Blade, propeller, power module and aircraft

Abstract

Embodiments of the present application provide a blade, a propeller, a power module and an aircraft. The blade is applied to the aircraft, and comprises a leading edge; the leading edge comprises a protrusion structure protruding outwards; the protrusion structure is located at the end of the leading edge closer to the tip of the blade; and the amplitude of the protrusion structure is A. The magnitude of A satisfies the following relational expression: 0.035 R≤A≤0.15 R, wherein R represents the distance from the center of rotation of the blade to the tip, and the center of rotation represents the position where the axis of rotation of the blade is located when the blade is mounted on a driver of the aircraft. The shape of the blade of the embodiments of the present application is redesigned to incorporate a structure that is favorable for noise reduction, such that noise is reduced without reducing the size or decreasing the rotational speed. Therefore, compared with conventional noise reduction measures for blades, the aerodynamic efficiency of the blades would not be reduced.

Description

Blades, propellers, power modules and aircraft Technical Field

[0001] This application relates to the field of aircraft technology, and in particular to a blade, propeller, power module and aircraft. Background Technology

[0002] The aerodynamic noise caused by the rotation of aircraft propellers has gradually attracted attention in the industry. In order to reduce the noise caused by the rotation of propellers, common measures in related technologies include reducing the speed of propellers and reducing the size of propellers.

[0003] However, these improvements result in reduced power output from the blades, severely compromising their aerodynamic performance.

[0004] Therefore, there is an urgent need to redesign a propeller blade that meets the requirements for low noise without significantly sacrificing aerodynamic performance, in order to adapt to the low-noise use scenarios of aircraft. Summary of the Invention

[0005] In view of this, in order to solve the problem that existing blades reduce aerodynamic performance when noise is reduced, this application provides a blade, a propeller, a power module, and an aircraft to solve the above problems.

[0006] In a first aspect, embodiments of this application provide a propeller blade, which is applied to an aircraft, and the propeller blade includes:

[0007] Leading edge, the leading edge including an outwardly protruding protrusion structure located at one end of the leading edge relatively close to the tip of the blade, the amplitude of the protrusion structure being A;

[0008] Wherein, the size of A satisfies the following relationship: 0.035R≤A≤0.15R, where R represents the distance from the rotation center of the blade to the blade tip, and the rotation center represents the position of the rotation axis of the blade when the blade is installed on the drive of the aircraft.

[0009] The blade of this embodiment has an outwardly protruding structure at the end of the blade leading edge near the blade tip. By reasonably setting the degree of outward protrusion, aerodynamic noise can be significantly reduced while maintaining high aerodynamic efficiency.

[0010] Secondly, embodiments of this application provide a propeller blade, which is applied to an aircraft, and the propeller blade includes:

[0011] Leading edge, the leading edge including an outwardly projecting protrusion located at one end of the leading edge relatively close to the tip of the blade; and,

[0012] A trailing edge disposed opposite to the leading edge, the trailing edge including a specific portion corresponding to the protrusion structure, the specific portion being located at one end of the trailing edge relatively close to the tip of the blade;

[0013] The smoothness of the specific portion is greater than the smoothness of the protruding structure.

[0014] The blade of this embodiment has an outwardly protruding structure at the end of the blade leading edge near the blade tip, and the smoothness of a certain part of the trailing edge corresponding to the protruding structure is greater than the smoothness of the protruding structure. This can significantly reduce aerodynamic noise while maintaining high aerodynamic efficiency.

[0015] Thirdly, embodiments of this application provide a propeller, the propeller comprising:

[0016] A propeller mount; and a propeller blade as described in the first or second aspect above, the root of which is connected to the propeller mount.

[0017] Fourthly, embodiments of this application provide a power module, the power module comprising: the propeller described in the third aspect above; and a driver connected to the propeller, the driver being used to drive the propeller to rotate.

[0018] Fifthly, embodiments of this application provide an aircraft, the aircraft including: the power module described in the fourth aspect above.

[0019] The propeller, power module, and aircraft of the present application embodiments have at least the same advantages as the propeller blades, which will not be described in detail here.

[0020] The above description is merely an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it according to the contents of the specification, and to make the above and other objects, features and advantages of this application more apparent and understandable, the following are specific examples of this application. Detailed implementation method. Attached Figure Description

[0021] 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 shows an isometric schematic diagram of a blade with a protruding structure on the leading edge according to an embodiment of this application;

[0023] Figure 2 shows a top view of Figure 1 along the -Z direction in an embodiment of this application;

[0024] Figure 3 shows a schematic diagram of a blade with a straight protruding structure according to an embodiment of this application;

[0025] Figure 4 shows a schematic diagram of the radial structural division of the blades according to an embodiment of this application;

[0026] Figure 5 shows a schematic diagram of the shape and size definition of the blade in an embodiment of this application;

[0027] Figure 6 shows a schematic diagram of the position of a specific portion of the trailing edge of the blade in an embodiment of this application;

[0028] Figure 7 shows a schematic diagram of the shape of a specific portion of the trailing edge of a blade according to an embodiment of this application;

[0029] Figure 8 shows another shape schematic diagram of a specific portion of the trailing edge of the blade according to an embodiment of this application;

[0030] Figure 9 shows an isometric schematic diagram of a propeller according to an embodiment of this application;

[0031] Figure 10 shows a schematic diagram of the positions of two blades on another propeller according to an embodiment of this application;

[0032] Figure 11 shows a schematic diagram of the positions of the three blades on another propeller according to an embodiment of this application;

[0033] Figure 12 shows a simplified schematic diagram of a power module according to an embodiment of this application;

[0034] Figure 13 shows a simplified schematic diagram of an aircraft according to an embodiment of this application;

[0035] Figure 14 shows the projection of the blade along the thickness direction when the peak amplitude A is 0.73R and the peak radius r2 is different parameters in the embodiments of this application.

