A paddle, propeller and aircraft

Abstract

This utility model discloses a blade, a propeller, and an aircraft, belonging to the field of aircraft technology. The blade includes a connected root and a shaft. The root has a root centerline, and the distance from the end of the blade furthest from the root to the root centerline is a first length. At the first position of the blade, the angle of attack is 18.38°±2.5°; at the second position, the angle of attack is 9.58°±2.5°; and at the third position, the angle of attack is 6.61°±2.5°. The distance from the first position of the blade to the root centerline is 20% to 25% of the first length; the distance from the second position of the blade to the root centerline is 50% to 58% of the first length; and the distance from the third position of the blade to the root centerline is 80% to 95% of the first length. The blade of this utility model, through the design of the angle of attack at multiple key positions of the main body of the propeller shaft, reduces air resistance and improves aerodynamic efficiency. The propeller and aircraft of this invention improve the aerodynamic efficiency of the propeller and the flight efficiency of the aircraft.

Description

Technical Field

[0001] This utility model relates to the field of aircraft, and more particularly to a blade, a propeller, and an aircraft. Background Technology

[0002] A propeller is a crucial component of an aircraft. It converts engine power into thrust or lift by rotating its blades in the air, enabling unmanned aerial vehicles (UAVs) to take off, land, and hover. A propeller typically consists of a hub and blades. The hub is connected to the motor's output shaft via a transmission mechanism. When the motor drives the output shaft to rotate, the hub, connected to the output shaft, also rotates, causing the blades to rotate. This, in turn, creates airflow around the blades, generating lift or thrust for the aircraft.

[0003] In related technologies, when medium and large-sized propellers exceeding 48 inches are used in aircraft, there are cases where the blade shape design is unreasonable, affecting flight efficiency. Utility Model Content

[0004] The purpose of this utility model embodiment is to provide a blade, a propeller, and an aircraft, which optimizes the shape of the blade, improves the aerodynamic efficiency of the blade and propeller, and improves the flight efficiency of the aircraft.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A blade includes a blade root and a blade body connected together, the blade root having a root centerline, and the distance from the end of the blade away from the blade root to the root centerline is a first length.

[0007] At the first position of the blade, the angle of attack of the blade is 18.38°±2.5°;

[0008] At the second position of the blade, the angle of attack of the blade is 9.58°±2.5°;

[0009] At the third position of the blade, the angle of attack of the blade is 6.61°±2.5°;

[0010] The distance from the first position of the blade to the center line of the root is 20% to 25% of the first length; the distance from the second position of the blade to the center line of the root is 50% to 58% of the first length; and the distance from the third position of the blade to the center line of the root is 80% to 95% of the first length.

[0011] Optionally, at the first position of the blade, the chord length of the blade is 75.87 mm ± 10 mm;

[0012] At the second position of the blade, the chord length of the blade is 61.96 mm ± 10 mm;

[0013] At the third position of the blade, the chord length of the blade is 45.13 mm ± 10 mm.

[0014] Optionally, at the fourth position of the blade, the angle of attack of the blade is 12.60°±2.5°; and / or, at the fifth position of the blade, the angle of attack of the blade is 8.05°±2.5°.

[0015] The fourth position is between the first position and the second position, and the fifth position is between the second position and the third position.

[0016] Optionally, at the fourth position of the blade, the chord length of the blade is 69.88 mm ± 10 mm; and / or, at the fifth position of the blade, the chord length of the blade is 53.40 mm ± 10 mm.

[0017] Optionally, the distance from the fourth position of the blade to the center line of the root is 35% to 40% of the first length; the distance from the fifth position of the blade to the center line of the root is 65% to 75% of the first length.

[0018] Optionally, at a distance of 21% to 22% of the first length from the center line of the root of the blade, the chord length of the blade is 75.87 mm ± 2 mm, and the angle of attack of the blade is 18.38° ± 0.5°.

[0019] And / or, at a distance of 37% to 38% of the first length from the center line of the root of the blade, the chord length of the blade is 69.88 mm ± 2 mm, and the angle of attack of the blade is 12.60° ± 0.5°.

[0020] And / or, at a distance of 52% to 53% of the first length from the center line of the root of the blade, the chord length of the blade is 61.96 mm ± 2 mm, and the angle of attack of the blade is 9.58° ± 0.5°.

