal lift wing is provided with ailerons and elevators, and the ailerons and the elevators are electrically connected with the flight controller; the unmanned aerial vehicle with the near-distance coupling tandem wing layout is designed with two wings which can both provide normal lift and are connected in series, and the aerodynamic performance of the whole machine is improved by utilizing the advantageous aerodynamic coupling effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicles, and particularly relates to an unmanned aerial vehicle with a near-coupling tandem wing layout. BACKGROUND

[0002] Solar-powered aircraft has many advantages over traditional aircraft, such as environmental protection, energy saving, long flight duration, and the like, and has a very broad application in both civilian and military directions.

[0003] However, the existing solar-powered aircraft configuration has problems such as insufficient structural stiffness, difficulty in ensuring stability and maneuverability, and less payload. The emerging tandem wing layout solar-powered aircraft does not fully exploit the advantages of the tandem wing layout combined with solar-powered unmanned aerial vehicles, and has problems such as loose structure, insufficient structural stiffness, large wetted area, and large frictional resistance. How to further improve the performance of the tandem wing solar-powered unmanned aerial vehicle becomes a problem to be solved. SUMMARY

[0004] The technical problem solved by the present application is to provide an unmanned aerial vehicle with a near-coupling tandem wing layout. By adopting a near-coupling tandem wing design, two wings that can provide positive lift are connected in series, and the lift distribution of the front and rear wings is reasonably designed, so that the overall aerodynamic trim design of the aircraft is better completed. The design of removing the horizontal tail reduces the loss of positive lift, thereby improving the overall lift of the aircraft and improving the lift-drag ratio characteristics of the aircraft.

[0005] To solve the above problems, the present application adopts the following technical solutions:

[0006] An unmanned aerial vehicle with a near-coupling tandem wing layout, comprising a holder, a front positive lift wing, a rear positive lift wing, a flight controller, a propeller, and an energy management system.

[0007] The front positive lift wing is fixedly arranged on the holder.

[0008] The rear positive lift wing is fixedly arranged on the holder, the rear positive lift wing is located below and behind the front positive lift wing, and the rear positive lift wing and the front positive lift wing form a tandem wing layout.

[0009] The propeller is electrically connected to the flight controller, and the propeller is located in front of the front positive lift wing.

[0010] The energy management system is electrically connected to the flight controller and the propeller.

[0011] The distance between the trailing edge of the front positive lift wing and the leading edge of the rear positive lift wing in the horizontal direction is less than the average chord length of the front positive lift wing and the rear positive lift wing.

[0012] The distance between the trailing edge of the front lift wing and the leading edge of the rear lift wing in the vertical direction is less than the average chord length of the front lift wing and the rear lift wing.

[0013] The span of the front lift wing is less than the span of the rear lift wing.

[0014] The rear lift wing has a rudder.

[0015] The holding frame is provided with ailerons and elevators, and the ailerons, elevators and rudder are electrically connected to the flight controller.

[0016] The propeller is fixedly connected to the holding frame.

[0017] The energy management system of the near-coupling tandem wing layout unmanned aerial vehicle provided by at least one embodiment of the present disclosure comprises a solar cell array, an MPPT maximum power point tracker, a lithium battery and an electronic speed controller.

[0018] The solar cell array is fixedly arranged on the front lift wing and the rear lift wing.

[0019] The MPPT maximum power point tracker, the lithium battery, the electronic speed controller and the flight controller are arranged in the front lift wing or the rear lift wing.

[0020] The near-coupling tandem wing layout unmanned aerial vehicle provided by at least one embodiment of the present disclosure is provided with a front landing gear and a rear landing gear fixedly arranged on the holding frame.

[0021] The near-coupling tandem wing layout unmanned aerial vehicle provided by at least one embodiment of the present disclosure is provided with an elevator located at an intermediate position below the trailing edge of the rear lift wing.

[0022] The aileron surface is located below the trailing edge of the rear lift wing.

[0023] Both sides of the rear lift wing are provided with winglet, and the rudder is arranged on the winglet.

[0024] The near-coupling tandem wing layout unmanned aerial vehicle provided by at least one embodiment of the present disclosure is provided with an engine nacelle and a nose nacelle arranged on the holding frame.

