Heavy-load fixed-wing bomb-dropping unmanned aerial vehicle

Abstract

The invention discloses a large-load fixed-wing bomb dropping unmanned aerial vehicle, and relates to the technical field of unmanned aerial vehicles. The large-load fixed-wing bomb-dropping unmanned aerial vehicle is composed of a vehicle body, main wings, ailerons, a horizontal tail wing, a vertical tail wing and a rudder. A main beam of the main wing is formed by CNC (computer numerical control) processing of a PMI (polymethacrylimide) material, and thin-layer carbon sheets are adhered to the upper and lower parts of the main beam and are The aileron PMI foam is made of a material; the horizontal empennage, the vertical empennage and the rudder are of cork wood frame skin structures; the fuselage adopts four square carbon tubes as a longitudinal main force transmission structure to bear main loads in the flying process; the power system mainly adopts a two-stroke 3.5 cc methanol engine as a power source, and is provided with a set of speed reduction group gears, so that the rotating speed is reduced, and the output is increased. Compared with an existing design, the loading capacity of the unmanned aerial vehicle system is improved, meanwhile, light weight, low cost, high loading capacity and high maneuverability are taken into consideration, and after the missile cabin is transformed, specific tasks in other fields can be executed by additionally installing instruments and equipment in other fields.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and in particular to a large-load fixed-wing bomb-dropping unmanned aerial vehicle. Background Art

[0002] Unmanned aerial vehicle (UAV) is an unmanned aircraft controlled by radio remote control and program control devices installed on the aircraft. Compared with manned aircraft, unmanned aircraft have the advantages of smaller size, lower cost, more convenient and simple to use, lower environmental requirements, and no need for onboard personnel. Unmanned aerial vehicles are of great significance to future wars. At the same time, they have developed rapidly in recent years and are increasingly widely used. They have shined in the fields of aerial photography, agriculture and plant protection, logistics and express delivery, military and security, surveying and exploration, disaster relief and power inspection, showing the huge potential and prospects of drone technology.

[0003] Common traditional bomb-dropping drones have many shortcomings, which limit their application effect in actual combat. The main disadvantages are: 1. Expensive price, complicated production process, not conducive to large-scale manufacturing and deployment. Most of the common drones on the market are currently made of composite materials, which require mold opening, vacuum forming and other technologies, and are expensive. 2. They are heavy, but have a small load capacity and cannot meet a variety of combat needs. Most of the current drones are single-purpose. The reason is that due to their limited load capacity, it is difficult to replace equipment of different weights and volumes if multiple tasks are to be performed. 3. They are not easy to maintain, are easily damaged, and have high maintenance costs. In order to solve the above problems, the present invention proposes a large-load fixed-wing bomb-dropping drone. Summary of the invention

[0004] The purpose of the present invention is to propose a lightweight, low-cost, high-load-bearing, high-maneuverability fixed-wing bomb-dropping UAV to solve the problems raised in the background technology. The present invention combines aerodynamics, material mechanics analysis and basic flight principles to study the difficult problems of light wood frame structure UAVs with large loads, high energy consumption, unstable flight, easy breakage of wings, and heavy weight and high cost of composite material UAVs, and designs and manufactures physical models for functional verification.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A large-load fixed-wing bomb-dropping UAV comprises a fuselage, main wings, ailerons, a horizontal tail, a vertical tail and a rudder, wherein the main wings are mounted on both sides of the fuselage, and the ailerons are connected to the main wings; the horizontal tail is horizontally connected to the tail of the fuselage, the vertical tail is vertically connected to the tail of the fuselage, and the rudder is mounted on the vertical tail.

[0007] Preferably, the fuselage includes square carbon tubes, and the main longitudinal force transmission structure of the fuselage is formed by four of the square carbon tubes; one end of the square carbon tube is fixedly connected to the engine frame, and the other end is fixedly connected to the rear top plate and the rear side plate, partitions and partition frames are fixedly connected between the four square carbon tubes, and side panels are connected at the side edges of the partitions and partition frames, and the side panels are also fixedly connected to the square carbon tubes, and bolt holes are opened through the side panels; a plurality of the partition frames are provided, and a fuselage diagonal brace is cross-fixedly connected between two adjacent partition frames.