[0021] And / or, at a distance of 67% to 68% of the first length from the center line of the root of the blade, the chord length of the blade is 53.40 mm ± 2 mm, and the angle of attack of the blade is 8.05° ± 0.5°.

[0022] And / or, at a distance of 83% to 84% of the first length from the center line of the root of the blade, the chord length of the blade is 45.13 mm ± 2 mm, and the angle of attack of the blade is 6.61° ± 0.5°.

[0023] Optionally, at the first position of the blade, the distance from the first position of the blade to the center line of the root is D1, the chord length of the blade is L1, and the angle of attack of the blade is α1.

[0024] At the fourth position of the blade, the distance from the third position of the blade to the center line of the root is D2, the chord length of the blade is L2, and the angle of attack of the blade is α2.

[0025] At the second position of the blade, the distance from the third position of the blade to the center line of the root is D3, the chord length of the blade is L3, and the angle of attack of the blade is α3.

[0026] At the fifth position of the blade, the distance from the third position of the blade to the center line of the root is D4, the chord length of the blade is L4, and the angle of attack of the blade is α4.

[0027] At the third position of the blade, the distance from the third position of the blade to the center line of the root is D5, the chord length of the blade is L5, and the angle of attack of the blade is α5.

[0028] When D1=122.47mm, L1=75.87mm±2mm, and α1=18.38°±0.5°;

[0029] When D2 = 211.40 mm, L2 = 69.88 mm ± 2 mm, and α2 = 12.60° ± 0.5°;

[0030] When D3 = 296.88 mm, L3 = 61.96 mm ± 2 mm, and α3 = 9.58° ± 0.5°;

[0031] When D4 = 380.93 mm, L4 = 53.40 mm ± 2 mm, and α4 = 8.05° ± 0.5°;

[0032] When D5=466.89mm, L5=45.13mm±2mm, and α5=6.61°±0.5°.

[0033] A propeller includes a hub and at least two blades of the above-described configuration, wherein the root of each blade is connected to the hub.

[0034] Optionally, the length of the blade is between 22 inches and 24.5 inches; and / or, the diameter of the propeller is between 48 inches and 49 inches.

[0035] An aircraft includes a fuselage and a power unit mounted on the fuselage;

[0036] The power unit includes a drive unit and a propeller as described above. The drive unit is connected to the propeller and is used to drive the propeller to rotate.

[0037] The beneficial effects of this invention are as follows: The propeller blades of this invention, through the design of the angle of attack at multiple key locations on the main body of the propeller, reduce air resistance and improve aerodynamic efficiency. The propeller and aircraft of this invention, employing the aforementioned blades, achieve improved aerodynamic efficiency of the propeller and improved flight efficiency of the aircraft. Attached Figure Description

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0039] Figure 1 This is a schematic diagram of the arrangement of the two blades in the propeller according to an embodiment of the present utility model;

[0040] Figure 2 This is one of the structural schematic diagrams of the blade described in the embodiment of this utility model;

[0041] Figure 3 This is a second schematic diagram of the blade structure described in an embodiment of the present utility model;

[0042] Figure 4 This is a second schematic diagram of the blade structure described in an embodiment of the present utility model;

[0043] Figure 5 for Figure 4 AA section diagram;

[0044] Figure 6 for Figure 4 BB section diagram;

[0045] Figure 7 for Figure 4 CC section diagram in the image;

[0046] Figure 8 for Figure 4 DD cross-section diagram;

[0047] Figure 9 for Figure 4 EE section diagram;

[0048] Figure 10 This is a schematic diagram of the propeller in an embodiment of the present invention.

[0049] In the diagram: 10. Blade body; 11. Connecting part; 12. Main body; 13. Leading edge; 14. Trailing edge; 101. First position; 102. Fourth position; 103. Second position; 104. Fifth position; 105. Third position; 20. Blade root; 21. Root centerline; 22. Rotating shaft hole; 30. Blade tip; 40. Blade hub; 41. Hub centerline. Detailed Implementation

[0050] To make the technical problems solved by this utility model, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0051] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected" and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0053] In related technologies, propellers include at least two blades, and when the propeller rotates, multiple rotating blades form a disk plane. For plastic blades, when the blade length and propeller diameter are large, such as a blade length greater than 22 inches and a propeller diameter greater than 45 inches, it is difficult to control deformation during use if the blade shape adopts a conventional design. This makes it impossible to balance high structural strength and good blade aerodynamic efficiency, thus affecting flight efficiency.