[0025] The engine nacelle and the nose nacelle are detachably connected to the holding frame.

[0026] The nose nacelle is fixedly connected to the front landing gear.

[0027] The rear landing gear is located below the rear lift wing.

[0028] The engine nacelle and the nose nacelle are both located below the front lift wing.

[0029] The unmanned aerial vehicle provided by at least one embodiment of the present disclosure is a near-coupling tandem wing layout unmanned aerial vehicle, and the holder comprises a plurality of wing connecting frames, a plurality of first connecting pipes and a plurality of second connecting pipes.

[0030] The plurality of first connecting pipes are configured to be fixed with the plurality of wing connecting frames.

[0031] The plurality of second connecting pipes are configured to be fixed with the plurality of wing connecting frames, and the second connecting pipes are parallel to the first connecting pipes.

[0032] The first connecting pipes and the second connecting pipes are both perpendicular to the wing connecting frames, and the wing connecting frames are arranged in a streamlined manner.

[0033] The front lift wing and the rear lift wing are both fixedly connected with the wing connecting frames.

[0034] The front lift wing is fixedly connected with the plurality of first connecting pipes at both ends.

[0035] The rear lift wing is fixedly connected with the plurality of second connecting pipes at both ends.

[0036] The wing connecting frame has a profiled portion, and the profiled portion is profiled with the airfoil of the front lift wing.

[0037] The engine nacelle and the nose nacelle are both hollow.

[0038] The airfoil of the front lift wing is MH114.

[0039] The installation angle of the airfoil of the front lift wing is 3.5°.

[0040] The aspect ratio of the airfoil of the front lift wing is 5.14.

[0041] The airfoil of the rear lift wing is RG15.

[0042] The installation angle of the airfoil of the rear lift wing is 2.5°.

[0043] The aspect ratio of the airfoil of the rear lift wing is 9.14.

[0044] The beneficial effects of the present application are: the design of near-coupling series wings is adopted, two wings which can provide positive lift are designed in series, the aerodynamic performance of the whole machine is improved by using the beneficial aerodynamic coupling effect, the aerodynamic coupling effect specifically shows that the boundary layer formed on the rear positive lift wing makes the speed of the trailing edge of the front positive lift wing lower than the free flow speed, thereby delaying the flow separation of the front positive lift wing, reducing the effective angle of attack, delaying the stall, and further improving the lift characteristics and the lift-drag ratio of the whole machine; meanwhile, the airflow is accelerated when passing through the front positive lift wing, and when passing through the rear positive lift wing, the size and direction of the airflow are changed, which shows that the airflow speed is increased and the relative effective angle of attack is reduced.

[0045] The connection of the front positive lift wing and the rear positive lift wing is realized by using a simple structure, which on the one hand reduces the adverse effects of the immersion area and frictional resistance of the whole machine, reduces the induced drag, and improves the lift-drag characteristics of the whole machine; on the other hand, the structural strength and rigidity of the whole machine are strengthened, the total weight is reduced, and the load capacity is improved; in addition, the bodyless design can avoid the problem that the solar cell sheets cannot be laid on the body in the traditional body design, and the solar cell laying rate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0047] Figure 1 It is a schematic diagram of the overall structure of the unmanned aerial vehicle with the near-coupling series wing layout of the present application.

[0048] Figure 2 It is a perspective view of the retainer.

[0049] Figure 3 It is a perspective view of the retainer.

[0050] Figure 4 It is a schematic diagram of the structure of the wing connecting frame.

[0051] Figure 5 It is a connection block diagram of some parts of the unmanned aerial vehicle with the near-coupling series wing layout of the present application.

[0052] In the drawings:

[0053] 10, retainer; 11, aileron; 12, elevator; 13, front landing gear; 14, rear landing gear; 15, engine nacelle; 16, nose nacelle; 17, wing connecting frame; 18, first connecting pipe; 19, second connecting pipe; 171, profiling part;

[0054] 20. Front positive lift wing;

[0055] 30. Rear positive lift wing; 31. Rudder; 32. Winglet;

[0056] 40. Flight controller;

[0057] 50. Propeller;

[0058] 61. Solar cell array; 62. MPPT maximum power point tracker; 63. Lithium battery; 64. Electronic speed regulator. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments.