[0008] Preferably, the main wing adopts a double-beam design, including a main wing main beam and a main wing rear beam, the main wing main beam and the main wing rear beam are fixedly connected to the main wing ribs, the main wing leading edge is fixedly connected to the main wing rib at the front edge, the main wing trailing edge is fixedly connected to the main wing rib at the rear edge, and an aileron installation area is reserved on the side of the main wing close to the main wing trailing edge.

[0009] Preferably, the main wing main beam is made of PMI foam by laser cutting, and thin layers of carbon sheets are glued on the upper and lower sides and bound with Kevlar fibers to ensure strength; the main wing rear beam, the main wing trailing edge, the main wing leading edge and the main wing ribs at the wing root are all made of layer plates by laser cutting, and the remaining main wing ribs are made of light wood plates by laser cutting; the main wing is fixed to the fuselage by the main wing ribs at the wing root and pins.

[0010] Preferably, the aileron is made of PMI foam material and is hingedly movably connected to the aileron installation area of ​​the main wing near the trailing edge of the main wing.

[0011] Preferably, the horizontal tail adopts a double-beam design, including a horizontal tail main beam and a horizontal tail rear beam, the horizontal tail main beam and the horizontal tail rear beam are fixedly connected to the horizontal tail wing ribs, the front and rear edges of the horizontal tail wing ribs are respectively fixedly connected to the horizontal tail leading edge and the horizontal tail trailing edge, the horizontal tail main beam is also fixedly connected to a horizontal tail reinforcement rib near the middle position, and a rotating shaft is fixedly connected between the two horizontal tail reinforcement ribs.

[0012] Preferably, the horizontal tail is connected to the tail of the fuselage by a rotating shaft hinge structure, using a carbon rod as the rotating shaft, and a hinge is formed by a semicircular groove on the rear side panel of the tail of the fuselage and the horizontal tail reinforcing ribs; the horizontal tail main beam, the horizontal tail trailing edge, the horizontal tail rear beam and the horizontal tail leading edge are made of plywood material, and the horizontal tail reinforcing ribs are made of carbon plate material; the horizontal tail ribs are made of balsa wood material.

[0013] Preferably, the vertical tail includes a vertical tail main beam, a vertical tail rib is fixedly connected to the vertical tail main beam, a vertical tail leading edge is fixedly connected to the edge of one end of the vertical tail rib, and a rear plate is fixedly connected to the end of the vertical tail rib away from the vertical tail leading edge; the vertical tail is fixedly connected to the fuselage through the vertical tail leading edge, the vertical tail main beam and the rear plate. The pins of the lower ribs extending out of the vertical tail are inserted into the sockets on the rear top plate of the fuselage to fix the vertical tail to the fuselage.

[0014] Preferably, the rudder includes a rudder vertical plate and a rudder edge, the rudder vertical plate is fixedly connected with a rudder rib, and a rudder diagonal brace is fixedly connected between the rudder rib, the rudder edge and the rudder vertical plate; the upper end of the rudder is fixedly connected with a horizontal plate, and the rudder is horizontally rotatably mounted on the top of the vertical tail through the horizontal plate and is connected to the steering gear inside the fuselage.

[0015] Preferably, the present invention optimizes the aerodynamic layout of the wing, selects an upper wing, which has low induced drag and is convenient for wing-body integration; adopts a trapezoidal wing with a high aspect ratio and a swept wing to increase the lift coefficient of the wing, reduce the drag coefficient of the wing, and improve the gliding performance of the wing;

[0016] The lift of the drone is mainly generated by the main wing of the drone. When flying level, the lift calculation formula of the main wing is:

[0017]

[0018] Where: L1 is the lift of the drone in level flight; G is the gravity of the drone; ρ is the atmospheric density corresponding to the flight altitude; v is the airspeed of the drone; C l is the total lift coefficient of the UAV; S is the wing area of ​​the UAV.

[0019] The aspect ratio λ is:

[0020]

[0021] Where b is the wingspan of the UAV; l is the average aerodynamic chord length of the UAV wing;

[0022] Verify the values ​​of Reynolds number and lift-to-drag ratio according to the formula.