[0054] The diameter of a propeller refers to the diameter of its disk plane. The propeller disk is a circular surface within the propeller plane, centered at the midpoint of the propeller and with the propeller radius as its radius; it is the plane formed by the rotating rotor blades during flight. The aerodynamic efficiency of a propeller blade refers to the ratio of the work done by the blade on the air per unit time to the power of the blade. It reflects the blade's energy utilization efficiency and is generally evaluated by the thrust achievable at a given shaft power.

[0055] To address the issue of poor aerodynamic efficiency of medium and large-sized propeller blades, especially those with a diameter greater than or equal to 48 inches, this invention provides a blade that optimizes the blade profile by controlling the blade shape parameters at several key locations of the blade body 10 main body 12. This reduces air resistance, resulting in better aerodynamic efficiency during use, improved blade strength, and reduced blade deformation.

[0056] This utility model also provides a propeller and an aircraft. By using the aforementioned propeller blades, the aerodynamic efficiency of the propeller can be improved, the flight efficiency of the aircraft can be increased, and it is more practical.

[0057] This aircraft can be, but is not limited to, an agricultural drone. The propeller, driven by an electric motor, generates wind to provide lift. Agricultural drones are unmanned aerial vehicles used to optimize agricultural operations, increase crop yields, and monitor crop growth. Agricultural drones often require the payload of agricultural materials; by using larger propellers, stronger flight power can be achieved, meeting the greater payload requirements of agricultural drones. Aircraft using the blades and propellers of this invention not only meet higher flight power requirements but also ensure the structural strength of the blades and propellers, improving flight safety. In other embodiments, this aircraft can also be a logistics drone, a photography / videography drone, etc.

[0058] The blades, propellers, and aircraft of this utility model will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementation methods can be combined with each other.

[0059] The terms "up" and "down" used in this embodiment refer to the propeller and the normal operating attitude of the aircraft after the propeller is installed, and should not be considered restrictive.

[0060] Please continue to refer to Figures 1 to 10 In an embodiment of the propeller of this utility model, the propeller includes a hub 40 and multiple blades. The figure illustrates a propeller with two blades.

[0061] In one embodiment, the propeller diameter (i.e., the diameter of the propeller disk plane) is 48 to 49 inches. The propeller diameter can be, but is not limited to, 48 inches, 48.5 inches, and 49 inches. One inch equals 25.4 millimeters.

[0062] In one embodiment, the blade length is 22 inches to 24.5 inches, and the blade length can be, but is not limited to, 22 inches, 22.5 inches, 23 inches, 23.5 inches, 24 inches, and 24.5 inches. For large-sized propellers with a diameter greater than 47 inches, the blade design of this application can improve the dynamic performance of the propeller body 10, thereby improving the aerodynamic efficiency and flight efficiency of the blade, propeller, and aircraft, achieving the effects of improving blade strength, improving blade deformation, improving flight efficiency, and improving flight safety.

[0063] This application enables the aircraft to have lower hovering power at the same takeoff weight by aerodynamic design and optimization of the propeller blades, and can reduce battery load to increase endurance and improve operational efficiency.

[0064] Please refer to Figures 1 to 3 The blade includes a blade root 20, a blade body 10, and a blade tip 30. The blade body 10 includes a connecting part 11 and a main body 12. Along the length direction, the blade root 20, the blade body 10 connecting part 11, the blade body 10 main body 12, and the blade tip 30 are connected in sequence. The blade root 20 is used to connect with the blade hub 40. The blade body 10 is the part that mainly provides propulsion or lift.

[0065] In this embodiment, the thickness of the blade root 20 is greater than the thickness of the main body 12 of the blade body 10 to ensure a reliable connection between the blade root 20 and the blade hub 40, and to ensure the structural strength of the blade root 20, so as to reliably transmit torque and realize blade rotation. Furthermore, the blade smoothly transitions between the blade root 20 and the main body 12 of the blade body 10 through the blade body 10 connecting part 11, and maintains a large thickness at the connection between the blade root 20 and the blade body 10. This effectively solves the problem of blade deformation at the root of the blade root 20 during production and use, and also solves the problem of high stress and easy breakage at the root of the blade root 20 under high speed and high vibration.