[0036] Figure 15 shows a comparison of noise reduction when the propeller blades of different configurations in Figure 14 of this application are used in the whole aircraft.

[0037] Figure 16 shows that the crest radius r2 of the embodiments of this application is 0.85R, and the crest amplitude A is the projection of the blade along the thickness direction when different parameters are used.

[0038] Figure 17 shows a comparison of noise reduction when the blades of different configurations in Figure 16 of this application are used in the whole aircraft.

[0039] Figure 18 shows the sound pressure level curves of the blade of the present application embodiment and the conventional blade of the comparative configuration;

[0040] Figure 19 shows the noise performance of the propeller blade of the present application embodiment and the conventional propeller blade of the comparative configuration on the aircraft as a whole;

[0041] Figure 20 shows the single-blade noise performance of the blades of the present application embodiment and the conventional blades of the comparative configuration;

[0042] Figure 21 shows the single-blade thrust performance of the blades of the present application embodiment and the conventional blades of the comparative configuration;

[0043] Figure 22 shows the single-blade torque performance of the blades of the present application embodiment and the conventional blades of the comparative configuration.

[0044] Explanation of reference numerals in the attached drawings: Blade - 10, Leading edge - 101, Trailing edge - 102, Protruding structure - 1011, Specific part - 1021, First leading edge part - 101a, First trailing edge part - 102a, First starting point - S1, First peak point - M1, First ending point - F1, First extension line - l1, First intersection point - G1, Second starting point - S2, Second peak point M2, Second ending point - F2, Second extension line - l2, Second intersection point - G2, Blade root - 10a, Blade body - 10b, Blade tip - 10c, First connecting segment - 1011a, Second connecting segment - 1011b, Third connecting segment - 1021a, Second connecting segment - 1021b, First position point - D1, Second position point - D2, Third position point - D3. Specific Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Additionally, terms such as "basically" or "approximately" in the specification indicate a degree, meaning that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect.

[0047] This application discloses a propeller blade 10 that can be used on an aircraft. This propeller blade 10 adds a structure that helps reduce noise by redesigning its shape, without reducing noise by reducing size or speed.

[0048] In this application, aircraft are classified according to whether or not a person is piloting them inside the cabin, including unmanned aircraft and manned aircraft; according to configuration, including rotorcraft (such as single-rotor or multi-rotor) and aircraft combining rotor and fixed wings; and according to purpose, including aerial photography aircraft, agricultural aircraft, surveying aircraft, logistics aircraft, etc.

[0049] Specifically, Figure 1 shows an isometric view of the blade 10 according to an embodiment of this application. To facilitate the description of the shape and structure of the blade 10, a relative coordinate system consisting of mutually perpendicular X-axis, Y-axis, and Z-axis is established for the blade 10 itself, as shown in the figure. The Z-axis is the thickness direction of the blade 10, which coincides with the rotation axis of the blade 10 when it is installed on the aircraft's actuator. The +Z direction points from the pressure surface to the suction surface. At this time, the rotation center O where the rotation axis is located is also the origin of the coordinate system. The X-axis is parallel to the chord of the blade 10, and the +X direction points from the leading edge 101 to the trailing edge 102. The Y-axis represents the radial direction of the blade 10, and the +Y direction points from the rotation center O of the blade 10 to the blade tip.

[0050] The blade tip refers to the farthest point of the blade from the center of rotation O. In some configurations, the blade tip can be a single end point; in others, it can be a single end face.

[0051] Where R represents the radius of blade 10, and represents the distance from the rotation center O of blade 10 to the blade tip. Further, this distance is the distance between the vertical projection point of the blade tip in the Y direction and the rotation center O.

[0052] In some embodiments, for example, the value of R ranges from 10 mm to 20 mm, for example, R is 13 mm.

[0053] It should be noted that the relative coordinate system is used to represent the relative positional relationship between the various parts of the propeller 10 itself, and does not represent the relative positional relationship between it and the aircraft on which it is installed.

[0054] Figure 2 is a top view of the blade 10 according to an embodiment of this application. The blade 10 in this embodiment includes a leading edge 101 located on one side of the blade 10's rotational direction. The leading edge 101 includes an outwardly protruding protrusion 1011. "Outwardly protruding" means protruding in a direction away from the solid structure of the blade 10. As shown in Figure 2, the protrusion 1011 protrudes towards the rotational direction of the blade 10 (as shown in the -X direction). Furthermore, referring to Figure 2, along the Y direction shown in the figure, the protrusion 1011 is closer to the blade tip and farther from the rotation center O of the blade 10.

[0055] From a gas dynamics perspective, the blade 10 of this embodiment effectively reduces the surface pressure pulsation intensity (also known as sound source intensity) and turbulence intensity. Furthermore, the protruding structure 1011 on one side of the leading edge 101 reduces the radial spatial correlation coefficient and spanwise coherence of the leading edge 101. Additionally, it enhances the interference effect between sound source phases, and this destructive interference effect reduces noise radiation efficiency. Therefore, the blade 10 with the protruding structure 1011 exhibits lower noise. Moreover, compared to conventional noise reduction methods, it does not cause a significant reduction in aerodynamic performance.

[0056] It should be noted that the shape of the protrusion structure 1011 and its distribution on the leading edge 101 have a significant impact on the noise reduction effect of the blade 10, affecting at least the degree of pressure pulse reduction and the degree of pressure pulse phase interference effect. Therefore, some key parameters of the protrusion structure 1011 will be introduced below.

