High-efficiency UAV flight apparatus integrating gurney flap and distributed propulsion system

Abstract

The present invention is a UAV flight apparatus that integrates a Gurney flap with a distributed propulsion system. By incorporating the Gurney flap into the distributed propulsion system, the invention enhances aerodynamic efficiency and overall system performance, addressing the low efficiency issues of existing UAV systems.

Description

Technical Field

[0001] This invention relates to a drone flight device, and more particularly to a drone flight device with Gurney flaps and a distributed propulsion system. Prior Technology

[0002] An airfoil, also known as an airfoil profile, refers to the cross-sectional shape of a rotor, propeller, turbine, wing, and sail. The geometry of an airfoil affects the aerodynamic forces it generates in a fluid, altering the direction of airflow and thus producing lift and drag. For example, by changing the angle of attack, an airfoil can increase lift to overcome gravity, making it suitable for applications requiring lift, such as wings and rotors. A Gurney flap is a small attachment installed at the tail of an airfoil that effectively increases the lift coefficient and improves aerodynamic performance. It is particularly suitable for applications requiring high lift or lift efficiency, such as racing car tail wings, wind turbine blades, and airfoil designs for fixed-wing or rotary-wing aircraft.

[0003] In related patent precedents, US Patent No. 20180162515 discloses a retractable Gurney flap integrated within an airfoil. Its key feature is that the Gurney flap can extend or retract as needed, dynamically adjusting aerodynamic performance. Its main function is to increase lift by deploying the flap and reduce drag when not needed, thereby improving aerodynamic efficiency. Furthermore, US Patent No. 9,751,614, from NASA, discloses an airfoil design using a distributed propulsion system, also encompassing adaptive airfoil technology. Its focus is on using a distributed propulsion system to independently adjust thrust, control wing twist and flight dynamics, and combine this with adaptive airfoil technology to continuously optimize aerodynamic performance during flight. Additionally, Chinese mainland patent No. 109436316A proposes an adaptive Gurney flap drive system for variable-speed rotors. This system relies on changes in centrifugal force at different speeds to automatically extend or retract the Gurney flap, requiring no additional signal control. This design improves pneumatic control performance while avoiding the added weight and operational burden of complex mechanisms.

[0004] Research by Yao, Y. et al. explored how Gurney flaps improve the aerodynamic efficiency of low Reynolds number propellers, particularly for ultra-high-altitude unmanned aerial vehicles (UAVs). The addition of Gurney flaps demonstrated improved propeller performance, representing a significant advancement for UAVs operating at high altitudes. Furthermore, research by Basso, M. et al., focusing on how Gurney flaps improve downforce on Formula 1 car front wings, resulting in significant performance gains, shows that Gurney flaps can be widely applied to improve aerodynamic efficiency across various fields. Wu, J. et al. focused on the optimization of distributed electric propulsion systems, particularly in general aviation, analyzing the interaction between propeller slipstream and wing. Their results show that by incorporating aerodynamic modifications, distributed propulsion systems can not only improve cruise efficiency but also increase range without affecting takeoff and landing performance, providing valuable reference for the design and application of fixed-wing aircraft.

[0005] Distributed propulsion (DP) systems have received considerable attention in recent years, particularly in the development of unmanned aerial vehicles (UAVs). These systems are characterized by multiple small propellers distributed along the leading edge of the wing, enabling short takeoff and landing (STOVL) or vertical takeoff and landing (VTOL) capabilities. While distributed propulsion systems increase the lift generated by the aircraft, several significant efficiency issues remain:

[0006] 1. Low Cruise Efficiency: Distributed propulsion systems can indeed effectively generate high lift at low speeds, especially during takeoff and landing. However, at higher speeds and under cruise conditions, the interaction between the propeller slipstream and the wing surface becomes quite complex. This complexity can lead to increased drag, ultimately reducing the aircraft's overall aerodynamic efficiency. Therefore, the cruise efficiency of aircraft equipped with distributed propulsion systems is significantly limited.

[0007] 2. Limited improvement in lift-to-drag ratio: Although distributed propulsion systems can increase the lift of the wing, they do not significantly improve the lift-to-drag ratio under all flight conditions. In particular, at higher Reynolds numbers, the drag generated by the interaction between the propeller and the wing surface often offsets the increased lift benefits, resulting in reduced system efficiency during cruise flight.