[0066] The inventors discovered that the aerodynamic efficiency of a propeller is related to the angle of attack and chord length of its blades. In a propeller, the shape and structure of the blades directly affect the direction and magnitude of the thrust generated during rotation. Therefore, please refer to... Figure 4 The larger blades are controlled along their length by adjusting the chord length and angle of attack at more than 10 key locations on the blade body to control the overall blade profile and achieve better aerodynamic efficiency.

[0067] The angle of attack, also known as the angle of attack, is the angle between the direction of the incoming wind and the chord line of the blade. The blade has two sides forming a suction surface and a pressure surface. The larger the angle of attack, the greater the twist and tilt angle of the blade at that position, making it easier to draw in air. The side edge where the suction and pressure surfaces connect is the leading edge 13, and the other side edge is the trailing edge 14. The leading edge 13 is the side facing the wind, and the arched part of the leading edge 13 facilitates air intake.

[0068] In this invention, the angle of attack design at three positions—first position 101, second position 103, and third position 105—of the propeller body 10 controls the propeller profile. The first position 101 is located at the center of the root of the propeller root 20, and the third position 105 is located at a certain distance from the tip of the propeller tip 30. These three positions correspond to the front, middle, and rear positions of the main body 12 of the propeller body 10, respectively. By controlling the angle of attack and chord length of the propeller body 10 in these front, middle, and rear regions, the efficiency of propeller profile control can be improved.

[0069] To facilitate the description of the parameter design at each position of the blade, the root centerline 21 of the blade root 20 will be used as a reference for explanation. Specifically, the blade root 20 has a root centerline 21. When the blade is installed to the blade hub 40, the root centerline 21 is the installation center. The distance from the end of the blade furthest from the blade root 20 to the root centerline 21 is the first length. Figure 3 D0 in the middle indicates the first length.

[0070] It should be noted that in this application, "±" means that when x is y±z, yz≤x≤y+z, and both y and z are positive numbers.

[0071] The distance from the first position 101 of the blade to the root centerline 21 is 20% to 25% of the first length.

[0072] The distance from the second position 103 of the blade to the root centerline 21 is 50% to 58% of the first length.

[0073] The distance from the third position 105 of the blade to the root centerline 21 is 80% to 95% of the first length.

[0074] At the first position 101 of the blade, the angle of attack of the blade is 18.38°±2.5°.

[0075] At the second position 103 of the blade, the angle of attack of the blade is 9.58°±2.5°.

[0076] At position 105 on the third position of the blade, the angle of attack of the blade is 6.61°±2.5°.

[0077] At the first position 101 of the blade, the chord length of the blade is 75.87mm ± 10mm.

[0078] At the second position 103 of the blade, the chord length of the blade is 61.96 mm ± 10 mm.

[0079] At position 105 on the third blade, the chord length of the blade is 45.13 mm ± 10 mm.

[0080] In one embodiment, the first position 101 of the blade is 21% to 22% of the first length from the root centerline 21. The second position 103 of the blade is 52.5% to 53.5% of the first length from the root centerline 21. The third position 105 of the blade is 83% to 84% of the first length from the root centerline 21.

[0081] In one embodiment, the distance from the first position 101 of the blade to the root centerline 21 is 21.85% of the first length. The distance from the second position 103 of the blade to the root centerline 21 is 52.98% of the first length. The distance from the third position 105 of the blade to the root centerline 21 is 83.32% of the first length.

[0082] In one embodiment, at the first position 101 of the blade, the chord length of the blade is 75.87 mm ± 5 mm. At the second position 103 of the blade, the chord length of the blade is 61.96 mm ± 5 mm. At the third position 105 of the blade, the chord length of the blade is 45.13 mm ± 5 mm.

[0083] In one embodiment, at the first position 101 of the blade, the angle of attack is 18.38°±1°. At the second position 103 of the blade, the angle of attack is 9.58°±1°. At the third position 105 of the blade, the angle of attack is 6.61°±1°.

[0084] Referring to the attached diagram and based on the previous description of the layout of the first position 101 to the third position 105, it can be understood that the first position 101 is a certain distance from the root centerline 21 of the propeller root 20, and the third position 105 is a certain distance from the end of the propeller tip 30. The first position 101, the second position 103, and the third position 105 correspond to the front, middle, and rear positions of the main body 12 of the propeller body 10, respectively. By controlling the angle of attack and chord length of the propeller body 10 in the front, middle, and rear regions, the efficiency of propeller shape control can be improved.