[0057] In some embodiments, the outward protrusion height of the aforementioned protrusion structure 1011 is defined as the amplitude, with parameter A. The larger A is, the higher the protrusion height of the protrusion structure 1011, the more significant the reduction in sound source intensity when the blade 10 rotates, and the enhanced phase interference of the sound waves, resulting in better noise reduction. However, when A increases beyond a certain preset value, it will cause a significant loss in the aerodynamic performance of the blade 10.

[0058] In some implementations, the amplitude A satisfies the following condition: 0.035R ≤ A ≤ 0.15R. When A is within the above range, the blade 10 achieves low noise without significantly sacrificing aerodynamic performance. For example, A can take values ​​of 0.035R, 0.045R, 0.05R, 0.06R, 0.07R, 0.08R, 0.09R, 0.1R, or 0.15R, etc.

[0059] In some implementations, A can be preferably designed to be 0.073R.

[0060] In some embodiments, the ratio between the amplitude A and R corresponding to the protrusion structure 1011 may differ for blades of different sizes. For example, for blades with a larger R, the ratio of A to R of the corresponding protrusion structure 1011 is smaller compared to blades with a smaller R.

[0061] In another embodiment, as shown in FIG2, along the Y direction, the protruding structure 1011 is sequentially distributed with a first starting point S1, a first peak point M1, and a first ending point F1. The part of the leading edge 101 that begins to protrude outward is the first starting point S1 of the protruding structure 1011, the highest part of the protruding structure 1011 that protrudes outward is the first peak point M1, and the part of the protruding structure 1011 that continues to fall back to the leading edge 101 is the first ending point F1. The outer contour shape of the protruding structure 1011 can be continuously drawn between the first starting point S1, the first peak point M1, and the first ending point F1.

[0062] Optionally, based on the above description of the key points for forming the protruding structure 1011, the amplitude A can be further explained as follows: The portion of the leading edge 101 outside the protruding structure 1011 and close to the first starting point S1 is defined as the first leading edge portion 101a. The extension line in the leading edge 101 that originates from the first leading edge portion 101a and passes through the first starting point S1 is taken as the first extension line l1. The chord line passing through the first peak point M1 intersects the first extension line l1 to form the first intersection point G1. The distance between the first peak point M1 and the first intersection point G1 is the aforementioned amplitude A.

[0063] Optionally, in one embodiment, as shown in FIG3, the protruding structure 1011 does not necessarily present a peak shape. Its outward protruding part can also be an approximately straight structure formed by a straight line or a curve. Correspondingly, the amplitude A is the distance between the outermost point in the X direction of the straight structure and the intersection point formed by the chord line passing through that point and the first extension line.

[0064] Optionally, in one embodiment, as shown in FIG4, along the radial direction of the blade 10 (i.e., the Y direction in the figure), from the rotation center O to the blade tip, the blade 10 sequentially includes a root portion 10a, a blade body portion 10b, and a blade tip portion 10c. Referring to the illustration in FIG4, it should be noted that the root portion 10a may be spaced apart from the rotation center O, or it may extend to the location of the rotation center O. The blade body portion 10b is the larger area in the middle of the blade 10. The blade tip portion 10c and the root portion 10a are respectively fixedly connected to both sides of the blade body portion 10b, and are usually integrally formed. When the blade 10 is connected to the aircraft's actuator, the root portion 10a is close to the actuator's shaft, while the blade tip portion 10c is located farther from the actuator's shaft.

[0065] When a rotorcraft performs complex flight maneuvers, the aerodynamic state of the blades becomes more complex. For example, when a rotorcraft flies forward, the flow field may simultaneously exhibit transonic flow at the rotor tip and low-speed reverse flow at the blade root, accompanied by dynamic stall, blade vortex interference, and other complex aerodynamic phenomena.

[0066] Therefore, in one embodiment of this application, referring to the illustrations in Figures 2 and 4, in this blade 10, when the protrusion structure 1011 is located at the blade tip 10a, it is closer to the blade tip, which makes it easier to reduce the blade tip vortex intensity and has a better noise reduction effect.

[0067] Optionally, in one embodiment, as shown in FIG4, the aforementioned protrusion structure 1011 includes two parts along the radial direction of the blade 10, one part being a first connecting segment 1011a extending from the first starting point S1 to the first peak point M1, and the other part being a second connecting segment 1011b extending from the first peak point M1 to the first ending point F1.

[0068] Optionally, in one embodiment, as shown in FIG4, the first connecting segment 1011a is located to the left of the first peak point M1, which is the part of the protruding structure 1011 that is farther from the tip of the blade 10. The second connecting segment 1011b is located to the right of the first peak point M1, which is the part of the protruding structure 1011 that is closer to the tip of the blade 10.

[0069] Optionally, in one embodiment, as shown in FIG4, viewed from the rotation center O to the propeller tip, the leading edge 101 formed by the first connecting segment 1011a gradually moves away from the trailing edge 102, that is, the distance between the first connecting segment 1011a and the trailing edge 102 gradually increases, causing the first connecting segment 1011a to have an upward trend, while the leading edge 101 formed by the second connecting segment 1011b gradually moves closer to the trailing edge 102, that is, the distance between the second connecting segment 1011b and the trailing edge 102 gradually decreases, causing the second connecting segment 1011b to have a downward trend. Thus, the intersection of the first connecting segment 1011a and the second connecting segment 1011b forms the first peak point M1 of the protruding structure 1011.

[0070] It should be noted that the line segments of the first connecting segment 1011a and the second connecting segment 1011b can be straight lines or curves. For any connecting segment with a curved shape, it can be a smooth curve or a waveform curve with multiple undulating peaks and troughs. The first connecting segment 1011a and the second connecting segment 1011b together form an outwardly protruding protrusion structure 1011. The specific shape of the first connecting segment 1011a and the second connecting segment 1011b is not limited in this embodiment.

