Lightweight wing rigidity strengthening device capable of reducing aerodynamic loss

Abstract

The invention belongs to the technical field of aircraft structure design, and particularly relates to a light wing rigidity strengthening device for reducing aerodynamic loss. According to the reinforcing device, the structural rigidity and the bearing capacity of the flexible light wing are improved through erecting and telescopic deformation of the telescopic wing-shaped supporting rod mechanism, the reinforcing device and the flexible light wing aircraft are designed in a rotary storage mode, the telescopic wing-shaped supporting rod mechanism is of a multi-stage telescopic structure, and all telescopic supporting arms are designed in a wing-shaped-like section mode; the pneumatic resistance can be effectively reduced; the wing-shaped telescopic supporting arms and the ends of the supporting rods can perform small-angle relative rotation within 10 degrees, rotation of the flexible light wing aircraft in the yaw direction is controlled in an auxiliary mode, and the control capacity is improved. According to the reinforcing device, the rigidity of the wing is improved through the telescopic wing-shaped supporting rod mechanism, by means of the design of the Y-shaped pull rope, the windward projection area of the pull rope when the flexible light wing aircraft flies is remarkably reduced while the torsional rigidity of the flexible light wing is guaranteed, and the aerodynamic resistance is reduced.

Description

A lightweight wing stiffness enhancement device to reduce aerodynamic losses Technical Field

[0001] This invention belongs to the field of aircraft structural design technology, specifically relating to a lightweight wing stiffness enhancement device for reducing aerodynamic losses. Background Technology

[0002] In recent years, low-cost, high-performance, and easily mass-producible lightweight wing aircraft have been widely used in various applications due to their unique value. In some situations, specific vehicles impose strict limitations on the size and weight of the aircraft they carry, making traditional rigid-wing aircraft increasingly inadequate. Compared to rigid-wing aircraft, flexible lightweight wing aircraft, which are lighter, smaller, and have a higher storage ratio, can solve these problems.

[0003] Most flexible lightweight wing unmanned aerial vehicles on the market are small in size and are prone to structural instability when subjected to aerodynamic overloads without the support of stiffness reinforcement devices. Although the traditional method of using cables to reinforce key parts can strengthen the wing stiffness, the long cables will significantly increase the air resistance of the aircraft. The additional traditional circular or square cross-section struts will also significantly increase drag. The double drag will greatly reduce the lift-to-drag ratio of the flexible lightweight wing aircraft and affect its endurance.

[0004] Therefore, it is necessary to develop a stiffness strengthening device with lower drag and easier storage based on the traditional lightweight wing stiffness strengthening device, so as to improve the load-bearing capacity of the wing itself while minimizing aerodynamic losses. Summary of the Invention

[0005] To address the above problems, the present invention provides a lightweight wing stiffness enhancement device for reducing aerodynamic losses.

[0006] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0007] A lightweight wing stiffness enhancement device for reducing aerodynamic losses includes a flexible lightweight wing aircraft fuselage, a retractable airfoil strut mechanism, a flexible lightweight wing, ropes, and loops. The flexible lightweight wing is symmetrically arranged on both sides of the flexible lightweight wing aircraft fuselage. A retractable airfoil strut mechanism is provided at the top and bottom of the flexible lightweight wing aircraft fuselage. A rope storage device is provided at the end of each retractable airfoil strut mechanism. Two loops are fixedly connected to the wingtip and wing center of the upper and lower surfaces of each flexible lightweight wing. The two loops are distributed along the chord length direction of the flexible lightweight wing. Each loop at each wingtip is attached to a first Kevlar rope. The two first Kevlar ropes on the upper surface converge into one rope and are connected to the rope storage device at the top of the flexible lightweight wing aircraft fuselage. The two first Kevlar ropes on the lower surface converge into one rope and are connected to the rope storage device at the top of the flexible lightweight wing aircraft fuselage. The flexible lightweight wing aircraft has a cable retractor at the bottom of its fuselage; each of the loops in each wing is attached to a second Kevlar cable, the two second Kevlar cables on the upper surface converge into one cable and connect to the cable retractor at the top of the flexible lightweight wing aircraft fuselage, and the two second Kevlar cables on the lower surface converge into one cable and connect to the cable retractor at the bottom of the flexible lightweight wing aircraft fuselage; the cable retractor is used to pull each cable to apply preload. Tightening: The two pull loops at the mid-wing and wingtip of the upper surface of the single-sided flexible lightweight wing, when tightened, form a Y-shaped pull rope structure with the pull rope retractor. The two pull loops at the mid-wing and wingtip of the lower surface of the single-sided flexible lightweight wing, when tightened, also form a Y-shaped pull rope structure. The Y-shaped pull rope structure can ensure the torsional stiffness of the flexible lightweight wing while significantly reducing the windward area of ​​the pull ropes during the flight of the flexible lightweight wing aircraft.