[0023] The formula for Reynolds number Re is:

[0024]

[0025] Where: ρ is the atmospheric density corresponding to the flight altitude; v is the airspeed of the UAV; l is the average aerodynamic chord length of the wing; μ is the atmospheric viscosity corresponding to the flight altitude.

[0026] The calculation formula of lift-to-drag ratio K is:

[0027]

[0028] Where: L1 is the lift of the drone in level flight; D1 is the drag of the drone in level flight; C l is the total lift coefficient of the UAV, C d is the total drag coefficient of the UAV.

[0029] Compared with the prior art, the present invention provides a large-load fixed-wing bomb-dropping UAV, which has the following beneficial effects:

[0030] (1) Light weight. Through the selection and design of component materials, the present invention controls the empty weight to about 3 kg, which is convenient for transportation. The structure is simple and reliable, and the replaceable parts are easy to produce, so that quick replacement and deployment can be achieved.

[0031] (2) Low fuel consumption. The present invention uses an efficient power system, which can fly for a long time at low power, saving energy and reducing risks;

[0032] (3) High mobility. The present invention can perform somersaults and other movements. After being airdropped, it can quickly leave the battlefield, thereby improving the survival rate and increasing the difficulty of defense for the enemy.

[0033] (4) Large load capacity: the present invention can carry 15kg of explosives and airdrop, and has strong strike capability, and can accurately strike important targets of the enemy;

[0034] (5) Large aspect ratio. The aspect ratio of the present invention is about 10, which has excellent gliding performance and can fly a long distance without power, thus increasing the combat range and flexibility.

[0035] (6) The production cost is low. The cost of the whole machine is less than 50,000 yuan, which is far lower than other drones of the same level, and can achieve the strategic goal of low cost and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the main structure of a large-load fixed-wing bomb-dropping UAV mentioned in Example 2 of the present invention;

[0037] Figure 2 This is a schematic diagram of the fuselage structure of a large-load fixed-wing bomb-dropping UAV mentioned in Example 2 of the present invention;

[0038] Figure 3 This is a schematic structural diagram of the left main wing of a large-load fixed-wing bomb-dropping UAV mentioned in Example 2 of the present invention;

[0039] Figure 4 This is a schematic structural diagram of the horizontal tail of a large-load fixed-wing bomb-dropping UAV mentioned in Example 2 of the present invention;

[0040] Figure 5 This is a schematic structural diagram of a vertical tail of a large-load fixed-wing bomb-dropping UAV mentioned in Example 2 of the present invention;

[0041] Figure 6 This is a schematic diagram of the structure of a rudder of a large-load fixed-wing bomb-dropping UAV mentioned in Example 2 of the present invention.

[0042] Description of the markings in the figure:

[0043] 1. Main wing; 101. Main wing main beam; 102. Main wing rear beam; 103. Main wing rib; 104. Main wing leading edge; 105. Main wing trailing edge; 106. Latch;

[0044] 2. Aileron;

[0045] 3. Fuselage; 301. Square carbon tube; 302. Engine frame; 303. Rear top plate; 304. Rear side plate; 305. Bulkhead; 306. Bulkhead frame; 307. Side plate; 308. Fuselage diagonal brace;

[0046] 4. Horizontal tail; 401. Main beam of horizontal tail; 402. Rear beam of horizontal tail; 403. Ribs of horizontal tail; 404. Leading edge of horizontal tail; 405. Trailing edge of horizontal tail; 406. Reinforced ribs of horizontal tail; 407. Rotating shaft;

[0047] 5. vertical tail; 501. vertical tail main beam; 502. vertical tail wing rib; 503. vertical tail leading edge; 504. rear plate;

[0048] 6. Rudder; 601. Rudder vertical plate; 602. Rudder edge; 603. Rudder rib; 604. Rudder brace. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0050] Embodiment 1:

[0051] The present invention proposes a large-load fixed-wing bomb-dropping UAV. Starting from aerodynamics, material mechanics analysis and basic flight principles, the present invention studies the problems of large energy consumption, unstable flight, easy breakage of wings of light wood frame structure UAVs with large loads, and large weight and high cost of composite material UAVs, and designs and manufactures a physical model for functional verification.

[0052] The large-load fixed-wing bomb-dropping UAV proposed by the present invention is mainly composed of a power system, a main wing, a fuselage, a horizontal tail, a vertical tail and a bomb bay.