[0060] Existing solar aircraft have a large aspect ratio and are prone to deformation, causing problems such as structural vibration and aeroelasticity. For solar aircraft with conventional layouts or full-wing layouts, in order to meet the power requirements of cruising, sufficient wing area is required to lay out the solar cell array, which results in a large wing aspect ratio and large wing deflection, making the aircraft prone to deformation, and easily affecting the dynamic characteristics and aeroelastic characteristics of the structure. In response to the above shortcomings, the present invention adopts a close-coupled serial layout aircraft design. On the one hand, the double wings provide sufficient wing surface space to meet the requirements of laying solar panels. On the other hand, the double wings can reduce the aspect ratio of the aircraft, making the aircraft structure more compact and having better structural stiffness performance, effectively reducing the structural vibration and aeroelasticity problems caused by deformation, and having stronger wind resistance. In addition, the structural mass of the aircraft can be further reduced, thereby reducing the design cost of the aircraft.

[0061] Example

[0062] like Figures 1 to 5 As shown, this embodiment provides an unmanned aerial vehicle with a close-coupled tandem wing layout, including a cage 10, a front positive lift wing 20, a rear positive lift wing 30, a flight controller 40, a propeller 50 and an energy management system.

[0063] Furthermore, the front positive lift wing 20 is fixedly mounted on the retaining frame 10. The rear positive lift wing 30 is also fixedly mounted on the retaining frame 10. The rear positive lift wing 30 is positioned below and behind the front positive lift wing 20, and the rear positive lift wing 30 and the front positive lift wing 20 form a tandem wing configuration. The propeller 50 is configured to be fixedly connected to the retaining frame 10.

[0064] Further, the propeller 50 is configured to be electrically connected with the flight controller 40, and the propeller 50 is located in front of the front lift wing 20. The energy management system is configured to be electrically connected with the flight controller 40 and the propeller 50.

[0065] Further, the distance between the trailing edge of the front lift wing 20 and the leading edge of the rear lift wing 30 in the horizontal direction is less than the average chord length of the front lift wing 20 and the rear lift wing 30. The distance between the trailing edge of the front lift wing 20 and the leading edge of the rear lift wing 30 in the vertical direction is less than the average chord length of the front lift wing 20 and the rear lift wing 30. The span length of the front lift wing 20 is less than the span length of the rear lift wing 30. The near-coupled tandem wing design is adopted, and two wings that can provide lift are designed in series, and the aerodynamic performance of the whole machine is improved by using the beneficial aerodynamic coupling effect.

[0066] Further, the distance between the trailing edge of the front lift wing 20 and the leading edge of the rear lift wing 30 in the horizontal direction is less than the average chord length of the front lift wing 20 and the rear lift wing 30. The distance between the trailing edge of the front lift wing 20 and the leading edge of the rear lift wing 30 in the vertical direction is less than the average chord length of the front lift wing 20 and the rear lift wing 30. The span length of the front lift wing 20 is less than the span length of the rear lift wing 30. The near-coupled tandem wing design is adopted, and two wings that can provide lift are designed in series, and the aerodynamic performance of the whole machine is improved by using the beneficial aerodynamic coupling effect.

[0067] Further, the rear lift wing 30 has a rudder 31. The holder 10 is provided with ailerons 11 and elevators 12, and the ailerons 11, the elevators 12 and the rudder 31 are electrically connected with the flight controller 40.

[0068] In this embodiment, the energy management system includes a solar cell array 61, an MPPT maximum power point tracker 62, a lithium battery 63 and an electronic speed controller 64.

[0069] Further, the solar cell array 61 has two groups, and the two groups of solar cell arrays 61 are fixedly arranged on the front lift wing 20 and the rear lift wing 30 respectively.

[0070] Due to the unpredictability of solar energy and the operating conditions of solar-powered aircraft, a complex energy and task management needs to be designed to achieve long-time hovering flight. In order to improve the reliability of the aircraft, a reasonable energy management system needs to be designed, which can improve the energy supply level of the solar cell array to achieve self-sustaining flight, and can also store energy as energy supplement at night or during weather changes.