[0008] In other words, while existing distributed propulsion systems can successfully enhance lift through distributed propellers, they often encounter complex interactions between the slipstream and the wing surface under cruise conditions, which may lead to reduced efficiency. Therefore, these challenges increase flight drag and limit the overall aerodynamic performance at high speeds.

[0009] The aforementioned limitations emphasize the need for further improvements to distributed propulsion systems to enhance their flight efficiency under a wider range of flight conditions. Furthermore, there is currently no specific research revealing the application of "Gurney flaps" to improve the aerodynamic performance of "distributed propulsion wings." Therefore, once "Gurney flaps" are used to improve the aerodynamic performance of "distributed propulsion wings," the industry in related fields will be quite excited about what will be a completely new area of ​​development and progress for both "Gurney flaps" and "distributed propulsion wings." Summary of the Invention

[0010] This invention relates to an unmanned aerial vehicle (UAV) flight device that integrates a Gurney flap (GF) with a distributed propulsion system. It focuses on improving aerodynamic efficiency and overall performance of the propulsion system by introducing a Gurney flap through a distributed propulsion system, thereby solving the problem of low efficiency in existing distributed propulsion UAV systems.

[0011] The present invention provides an unmanned aerial vehicle (UAV) flight device with a Gurney flap and a distributed propulsion system, comprising a Gurney flap, a fixed wing, and multiple distributed propulsion systems. The combination is as follows: first, a fixed wing is provided, then multiple distributed propulsion systems are distributed on the leading edge of the fixed wing, and the Gurney flap is installed on the trailing edge of the fixed wing.

[0012] One of the advantages of this invention, which combines the lift-enhancing characteristics of the Gurney flaps with the distributed thrust generated by the distributed propulsion system, is that the lift and drag are optimized by combining the lift-enhancing characteristics of the Gurney flaps with the distributed thrust generated by the distributed propulsion system, thereby improving the overall aerodynamic performance.

[0013] One of the advantages of this invention, which is a UAV flight device with Gurney flaps and a distributed propulsion system, is that it improves the aerodynamic performance of unmanned aerial vehicles and small aircraft. By integrating a distributed propulsion system and Gurney flaps, the lift-to-drag ratio of flight can be improved.

[0014] One of the advantages of this invention, which combines a Gurney flap and a distributed propulsion system for unmanned aerial vehicle (UAV) flight devices, is that it makes flight more efficient under low-speed, high-lift conditions, while reducing drag under cruise conditions.

[0015] One of the advantages of this invention, which combines a Gurney flap with a distributed propulsion system for unmanned aerial vehicles (UAVs), is that it is crucial for vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) UAV applications, thereby enabling greater operational flexibility.

[0016] One of the advantages of this invention, which combines a Gurney flap with a distributed propulsion system for unmanned aerial vehicle (UAV) flight devices, is that it can overcome the inherent low efficiency of existing distributed propulsion systems.

[0017] One of the advantages of this invention, which is a UAV flight device with Gurney flaps and a distributed propulsion system, is that the Gurney flaps, which are known for increasing lift efficiency, can control drag at the same time, thereby improving the lift-to-drag ratio.

[0018] One of the advantages of this invention is that of a UAV flight device with Gurney flaps and a distributed propulsion system. This enhancement can reduce the negative impact of propeller slipstream and wing interaction, thereby improving cruise efficiency.

[0019] Therefore, the UAV with the Gurney flaps and distributed propulsion system of the present invention can achieve higher efficiency, extend the range and improve the overall flight performance, especially for small aircraft operating in urban or restricted environments, with great potential for improvement. Simple Explanation of the Diagram

[0020] Figure 1 shows the UAV flight device of the present invention, which has Gurney flaps and a distributed propulsion system. Figure 2 shows a cross-sectional view of the NACA airfoil with Gurney flaps and a distributed propulsion system. Figure 3A shows the overall flow field and vortex cloud map around the airfoil of the present invention. Figure 3B is an enlarged view of the trailing edge flow field and vorticity cloud map of the airfoil of the present invention. Figure 4A shows the system lift coefficient (CLsys) of the NACA4415 airfoil equipped with a distributed propulsion system as a function of angle of attack (AOA) under different Gurney flap configurations. Figure 4B shows the system thrust coefficient (CTsys) of the NACA4415 airfoil equipped with a distributed propulsion system as a function of angle of attack (AOA) under different Gurney flap configurations. Implementation

[0021] The present invention relates to an unmanned aerial vehicle (UAV) flight device with a Gurney flap (GF) and a distributed propulsion system, which aims to solve the key inefficiency problem of existing distributed propulsion (DP) systems, especially in the high-speed and cruise phases, and can improve lift generation and aerodynamic performance.