[0053] The power system is mainly a two-stroke 3.5cc methanol engine as the power source of the UAV. In order to increase the engine output torque, a set of reduction gears is designed to reduce the speed and increase the output.

[0054] Taking into account the weight requirements and manufacturing difficulty of the aircraft, it was decided that the aircraft would adopt a skin frame structure mainly made of balsa wood, with carbon fiber materials and plywood as reinforcements.

[0055] The fuselage of the aircraft uses four 5*5mm square carbon tubes as the main longitudinal force transmission structure, which bears the main load during the flight of the aircraft. Considering the poor stress condition of the left and right wing connection parts, 4mm carbon plates are used to make appropriate hollowing as force transmission parts. In order to reduce weight, other parts need to use plywood and light wood as bulkheads and side panels to transfer engine tension and other wing surface aerodynamic loads to the square carbon tubes. At the same time, the bulkhead side panel structure can improve the rigidity and stability of the structural fuselage and link various parts of the aircraft. The plastic skin fits smoothly on the fuselage frame to maintain an excellent aerodynamic shape while providing a certain strength.

[0056] Light wood and laminate are used as the main materials of the wing. Through reasonable wing structure design, the dead weight of the wing can be effectively reduced, and the load-bearing capacity and bending resistance of the wing can be improved. At the same time, the present invention optimizes the aerodynamic layout of the wing, and intends to select an upper wing with small induced drag and convenient wing-body integration; a trapezoidal wing with a high aspect ratio and a swept wing is used to increase the lift coefficient of the wing, reduce the drag coefficient of the wing, and improve the gliding performance of the wing. The present invention also optimizes the structural design of the wing, increases the rigidity and strength of the wing, reduces the weight and thickness of the wing, and improves the fatigue resistance of the wing.

[0057] According to the design requirements, the present invention needs to select airfoils that meet the following conditions in the airfoil library: high lift-to-drag ratio, large thickness to ensure sufficient bending torsional stiffness; good anti-stall performance, and the lift coefficient slowly decreases after stalling. The lift coefficient of the airfoil is obtained by calculation, and the airfoil that meets the above conditions is simulated using profili software. When the Reynolds number is 510000, although SG6043 has the highest lift-to-drag ratio, it is thin and the lift coefficient is not large enough, so the main wing airfoil selects MH114.

[0058] For low-speed aircraft, the aspect ratio increases and the induced drag decreases, but at the same time the bending moment at the root of the wing increases and the structural weight increases. Taking into account the wing strength and structural weight, the aspect ratio is taken as 9.2. Considering that there is no need to excessively pursue the aircraft's ultimate load-bearing capacity, the aircraft's wingspan is finally determined to be about 4 meters. In theory, the aerodynamic load on a straight wing is elliptical, so the aerodynamic efficiency of an elliptical wing is the highest. However, the processing of the front and rear curves of an elliptical wing is more complicated and the workload is large. Therefore, it is finally decided to use an approximate elliptical wing to make the wing zero-sweep at the quarter chord line. Finally, it is determined that the root-tip ratio is 2.3, the leading edge is swept, and the trailing edge is swept forward. The leading edge sweep angle is about 3°. The wing torsions of large aspect ratio aircraft at large angles of attack are more serious, and the wingtip angle of attack is greater than the wing root angle of attack, which is prone to wingtip stall. Therefore, we designed a 2° negative wing tip twist, and adjusted the angle of attack of each section along the span of the wing through geometric twist to prevent the wing tip from stalling before the wing root. At the same time, we can adjust the span distribution of aerodynamic loads and improve aerodynamic efficiency. Using Xflr5 to perform aerodynamic simulation on the designed wing, the lift-to-drag ratio of the clean configuration of the aircraft is greater than 25, and the lift-to-drag ratio decreases slowly after reaching the maximum value. The lift coefficient in level flight is about 0.5, and the results meet the expected design goals.

[0059] The lift is mainly generated by the main wing of the drone. When flying level, the lift calculation formula of the wing is:

[0060]

[0061] Where: L1 is the lift of the drone in level flight; G is the gravity of the drone; ρ is the atmospheric density corresponding to the flight altitude; v is the airspeed of the drone; C l is the total lift coefficient of the UAV; S is the wing area of ​​the UAV.