[0071] The aircraft adopts a solar cell array 61, an MPPT maximum power point tracker 62, a lithium battery 63 and an electronic speed controller 64. Figure 5The energy management system shown, the aircraft obtains energy by the photoelectric effect of the solar array to convert light energy into electrical energy, but due to the light angle, light intensity, temperature and other factors are usually not constant, the output power of the solar array is also unstable, the maximum power point tracking (MPPT) needs to be connected, which can track and monitor the real-time voltage and current of the solar array and the rechargeable battery. After the maximum power point tracker, the solar array supplies power to the rechargeable lithium battery, the solar array voltage should be higher than the lithium battery, when the solar array power is insufficient, the lithium battery discharges power, when the solar array power is sufficient, the excess energy is stored in the storage battery when supplying power to the load, completing the long-time endurance requirement.

[0072] In this embodiment, the front landing gear 13 and the rear landing gear 14 are fixedly arranged on the holder 10.

[0073] In this embodiment, the elevator 12 is located at the middle position below the trailing edge of the rear lift wing 30.

[0074] Further, the aileron 11 is located below the trailing edge of the rear lift wing 30. The wing tip winglet 32 is arranged on the wing tip winglet 32. The rudder 31 is arranged on the wing tip winglet 32. The wing tip winglet 32 can play a role in lateral stability.

[0075] In this embodiment, the engine nacelle 15 and the nose nacelle 16 are arranged on the holder 10. The engine nacelle 15 and the nose nacelle 16 are detachably connected with the holder 10.

[0076] Further, the nose nacelle 16 is fixedly connected with the front landing gear 13. The rear landing gear 14 is located below the rear lift wing 30. The engine nacelle 15 and the nose nacelle 16 are located below the front lift wing 20.

[0077] In use, the elevator, aileron and rudder are mixed controlled, which can superimpose control moment and improve the control performance and maneuverability of the aircraft. The rudder is designed on the vertical stabilizer on both sides, and the rear wing has large span to provide sufficient control moment.

[0078] In this embodiment, the holder 10 comprises a wing connecting frame 17, a first connecting pipe 18 and a second connecting pipe 19.

[0079] Exemplarily, the wing connecting frame 17 is arranged with four, and the first connecting pipe 18 and the second connecting pipe 19 are arranged with two.

[0080] Further, the first connecting pipe 18 is configured to be fixed with the wing connecting frame 17. The second connecting pipe 19 is configured to be fixed with the wing connecting frame 17, and the second connecting pipe 19 is parallel with the first connecting pipe 18.

[0081] Further, the first connecting pipe 18 and the second connecting pipe 19 are both perpendicular to the wing connecting frame 17, and the wing connecting frame 17 is arranged in a streamline shape.

[0082] Further, the front lift wing 20 and the rear lift wing 30 are both fixedly connected with the wing connecting frame 17. The front lift wing 20 is fixedly connected with the first connecting pipe 18 at both ends. The rear lift wing 30 is fixedly connected with the second connecting pipe 19 at both ends.

[0083] Further, the wing connecting frame 17 has a profiling part 171 which is profiled with the airfoil of the front lift wing 20. The engine nacelle 15 and the nose nacelle 16 are both arranged in a hollow shape.

[0084] The simple structure is adopted to realize the connection of the front lift wing and the rear lift wing, which reduces the adverse effects of the immersion area and the frictional resistance of the whole machine, reduces the induced drag, and improves the lift-drag characteristics of the whole machine.

[0085] In the embodiment, the airfoil of the front lift wing 20 is MH114. The installation angle of the front lift wing 20 is 3.5°. The aspect ratio of the airfoil of the front lift wing 20 is 5.14.

[0086] In the embodiment, the airfoil of the rear lift wing 30 is RG15. The installation angle of the airfoil of the rear lift wing 30 is 2.5°. The aspect ratio of the airfoil of the rear lift wing 30 is 9.14.

[0087] In some embodiments, the electronic speed controller 64 and the flight controller 40 are arranged in the front lift wing 20.