[0022] Figure 1 shows the UAV flight device of the present invention with Gurney flaps and distributed propulsion systems, including Gurney flaps 10, a fixed wing 12, and a plurality of distributed propulsion systems 14, wherein the plurality of distributed propulsion systems 14 are composed of multiple individual distributed propulsion systems 14. As shown in Figure 2, each individual distributed propulsion system 14 includes a propeller 141 and a motor support nacelle 142. The assembly method of the present invention is to first provide a fixed wing 12, and then distribute and install the plurality of distributed propulsion systems 14 along the leading edge of the fixed wing 12. The Gurney flaps 10 are then installed on the trailing edge of the fixed wing 12.

[0023] As shown in Figure 1, the present invention relates to an unmanned aerial vehicle (UAV) flight device with a Gurney flap and a distributed propulsion system. The Gurney flap 10 is an elongated thin flat plate structure, which is installed on the pressure surface side of the trailing edge (also known as the trailing edge) of the fixed wing 12 and is perpendicular to the chord length. The "chord length" refers to the straight-line distance between the leading edge and the trailing edge of an aircraft wing or other airfoil component. In addition, the chord length is one of the most basic parameters in the description of airfoil geometry and is usually used to calculate important aerodynamic parameters such as lift coefficient and angle of attack. In the present invention, the Gurney flap 10 is installed perpendicular to the chord length, indicating that the installation direction of the Gurney flap 10 is perpendicular to the airflow direction of the wing.

[0024] The primary function of the Gurney flap 10 is to increase lift by enhancing the pressure difference between the upper and lower surfaces of the airflow through the effective camber of the airfoil. Simultaneously, the recirculation zone formed behind the Gurney flap 10 helps stabilize the pressure distribution. Furthermore, the Gurney flap 10 can, to some extent, suppress flow separation on the suction surface, thereby improving airflow adhesion. Despite its relatively small size, the Gurney flap 10 significantly alters the airflow distribution at the trailing edge of the fixed wing 12, optimizing its aerodynamic performance in distributed electric propulsion technology and improving the lift-to-drag ratio (L / D) under specific conditions. Its simplicity and efficiency make it an effective method for improving the aerodynamic efficiency of fixed wings.

[0025] Continuing with Figure 1, the present invention relates to an unmanned aerial vehicle (UAV) flight device with Gurney flaps and a distributed propulsion system. The fixed wing 12 is a NACA airfoil (NACA 4415 wing). Referring further to Figure 2, which shows a cross-sectional view of the NACA airfoil with Gurney flaps and a distributed propulsion system, its configuration includes: a leading edge 1, an upper surface 2, a trailing edge 3, and a lower surface 4. The geometric characteristics of the NACA 4415 airfoil are as follows:

[0026] Please refer to Figure 2 for the cross-sectional view of the NACA4415 airfoil. The leading edge 1 is a smooth curve, gradually transitioning to form the convex upper surface 2.

[0027] Please refer to the NACA4415 airfoil cross-section shown in Figure 2. The upper surface 2 extends from the leading edge 1 along a gentle convex arc to the trailing edge 3.

[0028] Please also refer to the cross-sectional view of the NACA4415 airfoil shown in Figure 2. The trailing edge 3 is located at the very end of the airfoil and has a relatively sharp shape to ensure a good aerodynamic flow field.

[0029] Please refer to the NACA4415 airfoil cross-section shown in Figure 2. The lower surface 4 extends forward from the trailing edge 3 along a relatively gentle arc, connecting back to the leading edge 1 to form a complete airfoil profile.

[0030] Please refer to Figure 2 for the NACA4415 airfoil profile. The NACA4415 airfoil belongs to the four-digit NACA airfoil family. The meaning of the number "4415" is as follows:

[0031] The first number "4" indicates that the maximum camber is 4% of the wing chord length.

[0032] The second number "4" indicates that the maximum radian occurs at 40% of the wing chord length (calculated from the leading edge).

[0033] The last two numbers "15" indicate that the maximum thickness of the airfoil is 15% of the chord length.