[0062] The aspect ratio λ is:

[0063]

[0064] Among them, b is the wingspan of the UAV; l is the average aerodynamic chord length of the UAV wing.

[0065] Verify the values ​​of Reynolds number and lift-to-drag ratio according to the formula.

[0066] The formula for Reynolds number Re is:

[0067]

[0068] Where: ρ is the atmospheric density corresponding to the flight altitude; v is the airspeed of the UAV; l is the average aerodynamic chord length of the wing; μ is the atmospheric viscosity corresponding to the flight altitude.

[0069] The calculation formula of lift-to-drag ratio K is:

[0070]

[0071] Where: L1 is the lift of the drone in level flight; D1 is the drag of the drone in level flight; C l is the total lift coefficient of the UAV, C d is the total drag coefficient of the UAV.

[0072] The wing uses a skin frame structure with a double beam design. The front beam uses PMI foam as the main structure, with thin layers of carbon sheets glued to the upper and lower parts and Kevlar fiber tied to ensure strength. The rear beam is a wooden beam, using 3mm ply as the web and 2mm ply as the wing plate to form an I-beam structure. The leading edge of the wing is masked to form a D-shaped box structure with the front beam to resist torsion. The wing pin is made of 3mm carbon plate and fixed to the 4mm carbon plate of the fuselage with M5 screws.

[0073] In order to improve the aircraft's maneuverability, the aircraft adopts a fully movable horizontal tail design. The aircraft's fully movable horizontal tail adopts a rotating shaft hinge design, using a carbon rod as the rotating shaft, and a hinge formed by a carbon plate and wing ribs. The carbon plate is fixed to the fuselage with three screws.

[0074] The vertical tail's heading maneuverability is crucial. Therefore, an elliptical vertical tail is designed. The rudder has a compensation surface, which enhances the rudder effect and improves the heading control performance. The reverse twisting of the vertical tail stabilizer caused by the rudder force is small, which prevents the occurrence of rudder reverse effect. The output force required by the servo is small, and the reliability is strong.

[0075] Embodiment 2:

[0076] Based on Example 1, but with the following differences: Figure 1-6 The following is a description of a large-load fixed-wing bomb-dropping UAV proposed by the present invention in conjunction with specific drawings. Figure 1 As shown, it includes a main wing 1, ailerons 2, a fuselage 3, a horizontal tail 4, a vertical tail 5 and a rudder 6.

[0077] The main wing 1 takes the left wing as an example, and the structural diagram of the main wing 1 is shown in Figure 3, which is mainly composed of the main wing rear beam 102, the main wing ribs 103, the main wing trailing edge 105, the main wing beam 101, the main wing leading edge 104 and the latch 106. The main wing rear beam 102, the main wing ribs 103 at the wing root, the main wing trailing edge 105 and the main wing leading edge 104 are all made of laminates and processed by laser cutting; the remaining main wing ribs 103 are made of light wood and laser cut; the main wing beam 101 is mainly structured with PMI foam, with thin layers of carbon sheets glued on the upper and lower parts and tied with Kevlar fibers to ensure strength; the latch 106 is carved from a carbon fiber plate. Each wing rib is fixed to the main wing beam 101 and the main wing rear beam 102 by gluing, the main wing leading edge 104 and the main wing trailing edge 105 are glued to the leading and trailing edges of the ribs by gluing, the pin 106 is glued to the slot of the main wing beam 101 at the wing root and tied with Kevlar fiber.

[0078] The aileron 2 is made of PMI foam and is fixed to the main wing by fiber tape as a hinge to ensure single-degree-of-freedom movement.

[0079] The structural diagram of the fuselage 3 is shown in Figure 2 , which is mainly composed of engine frame 302, square carbon tube 301, partition 305, bulkhead 306, fuselage diagonal brace 308, rear top plate 303, rear side plate 304, and side plate 307. Except for square carbon tube 301, all parts are cut by laser cutting of laminate. The fuselage uses four square carbon tubes 301 as the longitudinal main force transmission structure to bear the main load during the flight of the aircraft. Considering the poor stress condition of the left and right wing connection parts, 4mm carbon plate is used to make appropriate hollowing as a force transmission component. For other parts, laminate and balsa wood are used as bulkhead 306 and side plate 307 to transfer engine tension and other wing surface aerodynamic loads to square carbon tube 301 in order to reduce weight. At the same time, partition 305, bulkhead 306, fuselage diagonal brace 308, rear top plate 303, rear side plate 304, and side plate 307 can improve the structural fuselage rigidity and stability and link various parts of the aircraft.

