An unmanned rotorcraft propeller 73 inch propeller blade

Abstract

This application relates to a 73-inch propeller blade for an unmanned rotary-wing aircraft, comprising a blade body with a stalk and a tip at both ends. Six airfoils are sequentially arranged in the middle section of the blade body between the stalk and the tip. The installation angles of the six airfoils satisfy 13°≥β1≥β2>β3>β4>β5>β6≥5°. The maximum thickness of the cross-section of each airfoil decreases sequentially from the stalk to the tip; the width of the cross-section of the airfoils also decreases sequentially from the stalk to the tip. This invention belongs to the field of propeller blade technology. The progressive installation angle design of each airfoil effectively suppresses tip vortices and reduces induced drag; the optimized chord length distribution of each airfoil improves the lift-to-drag ratio and enhances power efficiency.

Description

Technical Field

[0001] This application relates to the field of propeller blade technology, and in particular to a 73-inch propeller blade for an unmanned rotorcraft. Background Technology

[0002] The propeller is a crucial power component of vertical takeoff and landing (VTOL) aircraft, providing upward lift and forward thrust during flight. The propeller's power efficiency, i.e., the power consumed by the propeller to generate thrust per unit weight, significantly impacts the VTOL aircraft's endurance. Existing propellers generally employ a trapezoidal chord distribution along the radial direction and a linear negative torsion angle, resulting in low power efficiency. For example, Chinese patent CN117485621A discloses a propeller blade, a UAV propeller, and a UAV, including a blade body. The blade body is a swept blade, with a root at one end near the propeller blade's rotation center and a tip at the other. Multiple airfoils are sequentially arranged along the direction from the root to the tip on the blade body, and these airfoils have a torsion angle. However, the sixth airfoil has an angle of -8.58° relative to the blade's rotation plane, severely affecting the propeller's power efficiency.

[0003] Therefore, there is an urgent need for a 73-inch rotor blade for unmanned rotary-wing aircraft. Utility Model Content

[0004] Based on this, it is necessary to provide a 73-inch rotor blade for an unmanned rotary-wing aircraft, and its specific technical solution is as follows.

[0005] A 73-inch rotor blade for an unmanned rotary-wing aircraft includes a blade body with a stalk and a tip at both ends. Six airfoils are sequentially arranged in the middle section of the blade body between the stalk and the tip. The installation angles of the six airfoils satisfy 13°≥β1≥β2>β3>β4>β5>β6≥5°. The maximum thickness of the cross-section of each airfoil decreases sequentially from the stalk to the tip. The width of the cross-section of the multiple airfoils also decreases sequentially from the stalk to the tip.

[0006] Furthermore, the blade body is a swept blade, the leading edge and trailing edge of the middle section of the blade body are both oblique lines, the upper surface of each airfoil is an arc-shaped convex surface, and the lower surface of each airfoil is an oblique surface.

[0007] Furthermore, the blade handle is a flat plate structure, and the blade handle is provided with a hinge hole that runs through it from top to bottom. The center line of the hinge hole is parallel to the rotation center line of the blade body, and a torsional transition section is provided between the blade handle and the first airfoil.

[0008] Furthermore, the torsional transition section is a spiral plate structure connecting the blade stalk and the first airfoil, and the cross-sectional width of the torsional transition section gradually increases along the direction from the blade stalk to the first airfoil.

[0009] Furthermore, the turning radius of the blade body is R, and the distance r1 of the first airfoil from the center of rotation of the blade body is 25%R; the distance r2 of the second airfoil from the center of rotation of the blade body is 40%R; the distance r3 of the third airfoil from the center of rotation of the blade body is 55%R; the distance r4 of the fourth airfoil from the center of rotation of the blade body is 70%R; the distance r5 of the fifth airfoil from the center of rotation of the blade body is 85%R; and the distance r6 of the sixth airfoil from the center of rotation of the blade body is 95%R.

[0010] Furthermore, the radius of rotation R of the blade body is 927.1 mm.

[0011] Furthermore, the chord lengths L1 of the first airfoil, L2 of the second airfoil, L3 of the third airfoil, L4 of the fourth airfoil, L5 of the fifth airfoil, and L6 of the sixth airfoil are 104.5mm±4mm, 95mm±4mm, 84.7mm±4mm, 70mm±4mm, 54.8mm±4mm, and 41mm±4mm, respectively.