[0085] From the first position 101 towards the direction away from the center, the angle of attack of the blades gradually decreases, and the chord length of the blades gradually decreases. By coordinating the chord length and angle of attack at the first position 101, the second position 103, and the third position 105, air can be easily drawn in at the point of maximum angle of attack between the connecting part 11 and the main body 12, thereby improving aerodynamic efficiency.

[0086] The blade of this application is also designed with angle of attack and chord length at a fourth position 102 between the first position 101 and the second position 103, in order to control the propeller profile of the front half of the blade body 10.

[0087] The distance from the fourth position 102 of the blade to the root centerline 21 is 35% to 40% of the first length.

[0088] At position 102 of the fourth position on the blade, the angle of attack of the blade is 12.60°±2.5°.

[0089] At position 102 of the fourth position on the blade, the chord length of the blade is 69.88 mm ± 10 mm.

[0090] In one embodiment, the fourth position 102 of the blade is 37% to 38% of the first length from the root centerline 21.

[0091] In one embodiment, the distance from the fourth position 102 of the blade to the root centerline 21 is 37.72% of the first length.

[0092] In one embodiment, at the fourth position 102 of the blade, the chord length of the blade is 69.88 mm ± 5 mm.

[0093] In one embodiment, at the fourth position 102 of the blade, the angle of attack of the blade is 12.60°±1°.

[0094] By designing the angle of attack and chord length of the first position 101, the fourth position 102, and the second position 103, the front half of the main body 12 of the propeller 10 can be designed to easily take in wind and efficiently utilize wind power to achieve lift, thereby improving aerodynamic efficiency.

[0095] The blade of this application is also designed with angle of attack and chord length at the fifth position 104 between the second position 103 and the third position 105, in order to control the propeller profile of the rear half of the blade body 10.

[0096] The distance from the fifth position 104 of the blade to the root centerline 21 is 65% to 75% of the first length.

[0097] At position 104 on the fifth position of the blade, the angle of attack of the blade is 8.05°±2.5°.

[0098] At position 104 of the fifth position on the blade, the chord length of the blade is 53.40 mm ± 10 mm.

[0099] In one embodiment, the distance from the fifth position 104 of the blade to the root centerline 21 is 67.5% to 68.5% of the first length.

[0100] In one embodiment, the distance from the fifth position 104 of the blade to the root centerline 21 is 67.98% of the first length.

[0101] In one embodiment, at the fifth position 104 of the blade, the chord length of the blade is 53.40 mm ± 5 mm.

[0102] In one embodiment, the angle of attack of the propeller blade is 8.05°±1°.

[0103] By designing the angle of attack and chord length at the second position 103, the fifth position 104, and the third position 105, the rear half of the main body 12 of the propeller 10 can be designed to be relatively gentle, reducing wind resistance and improving aerodynamic efficiency.

[0104] Combination Figures 2 to 9 The blade profile is described by the parameters in Table 1-1. The position range in Table 1-1 refers to the ratio of the distance from the critical position of the blade to the root centerline 21 to the first length.

[0105] Table 1-1

[0106]

[0107] In one embodiment, the first position 101 of the blade is located at a distance of 21% to 22% of the first length from the center line 21 of the root of the blade. The chord length of the blade is L1 = 75.87 mm ± 2 mm, and the angle of attack of the blade is α1 = 18.38° ± 2.5°.

[0108] And / or, at a distance of 37% to 38% of the first length from the blade to the root centerline 21, the blade is at the fourth position 102, with a blade chord length of L2 = 69.88 mm ± 2 mm and a blade angle of attack of α2 = 12.60° ± 2.5°.

[0109] And / or, at a distance of 52% to 53% of the first length from the blade to the root centerline 21, the blade is at its second position 103, with a blade chord length of L3 = 61.96 mm ± 2 mm and a blade angle of attack of α3 = 9.58° ± 2.5°.

[0110] And / or, at a distance of 67% to 68% of the first length from the blade to the root centerline 21, the blade is at its fifth position 104, with a blade chord length of L4 = 53.40 mm ± 2 mm and a blade angle of attack of α4 = 8.05° ± 2.5°.