[0034] The NACA4415 airfoil design provides moderate lift and low drag, making it suitable for low- to medium-speed flight applications, such as small aircraft and drones.

[0035] Furthermore, the maximum camber of the NACA 4415 airfoil is 4% of the chord length, located at 0.4 chord lengths from the leading edge, while its maximum thickness is 15% of the chord length. Therefore, the NACA 4415 airfoil was chosen as the wing airfoil, which is the fixed wing 12 used in this invention. Its curved airfoil section can provide good lift characteristics at low speeds and low angles of attack.

[0036] The shape, airfoil curvature, and aerodynamic characteristics of the NACA4415 airfoil are described below:

[0037] Upper surface curve (convex curve): The upper surface of the airfoil starts from the leading edge arc and has a relatively steep lift curvature, which gradually decreases as the chord length increases.

[0038] Lower surface curve (concave curve): The lower surface of the airfoil has a relatively gentle curve starting from the leading edge, forming a slight concave shape, and gradually transitioning to the trailing edge.

[0039] Leading edge: The leading edge is arc-shaped, which ensures smooth fluid entry and reduces separation effects.

[0040] Trailing edge: The trailing edge is designed with a sharp shape to ensure smooth detachment of the boundary layer, reduce drag, and control eddy separation.

[0041] Aerodynamic performance advantages of the NACA4415 airfoil:

[0042] The NACA4415 airfoil exhibits good lift coefficient and low drag characteristics in the low to medium Reynolds number range (10⁵ to 10⁶), making it suitable for applications such as small aircraft, drones, and wind turbine blades. At moderate angles of attack, the NACA4415 airfoil can provide relatively stable lift and delay stall, making it suitable for applications with high flight stability requirements.

[0043] The overall structural design of the NACA4415 airfoil includes the following detailed specifications:

[0044] The manufacturing method of the NACA4415 airfoil: The wing and motor support nacelle are manufactured using 3D printing technology with a printing accuracy of 0.3 mm, which ensures high precision and surface smoothness.

[0045] The NACA4415 airfoil is made of polylactic acid (PLA), which provides good rigidity and structural integrity.

[0046] After the NACA4415 airfoil is 3D printed, it can be polished, sanded and coated with a surface coating to improve airflow and reduce frictional drag. The internal structure of the NACA4415 airfoil can be constructed with stainless steel to strengthen and improve structural rigidity.

[0047] The NACA4415 airfoil has a wingspan of 400 mm to 420 mm.

[0048] The chord length of the NACA4415 airfoil can range from 140 mm to 160 mm.

[0049] The modular design of the NACA4415 airfoil allows for the replacement of the trailing edge, enabling the creation of the original airfoil's sharp trailing edge using 3D printing technology. This includes 1%, 1.5%, and 2% Gurney flaps. The effect of the Gurney flaps was then tested after the trailing edge replacement.

[0050] As shown in Figure 1, the UAV flight device of the present invention, which features Gurney flaps and a distributed propulsion system, has multiple (or a plurality of) distributed propulsion system units 14 with small diameters distributed along the leading edge of the wing. This design aims to optimize aerodynamic and propulsive performance through distributed propulsion technology. These multiple propellers 141 can increase the dynamic pressure on the wing surface by accelerating the airflow, thereby improving the lift coefficient, especially during takeoff and low-speed flight. Therefore, the leading edge of the fixed wing 12 is equipped with multiple (or a plurality of) distributed propulsion system units 14, and the trailing edge of the fixed wing 12 is equipped with Gurney flaps 10.

[0051] Referring again to Figure 1, in the UAV flight device of the present invention, multiple (or a plurality of) distributed propulsion systems 14 are distributed along the leading edge of the fixed wing 12, while the Gurney flap 10 is mounted on the trailing edge of the fixed wing 12 at a height of 1% to 2% of the chord length. As shown in Figure 1, the multiple (or a plurality of) distributed propulsion systems 14 may include, but are not limited to, four, and may include multiple (or a plurality of) distributed propulsion systems 14.

[0052] Figure 3A illustrates the overall flow field and vorticity cloud map around the airfoil of this invention. The Gurney flap, with a size of 1% of the chord length, significantly alters the airflow structure at the trailing edge, increasing the pressure difference between the upper and lower surfaces of the airfoil and thus improving its lift-to-drag ratio. The vorticity cloud map shows the interaction between the propeller slipstream and the airflow around the airfoil, particularly near the trailing edge, enhancing wake dynamics and pressure distribution. The presence of the Gurney flap not only alters the wake structure but also influences the overall flow field around the airfoil by stabilizing and adjusting the airflow, contributing to improved aerodynamic performance of the UAV.