[0080] The main wing 1 is inserted into the socket on the side panel 307 of the fuselage 3 through the pin 106 and is fixed to the 4 mm carbon plate of the fuselage 3 through the M5 screw.

[0081] The main structure of the horizontal tail 4 is shown in Figure 4, which is mainly composed of a horizontal tail main beam 401, a horizontal tail trailing edge 405, a horizontal tail rear beam 402, a horizontal tail rib 403, a rotating shaft 407, a horizontal tail reinforcement rib 406 and a horizontal tail leading edge 404, wherein the horizontal tail main beam 401, the horizontal tail trailing edge 405, the horizontal tail rear beam 402 and the horizontal tail leading edge 404 are laminated plates, the horizontal tail reinforcement rib 406 is a carbon plate, and the horizontal tail rib 403 is balsa wood. In order to improve the maneuverability of the aircraft, the aircraft's full-moving horizontal tail adopts a rotating shaft hinge design, using a carbon rod as the rotating shaft 407, and forming a hinge through a semicircular groove on the rear side panel 304 of the fuselage 3 and the horizontal tail reinforcement rib 406.

[0082] The main structure of the vertical tail 5 is shown in Figure 5 The main structure is composed of the vertical tail leading edge 503, the vertical tail main beam 501, the rear plate 504 and the vertical tail rib 502. The vertical tail 5 is fixed to the fuselage by inserting the pin 106 extending from the lower end rib of the vertical tail leading edge 503, the vertical tail main beam 501 and the rear plate 504 into the socket on the rear top plate of the fuselage. There are several thin slits that are not connected to each other at the vertical center line of the vertical tail main beam 501, which are used to connect the vertical tail 5 and the rudder 6.

[0083] The main structure of the rudder 6 is shown in Figure 6 The main structure is composed of a rudder edge 602, a rudder vertical plate 601, a rudder diagonal brace 604 and a rudder rib 603. There are several thin slits that are not connected to each other at the vertical center line of the rudder vertical plate 601. The paper hinge is inserted into the thin slits on the rudder vertical plate 601 and glued, and then inserted into the corresponding thin slits on the main beam plate and glued, so that the vertical tail 5 can be connected to the rudder 6, and the rudder 6 can move with a single degree of freedom. The reverse torsion of the vertical tail stabilizer caused by the force on the rudder 6 is small, which prevents the occurrence of the reverse effect of the rudder 6; the output force required by the steering gear is small, and the reliability is strong.

[0084] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A large-load fixed-wing bomb-dropping drone, comprising a fuselage (3), a main wing (1), an aileron (2), a horizontal tail (4), a vertical tail (5) and a rudder (6), characterized in that: The main wings (1) are mounted on both sides of the fuselage (3), and the ailerons (2) are connected to the main wings (1); the horizontal tail wing (4) is horizontally connected to the tail of the fuselage (3), the vertical tail wing (5) is vertically connected to the tail of the fuselage (3), and the rudder (6) is mounted on the vertical tail wing (5).

2. A large-load fixed-wing bomb-dropping UAV according to claim 1, characterized in that: The fuselage (3) comprises a square carbon tube (301), and the longitudinal main force transmission structure of the fuselage (3) is formed by four of the square carbon tubes (301); one end of the square carbon tube (301) is fixedly connected to the engine frame (302), and the other end is fixedly connected to the rear top plate (12) and the rear side plate (304); a partition plate (305) and a partition frame (306) are fixedly connected between the four square carbon tubes (301); the side edges of the partition plate (305) and the partition frame (306) are connected to a side plate (307); the side plate (307) is also fixedly connected to the square carbon tube (301); and bolt holes are penetrated through the side plate (307); a plurality of the partition frames (306) are provided, and a fuselage diagonal brace (308) is cross-fixedly connected between two adjacent partition frames (306).