[0071] Optionally, in one embodiment, as shown in FIG5, the distance parameter between the first starting point S1 and the rotation center O is r1. Further, this distance is the distance between the intersection of the chord line passing through the first starting point S1 and the Y-axis and the rotation center O. A larger r1 indicates that the first starting point S1 is closer to the propeller tip.

[0072] In some implementations, r1 satisfies 0.65R ≤ r1 ≤ 0.8R. For example, r1 can take values ​​of 0.65R, 0.7R, 0.73R, 0.75R, 0.78R, or 0.8R, etc.

[0073] In some implementations, r1 can preferably be designed to be 0.75R.

[0074] Optionally, in one embodiment, as shown in FIG5, the distance parameter between the first peak point M1 and the rotation center O is r2. Further, this distance is the distance between the intersection of the chord line passing through the first peak point M1 and the Y-axis and the rotation center O.

[0075] In some implementations, r2 satisfies 0.75R ≤ r2 ≤ 0.95R. For example, r2 can take values ​​of 0.75R, 0.77R, 0.8R, 0.82R, 0.85R, 0.88R, 0.9R, or 0.95R, etc.

[0076] In some implementations, r2 can preferably be designed to be 0.85R.

[0077] Optionally, in one embodiment, as shown in FIG5, the distance parameter between the first starting point S1 and the first ending point F1 is d. Further, this distance is the radial width range of the protrusion structure 1011.

[0078] In some implementations, d satisfies 0.15R ≤ d ≤ 0.35R. For example, d can take values ​​of 0.15R, 0.2R, 0.25R, 0.3R, or 0.35R, etc.

[0079] In some implementations, preferably, d can be designed to be 0.25R.

[0080] Optionally, in one embodiment, as shown in FIG2, the blade 10 of this application embodiment further includes a trailing edge 102 disposed opposite to the leading edge 101. The trailing edge 102 includes a specific portion 1021 corresponding to the protrusion structure 1011, and the specific portion 1021 is located at one end of the trailing edge 102 that is relatively close to the tip of the blade 10. Further, the specific portion 1021 represents the portion of the trailing edge 102 between a first position point and a second position point, wherein the first position point represents the intersection of the chord line containing the first starting point S1 of the protrusion structure 1011 on the trailing edge 102, and the second position point represents the intersection of the chord line containing the first ending point F1 of the protrusion structure 1011 on the trailing edge 102.

[0081] In some embodiments, the smoothness of the specific portion 1021 is greater than the smoothness of the protrusion 1011. For example, the smoothness of the specific portion 1021 is considered to be greater than the smoothness of the protrusion 1011 when at least one of the following conditions is met: (1) the projected area of ​​the specific portion 1021 along the Z direction is smaller than the projected area of ​​the protrusion 1011; (2) the included angle of the opening of the specific portion 1021 is greater than the included angle of the protrusion 1011; (3) the depth of the recess of the specific portion 1021 is less than the height of the protrusion of the protrusion 1011.

[0082] Optionally, the specific portion 1021 described above may be a recessed structure that is concave from the trailing edge 102 toward the leading edge 101.

[0083] Alternatively, the specific portion 1021 mentioned above may also be a portion of the trailing edge 102 that transitions smoothly with other portions.

[0084] A specific portion 1021 of the trailing edge 102 of the blade 10 helps to reduce the flapping deformation amplitude of the blade 10, thereby stabilizing its aerodynamic performance.

[0085] Optionally, in one embodiment, as shown in FIG6, when a specific portion 1021 located at the trailing edge 102 is a recessed structure, it can, on the one hand, reduce weight and unload load, thereby reducing the flapping deformation amplitude of the blade 10; on the other hand, it can increase the chord length at the protruding structure 1011 while keeping the amplitude of the protruding structure 1011 unchanged. The depth of the inward recess of the above-mentioned recessed structure is defined as the amplitude, and its parameter is B. The magnitudes of B and A satisfy the following relationship: 0 < B < A. Thus, the recessed structure can be made more gentle than the protruding structure 1011.

[0086] Alternatively, in one embodiment, for the amplitude B, the larger B is, the lighter the blade 10 is, the smaller the force it experiences, and the smaller the flapping deformation. However, if B is too small, the chord length of the concave structure will decrease, the Reynolds number will decrease, and it will easily cause a loss of aerodynamic performance. Conversely, when B is larger, the Reynolds number will increase, which is more conducive to improving aerodynamic performance.

[0087] In some embodiments, the value of B in the present application embodiments satisfies the following relationship: 0 < B ≤ 0.03R, which can reduce flapping deformation while maintaining high aerodynamic performance. For example, B can take the value of 0.01R, 0.02R, or 0.03R.

[0088] In some implementations, B can preferably be designed as 0.026R.

[0089] Optionally, in one embodiment, as shown in FIG4, the recessed structure in this application embodiment can also be located at the leaf tip 10c, which is beneficial to reduce the weight of the leaf tip 10c and reduce the impact of the flapping deformation caused by the self-weight of the leaf tip 10c.

[0090] In another embodiment, as shown in FIG6, a second starting point S2, a second peak point M2, and a second ending point F2 are sequentially distributed along the Y direction. The part of the trailing edge 102 that just begins to indent inward is the second starting point S2 of the concave structure, the apex of the indentation of the concave structure is the second peak point M2, and the part where the concave structure continues to extend to the trailing edge 102 is the second ending point F2. The second starting point S2, the second peak point M2, and the second ending point F2 can continuously depict the outline shape of the concave structure.

[0091] Optionally, based on the above description of the key points for forming the concave structure, the amplitude B can be further explained as follows: The portion of the trailing edge 102 outside the concave structure and close to the second starting point S2 is defined as the first trailing edge portion 102a, and the extension line in the trailing edge 102 that originates from the first trailing edge portion 102a and passes through the second starting point S2 is defined as the second extension line l2. The chord line passing through the second peak point M2 intersects the second extension line l2 to form the second intersection point G2, and the distance between the second peak point M2 and the second intersection point G2 is the aforementioned amplitude B.