[0053] Furthermore, Figure 3B is an enlarged view of the trailing edge flow field and vortex cloud diagram of the airfoil of this invention. It shows the vortex structure generated by the Gurney flap near the trailing edge. The Gurney flap generates a significant backflow zone and vortices near the trailing edge. These vortices alter the downstream airflow distribution, further improving the lift coefficient and overall aerodynamic performance of the airfoil. The interaction between the propeller slipstream and the vortices generated by the Gurney flap increases the dynamic pressure on the airfoil and enhances circulation control, especially at low speeds and high angles of attack, which helps stabilize the airflow and improve lift. This interaction plays a crucial role in improving the aerodynamic efficiency and low-speed performance of distributed propulsion systems, thereby achieving a synergistic enhancement of higher system propulsion efficiency and aerodynamic performance.

[0054] Figure 4A shows the system lift coefficient (CLsys) of the NACA4415 airfoil equipped with a distributed propulsion system as a function of angle of attack (AOA) under different Gurney flap configurations, while Figure 4B shows the system thrust coefficient (CTsys) of the NACA4415 airfoil equipped with a distributed propulsion system as a function of angle of attack (AOA) under different Gurney flap configurations. As shown in Figures 4A and 4B, when the Reynolds number is set to 90 × 10³, simulating the operating environment of an unmanned aerial vehicle (UAV) under cruise conditions, the combination of a distributed electric propulsion system and the Gurney flap design shows significant improvements in aerodynamic performance. The results indicate that the system can effectively enhance lift and optimize airflow distribution under appropriate conditions, thereby improving cruise efficiency and achieving a higher lift-to-drag ratio. Furthermore, the Gurney flap design fully leverages its role in the distributed propulsion system by enhancing hydrodynamic control and optimizing lift generation and wake management. The airflow interaction between the propeller slipstream and the Gurney flap is crucial for improving system performance under various flight conditions, further highlighting the potential of this design in optimizing the aerodynamic efficiency of UAVs.

[0055] Furthermore, the charts in Figures 4A and 4B above show the aerodynamic performance of the NACA4415 airfoil equipped with a distributed propulsion (DP) system under different Gurney flap (GF) configurations. For example, GF000 indicates no Gurney flaps installed, while GF100, GF150, and GF200 correspond to Gurney flaps with heights of 1%, 1.5%, and 2% of the wing chord length, respectively. In addition, Figure 4A shows the system lift coefficient (CLsys) as a function of angle of attack (AOA), while Figure 4B shows the system thrust coefficient (CTsys), which is the net thrust generated by the propeller minus the drag acting on the wing. Since the thrust generated by the propeller is constant, any decrease in the system thrust coefficient directly indicates an increase in wing drag.

[0056] Furthermore, the results of the graphs in Figures 4A and 4B show that although installing the Gurney flaps slightly reduces the system's thrust coefficient (meaning a slight increase in wing drag), the increase in the system's lift coefficient (i.e., lift) is significantly greater. This demonstrates that the Gurney flaps effectively increase the lift generated by the wing, while the corresponding increase in drag is relatively small, especially in the cruise angle of attack range of 0° to 4°. Therefore, with the addition of the Gurney flaps, the overall lift-to-drag ratio (L / D) is improved, greatly enhancing the system's aerodynamic efficiency during flight.

[0057] The following describes the features and advantages of the "distributed propulsion technology" of the UAV flight device with Gurney flaps and a distributed propulsion system of the present invention:

[0058] In the field of distributed propulsion technology, particularly distributed electric propulsion (DEP), it is increasingly recognized as a breakthrough in UAV and aircraft design. Distributed electric propulsion technology, by distributing smaller electric motors and propellers along the wingspan, provides significant advantages in lift and control during takeoff, landing, and low-speed flight. NASA has conducted extensive research in this area, demonstrating through projects such as LEAPTech and X-57 Maxwell that distributed propellers can significantly improve wing aerodynamic efficiency, thereby enhancing lift.