[0008] Furthermore, the retractable airfoil strut mechanism includes a first retractable support arm, a second retractable support arm, a rotating gear pin, and a strut end; both the first and second retractable support arms are hollow strut mechanisms with airfoil-like cross-sections; the second retractable support arm can be housed inside the first retractable support arm, and the second retractable support arm achieves relative sliding with the first retractable support arm along its length direction through a built-in sliding control mechanism, thereby realizing the retractable airfoil strut mechanism's telescopic deformation; the strut end is installed at the end of the first retractable support arm facing the flexible lightweight wing aircraft body; cylindrical rotating pins are fixed on both sides of the strut end. A gear pin is rotatably mounted on the flexible lightweight wing aircraft body via the rotating gear pin; a locking device is installed inside the flexible lightweight wing aircraft body; the locking device is located on the outer side of the end of the strut and is used to lock the relative position of the retractable airfoil strut mechanism and the flexible lightweight wing aircraft body; a pull rope storage device is provided on each side of the end of the second retractable support arm; a drive motor is installed inside the flexible lightweight wing aircraft body to drive the first retractable support arm to rotate around a horizontal axis; the drive motor is connected to the rotating gear pin and is used to drive the retractable airfoil strut mechanism to switch between a horizontal and a vertical state.

[0009] Furthermore, a storage device reinforcing frame is fixedly installed on both sides of the outer end of the telescopic support arm two; the storage device reinforcing frame is used to strengthen the strength of the pull rope storage device; storage openings are provided on both sides of the other end of the telescopic support arm one; the storage openings are used to accommodate the storage device reinforcing frame when the telescopic airfoil strut mechanism is in the retracted state; the pull rope storage device includes a wing-center pull rope storage device, a wingtip pull rope storage device, a transition pulley, and a pull rope winding machine; the wing-center pull rope storage device and the wingtip pull rope storage device are respectively fixedly installed on the inner wall of the storage device reinforcing frame; a freely rotatable transition pulley is installed on both the wing-center pull rope storage device and the wingtip pull rope storage device; the transition pulley is used to guide the pull rope; the pull rope winding machine is used to pull the pull rope to apply a preload.

[0010] Furthermore, the pull rope connected to the wingtip pulley passes over the transition pulley installed in the wingtip pull rope receiver and is then connected to the pull rope winding machine, while the pull rope connected to the middle pulley passes over the transition pulley installed in the middle pull rope receiver and is then connected to the pull rope winding machine.

[0011] Furthermore, the flexible lightweight wing aircraft body has a strut mechanism storage cavity on both the top and bottom surfaces to accommodate the retractable airfoil strut mechanism; one retractable airfoil strut mechanism is installed in each strut mechanism storage cavity.

[0012] Furthermore, the side wall of the support mechanism receiving cavity is provided with a servo interface corresponding to each of the rotating gear pins; the servo interface is used to install the corresponding rotating gear pin; the lock is installed on the side wall of the support mechanism receiving cavity.

[0013] Furthermore, the first telescopic support arm, the second telescopic support arm, the rotating gear pin, and the end of the strut are all machined from titanium alloy.

[0014] Furthermore, the first telescopic support arm is rotatably mounted on the end of the strut around a vertical axis; a rotary motor is installed inside the first telescopic support arm; the rotary motor is used to drive the first telescopic support arm to rotate within 10° relative to the end of the strut, thereby assisting in controlling the rotation of the yaw direction of the flexible lightweight wing aircraft through the first telescopic support arm and the second telescopic support arm.

[0015] Furthermore, the flexible lightweight wing adopts an aerodynamically optimized NACA airfoil, with a high-strength aramid fiber fabric layer covered by an airtight membrane and an internal reinforcing structure.

[0016] Furthermore, of the two loops distributed along the chord length direction of the flexible lightweight wing, one loop is located at the leading edge of the flexible lightweight wing, and the other loop is located at the trailing edge of the flexible lightweight wing.

[0017] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. In the lightweight wing stiffness strengthening device of the present invention, the pull rope connecting the pull loops at the middle and tip of the upper and lower surfaces of the single-sided flexible lightweight wing and the retractable airfoil strut mechanism is Y-shaped. Compared with the traditional method of tying a strut to a single pull loop and a single pull rope, the Y-shaped pull rope structure significantly reduces the windward area of ​​the pull rope when the flexible lightweight wing aircraft is in flight. Especially in the case of sideslip angle, the Y-shaped pull rope reduces the aerodynamic projection area of ​​the pull rope and thus reduces aerodynamic drag. Its drag reduction effect is similar to reducing the number of pull ropes.