[0092] Optionally, in one embodiment, as shown in FIG7, the aforementioned recessed structure includes two parts along the radial direction of the blade 10, one part being a third connecting segment 1021a extending from the second starting point S2 to the second peak point M2, and the other part being a fourth connecting segment 1021b extending from the second peak point M2 to the second ending point F2.

[0093] Optionally, in one embodiment, as shown in FIG7, the third connecting segment 1021a is located to the left of the second peak point M2, which is the part of the recessed structure that is farther from the tip of the blade 10. The fourth connecting segment 1021b is located to the right of the second peak point M2, which is the part of the recessed structure that is closer to the tip of the blade 10.

[0094] Optionally, in one embodiment, as shown in FIG7, viewed from the rotation center O to the propeller tip, the trailing edge 102 formed by the third connecting segment 1021a gradually approaches the leading edge 101, that is, the distance between the third connecting segment 1021a and the leading edge 101 gradually decreases, causing the third connecting segment 1021a to show an upward trend, while the trailing edge 102 formed by the fourth connecting segment 1021b gradually moves away from the leading edge 101, that is, the distance between the fourth connecting segment 1021b and the leading edge 101 gradually increases, causing the fourth connecting segment 1021b to show a downward trend. Thus, the intersection of the third connecting segment 1021a and the fourth connecting segment 1021b forms the second peak point M2 of the concave structure.

[0095] It should be noted that the line segments of the third connecting segment 1021a and the fourth connecting segment 1021b can be straight lines or curves. For any connecting segment with a curved shape, it can be a smooth curve or a waveform curve with multiple undulating peaks and troughs. The third connecting segment 1021a and the fourth connecting segment 1021b can together form an inwardly concave structure. The specific shapes of the third connecting segment 1021a and the fourth connecting segment 1021b are not limited in the embodiments of this application.

[0096] Optionally, as shown in Figure 8, the portion of the trailing edge 102 corresponding to the protruding structure 1011 is continuously and gently arranged. Compared with the recessed structure, this blade has greater lift and better aerodynamic performance due to the larger area of ​​this part.

[0097] Optionally, as shown in FIG8 and in conjunction with the description of the foregoing embodiments, when a straight line or a curve with substantially the same slope is used to connect the second starting point S2 and the second ending point F2, a smooth portion corresponding to the protruding structure 1011 can be constructed.

[0098] Optionally, as shown in FIG8, in one embodiment, the blade 10 further has a first position point D1 and a second position point D2. The first position point represents the intersection of the chord line containing the first starting point S1 of the protruding structure 1011 on the trailing edge 102, and the second position point D2 represents the intersection of the chord line containing the first ending point F1 of the protruding structure 1011 on the trailing edge 102. The portion of the trailing edge 102 between the first position point D1 and the second position point D2 represents the portion corresponding to the protruding structure 1011. In this case, the first position point D1 and the second position point D2 can be connected by a straight line or an approximately straight line.

[0099] Optionally, as shown in FIG8, in one embodiment, the blade 10 further has a third position point D3, which represents the intersection of the chord line containing the first peak point M1 of the protrusion structure 1011 on the trailing edge 102. The extension line between the first position point D1 and the third position point D3 passes through the blade tip. Thus, this shape design of the blade 10 ensures that the portion of the trailing edge 102 corresponding to the protrusion structure 1011 is continuously and gently sloped.

[0100] Optionally, in one embodiment, the blade 10 is made of a lightweight material. For example, the blade 10 can be made of any of the following materials: plastic, fiber, alloy, or fiber composite. Especially in the field of unmanned aerial vehicles, there are strict requirements on the weight of the aircraft itself. Making the blade 10 of a lightweight material helps to reduce the weight of the aircraft itself and also reduces the manufacturing cost of the blade 10.

[0101] However, while reducing weight, lightweight blades inevitably suffer from a loss of structural strength compared to blades made of heavy materials such as metal. In particular, the side of blade 10 closest to the rotation center O is more susceptible to greater centrifugal force, requiring even higher structural strength. Therefore, this embodiment of the application further enhances the structural strength of blade 10 while reducing weight through its configuration design.

[0102] Optionally, as shown in FIG4, in one embodiment, the blade 10 sequentially includes a root portion 10a, a blade body portion 10b, and a tip portion 10c. The root portion 10a of the blade 10 also has one of the following shape characteristics: (1) viewed from the rotation center O to the blade tip, the root portion 10a has at least one region where the corresponding chord length gradually increases. This ensures ease of installation and enhances the connection strength of the blade by utilizing at least a portion of the gradually widening root portion 10a; (2) viewed from the rotation center O to the blade tip, the chord length of the entire root portion 10a gradually increases, ensuring ease of installation and enhancing the connection strength of the blade by utilizing the gradually widening root portion 10a. For example, the point where the chord length begins to increase is between 0.2R and 0.3R, for example, 0.246R.

[0103] Optionally, as shown in FIG4, in one embodiment, the blade body 10b of the blade 10 also has one of the following shape characteristics: (1) from the rotation center O to the blade tip, the blade body 10b has at least one region where the corresponding chord length gradually decreases, thereby reducing the weight of the blade and improving the smoothness of the airflow on the blade surface; (2) from the rotation center O to the blade tip, the corresponding chord length of the entire blade body 10b gradually decreases, thereby reducing the weight of the blade 10 and improving the smoothness of the airflow on the blade surface.