[0012] Furthermore, the chord lengths L1, L2, L3, L4, L5, and L6 of each of the aforementioned airfoils are 104.5 mm, 95 mm, 84.7 mm, 70 mm, 54.8 mm, and 41 mm, respectively.

[0013] Furthermore, the installation angle of the airfoil is the angle between the cross section of the airfoil and the plane of rotation relative to the blade; the installation angle β1 of the first airfoil is 11°±2°; the installation angle β2 of the second airfoil is 11°±2°; the installation angle β3 of the third airfoil is 10°±2°; the installation angle β4 of the fourth airfoil is 9.5°±2°; the installation angle β5 of the fifth airfoil is 7°±2°; and the installation angle β6 of the sixth airfoil is 5°±2°.

[0014] Furthermore, the installation angle β1 of the first airfoil is 11°; the installation angle β2 of the second airfoil is 11°; the installation angle β3 of the third airfoil is 10°; the installation angle β4 of the fourth airfoil is 9.5°; the installation angle β5 of the fifth airfoil is 7°; and the installation angle β6 of the sixth airfoil is 5°.

[0015] Compared with existing technologies, this utility model has the following beneficial effects:

[0016] The 73-inch propeller blades of this utility model have progressive installation angle designs for each airfoil, which effectively suppresses tip vortices and reduces induced drag; the optimized chord length distribution of each airfoil improves the lift-to-drag ratio and enhances force efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a top view of the structure of the 73-inch propeller blade of the unmanned rotorcraft of this utility model;

[0019] Figure 2 yes Figure 1 Enlarged sectional view of the structure along the AA direction;

[0020] Figure 3 yes Figure 1 Enlarged sectional view of the structure in the middle BB direction;

[0021] Figure 4 yes Figure 1 Enlarged sectional view of the structure in the CC direction;

[0022] Figure 5 yes Figure 1 Enlarged sectional view of the structure in the DD direction;

[0023] Figure 6 yes Figure 1 Enlarged sectional view of the structure in the EE direction;

[0024] Figure 7 yes Figure 1 Enlarged cross-sectional view of the structure in the FF direction.

[0025] Explanation of reference numerals in the attached diagram: 1. Petiole; 2. Leaf tip; 3. Airfoil; 4. Hinge hole; 5. Torsional transition section. Detailed Implementation

[0026] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0027] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and 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 application.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0032] The embodiments of this utility model will be described below based on its overall structure.

[0033] Reference Figures 1-7 As shown, this embodiment provides a 73-inch rotor blade for an unmanned rotary aircraft, including a blade body. The blade body has a stalk 1 and a tip 2 at both ends. The middle section of the blade body, located between the stalk 1 and the tip 2, has multiple airfoils 3. The installation angle of the multiple airfoils 3 gradually decreases, and the maximum thickness of the multiple airfoils 3 decreases sequentially from the stalk 1 to the tip 2. The width of the multiple airfoils 3 decreases sequentially from the stalk 1 to the tip 2.

[0034] Specifically, refer to Figures 1-7 The blade body is a swept blade, and the leading and trailing edges of the middle section of the blade body are both oblique lines. The upper surface of each airfoil 3 is an arc-shaped convex surface, and the lower surface of each airfoil 3 is an oblique surface.

[0035] Specifically, refer to Figure 1 The blade shank 1 is a flat plate structure. The blade shank 1 is provided with a hinge hole 4 that runs vertically through it. The center line of the hinge hole 4 is parallel to the rotation center line of the blade body. A torsional transition section 5 is provided between the blade shank 1 and the first airfoil 3.

[0036] Specifically, refer to Figure 1 The torsional transition section 5 is a spiral plate structure connecting the blade shank 1 and the first airfoil 3. The cross-sectional width of the spiral plate structure gradually increases along the direction from the blade shank 1 to the first airfoil 3. In this embodiment, the spiral plate structure transfers the stress peak from the 40%R region to the 25%R region, thereby extending the fatigue life of the entire blade.