[0059] In the field of distributed propulsion technology, a major advantage of distributed propulsion systems lies in their ability to generate distributed airflow over the wing surface, increasing lift and delaying stall. Furthermore, by arranging the propellers at the leading edge of the wing, the airflow is accelerated across the wing, thereby increasing the pressure difference between the upper and lower surfaces. This is particularly beneficial during the low-speed operation of vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) UAVs, significantly improving the lift coefficient. Research by NASA shows that this configuration can achieve a lift coefficient exceeding 5, far higher than traditional fixed-wing designs.

[0060] In summary, the distributed propulsion technology of this invention represents a significant advancement in aircraft design, not only improving lift performance but also enhancing control during takeoff and landing and increasing operational flexibility. With further advancements in battery technology, electric motors, and aerodynamics, the full potential of distributed electric propulsion technology is expected to be realized, particularly in long-range, energy-efficient, and low-emission aircraft.

[0061] Furthermore, the following describes the features and advantages of the "Gurney flap technology" of the present invention, which includes a UAV flight device with Gurney flaps and distributed propulsion:

[0062] The "Gurney flap technology" of this invention is a small vertical plate installed on the trailing edge of the wing, typically not exceeding 3% of the wing chord length. Despite its simple design, the Gurney flap has a significant impact on the aerodynamic performance of the wing, especially in increasing lift at low angles of attack. When installed, the Gurney flap alters the airflow near the wing's trailing edge, increasing the pressure difference between the upper and lower wing surfaces. This leads to an increase in the lift coefficient, particularly under low-speed flight conditions, and also improves overall efficiency.

[0063] The "Gurney flap technology" of this invention maintains a stable airflow on the suction surface of the wing (the upper surface of the wing), while the airflow on the pressure surface of the wing (the lower surface of the wing) is blocked by the Gurney flap, resulting in a wake region in front of the Gurney flap. This redirection of airflow increases the downwash effect at the trailing edge, further enhancing lift. At low angles of attack, studies show that when the Gurney flap is optimal relative to the wing chord length, the lift-to-drag ratio is significantly improved.

[0064] Therefore, the main advantages of the UAV flight device of the present invention, which features Gurney flaps and a distributed propulsion system, are described below:

[0065] I. Optimized Lift-to-Drag Ratio: By combining the Gurney flap with the distributed propulsion system, this invention optimizes the lift-to-drag ratio at different angles of attack. The Gurney flap is installed on the trailing edge of the wing and increases lift by enhancing the pressure difference between the upper and lower surfaces of the wing. This helps maintain laminar flow and reduces drag, especially at low speeds, without affecting the aerodynamic efficiency of the distributed propulsion system. This balance significantly improves the system's performance during takeoff and cruise.

[0066] II. Improved Cruise Efficiency: The efficiency of traditional distributed propulsion systems at cruise speed is often reduced due to the increased drag caused by the propeller. The Gurney flap can solve this problem by stabilizing the trailing edge airflow, ensuring that the lift-to-drag ratio remains at a high level during the cruise phase, reducing adverse drag effects, thereby significantly improving energy efficiency and overall flight performance, which is especially important for long-range and high-speed operations.

[0067] 3. Reduced aerodynamic drag at high angles of attack: The Gurney flaps effectively alter the wake dynamics behind the wing, making the flow field more streamlined and reducing drag at high angles of attack or cruise speeds. By improving airflow stability and reducing turbulence in the propeller slipstream, this design improves energy efficiency, enabling UAVs to achieve longer flight distances during the cruise phase. Improved drag reduction at high speeds is crucial for extending flight range.

[0068] IV. Flexible and Scalable Design: The design combining the Gurney flaps and distributed propulsion system offers high flexibility, enabling it to adapt to UAVs of different sizes and configurations. This flexibility is particularly advantageous for both civilian and military applications, allowing for optimization of short takeoff and landing (STOL / VTOL) capabilities as needed, while also enhancing cruise performance. The scalability of this design enables it to adapt to a wide range of mission requirements, from urban air traffic control to tactical unmanned systems applications.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the patent application of the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed in the present invention should be included in the scope of the patent application below.