[0111] And / or, at a distance of 83% to 84% of the first length from the blade to the root centerline 21, the blade is at its third position 105, with a blade chord length of L5 = 45.13 mm ± 2 mm and a blade angle of attack of α5 = 6.61° ± 2.5°.

[0112] Combination Figures 4 to 9 The blade profile is described by the parameters in Table 2-1. The position range in Table 2-1 refers to the ratio of the distance from the critical position of the blade to the root centerline 21 to the first length. The specific position D in Table 2-1 refers to the specific distance of that section of the blade from the root centerline 21. Figure 4 D1, D2, D3, D4, and D5 in the diagram represent the distances from the first position 101, the fourth position 102, the second position 103, the fifth position 104, and the third position 105 to the center line 21 of the root.

[0113] Table 2-1

[0114]

[0115] In one embodiment, at section AA (i.e., the first position 101) at a distance of D1=122.47mm from the center line 21 at the root of the propeller blade, L1=75.87mm±2mm and α1=18.38°±0.5°.

[0116] At section BB (i.e., the fourth position 102), which is 211.40 mm away from the center line 21 at the root of the propeller blade, L2 = 69.88 mm ± 2 mm and α2 = 12.60° ± 0.5°.

[0117] At section CC (i.e., second position 103), which is 296.88 mm away from the center line 21 at the root of the propeller blade, L3 = 61.96 mm ± 2 mm and α3 = 9.58° ± 0.5°.

[0118] At section DD (i.e., the fifth position 104), which is 380.93 mm away from the center line 21 at the root of the propeller blade, L4 = 53.40 mm ± 2 mm and α4 = 8.05° ± 0.5°.

[0119] At section EE (i.e., the third position 105), which is 466.89 mm away from the center line 21 at the root of the propeller blade, L5 = 45.13 mm ± 2 mm and α5 = 6.61° ± 0.5°.

[0120] This application, through the design of the angle of attack and chord length of at least five sections of the propeller shaft from section AA to section EE, achieves a larger angle of attack near the root, facilitating wind intake. The angle of attack gradually decreases outwards along the length, which is beneficial for increasing lift. Furthermore, it can be seen that the propeller shaft body has a certain curvature variation in the front half region near the root centerline, while the trailing edge curvature of the propeller shaft body is gentler in the rear half region near the root centerline, and the leading edge of the entire propeller shaft body is relatively gentle. This helps reduce wind resistance and obtains greater lift and thrust in the forward part of the propeller shaft.

[0121] To verify the aerodynamic efficiency of the blade of this invention, the inventors conducted an aerodynamic efficiency experiment, and the experimental data are shown in the table below.

[0122]

[0123] As can be seen from the table above, the propeller of this invention can effectively increase lift compared to conventional propellers with a smaller angle of attack variation of 10°. Under the condition of achieving the same thrust, the required shaft power is reduced. In other words, it can achieve greater thrust with the same power, or reduce the power of the drive mechanism while meeting the same thrust requirements.

[0124] In one embodiment, D0 = 558 mm to 562 mm. It is understood that the blade length is generally greater than the D0 value; the propeller diameter is generally greater than or equal to the length of two blades.

[0125] In one embodiment, the top and bottom of the propeller root 20 are set as planes to facilitate installation and mating with the propeller hub 40. In this embodiment, a first root plane and a second root plane are formed on both sides of the propeller root 20 to provide a mating plane for the propeller root 20 and the propeller hub 40.

[0126] In one embodiment, the thickness of the connecting portion 11 of the propeller body 10 near the propeller root 20 is basically the same as or less than the thickness of the propeller root 20. Through the design of the angle of attack and chord length, the connecting portion 11 of the propeller body 10 allows for a smooth transition between the propeller root 20 and the main body 12 of the propeller body 10, making it less prone to breakage. Since both the upper and lower surfaces of the propeller root 20 are parallel to the reference horizontal plane, the propeller shape of the connecting portion 11 can be controlled by varying the angle of attack. This ensures a smooth connection between the upper surface of the propeller root 20 and the upper surface of the connecting portion 11, and a smooth connection between the lower surface of the propeller root 20 and the lower surface of the connecting portion 11, avoiding significant step differences between the propeller root 20 and the connecting portion 11. This reduces air resistance experienced by the connecting portion 11 during propeller rotation, prevents stress concentration, and improves the overall structural strength of the propeller blade. Furthermore, the angle of attack of the connecting portion 11 gradually changes along the length of the propeller blade, preventing sudden bulges or depressions in the middle section of the connecting portion 11 and avoiding localized stress concentration. The propeller blade of this invention is less prone to deformation and breakage, exhibiting high structural strength.