[0018] 2. In the lightweight wing stiffness enhancement device of the present invention, the retractable airfoil strut mechanism adopts a telescopic structure. The retractable airfoil strut mechanism is rotated and retracted via a rotating gear pin, a servo interface on the side wall of the strut mechanism's housing cavity, and an internal drive motor. The multi-stage telescopic support arm increases the height of the retractable airfoil strut mechanism after it is erected. By increasing the angle (acute angle) between the tensioned cable and the horizontal of the flexible lightweight wing, the wing stiffness is significantly improved, reducing the risk of instability. The telescopic support arms of the retractable airfoil strut mechanism all adopt an airfoil-like structure design, which significantly reduces the aerodynamic drag of the flexible lightweight wing aircraft compared to traditional cylindrical or square strut mechanisms.

[0019] 3. In the lightweight wing stiffness strengthening device of the present invention, the telescopic support arm one of the telescopic airfoil strut mechanism and the strut end adopt a semi-fixed connection method that allows for small-angle relative rotation. The rotary motor drives the telescopic support arm one to rotate within a small angle of 10°. At this time, the telescopic support arm one and the telescopic support arm two with airfoil cross sections are equivalent to rotation control rudders, which can assist in controlling the rotation of the yaw direction of the flexible lightweight wing aircraft and improve the yaw control capability of the aircraft.

[0020] 4. In the lightweight wing stiffness strengthening device of the present invention, the wing tension ropes on both sides of the retractable airfoil strut mechanism enable the tension of the wing tension ropes on the retractable airfoil strut mechanism to form a self-balance, which can reduce the risk of large deformation, bending, or even breakage of the telescopic support arm in the retractable airfoil strut mechanism. After the retractable airfoil strut mechanism has completed deformation and the tension rope is in a taut state, the preload of the tension rope is further controlled by the tension rope winding machine installed in the second telescopic support arm. It is expected that the load-bearing capacity of the flexible lightweight wing can reach 2 to 4 times that of a conventional flexible lightweight wing without tension ropes.

[0021] The aforementioned lightweight wing stiffness enhancement device can be widely applied in the field of aircraft structural design. Attached Figure Description

[0022] Figure 1 is a three-dimensional overall structural schematic diagram of the lightweight wing stiffness strengthening device of the present invention; Figure 2 is a structural schematic diagram of the support mechanism storage cavity; Figure 3 is a structural schematic diagram of the retractable airfoil support mechanism; Figure 4 is a structural schematic diagram of the pull rope storage device; Figure 5 is a structural schematic diagram of the retractable airfoil support mechanism stored in the support mechanism storage cavity; Figure 6 is a structural schematic diagram of the retractable airfoil support mechanism rotating 90° from the support mechanism storage cavity from a horizontal state to a vertical state; Figure 7 is a schematic diagram of the working state of the lightweight wing stiffness strengthening device of the present invention.

[0023] Reference numerals: 1-Flexible lightweight wing aircraft fuselage; 2-Retractable airfoil strut mechanism; 3-Flexible lightweight wing; 4-Strut mechanism storage cavity; 21-Retractable support arm one; 22-Retractable support arm two; 23-Storage port; 24-Rotating gear pin; 25-Strut end; 41-Front wall of storage cavity; 42-Servo interface; 43-Locking device; 44-Leading edge of storage cavity; 81-Wing mid-section pull rope retractor; 82-Wingtip pull rope retractor; 83-Transition pulley; 84-Retractor reinforcing frame; 101-Pull rope; 102-Pull loop; 201-Pull rope retractor. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0026] As shown in Figures 1 and 6, this embodiment of the invention provides a lightweight wing stiffness enhancement device for reducing aerodynamic losses. The device includes a flexible lightweight wing aircraft body 1, a retractable airfoil strut mechanism 2, a flexible lightweight wing 3, a pull rope 101, and a pull loop 102. The flexible lightweight wing aircraft body 1 has flexible lightweight wings 3 symmetrically arranged on both sides. A retractable airfoil strut mechanism 2 is provided at both the top and bottom of the flexible lightweight wing aircraft body 1. A pull rope storage device 201 is provided at the end of the retractable airfoil strut mechanism 2. As shown in Figure 1, a flexible lightweight wing 3 is provided on the left side of the flexible lightweight wing aircraft body 1, and a flexible lightweight wing 3 is provided on the right side of the flexible lightweight wing aircraft body 1. The left and right flexible lightweight wings 3 are symmetrically arranged. The flexible lightweight wing 3 adopts an aerodynamically optimized NACA airfoil, is made of a high-strength aramid fiber fabric layer covered with an airtight membrane, and has an internal reinforcing structure. A retractable airfoil strut mechanism 2 is provided on the top of the flexible lightweight wing aircraft body 1, and a retractable airfoil strut mechanism 2 is provided on the bottom of the flexible lightweight wing aircraft body 1; a pull rope storage device 201 is provided at the end of each retractable airfoil strut mechanism 2 away from the flexible lightweight wing aircraft body 1.