[0037] Specifically, refer to Figures 1-7The middle section of the blade body, located between the blade stalk 1 and the blade tip 2, has six airfoils 3 arranged sequentially. The turning radius of the blade body is R. The distance r1 of the first airfoil 3 from the center of rotation of the blade body is 25%R; the distance r2 of the second airfoil 3 from the center of rotation of the blade body is 40%R; the distance r3 of the third airfoil 3 from the center of rotation of the blade body is 55%R; the distance r4 of the fourth airfoil 3 from the center of rotation of the blade body is 70%R; the distance r5 of the fifth airfoil 3 from the center of rotation of the blade body is 85%R; and the distance r6 of the sixth airfoil 3 from the center of rotation of the blade body is 95%R. Specifically, refer to... Figure 1 The blade body has a rotation radius of 36.5 inches, or a rotation radius R of 927.1 mm, and the rotation diameter of the entire blade body is 73 inches. The blade body is mounted on the turntable of the aircraft body via a hinge.

[0038] Specifically, refer to Figures 2-7 The first airfoil 3 has a chord length L1 of 104.5 mm ± 4 mm, and the ratio of the chord length L1 to the radius of rotation is 0.113 ± 0.05; the second airfoil 3 has a chord length L2 of 95 mm ± 4 mm, and the ratio of the chord length L2 to the radius of rotation is 0.102 ± 0.05; the third airfoil 3 has a chord length L3 of 84.7 mm ± 4 mm, and the ratio of the chord length L3 to the radius of rotation is 0.091 ± 0.0. 5; The chord length L4 of the fourth airfoil 3 is 70mm ± 4mm, and the ratio of the chord length L4 of the fourth airfoil 3 to the rotation radius is 0.075 ± 0.05; the chord length L5 of the fifth airfoil 3 is 54.8mm ± 4mm, and the ratio of the chord length L5 of the fifth airfoil 3 to the rotation radius is 0.059 ± 0.05; the chord length L6 of the sixth airfoil 3 is 41mm ± 4mm, and the ratio of the chord length L6 of the sixth airfoil 3 to the rotation radius is 0.044 ± 0.05. In this embodiment, the chord length of the cross-section of each airfoil 3 decreases progressively and non-linearly along the radial direction, which significantly improves the overall propeller efficiency and significantly reduces the power consumed to generate the same thrust.

[0039] Specifically, refer to Figures 2-7The first airfoil 3 has a chord length L1 of 104.5 mm; the second airfoil 3 has a chord length L2 of 95 mm; the third airfoil 3 has a chord length L3 of 84.7 mm; the fourth airfoil 3 has a chord length L4 of 70 mm; the fifth airfoil 3 has a chord length L5 of 54.8 mm; and the sixth airfoil 3 has a chord length L6 of 41 mm. In this embodiment, the chord lengths L1-L6 are reduced by a compound curve from 104.5 mm to 41 mm to match the Reynolds number change, resulting in a significant improvement in the lift-to-drag ratio. Furthermore, because the traditional trapezoidal chord length distribution leads to stress concentration at 40%R, the service life at this location is relatively short. In this embodiment, the chord length L2 of the second airfoil 3, located at 40%R from the rotation center, is 95 mm, a smaller reduction compared to the first airfoil 3's chord length L1 of 104.5 mm. This ensures that the second airfoil 3 at 40%R can withstand greater stress concentration, increasing its service life.

[0040] Specifically, refer to Figures 2-7 The installation angle of the airfoil 3 is the angle between the cross section of the airfoil 3 and the plane of rotation relative to the blade; the installation angle β1 of the first airfoil 3 is 11°±2°; the installation angle β2 of the second airfoil 3 is 11°±2°; the installation angle β3 of the third airfoil 3 is 10°±2°; the installation angle β4 of the fourth airfoil 3 is 9.5°±2°; the installation angle β5 of the fifth airfoil 3 is 7°±2°; and the installation angle β6 of the sixth airfoil 3 is 5°±2°.

[0041] Specifically, refer to Figures 2-7 The first airfoil 3 has an installation angle β1 of 11°; the second airfoil 3 has an installation angle β2 of 11°; the third airfoil 3 has an installation angle β3 of 10°; the fourth airfoil 3 has an installation angle β4 of 9.5°; the fifth airfoil 3 has an installation angle β5 of 7°; and the sixth airfoil 3 has an installation angle β6 of 5°. In this embodiment, the installation angles β1-β6 of each airfoil 3 gradually decrease non-linearly from 11° to 5°, and the installation angle of the blade tip 2 is less than 5°. Compared with the negative tilt angle setting of the prior art, this can effectively reduce induced drag.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The above embodiments only illustrate one or more implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A 73-inch rotor blade for an unmanned rotary-wing aircraft, comprising a blade body, characterized in that, The blade body has a stalk (1) and a tip (2) at both ends. The middle section of the blade body is provided with six airfoils (3) between the stalk (1) and the tip (2). The installation angle of the six airfoils (3) satisfies 13°≥β1≥β2>β3>β4>β5>β6≥5°. The maximum thickness of the cross section of each airfoil (3) decreases sequentially from the stalk (1) to the tip (2). The width of the cross section of the multiple airfoils (3) decreases sequentially from the stalk (1) to the tip (2).