[0104] As shown in Figures 2 and 8, this application embodiment also provides a propeller blade 10 that can be used in an aircraft. Similar to the propeller blade 10 described in the previous embodiments, this propeller blade 10 also includes a leading edge 101 and a trailing edge 102, and the leading edge 101 includes a protrusion structure 1011. The difference lies in that the trailing edge 102 includes a specific portion 1021 corresponding to the protrusion structure 1011. This specific portion 1021 is located at one end of the trailing edge 102 that is relatively close to the tip of the propeller blade 10, and the smoothness of the specific portion 1021 is greater than the smoothness of the protrusion structure 1011.

[0105] In specific implementation, the specific part 1021 can be a recessed structure that is concave from the rear edge 102 toward the front edge 102, or it can be a part that transitions smoothly with other parts of the rear edge 102.

[0106] Obviously, as can be seen from the description of the foregoing embodiments, the blade 10 in this embodiment also improves the noise reduction effect without significantly sacrificing aerodynamic performance, thus achieving a balance between good aerodynamic performance and noise reduction effect.

[0107] As shown in Figures 9 to 11, this application embodiment also provides a propeller, which includes: a propeller base 11 and the propeller blades 10 disclosed in the foregoing embodiments. The propeller base 11, also known as a propeller hub, is used to connect the propeller blades 10 to a corresponding driver. The propeller base 11 can be fixedly connected to the rotation shaft of the driver, and the root of the propeller blades 10 can be fixed to the propeller base 11 to maintain relative stillness and thus move synchronously. The root of the propeller blades 10 can also be hinged to the propeller base 11 to achieve folding and storage of the propeller blades 10.

[0108] Optionally, when the number of blades 10 is two or more, each blade 10 is connected to a propeller base 11, and all blades 10 are evenly spaced around the center of the propeller base 11, which is the rotation center O. For example, in Figure 10, two blades 10 are arranged along the same straight line, with an included angle of 180°. In Figure 11, three blades 10 are evenly distributed around the center of the propeller base 11 at 120° intervals. In this case, more evenly distributed blades 10 can provide smooth and sufficient lift, resulting in better aerodynamic performance of the propeller. Furthermore, due to the lower noise of each blade 10, this propeller also has better low-noise performance.

[0109] As shown in Figure 12, this application also discloses a power module, which includes a propeller as described in the previous embodiment and a driver 12 for driving the propeller to rotate. The driver 12 in this power module can be an electric motor, a fuel engine, or a hydraulically driven device. The driver 12 can be mounted on the main body of the aircraft or on a support member (such as an arm or propeller blade protection device) extending from the main body of the aircraft. This power module using the aforementioned propeller also has lower noise, meeting the requirements for use in low-noise environments.

[0110] As shown in Figure 13, this application also discloses an aircraft, which includes the power module described in the foregoing embodiments.

[0111] It will be apparent to those skilled in the art that any type of aircraft can be used without restriction; for example, the aircraft can be small or large. The aircraft can be manned or unmanned. Specifically, the aircraft can include rotorcraft or fixed-wing-rotor hybrid aircraft, etc. Rotorcraft can be single-rotor, dual-rotor, multi-rotor, etc. The aircraft can include, but is not limited to, manned aircraft, logistics aircraft, aerial photography aircraft, agricultural plant protection aircraft, industry rescue aircraft, or performance aircraft. The above are merely illustrative examples, and the embodiments of this application do not specifically limit the type of aircraft. Aircraft include unmanned aerial vehicles (UAVs) and manned aircraft, etc. Aircraft can be used for one or more tasks such as aerial photography, aerial reconnaissance, geographic mapping, transportation, agricultural operations, performances, environmental monitoring, and security patrols.

[0112] Applying the power module of the aforementioned embodiments to aircraft can reduce the operating noise of the aircraft and expand the applicable scenarios of the aircraft.

[0113] As a specific application example, let's take the application of high-efficiency, low-noise propellers in multi-rotor aircraft as an example:

[0114] Most multi-rotor drones currently face the problem of aerodynamic noise exceeding standards. Propeller noise is the main source of drone noise, and as noise standards in some regions become increasingly stringent year by year, the requirements for drone propeller noise reduction design are gradually increasing. Currently, common noise reduction methods reduce noise by lowering the propeller tip speed through methods such as reducing rotational speed and size. This causes motor temperature rise and reduced propeller aerodynamic efficiency. To address the efficiency, rotational speed, and noise issues, traditional noise reduction methods reduce noise by lowering the propeller tip speed through methods such as reducing rotational speed and size. However, these methods sacrifice propeller aerodynamic efficiency and cause motor temperature rise. As the load on the motor, reducing the propeller rotational speed has certain negative effects: it increases motor torque, reduces motor efficiency, and increases motor temperature rise, ultimately leading to a significant decrease in the efficiency of the entire power system, affecting the drone's flight performance and safety.

[0115] Therefore, in order to simultaneously solve the problems of efficiency, speed and noise, the main noise reduction mechanism of the embodiments of this application is as follows: the blade effectively reduces the pressure pulsation intensity (also called sound source intensity) on the blade surface; due to the special protrusion of the wave crest (the protrusion structure 1011 shown in Figure 1) and the unusual structure (most conventional blades are flat), the blade reduces the radial correlation coefficient and coherence of the leading edge 101; the blade increases the interference between sound source phases, and the destructive interference effect reduces the noise radiation efficiency.

[0116] The embodiments of this application mainly relate to the design of noise-reducing blades. The protruding structure 1011 shown in Figure 1 can be regarded as a wave crest, and its structure specifically includes the wave crest position, wave crest height, wave initiation position, wave width, etc. In Figures 1 to 5, the blade coordinate system is defined as a right-handed system, the Y-axis is defined as the blade radial direction, from the blade root to the blade tip, the Z-axis is the blade thickness direction, from the blade pressure surface to the blade suction surface, the X-axis is the blade chord direction, and R is the blade radius.