[0027] Two loops 102 are fixedly connected to the wingtips and wing center of the upper and lower surface skins of each flexible lightweight wing 3, as shown in Figure 1. Eight loops 102 are fixedly connected to each flexible lightweight wing 3, and there are a total of 16 loops 102 on the flexible lightweight wing aircraft. Whether it is the upper surface of the flexible lightweight wing 3 or the upper surface of the flexible lightweight wing 3, the two loops 102 set in the middle and the wingtip are distributed along the chord length direction of the flexible lightweight wing 3. Among the two loops 102 distributed along the chord length direction of the flexible lightweight wing 3, one loop 102 is located at the leading edge of the flexible lightweight wing 3, and the other loop 102 is located at the trailing edge of the flexible lightweight wing 3.

[0028] Each wingtip loop 102 on each side is attached to a first Kevlar rope. The two first Kevlar ropes attached to the upper wingtip converge into a single rope 101 and are connected to a rope retractor 201 on the top of the flexible lightweight wing aircraft body 1. The two first Kevlar ropes attached to the lower wingtip converge into a single rope 101 and are connected to a rope retractor 201 at the bottom of the flexible lightweight wing aircraft body 1. Similarly, each loop 102 in each wing is secured with a second Kevlar rope. The two second Kevlar ropes secured in the middle of the upper wing converge into a single rope 101, which is then connected to a rope retractor 201 at the top of the flexible lightweight wing aircraft body 1. The two second Kevlar ropes secured in the middle of the lower wing converge into a single rope 101, which is then connected to a rope retractor 201 at the bottom of the flexible lightweight wing aircraft body 1. The rope retractor 201 tensions the ropes 101 connecting the loops 102. The rope retractor 201 is used to pull each rope 101 to apply preload, thereby keeping the ropes 101 taut.

[0029] When the two pull loops 102 at the wingtip and mid-wing surface of the upper surface of the single-sided flexible lightweight wing 3 are tightened, the pull rope 101 between them and the pull rope retractor 201 forms a Y-shaped pull rope structure. Similarly, when the two pull loops 102 at the wingtip and mid-wing surface of the lower surface of the single-sided flexible lightweight wing 3 are tightened, the pull rope 101 between them also forms a Y-shaped pull rope structure. In other words, when the two pull loops 102 at the wingtip and mid-wing surface of the left side of the flexible lightweight wing aircraft fuselage 3 are tightened, the pull rope 101 between them and the pull rope retractor 201 at the top of the flexible lightweight wing aircraft fuselage 1 forms a Y-shaped pull rope structure, and the pull rope 101 between the two pull loops 102 at the wingtip and mid-wing surface of the left side of the flexible lightweight wing 3 is tightened, the pull rope 101 between them also forms a Y-shaped pull rope structure. The Y-shaped cable structure, when tightened, also forms a Y-shaped cable structure between the two loops 102 on the lower surface of the flexible lightweight wing 3 and the cable retractor 201 on the top of the flexible lightweight wing aircraft body 1. Similarly, when tightened, the two loops 102 on the upper surface of the flexible lightweight wing 3 and the cable retractor 201 on the top of the flexible lightweight wing aircraft body 1 also form a Y-shaped cable structure. Likewise, the cable 101 on the right side of the flexible lightweight wing aircraft body 1 and the cable 101 on the left side form the same shape and can be symmetrical structures after tightening. The Y-shaped cable structure can ensure the torsional stiffness of the flexible lightweight wing 3 while significantly reducing the windward area of ​​the cable 101 during the flight of the flexible lightweight wing aircraft.

[0030] As shown in Figure 3, the retractable airfoil strut mechanism 2 includes a first telescopic support arm 21, a second telescopic support arm 22, a rotating gear pin 24, and a strut end 25. The first telescopic support arm 21, the second telescopic support arm 22, the rotating gear pin 24, and the strut end 25 are all machined from titanium alloy. Both the first telescopic support arm 21 and the second telescopic support arm 22 are hollow support rod mechanisms with an airfoil-like cross-section. The second telescopic support arm 22 can be housed inside the first telescopic support arm 21. The second telescopic support arm 22 achieves relative sliding along its length with the first telescopic support arm 21 through a built-in sliding control mechanism, thus realizing the telescopic deformation of the retractable airfoil strut mechanism 2. A strut end 25 is mounted on one end of the telescopic support arm 21 facing the flexible lightweight wing aircraft body 1. The telescopic support arm 21 is rotatably mounted on the strut end 25 around a vertical axis. A rotary motor is installed inside the telescopic support arm 21. The rotary motor drives the telescopic support arm 21 to rotate within 10° relative to the strut end 25, thereby assisting in controlling the yaw direction rotation of the flexible lightweight wing aircraft through the telescopic support arm 21 and the telescopic support arm 22. In this embodiment, the telescopic airfoil strut mechanism 2 is described using a two-stage telescopic structure as an example. In practice, a three-stage or more telescopic structure can also be used.