[0088] In some embodiments, the lithium battery 63 and the MPPT maximum power point tracker 62 are arranged in the rear lift wing 30.

[0089] In order to further disclose the unmanned aerial vehicle with the near-coupling tandem wing layout in the embodiments, the following will give a design example of the unmanned aerial vehicle with the near-coupling tandem wing layout provided by the embodiments.

[0090] Overall performance index:

[0091] Due to the low energy conversion efficiency, the cruising power provided by the energy management system is low, so the cruising speed index is set to 8m / s-10m / s. According to the characteristics of solar radiation, in order to enable the unmanned aerial vehicle to realize self-sustaining flight task, the self-sustaining cruising flight index of the unmanned aerial vehicle is set to 800W·m -2 .

[0092] According to the aircraft cruising state lift L and gravity W, resistance D and thrust T r Equal, the cruise power is P r So:

[0093]

[0094]

[0095] So,

[0096] According to the cruising state, the gravity W and cruising speed υ Of the aircraft can be expressed as:

[0097]

[0098] Summarized in the cruise power:

[0099]

[0100] Where, ρ ∞ The fluid density at infinity, S ref The reference area of the wing, C L The lift coefficient, C D The drag coefficient.

[0101] In order to improve the reliability, the design lift-drag ratio should be reduced, the design cruise power should be improved to ensure the energy supply of normal cruise, and the design lift-drag ratio is set to 4. Due to the limitation of energy conversion efficiency, try to keep the solar aircraft light, set the maximum take-off mass to 5.5 kg, and the effective load to 2 kg, the effective load ratio can reach 36%.

[0102] According to the overall performance, the maximum take-off mass is set to 5.5 kg, the design lift-drag ratio is 4, and according to the cruising state resistance D and propeller thrust T r Balance, get:

[0103] L=W=5.5×9.8=53.9N;

[0104]

[0105] So the cruise power demand P r Can be expressed as:

[0106] P r =T r ×v=13.475×8=107.8W;

[0107] In order to reserve the power margin, the design take-off weight is 5.5 kg according to the maximum take-off weight performance index, and the cruise power demand under ideal conditions is 107.8 W according to the formula. The energy supply power of the energy management system is set to be > 350 W considering the motor force efficiency in the actual flight process.

[0108] Aerodynamic layout design:

[0109] In order to solve the problems of aerodynamic elasticity, structural dynamics vibration, control difficulty, low load performance and the like of the conventional solar aircraft with a large aspect ratio conventional layout or flying wing layout, the present application adopts a near-coupling tandem wing layout.

[0110] According to the idea of near-coupling tandem wing layout, the wings of the tandem wing layout are arranged in near distance, so that the whole aircraft shows the aerodynamic characteristics of the flying wing layout relative to the far front airflow, and at the same time, due to the characteristics of the tandem wing layout, the problems of control difficulty and poor maneuverability of the flying wing layout are overcome.

[0111] The front and rear wings are arranged in near distance, and the favorable coupling interference between the airflow passing through the front wing and the airflow passing through the rear wing is utilized to improve the lift-drag ratio characteristics of the aircraft. For example, the boundary layer formed on the rear wing makes the velocity of the trailing edge of the front wing lower than the free stream velocity, delays flow separation, reduces the effective angle of attack, delays stall, and thus improves the lift-drag ratio.

[0112] The front and rear wings of the aircraft are arranged with a suitable area ratio, so that the lift distribution of the front and rear wings is more reasonable, and the trim design of the overall aerodynamics is more convenient. At the same time, sufficient solar cell array paving space is provided on the upper surface of the aircraft, which can more effectively distribute the series-parallel scheme of the front and rear wing solar cell arrays, improve the compactness of the energy management system design, and improve the cruise capability design of the solar aircraft.

[0113] Aerodynamic preliminary design:

[0114] According to the overall performance index and the subsystem performance index of the solar aircraft, the aerodynamic performance index is set according to the aerodynamics theory and the circulation iteration method, as shown in the following table.