[0117] As shown in Figure 5, the distance between the starting point S1 of the blade crest and the rotation center O is defined as the starting point radius r1; the distance between the peak point M1 and the rotation center O is defined as the crest radius r2; the crest height of the blade is defined as its crest amplitude A; and the distance between the starting point S1 and the ending point F1 of the blade crest is defined as the crest width d.

[0118] The above parameters have the following characteristics and meet the following requirements:

[0119] Wave initiation radius r1: Different wave initiation positions correspond to different wave crest shapes. Experimental verification revealed that a slightly later wave initiation position (i.e., closer to the propeller tip) results in a fuller wave shape and better noise reduction. In accordance with practical engineering needs, in this embodiment, r1 = 0.75, and the main range of r1 is 0.65R ≤ r1 ≤ 0.8R.

[0120] Wave crest radius r2: The position of the wave crest affects the radial distribution of the waveform, which has an impact on the aerodynamic and noise performance of the blade. Currently, the noise reduction effect is best at a wave crest position of 0.85R. The main range of r2 is 0.75R≤r2≤0.95R.

[0121] Peak amplitude A: Peak amplitude A affects the size of the peak. The larger the amplitude, the higher the peak, and the better the noise reduction effect (the sound source intensity is weakened and the phase interference is enhanced), but it will lose aerodynamic performance. In the embodiment of this application, A is taken as 0.073R, and the main range of A is 0.035R≤A≤0.15R.

[0122] Wave crest width d: is the difference between the wave start position and the wave end position. The wave crest width d affects the wave shape, and thus affects noise and aerodynamic performance. After the wave start position r1 is determined, the wave crest width is only affected by the end position. In the embodiment of this application, the wave end position can be the blade tip, so the wave crest width is 0.25R. The main range of d is 0.15R≤A≤0.35R.

[0123] Furthermore, it should be noted that the blade in this embodiment can also achieve noise reduction by using a downward-reverse design at its tip.

[0124] The propeller in this embodiment of the application achieves no loss of hovering endurance for the quadcopter drone, does not cause safety issues such as excessive motor temperature rise, and compared with conventional propellers with the same speed efficiency, it can achieve a single propeller noise reduction of 4dB and an overall noise reduction of 3.5dB, which can meet the noise index requirements of the relevant regional regulations.

[0125] This application embodiment also illustrates, with reference to Figures 14 to 22, the low noise and non-significantly reduced aerodynamic performance of the blade 10 with the protruding structure 1011 after optimization design. Figures 14 to 22 will be described in detail below:

[0126] In Figure 14, the different lines represent the different peak amplitudes A of the protruding structure 1011, all of which are 0.73R. The peak radius r2 represents the projection of the blade 10 along the thickness direction for different parameters. The horizontal axis represents the ratio of each part of the blade to the blade radius R, and the vertical axis represents the ratio of the chord length to the blade radius R. For example, line one represents a conventional blade with a contrasting configuration (without the protruding structure 1011), line two represents the blade configuration when the peak radius r2 of the protruding structure 1011 is 0.75R, line three represents the blade configuration when the peak radius r2 of the protruding structure 1011 is 0.85R, and line four represents the blade configuration when the peak radius r2 of the protruding structure 1011 is 0.95R.

[0127] Figure 15 compares the noise reduction of different blade configurations shown in Figure 14 when used in the overall aircraft. The horizontal axis represents the ratio of the wave crest radius r2 to the blade radius R, and the vertical axis represents the reduction in overall sound power, in dB. As can be seen from Figure 15, the reduction in overall sound power gradually increases as r2 increases from 0.75R to 0.85R. When r2 = 0.85R, the reduction in overall sound power reaches its maximum value, close to 3.5 dB. As r2 increases from 0.85R to 0.95R, the reduction in overall sound power gradually decreases. Therefore, when r2 = 0.85R and A = 0.73R for the protruding structure 1011, this blade configuration exhibits a significant low-noise effect.

[0128] In Figure 16, the different lines represent the different peak radii r2 of the protruding structure 1011, all of which are 0.85R. The peak amplitude A represents the projection of the blade 10 along the thickness direction for different parameters. The horizontal axis represents the ratio of each part of the blade to the blade radius R, and the vertical axis represents the ratio of the chord length to the blade radius R. For example, line one represents the conventional blade configuration (without the protruding structure 1011), line two represents the blade configuration when the peak amplitude A of the protruding structure 1011 is -0.073R, line three represents the blade configuration when the peak amplitude A of the protruding structure 1011 is 0.0365R, line four represents the blade configuration when the peak amplitude A of the protruding structure 1011 is 0.073R, and line five represents the blade configuration when the peak amplitude A of the protruding structure 1011 is 0.102R.

[0129] Figure 17 compares the noise reduction of different blade configurations shown in Figure 16 when used in the overall aircraft. The horizontal axis represents the ratio of the peak amplitude A to the blade radius R, with negative numbers indicating a concave peak. The vertical axis represents the reduction in overall acoustic power, in dB. As can be seen from Figure 17, the reduction in overall acoustic power gradually increases as the peak amplitude A increases from -0.1R to 0.12R. Therefore, a larger peak amplitude A in the protruding structure 1011 is more beneficial for noise reduction.

[0130] Figure 18 shows the sound pressure level (SPL) curves of conventional rotor blades (without the protrusion structure 1011) and rotor blades with the protrusion structure 1011 mounted on the aircraft at different frequencies. The aircraft weighs approximately 1220g. The horizontal axis represents the rotor blade rotation frequency, and the vertical axis represents the SPL. Line 1 shows the SPL curve of the conventional rotor blade, and line 2 shows the SPL curve of the rotor blade with the protrusion structure 1011. As can be seen from the figure, when the frequency exceeds 1000Hz, line 2 is significantly lower than line 1; therefore, the rotor blade with the protrusion structure 1011 has lower noise.