[0031] Cylindrical rotating gear pins 24 are fixed to both sides of the strut end 25, and are rotatably mounted to the flexible lightweight wing aircraft body 1 via the rotating gear pins 24. A locking device 43 is installed inside the flexible lightweight wing aircraft body 1; as shown in Figure 2, the locking device 43 is located on the outside of the strut end 25 and is used to lock the relative position of the retractable airfoil strut mechanism 2 and the flexible lightweight wing aircraft body 1. A rope storage device 201 is provided on both sides of the end of the retractable support arm 22, as shown in Figure 4. A drive motor is installed inside the flexible lightweight wing aircraft body 1 to drive the retractable support arm 21 to rotate around a horizontal axis; the drive motor is connected to the rotating gear pins 24 and is used to drive the retractable airfoil strut mechanism 2 to switch between a horizontal and a vertical state; as shown in Figure 5, the retractable airfoil strut mechanism 2 is in a horizontal state, and as shown in Figure 6, the retractable airfoil strut mechanism 2 is in a vertical state.

[0032] As shown in Figure 4, a storage device reinforcing frame 84 is fixedly installed on both sides of the outer end of the telescopic support arm 22; the storage device reinforcing frame 84 is used to strengthen the strength of the pull rope storage device 201. As shown in Figure 3, storage openings 23 are provided on both sides of the other end of the telescopic support arm 21; the storage openings 23 are used to accommodate the storage device reinforcing frame 84 when the telescopic airfoil strut mechanism 2 is in the retracted state.

[0033] As shown in Figure 4, the pull rope receiver 201 includes a wing-center pull rope receiver 81, a wingtip pull rope receiver 82, a transition pulley 83, and a pull rope winding machine. The wing-center pull rope receiver 81 and the wingtip pull rope receiver 82 are respectively fixedly installed on the inner wall of the receiver reinforcing frame 84. Both the wing-center pull rope receiver 81 and the wingtip pull rope receiver 82 can be round rods and are arranged in parallel. Compared with the wingtip pull rope receiver 82, the wing-center pull rope receiver 81 is closer to the telescopic support arm 21. Both the wing-center pulley 81 and the wingtip pulley 82 are equipped with a freely rotatable transition pulley 83. The corresponding pull ropes 101 bypass the transition pulleys 83. For example, the pull rope 101 connected to the wingtip pulley 102 bypasses the transition pulley 83 on the wingtip pulley 82, and the pull rope 101 connected to the wing-center pulley 102 bypasses the transition pulley 83 on the wing-center pulley 81. The transition pulley 83 guides the pull rope 101. The pull rope 101 connected to the wingtip pulley 102 bypasses the transition pulley 83 on the wingtip pulley 82 and then connects to the pull rope winding machine. The pull rope 101 connected to the wing-center pulley 102 bypasses the transition pulley 83 on the wing-center pulley 81 and then connects to the pull rope winding machine. The pull rope winding machine is used to pull the pull rope 101 to apply preload.

[0034] As shown in Figures 1 and 2, the flexible lightweight wing aircraft body 1 has a strut mechanism housing cavities 4 on both its top and bottom surfaces to accommodate the retractable airfoil strut mechanism 2; one retractable airfoil strut mechanism 2 is installed in each strut mechanism housing cavity 4. The side walls of the strut mechanism housing cavities 4 are provided with servo interfaces 42 corresponding one-to-one with the rotating gear pins 24; the servo interfaces 42 are used to install the corresponding rotating gear pins 24; a locking device 43 is installed on the side wall of the strut mechanism housing cavity 4.

[0035] The aforementioned sliding control mechanism, drive motor, rotary motor, rope winding machine, and locker 43 can all be connected to the main controller of the flexible lightweight wing aircraft, and the main controller can control the sliding control mechanism, drive motor, rotary motor, rope winding machine, and locker 43.

[0036] The aforementioned lightweight wing stiffness enhancement device includes a retractable airfoil strut mechanism 2, a flexible lightweight wing 3, a pull rope 101, and a pull loop 102. The retractable airfoil strut mechanism 2 is mainly used to pull the pull rope 101 to improve the structural stiffness and load-bearing capacity of the flexible lightweight wing 3. It has a rotating storage design with the flexible lightweight wing aircraft. The retractable airfoil strut mechanism 2 has a multi-stage retractable design, and each retractable support arm has an airfoil-like cross-section design, which can effectively reduce aerodynamic drag. The airfoil retractable support arm and the strut end 25 can rotate relative to each other at a small angle within 10°, which can help control the rotation of the yaw direction of the flexible lightweight wing aircraft and improve the maneuverability. The strut mechanism storage cavity 4 is used to store the retractable airfoil strut mechanism 2 in the folded state. The retractable airfoil strut mechanism 2 can keep the pull rope 101 taut by erecting and extending, thereby improving the rigidity of the wing. The pull rope 101 is further pre-tightened by the pull rope winding machine, so that the load-bearing capacity of the flexible lightweight wing 3 is 2-4 times that of a regular flexible lightweight wing 3 without pull rope 101. The unique Y-shaped pull rope 101 design significantly reduces the windward projection area of ​​the pull rope 101 when the flexible lightweight wing aircraft is in flight, while ensuring the torsional rigidity of the flexible lightweight wing 3, thus significantly reducing the aerodynamic drag caused by the pull rope 101.