[0127] In one embodiment, to ensure the structural strength of the blade, the blade root 20, the connecting portion 11 of the blade body 10, and the main body 12 of the blade body 10 are made of the same material, and are integrally formed. The blade root 20 and the blade body 10 can be made of materials such as plastic, carbon fiber, glass, or metal. The blade root 20, blade body 10, and blade tip 30 can be integrally formed using injection molding to create the blade.

[0128] In one embodiment, the propeller root 20 is connected to the propeller hub 40 by fasteners or other connection methods. In other embodiments, the propeller blade and the propeller hub 40 may also be integrally formed.

[0129] In this embodiment, the blade root 20 is relatively thick, while the thickness of the main body 12 of the blade body 10 is less than that of the blade root 20. To ensure a smoother connection between the blade root 20 and the main body 12 of the blade body 10, to achieve more uniform stress distribution, and to avoid stress concentration, the thickness of the connecting portion 11 gradually decreases from the side closest to the blade root 20 to the side closest to the main body 12 of the blade body 10, thus achieving a smooth transition. Here, "gradually decreasing thickness" means that the maximum thickness value at each location of the connecting portion 11 gradually decreases. This ensures the structural strength of the blade root 20 while also meeting the angle of attack design requirements of the main body 12, which is thinner than the blade root 20, and simultaneously achieves a smooth and secure connection between the blade root 20 and the main body 12.

[0130] In one embodiment, the propeller includes two blades symmetrically mounted on a hub 40. The hub 40 has a hub centerline 41, and the rotation center of the blades is the hub centerline 41. The root centerlines 21 of the two blades are symmetrical with respect to the hub centerline 41. The rotation radius of the blades is the distance between the end of the blade furthest from the hub 40 and the hub center of the hub 40.

[0131] In other embodiments, the number of propeller blades may be three, four, or others. The figure illustrates that the propeller root 20 is provided with a rotating shaft hole 22. The propeller root 20 can be mounted on the propeller hub 40 by passing a mounting shaft through the rotating shaft hole 22. The centerline of the rotating shaft hole 22 is the root centerline 21.

[0132] In one embodiment of the aircraft of this utility model, the aircraft includes a fuselage and a power unit. The power unit includes a drive unit and a propeller as described in any of the foregoing embodiments, and the power unit is mounted on the fuselage. The power unit provides flight power to the fuselage.

[0133] The drive unit is connected to the propeller and is used to drive the propeller to rotate in order to provide flight power.

[0134] The drive device can be, but is not limited to, a motor. The motor shaft is connected to the propeller hub 40, and the motor shaft drives the propeller hub 40 to rotate, thereby realizing the rotation of the propeller.

[0135] In one embodiment, the aircraft also includes a load device for carrying agricultural materials or other loads, the load device being mounted on the fuselage.

[0136] The blades can be manufactured using any material available in the prior art, including but not limited to plastics, steel, aluminum alloys, and carbon fiber. During manufacturing, various existing processing techniques, such as molding, stamping, and forging, can also be employed.

[0137] In the description herein, it should be understood that the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationships shown in the accompanying drawings, and are used only for ease of description and simplification of operation. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are merely used for distinction in description and have no special meaning.

[0138] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0139] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0140] The technical principles of this utility model have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this utility model and should not be construed as limiting the scope of protection of this utility model in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this utility model without any inventive effort, and these embodiments will all fall within the scope of protection of this utility model.

Claims

1. A blade, characterized in that, It includes a connected blade root (20) and blade body (10), the blade root (20) has a root centerline (21), and the distance from the end of the blade away from the blade root (20) to the root centerline (21) is a first length; At the first position (101) of the blade, the angle of attack of the blade is 18.38°±2.5°; At the second position (103) of the blade, the angle of attack of the blade is 9.58°±2.5°; At the third position (105) of the blade, the angle of attack of the blade is 6.61°±2.5°; The distance from the first position (101) of the blade to the root centerline (21) is 20% to 25% of the first length; the distance from the second position (103) of the blade to the root centerline (21) is 50% to 58% of the first length; and the distance from the third position (105) of the blade to the root centerline (21) is 80% to 95% of the first length.