3. A large-load fixed-wing bomb-dropping UAV according to claim 1, characterized in that: The main wing (1) adopts a double-beam design, comprising a main wing main beam (101) and a main wing rear beam (101), the main wing main beam (101) and the main wing rear beam (101) are fixedly connected to a main wing rib (103), the front edge of the main wing rib (103) is fixedly connected to a main wing leading edge (104), the rear edge of the main wing rib (103) is fixedly connected to a main wing trailing edge (105), and an aileron installation area is reserved on a side of the main wing (1) close to the main wing trailing edge (105).

4. A large-load fixed-wing bomb-dropping UAV according to claim 3, characterized in that: The main wing main beam (101) is made of PMI foam by laser cutting, and thin layers of carbon sheets are glued to the upper and lower parts and bound with Kevlar fibers to ensure strength; the main wing rear beam (101), the main wing trailing edge (105), the main wing leading edge (104) and the main wing ribs (103) at the wing root are all made of laminates by laser cutting, and the remaining main wing ribs (103) are made of light wood by laser cutting; the main wing (2) is fixedly mounted on the fuselage (3) by the main wing ribs (103) at the wing root and the latch (106).

5. The large-load fixed-wing bomb-dropping UAV according to claim 1, characterized in that: The aileron (2) is made of PMI foam material and is movably connected in a hinged manner to an aileron installation area on the main wing (1) close to the main wing trailing edge (105).

6. A large-load fixed-wing bomb-dropping UAV according to claim 1, characterized in that: The horizontal tail (4) adopts a double-beam design, including a horizontal tail main beam (401) and a horizontal tail rear beam (402), the horizontal tail main beam (401) and the horizontal tail rear beam (402) are fixedly connected to a horizontal tail wing rib (403), the front and rear edges of the horizontal tail wing rib (403) are respectively fixedly connected to a horizontal tail leading edge (404) and a horizontal tail trailing edge (405), the horizontal tail main beam (401) is also fixedly connected to a horizontal tail reinforcement rib (406) near the middle position, and a rotating shaft (407) is fixedly connected between the two horizontal tail reinforcement ribs (406).

7. A large-load fixed-wing bomb-dropping UAV according to claim 6, characterized in that: The horizontal tail (4) is connected to the tail of the fuselage (3) by using a rotating shaft hinge structure, using a carbon rod as a rotating shaft (407), and forming a hinge through a semicircular groove on the rear side plate (304) at the tail of the fuselage (3) and a horizontal tail reinforcement rib (406); the horizontal tail main beam (401), the horizontal tail trailing edge (405), the horizontal tail rear beam (402) and the horizontal tail leading edge (404) are made of a laminate material, and the horizontal tail reinforcement rib (406) is made of a carbon plate material; the horizontal tail rib (403) is made of a light wood material.

8. The large-load fixed-wing bomb-dropping UAV according to claim 1, characterized in that: The vertical tail (5) comprises a vertical tail main beam (501), a vertical tail wing rib (502) is fixedly connected to the vertical tail main beam (501), a vertical tail leading edge (503) is fixedly connected to one end edge of the vertical tail wing rib (502), and a rear plate (504) is fixedly connected to one end of the vertical tail wing rib (502) away from the vertical tail leading edge (503); the vertical tail (5) is fixedly connected to the rear plate (504); a pin extending from the lower end wing rib of the vertical tail (55) through the vertical tail leading edge (503), the vertical tail main beam (501) and the rear plate (504) is inserted into a socket on the rear top plate (12) of the fuselage (3) to fix the vertical tail (5) on the fuselage (3).

9. The large-load fixed-wing bomb-dropping UAV according to claim 1, characterized in that: The rudder (6) comprises a rudder vertical plate (601) and a rudder edge (602); a rudder rib (603) is fixedly connected to the rudder vertical plate (601); a rudder diagonal brace (604) is fixedly connected between the rudder rib (603), the rudder edge (602) and the rudder vertical plate (601); a horizontal plate is fixedly connected to the upper end of the rudder (6); the rudder (6) is horizontally rotatably mounted on the top end of the vertical tail (5) through the horizontal plate and is connected to a steering gear inside the fuselage (3).

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