[0037] Example 1, as shown in Figures 1-6, describes a lightweight wing stiffness enhancement device for reducing aerodynamic losses, comprising a flexible lightweight wing aircraft fuselage 1, a retractable airfoil strut mechanism 2, a flexible lightweight wing 3, pull tabs 102, and pull ropes 101. The flexible lightweight wing 3 has a cross-sectional shape obtained through aerodynamic optimization of the NACA airfoil, and is made of a high-strength aramid fiber fabric layer covered with an airtight membrane. Internally, it features a multi-spar or dot-matrix reinforcement structure. Pull tabs 102 are bonded to the upper and lower surfaces of the flexible lightweight wing 3 near the wingtip and mid-wing. Two pull tabs 102 are bonded to the upper and lower surfaces of the wingtip and mid-wing along the chord direction of the flexible lightweight wing 3, one near the leading edge and the other near the trailing edge. A single flexible lightweight wing 3 has four pull tabs 102 on each of its upper and lower surfaces, for a total of eight pull tabs 102 bonded to a single wing surface.

[0038] Two loops 102 located at the wingtip on the upper surface of the flexible lightweight wing 3 each have a Kevlar rope 101 attached to them, which then converge into a single rope 101. The other end of this rope 101 is connected to the wingtip rope holder 82 on the retractable airfoil strut mechanism 2. Similarly, two loops 102 located in the middle of the wing on the upper surface of the flexible lightweight wing 3 each have a Kevlar rope 101 attached to them, which then converge into a single rope 101. The other end of this rope 101 is connected to the middle wing rope holder 81 on the retractable airfoil strut mechanism 2. Thus, when the ropes 101 between the two loops 102 at the mid-wing and wingtip on the upper surface of the single-sided flexible lightweight wing 3 and the rope retractor 201 are tightened, they all form a Y-shape. Similarly, when the ropes 101 between the two loops 102 at the mid-wing and wingtip on the lower surface of the single-sided flexible lightweight wing 3 and the rope retractor 201 are tightened, they also form a Y-shape. Compared to the traditional method of attaching a single rope 101 to a strut using a single loop 102, the Y-shaped rope 101 significantly reduces the frontal area of ​​the ropes 101 during flight while ensuring the torsional stiffness of the flexible lightweight wing 3. Especially in the case of sideslip angle, the Y-shaped ropes 101 reduce the aerodynamic projection area of ​​the ropes 101, thereby reducing aerodynamic drag. The drag reduction effect is approximately equivalent to reducing the number of ropes 101.

[0039] The retractable airfoil strut mechanism 2 includes a first retractable support arm 21, a second retractable support arm 22, a rotating gear pin 24, and a strut end 25. The entire structure is machined from titanium alloy. Both the first and second retractable support arms 21 and 22 are hollow strut mechanisms with an airfoil-like cross-section. The front end of the first retractable support arm 21 is connected to the strut end 25. Cylindrical rotating gear pins 24 are fixed to both sides of the strut end 25. A locking device 43 is installed on the outside of the strut end 25 to lock the retractable airfoil strut mechanism 2 in relative position with the strut mechanism housing 4. The connection between the first retractable support arm 21 and the strut end 25 is a semi-fixed connection that allows for small-angle relative rotation. Rotation is achieved through a sliding bearing installed between them. The relative rotation between the first retractable support arm 21 and the strut end 25 is mainly achieved by a small rotary motor installed inside the first retractable support arm 21. The control of the small rotary motor is integrated into the main controller of the flexible lightweight wing aircraft. The small rotary motor drives the telescopic support arm 21 to rotate at a small angle within 10°. At this time, the telescopic support arm 21 and the telescopic support arm 22 with airfoil cross sections are equivalent to rotation control rudders, which can assist in controlling the rotation of the yaw direction of the flexible lightweight wing aircraft.

[0040] The telescopic support arms of the telescopic airfoil strut mechanism 2 are all designed with an airfoil-like structure, which significantly reduces the aerodynamic drag of the flexible lightweight wing aircraft compared to traditional cylindrical or square strut mechanisms.