2. The blade according to claim 1, characterized in that, At the first position (101) of the blade, the chord length of the blade is 75.87 mm ± 10 mm; At the second position (103) of the blade, the chord length of the blade is 61.96 mm ± 10 mm; At the third position (105) of the blade, the chord length of the blade is 45.13 mm ± 10 mm.

3. The blade according to claim 1, characterized in that, At the fourth position (102) of the blade, the angle of attack of the blade is 12.60°±2.5°; and / or, at the fifth position (104) of the blade, the angle of attack of the blade is 8.05°±2.5°; The fourth position (102) is between the first position (101) and the second position (103), and the fifth position (104) is between the second position (103) and the third position (105).

4. The blade according to claim 3, characterized in that, At the fourth position (102) of the blade, the chord length of the blade is 69.88 mm ± 10 mm; and / or, at the fifth position (104) of the blade, the chord length of the blade is 53.40 mm ± 10 mm.

5. The blade according to claim 3 or 4, characterized in that, The distance from the fourth position (102) of the blade to the root centerline (21) is 35% to 40% of the first length; the distance from the fifth position (104) of the blade to the root centerline (21) is 65% to 75% of the first length.

6. The blade according to any one of claims 1 to 4, characterized in that, At a distance of 21% to 22% of the first length from the center line (21) of the root of the blade, the chord length of the blade is 75.87 mm ± 2 mm, and the angle of attack of the blade is 18.38° ± 0.5°. And / or, at a distance of 37% to 38% of the first length from the blade to the root centerline (21), the chord length of the blade is 69.88 mm ± 2 mm, and the angle of attack of the blade is 12.60° ± 0.5°. And / or, at a distance of 52% to 53% of the first length from the blade to the root centerline (21), the chord length of the blade is 61.96 mm ± 2 mm, and the angle of attack of the blade is 9.58° ± 0.5°. And / or, at a distance of 67% to 68% of the first length from the blade to the root centerline (21), the chord length of the blade is 53.40 mm ± 2 mm, and the angle of attack of the blade is 8.05° ± 0.5°. And / or, at a distance of 83% to 84% of the first length from the blade to the root centerline (21), the blade has a chord length of 45.13 mm ± 2 mm and an angle of attack of 6.61° ± 0.5°.

7. The blade according to claim 3 or 4, characterized in that, At the first position (101) of the blade, the distance from the first position (101) of the blade to the root centerline (21) is D1, the chord length of the blade is L1, and the angle of attack of the blade is α1. At the fourth position (102) of the blade, the distance from the third position (105) of the blade to the root centerline (21) is D2, the chord length of the blade is L2, and the angle of attack of the blade is α2. At the second position (103) of the blade, the distance from the third position (105) of the blade to the root centerline (21) is D3, the chord length of the blade is L3, and the angle of attack of the blade is α3. At the fifth position (104) of the blade, the distance from the third position (105) of the blade to the root centerline (21) is D4, the chord length of the blade is L4, and the angle of attack of the blade is α4. At the third position (105) of the blade, the distance from the third position (105) of the blade to the root centerline (21) is D5, the chord length of the blade is L5, and the angle of attack of the blade is α5. When D1 = 122.47 mm, L1 = 75.87 mm ± 2 mm, and α1 = 18.38° ± 0.5°; When D2 = 211.40 mm, L2 = 69.88 mm ± 2 mm, and α2 = 12.60° ± 0.5°; When D3 = 296.88 mm, L3 = 61.96 mm ± 2 mm, and α3 = 9.58° ± 0.5°; When D4 = 380.93 mm, L4 = 53.40 mm ± 2 mm, and α4 = 8.05° ± 0.5°; When D5 = 466.89 mm, L5 = 45.13 mm ± 2 mm, and α5 = 6.61° ± 0.5°.

8. A propeller, characterized in that, It includes a hub (40) and at least two blades as described in any one of claims 1-7, wherein the root (20) of each blade is connected to the hub (40).

9. The propeller according to claim 8, characterized in that, The blades are between 22 inches and 24.5 inches in length; and / or the propeller is between 48 inches and 49 inches in diameter.

10. An aircraft, characterized in that, Includes the fuselage and the power unit installed on the fuselage; The power unit includes a drive unit and a propeller as described in claim 8 or 9, wherein the drive unit is connected to the propeller and is used to drive the propeller to rotate.

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