[0115] Aerodynamic performance index parameter table

[0116] Rated take-off weight 4.5kg Maximum take-off weight 5.5kg Cruise state lift-drag ratio ＞11.5 Pitch static stability margin 5％-10％

[0117] According to the aerodynamic performance index, the main aerodynamic parameter design process of the aircraft is as follows:

[0118] A comprehensive analysis of the lift and geometric characteristics of various airfoils, combined with the aircraft's performance requirements of low wing loading, low speed, high lift-to-drag ratio, and ultra-long endurance, suggests that the aircraft should utilize a low-Reynolds-number airfoil with minimal camber and thickness, with the maximum camber and thickness positioned near the front. To balance the requirements of high lift-to-drag ratio, winglet loading, and high planking ratio, the aircraft's forewing utilizes the MH114 high-lift airfoil with relatively large camber and thickness, while the rear wing utilizes the RG-15 high-lift-to-drag ratio airfoil with low camber and thickness. Furthermore, to simplify aircraft design and facilitate development and production, this design utilizes a straight wing design with no aerodynamic twist and no washout.

[0119] Combining the lift-to-drag characteristics of the MH114 and RG15 airfoils, we found that the two airfoils achieve the best lift-to-drag ratio at an angle of attack of 2 to 4°. To achieve the highest level flight cruise efficiency of the aircraft, we adopted a front wing installation angle of 4° and a rear wing installation angle of 2°. Through iterative optimization of the aerodynamic design, we finally determined the front wing installation angle to be 3.5° and the rear wing installation angle to be 2.5°.

[0120] The ratio of front to rear wing area is determined by:

[0121] Because the front wing of a closely coupled tandem wing aircraft provides significantly more lift than the rear wing, this results in a forward focus position, making pitch moment trimming difficult. Therefore, to facilitate pitch moment trimming, the focus is positioned as far back as possible, and the front wing area needs to be smaller than the rear wing area. After rough aerodynamic calculations and iterations, the front-to-rear wing area ratio was designed to be approximately 0.6.

[0122] Determination of wing area:

[0123] According to the cruise power requirement and lift requirement,

[0124] P r =T r ×v=13.475×8=107.8W;

[0125]

[0126] Where: The lift coefficient C of the aircraft takeoff is estimated based on the lift characteristics of the airfoil l =0.8, air density is ρ = 1.225 kg / m 3 Based on the aircraft's design takeoff weight W = 5.5 kg and design takeoff speed v = 8 m / s, the required wing area of ​​the aircraft is greater than S ref >1.72m 2 .

[0127] Determination of the basic shape of the wing:

[0128] The flight speed of the aircraft is far less than the speed of sound, and the design does not involve shock resistance reduction design, so the flat wing with high lift line slope and simple processing technology is designed.

[0129] Wing aspect ratio:

[0130] The design is designed according to the area ratio of the front and rear wings of the aircraft aerodynamic layout and the model and number of solar cell panels; according to the basic geometric theory, under the condition of equal wing area, the higher the wing aspect ratio, the larger the wing span; according to the basic theory of mechanics, under the condition of equal aircraft load, the larger the wing span, the stronger the normal stress and shear stress at the root of the wing, the higher the structural design requirement, and the worse the wing stiffness, which is difficult to adapt to large maneuvering flight; in order to reduce the weight of the aircraft structure as much as possible, improve the maneuverability of the aircraft, and at the same time meet the demand of solar cell panel paving, the front wing span is finally determined as 1800mm, the rear wing span is 3200mm, and the chord length is 350mm.

[0131] Aerodynamic design parameters of wing and vertical tail

[0132] Wing Airfoil Mounting angle Aspect ratio Forward-lift wing MH114 3.5° 5.14 Forward-lift wing RG15 2.5° 9.14

[0133] Design of wing tip winglet:

[0134] The increase of the height of the wing tip winglet can generate more lift, but it will also increase the structural weight and generate a large wing root bending moment, and the height of the winglet is about 10% of the wing span; the sweepback angle can reduce the wing root bending moment and reduce the induced drag, which is effective in the range of 0-45°; the selection of the tip root ratio in the range of 0.35-0.55 can make the spanwise load distribution better; the increase of the inclination angle in the range of 15°-20° can improve the overall lift-drag ratio. The final setting parameters are shown in the following table.