2. The 73-inch propeller blade for an unmanned rotary-wing aircraft according to claim 1, characterized in that, The blade body is a swept blade, and the leading and trailing edges of the middle section of the blade body are both oblique lines. The upper surface of each airfoil (3) is an arc-shaped convex surface, and the lower surface of each airfoil (3) is an oblique surface.

3. The 73-inch propeller blade for an unmanned rotary-wing aircraft according to claim 1, characterized in that, The blade shank (1) is a flat plate structure. The blade shank (1) is provided with a hinge hole (4) that runs through the blade from top to bottom. The center line of the hinge hole (4) is parallel to the rotation center line of the blade body. A torsional transition section (5) is provided between the blade shank (1) and the first airfoil (3).

4. The 73-inch propeller blade for an unmanned rotary-wing aircraft according to claim 3, characterized in that, The torsional transition section (5) is a spiral plate structure connecting the blade stalk (1) and the first airfoil (3). The cross-sectional width of the torsional transition section (5) gradually increases along the direction from the blade stalk (1) to the first airfoil (3).

5. A 73-inch rotor blade for an unmanned rotary-wing aircraft according to any one of claims 1-4, characterized in that, The rotation radius of the blade body is R. The distance r1 between the first airfoil (3) and the rotation center of the blade body is 25%R; the distance r2 between the second airfoil (3) and the rotation center of the blade body is 40%R; the distance r3 between the third airfoil (3) and the rotation center of the blade body is 55%R; the distance r4 between the fourth airfoil (3) and the rotation center of the blade body is 70%R; the distance r5 between the fifth airfoil (3) and the rotation center of the blade body is 85%R; and the distance r6 between the sixth airfoil (3) and the rotation center of the blade body is 95%R.

6. The 73-inch propeller blade for an unmanned rotary-wing aircraft according to claim 5, characterized in that, The rotation radius R of the blade body is 927.1 mm.

7. The 73-inch propeller blade for an unmanned rotary-wing aircraft according to claim 5, characterized in that, The chord lengths L1 of the first airfoil (3), L2 of the second airfoil (3), L3 of the third airfoil (3), L4 of the fourth airfoil (3), L5 of the fifth airfoil (3), and L6 of the sixth airfoil (3) are 104.5mm±4mm, 95mm±4mm, 84.7mm±4mm, 70mm±4mm, 54.8mm±4mm, and 41mm±4mm, respectively.

8. The 73-inch propeller blade of an unmanned rotary-wing aircraft according to claim 7, characterized in that, The chord lengths L1, L2, L3, L4, L5, and L6 of each of the airfoils (3) are 104.5 mm, 95 mm, 84.7 mm, 70 mm, 54.8 mm, and 41 mm, respectively.

9. The 73-inch propeller blade of an unmanned rotary-wing aircraft according to claim 7, characterized in that, The installation angle of the airfoil (3) is the angle between the cross section of the airfoil (3) and the plane of rotation of the blade; The installation angle β1 of the first airfoil (3) is 11°±2°; The installation angle β2 of the second airfoil (3) is 11°±2°; The installation angle β3 of the third airfoil (3) is 10°±2°; The installation angle β4 of the fourth airfoil (3) is 9.5°±2°; The installation angle β5 of the fifth airfoil (3) is 7°±2°; The installation angle β6 of the sixth airfoil (3) is 5°±2°.

10. The 73-inch propeller blade of an unmanned rotary-wing aircraft according to claim 9, characterized in that, The installation angle β1 of the first airfoil (3) is 11°; The installation angle β2 of the second airfoil (3) is 11°; The installation angle β3 of the third airfoil (3) is 10°; The installation angle β4 of the fourth airfoil (3) is 9.5°; The installation angle β5 of the fifth airfoil (3) is 7°; The installation angle β6 of the sixth airfoil (3) is 5°.

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