[0041] The second telescopic support arm 22 can be stored inside the first telescopic support arm 21. Its cross-sectional shape is also airfoil-like. The second telescopic support arm 22 achieves relative sliding with the first telescopic support arm 21 along the length direction through a built-in sliding control mechanism, realizing the telescopic deformation of the telescopic airfoil strut mechanism 2. There is a pull rope retractor 201 on each side of the end of the second telescopic support arm 22. Its function is to connect the pull rope 101 to the pull rope winding machine installed in the second telescopic support arm 22. When the pull rope winding machine is working, it protects the pull rope 101 from breaking when it pulls each pull rope 101 to apply pretension. The drawstring retractor 201 includes a mid-wing drawstring retractor 81, a wingtip drawstring retractor 82, a transition pulley 83, a retractor reinforcement frame 84, and a drawstring winding machine, as shown in Figure 4. The mid-wing drawstring retractor 81 and the wingtip drawstring retractor 82 are each fixed to the inner wall of the retractor reinforcement frame 84, and each is equipped with a freely rotating transition pulley 83. The drawstrings 101 of the mid-wing drawstring loop 102 and the wingtip drawstring loop 102 are wound and held on the transition pulleys 83 respectively. Since the flexible lightweight wing 3 is subjected to large overload aerodynamic loads, the drawstrings 101 will bear huge tension. The retractor reinforcement frame 84 is used to strengthen the strength of the drawstring retractor 201. The storage opening 23 is located at the end of the telescopic support arm 21 and is a notch that matches the shape of the retractor reinforcement frame 84. It is used to accommodate the drawstring retractor 201 when the telescopic airfoil strut mechanism 2 is in the retracted state.

[0042] The strut mechanism housing 4 is located on the upper and lower surfaces of the flexible lightweight wing aircraft, and includes a front wall 41, a servo interface 42, a locker 43, and a leading edge 44 of the housing. The servo interface 42 is used to connect to the rotating gear pins 24 on both sides of the retractable airfoil strut mechanism 2, and the retractable airfoil strut mechanism 2 can rotate around the servo interface 42 by a drive motor installed in the flexible lightweight wing aircraft through gear meshing with the rotating gear pins 24.

[0043] The working principle of the above-mentioned lightweight wing stiffness strengthening device is as follows: In the initial state, the retractable airfoil strut mechanism 2 is stored horizontally in the strut mechanism storage cavity 4, as shown in Figure 5; when the retractable airfoil strut mechanism 2 is working, the drive motor drives the retractable airfoil strut mechanism 2 to stand upright as a whole until it is perpendicular to the flexible lightweight wing aircraft body 1, as shown in Figure 6. When the retractable airfoil strut mechanism 2 has been erected, the locking device 43 immediately interlocks with the corresponding locking device on the strut end 25 to completely fix the retractable airfoil strut mechanism 2. The telescopic support arm 22 is driven by a built-in sliding control mechanism to slide out and lock from the telescopic support arm 21, completing the telescopic deformation of the retractable airfoil strut mechanism 2, as shown in Figure 7. After the retractable airfoil strut mechanism 2 has deformed, each pull rope 101 is in a taut state. The pull rope winding machine installed in the telescopic support arm 22 further pulls each pull rope 101, which can further increase the overall structural stiffness of the flexible lightweight wing 3 under positive and negative angles of attack, and enhance its load-bearing capacity. It is expected that the load-bearing capacity of the flexible lightweight wing 3 can reach 2-4 times that of the flexible lightweight wing 3 without pull ropes 101. By adjusting the pull ropes 101 on both sides of the retractable airfoil strut mechanism 2, the tension of the pull ropes 101 on both sides of the retractable airfoil strut mechanism 2 on the retractable airfoil strut mechanism 2 can be self-balanced, which can reduce the risk of large deformation, bending or even breakage of the telescopic support arm 22 of the retractable airfoil strut mechanism 2.

[0044] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

[0045] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lightweight wing stiffness enhancement device for reducing aerodynamic losses, characterized in that, The system includes a flexible lightweight wing aircraft fuselage, a retractable airfoil strut mechanism, flexible lightweight wings, pull ropes, and pull loops. The flexible lightweight wings are symmetrically arranged on both sides of the flexible lightweight wing aircraft fuselage. A retractable airfoil strut mechanism is located at both the top and bottom of the flexible lightweight wing aircraft fuselage. A pull rope storage device is located at the end of each retractable airfoil strut mechanism. Two pull loops are fixedly connected to the wingtips and wing center of the upper and lower skin surfaces of each flexible lightweight wing. The two pull loops are distributed along the chord length direction of the flexible lightweight wing. Each pull loop at each wingtips is attached to a first Kevlar pull rope. The two first Kevlar pull ropes on the upper surface converge into one pull rope and are connected to the pull rope storage device at the top of the flexible lightweight wing aircraft fuselage. The two first Kevlar pull ropes on the lower surface converge into one pull rope and are connected to the pull rope storage device at the bottom of the flexible lightweight wing aircraft fuselage. Rope retractor; each of the pull loops in each wing is attached to a second Kevlar rope. The two second Kevlar ropes on the upper surface converge into one rope and are connected to the rope retractor at the top of the flexible lightweight wing aircraft. The two second Kevlar ropes on the lower surface converge into one rope and are connected to the rope retractor at the bottom of the flexible lightweight wing aircraft. The rope retractor is used to pull each rope to apply preload. When the ropes between the two pull loops at the mid-wing and wingtip on the upper surface of a single flexible lightweight wing are tightened, they form a Y-shaped rope structure. When the ropes between the two pull loops at the mid-wing and wingtip on the lower surface of a single flexible lightweight wing are tightened, they also form a Y-shaped rope structure. The Y-shaped rope structure can ensure the torsional stiffness of the flexible lightweight wing while significantly reducing the windward area of ​​the ropes during flight.