[0135] Wing tip winglet parameter table

[0136] Height 300mm Angle of inclination 20° Sweep angle 45° Tip-taper ratio 210 / 350

[0137] Although the embodiments of the present application have been shown and described above, the scope of protection of the present application is not limited thereto, and any changes or substitutions not through creative labor should be covered within the scope of protection of the present application; unless explicitly stated, any element, action or instruction used herein should not be interpreted as critical or essential.

Claims

1. A near-coupled tandem wing layout unmanned aerial vehicle, characterized in that, The utility model relates to a kind of unmanned aerial vehicle, including: Holder; Front lift wing, fixedly arranged on the holder; Rear lift wing, fixedly arranged on the holder, the rear lift wing is located below the front lift wing, and the rear lift wing forms tandem wing layout with the front lift wing; Flight controller; Propeller, arranged to be electrically connected with the flight controller, and the propeller is located in front of the front lift wing; And Energy management system, arranged to be electrically connected with the flight controller and propeller; Wherein, the distance between the trailing edge of the front lift wing and the leading edge of the rear lift wing in horizontal direction is less than the average chord length of the front lift wing and the rear lift wing; The distance between the trailing edge of the front lift wing and the leading edge of the rear lift wing in vertical direction is less than the average chord length of the front lift wing and the rear lift wing; The span of the front lift wing is less than the span of the rear lift wing; The rear lift wing has rudder; The holder is provided with aileron and elevator, and the aileron, elevator and rudder are electrically connected with the flight controller; The propeller is arranged to be fixedly connected with the holder.

2. The near-coupled tandem wing layout UAV of claim 1, wherein, The energy management system includes: Solar cell array, fixedly arranged on the front lift wing and the rear lift wing; MPPT maximum power point tracker; Lithium battery;And Electronic governor; The MPPT maximum power point tracker, lithium battery, electronic governor and flight controller are arranged in the front lift wing or rear lift wing.

3. The near-coupled tandem wing layout UAV of claim 2, wherein, The holder is fixedly provided with front landing gear and rear landing gear.

4. The near-coupled tandem wing layout UAV of claim 3, wherein, The elevator is located at the middle position below the trailing edge of the rear lift wing; The aileron is located below the trailing edge of the rear lift wing; The rear lift wing is provided with winglet on both sides, and the rudder is arranged on the winglet.

5. The near-coupled tandem wing layout UAV of claim 4, wherein, The holder is provided with engine nacelle and nose nacelle; The engine nacelle and nose nacelle are detachably connected with the holder; The nose nacelle is fixedly connected with the front landing gear; The rear landing gear is located below the rear lift wing; The engine nacelle and nose nacelle are located below the front lift wing.

6. The near-coupled tandem wing layout UAV of claim 5, wherein, The holder includes: Multiple wing connecting frames; Multiple first connecting pipes arranged to be fixed with multiple wing connecting frames;And Multiple second connecting pipes arranged to be fixed with multiple wing connecting frames, and the second connecting pipe is parallel with the first connecting pipe; Wherein, the first connecting pipe and the second connecting pipe are perpendicular to the wing connecting frame, and the wing connecting frame is arranged in streamline shape; The front lift wing and the rear lift wing are fixedly connected with the wing connecting frame; The front lift wing is fixedly connected with multiple first connecting pipes at both ends; The rear lift wing is fixedly connected with multiple second connecting pipes at both ends.

7. The near-coupled tandem wing layout UAV of claim 6, wherein, The wing connecting frame has a profiled part, and the profiled part is profiled with the airfoil of the front lift wing.

8. The near-coupled tandem wing layout UAV of claim 5, wherein, The engine nacelle and nose nacelle are hollowed out.

9. The near-coupled tandem wing layout UAV of claim 8, wherein, The airfoil of the front lift wing is MH114. The mounting angle of the front lift wing is 3.5°; The aspect ratio of the front lift wing is 5.

14.

10. The near-coupled tandem wing layout UAV of claim 9, wherein, The airfoil of the rear lift wing is RG15; The mounting angle of the airfoil of the rear lift wing is 2.5°; The aspect ratio of the airfoil of the rear lift wing is 9.14.

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