[0070] 1: Front Edge 2: Upper surface 3: Trailing edge 4: Lower surface 10: Gurney flaps 12: Fixed-wing 14: Distributed Propulsion System 141: Propeller 142: Motor support compartment

Claims

1. An unmanned aerial vehicle (UAV) flight device comprising a NACA4415 airfoil fixed wing, a Gurney flap, and four distributed propulsion systems, wherein the four distributed propulsion systems are distributed at the leading edge of the NACA4415 airfoil fixed wing, and the Gurney flap is mounted at the trailing edge of the NACA4415 airfoil fixed wing, comprising at least: a NACA4415 airfoil fixed wing 12, wherein the wing length of the NACA4415 airfoil fixed wing 12 is up to 400 mm to 420 mm, and the chord length of the NACA4415 airfoil fixed wing 12 is up to 140 mm to 160 mm, wherein the shape of the NACA4415 airfoil fixed wing 12 comprises: a leading edge 1, the leading edge 1 being arc-shaped to ensure smooth fluid entry and reduce a separation effect; and a trailing edge 3, the trailing edge 3 having a sharp shape to ensure smooth boundary layer detachment, reduce drag, and control vortex separation; The NACA4415 airfoil fixed wing 12 has an upper surface curve 2, which begins with an arc at the leading edge 1 and has a relatively steep lift curvature that gradually decreases with increasing chord length; and a lower surface curve 4, which begins with a relatively gentle curve at the leading edge 1, forming a slight concavity that gradually transitions to the trailing edge 3. The maximum curvature of the NACA4415 airfoil fixed wing 12 is 4% of the chord length. Calculated from the leading edge 1, the maximum curvature occurs at 40% of the chord length. The maximum thickness of the NACA4415 airfoil fixed wing 12 is 15% of the chord length. A Gurney flap 10, which is an elongated thin flat plate structure, is mounted on the pressure surface side of the trailing edge 3 of the NACA4415 airfoil fixed wing 12, perpendicular to the chord length. The trailing edge 3 is selected from the group of 1% Gurney flaps 10, 1.5% Gurney flaps 10, and 2% Gurney flaps 10. Four distributed propulsion systems 14 are distributed and installed along the leading edge 1 of the NACA4415 airfoil fixed wing 12. Each of the four distributed propulsion systems 14 consists of four individual distributed propulsion systems, each comprising: a propeller 141; and a motor support nacelle 142, thereby improving lift generation and aerodynamic performance during high-speed and cruise phases.

2. A UAV flight device as described in claim 1, comprising a NACA4415 airfoil fixed wing, a Gurney flap, and four distributed propulsion systems, wherein the four distributed propulsion systems are distributed at the leading edge of the NACA4415 airfoil fixed wing, and the Gurney flap is mounted on the trailing edge of the NACA4415 airfoil fixed wing, wherein the NACA4415 airfoil fixed wing 12 is manufactured in a modular design, using polylactic acid as a manufacturing material for the NACA4415 airfoil fixed wing 12, and an internal structure of the NACA4415 airfoil fixed wing 12 made of stainless steel, and a replaceable trailing edge 3 of the NACA4415 airfoil fixed wing 12, wherein the trailing edge of the NACA4415 airfoil is selected from the group consisting of 1% Gurney flap 10, 1.5% Gurney flap 10, and 2% Gurney flap 10, including: Polylactic acid (PLA) is selected as a manufacturing material for the NACA4415 airfoil fixed wing 12 to provide good rigidity and structural integrity. An internal structure of the NACA4415 airfoil fixed wing 12 is made of stainless steel to enhance structural rigidity. A wing and a motor support nacelle 142 are manufactured using 3D printing technology, with a 3D printing precision of 0.3 mm to ensure high accuracy and surface smoothness. The trailing edge 3 of the NACA4415 airfoil fixed wing 12 is manufactured using 3D printing technology, and the trailing edge is selected from the groups of 1% Gurney flaps 10, 1.5% Gurney flaps 10, and 2% Gurney flaps 10. After 3D printing, polishing, grinding, and a surface coating are applied to improve airflow and reduce frictional drag, thereby increasing lift generation and aerodynamic performance during high-speed and cruise phases.

3. The unmanned aerial vehicle (UAV) flight device as described in claim 1 or 2, wherein the NACA4415 airfoil has the function of providing lift and drag, suitable for a medium-to-low speed flight application.

4. The unmanned aerial vehicle (UAV) flight device as described in claim 1 or 2, wherein the Gurney flap has the function of increasing a pressure difference between the upper and lower surfaces of an airflow by increasing an effective camber of an airfoil to enhance a lift.

5. The unmanned aerial vehicle (UAV) flight device as described in claim 1 or 2, wherein the four distributed propulsion systems have the function of increasing the dynamic pressure on a wing surface through an accelerated airflow, thereby increasing the lift coefficient.

Images