2. The lightweight wing stiffness strengthening device as described in claim 1, characterized in that, The retractable airfoil strut mechanism includes a first retractable support arm, a second retractable support arm, a rotary gear pin, and a strut end. Both the first and second retractable support arms are hollow strut mechanisms with airfoil-like cross-sections. The second retractable support arm can be housed within the first retractable support arm. The second retractable support arm achieves relative sliding with the first retractable support arm along its length via a built-in sliding control mechanism, thus enabling the retractable airfoil strut mechanism to extend and retract. The strut end is mounted on the end of the first retractable support arm facing the flexible lightweight wing aircraft body. Cylindrical rotary gear pins are fixed to both sides of the strut end. The retractable airfoil strut mechanism is rotatably mounted on the flexible lightweight wing aircraft body via the rotating gear pin. A locking device is installed inside the flexible lightweight wing aircraft body. The locking device is located on the outer side of the strut end and is used to lock the relative position of the retractable airfoil strut mechanism and the flexible lightweight wing aircraft body. A rope storage device is provided on each side of the end of the second retractable support arm. A drive motor is installed inside the flexible lightweight wing aircraft body to drive the first retractable support arm to rotate around a horizontal axis. The drive motor is connected to the rotating gear pin and is used to drive the retractable airfoil strut mechanism to switch between a horizontal and a vertical state.

3. The lightweight wing stiffness strengthening device as described in claim 2, characterized in that, A storage device reinforcing frame is fixedly installed on both sides of the outer end of the telescopic support arm two; the storage device reinforcing frame is used to strengthen the strength of the pull rope storage device; storage openings are provided on both sides of the other end of the telescopic support arm one; the storage openings are used to accommodate the storage device reinforcing frame when the telescopic airfoil strut mechanism is in the retracted state; the pull rope storage device includes a wing-center pull rope storage device, a wingtip pull rope storage device, a transition pulley, and a pull rope winding machine; the wing-center pull rope storage device and the wingtip pull rope storage device are respectively fixedly installed on the inner wall of the storage device reinforcing frame; a transition pulley that can rotate freely is installed on both the wing-center pull rope storage device and the wingtip pull rope storage device; the transition pulley is used to guide the pull rope; the pull rope winding machine is used to pull the pull rope to apply a preload.

4. The lightweight wing stiffness strengthening device as described in claim 3, characterized in that, The pull rope connected to the wingtip pulley passes over the transition pulley installed in the wingtip pull rope receiver and is then connected to the pull rope winding machine. The pull rope connected to the pull loop in the middle of the wing passes over the transition pulley installed in the middle pull rope receiver and is then connected to the pull rope winding machine.

5. The lightweight wing stiffness strengthening device as described in claim 4, characterized in that, The flexible lightweight wing aircraft body has a strut mechanism storage cavity on both the top and bottom surfaces to accommodate the retractable airfoil strut mechanism; one retractable airfoil strut mechanism is installed in each strut mechanism storage cavity.

6. The lightweight wing stiffness strengthening device as described in claim 5, characterized in that, The side wall of the support mechanism receiving cavity is provided with a servo motor interface corresponding to each of the rotating gear pins; the servo motor interface is used to install the corresponding rotating gear pin; the lock is installed on the side wall of the support mechanism receiving cavity.

7. The lightweight wing stiffness strengthening device as described in claim 2, characterized in that, The first telescopic support arm, the second telescopic support arm, the rotary gear pin, and the end of the support rod are all machined from titanium alloy.

8. The lightweight wing stiffness strengthening device according to any one of claims 2-7, characterized in that, The first telescopic support arm is rotatably mounted on the end of the strut around a vertical axis; a rotary motor is installed inside the first telescopic support arm; the rotary motor is used to drive the first telescopic support arm to rotate within 10° relative to the end of the strut, thereby assisting in controlling the rotation of the yaw direction of the flexible lightweight wing aircraft through the first telescopic support arm and the second telescopic support arm.

9. The lightweight wing stiffness strengthening device according to any one of claims 1-7, characterized in that, The flexible lightweight wing adopts an aerodynamically optimized NACA airfoil, and is made of a high-strength aramid fiber fabric layer covered with an airtight membrane, with an internal reinforcing structure.

10. The lightweight wing stiffness strengthening device according to any one of claims 1-7, characterized in that, Of the two pull loops distributed along the chord length of the flexible lightweight wing, one pull loop is located at the leading edge of the flexible lightweight wing, and the other pull loop is located at the trailing edge of the flexible lightweight wing.

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