[0131] Figure 19 shows the noise performance of two different blade configurations on the aircraft as a whole. The horizontal axis represents the total weight in g, and the vertical axis represents the total sound power in dBA. The stars represent the total sound power of the conventional blade configuration (without the protrusion structure 1011), while the dots represent the total sound power of the blade with the protrusion structure 1011. As can be seen from the figure, at the same total weight, the total sound power of the blade with the protrusion structure 1011 is significantly lower than that of the conventional blade, demonstrating a significant reduction in noise.

[0132] Figure 20 shows the noise performance of a single propeller with two different blade configurations. The horizontal axis represents the frequency of blade rotation, and the vertical axis represents the sound pressure level. Line 1 is the sound pressure level curve for the conventional blade configuration, and line 2 is the sound pressure level curve for the blade with the raised structure 1011. As can be seen from the figure, when the frequency exceeds approximately 1000Hz, line 2 is significantly lower than line 1. Therefore, the blade with the raised structure 1011 has lower noise.

[0133] Figure 21 shows the single-blade thrust of two different blade configurations. The horizontal axis represents the blade rotation speed in rpm, and the vertical axis represents the single-blade thrust in g. Dots represent the single-blade thrust of the conventional blade configuration (without the protrusion structure 1011), while stars represent the single-blade thrust of the blade with the protrusion structure 1011. As can be seen from the figure, at the same rotational speed, the single-blade thrust of the blade with the protrusion structure 1011 is essentially the same as that of the conventional blade. Therefore, this blade with the protrusion structure 1011 basically maintains its original aerodynamic performance, and the aerodynamic performance is not significantly reduced.

[0134] Figure 22 shows the single-blade torque performance of two different blade configurations. The horizontal axis represents the blade rotation speed in rpm, and the vertical axis represents the single-blade torque in mNm. The dots represent the single-blade torque of the conventional blade configuration (without the protrusion structure 1011), while the stars represent the single-blade torque of the blade with the protrusion structure 1011. As can be seen from the figure, at the same rotational speed, the single-blade torque of the blade with the protrusion structure 1011 is essentially the same as that of the conventional blade. Therefore, this blade with the protrusion structure 1011 basically maintains its original aerodynamic performance, and the aerodynamic performance is not significantly reduced.

[0135] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0136] The terms "an embodiment," "embodiment," or "one or more embodiments" as used herein mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Furthermore, please note that the examples of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0137] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0138] In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A paddle, characterized in that, The propeller blades are used in an aircraft, and the propeller blades include: Leading edge, the leading edge including an outwardly protruding protrusion structure located at one end of the leading edge relatively close to the tip of the blade, the amplitude of the protrusion structure being A; Wherein, the size of A satisfies the following relationship: 0.035R≤A≤0.15R, where R represents the distance from the rotation center of the blade to the blade tip, and the rotation center represents the position of the rotation axis of the blade when the blade is installed on the drive of the aircraft.

2. The paddle of claim 1, wherein A = 0.073R.

3. The paddle of claim 1, wherein, A represents the distance between the first peak point and the first intersection point of the protruding structure. The first intersection point represents the intersection of the chord at the first peak point and the first extension line. The first extension line represents the extension line that starts from the first leading edge portion in the leading edge and passes through the first starting point of the protruding structure. The first leading edge portion represents the portion of the leading edge outside the protruding structure and close to the first starting point.

4. The paddle of claim 1, wherein, Along the radial direction of the blade, from the center of rotation to the tip, the blade sequentially includes a root, a body, and a tip, with the protruding structure located at the tip.

5. The paddle of claim 1, wherein, The protruding structure includes a first connecting segment and a second connecting segment along the radial direction of the blade. The first connecting segment corresponds to a portion of the protruding structure extending from a first starting point to a first peak point, and the second connecting segment corresponds to another portion of the protruding structure extending from the first peak point to a first ending point.

6. The paddle of claim 5, wherein, The first connecting section is relatively far from the propeller tip, and the second connecting section is relatively close to the propeller tip.

7. The paddle of claim 5, wherein, Viewed from the center of rotation to the tip of the propeller, the first connecting segment shows an upward trend, while the second connecting segment shows a downward trend.

8. The paddle of claim 7, wherein, The distance parameter between the first starting point and the rotation center is r1, and 0.65R≤r1≤0.8R.

9. The paddle of claim 8, wherein, r1＝0.75R。 10. The paddle of claim 7, wherein, The distance parameter between the first peak point and the rotation center is r2, and 0.75R≤r2≤0.95R.

11. The paddle of claim 10, wherein, r2＝0.85R。 12. The paddle of claim 7, wherein, The distance parameter between the first starting point and the first ending point is d, and 0.15R≤d≤0.35R.

13. The paddle of claim 12, wherein, d = 0.25R.

14. The paddle of claim 1, wherein, The blade also includes a trailing edge disposed opposite to the leading edge, the trailing edge including a specific portion corresponding to the protrusion structure, the specific portion being located at one end of the trailing edge relatively close to the blade tip, wherein the smoothness of the specific portion is greater than the smoothness of the protrusion structure.

15. The paddle of claim 1, wherein, The blade also includes a trailing edge disposed opposite to the leading edge, the trailing edge including a recessed structure, the amplitude of the recessed structure being B, and the magnitudes of A and B satisfying the following relationship: 0 < B < A.

16. The paddle of claim 15, wherein, The value of B satisfies the following relationship: 0 < B ≤ 0.03R.

17. The paddle of claim 16, wherein, B = 0.026R.

18. The paddle of claim 16, wherein, Along the radial direction of the blade, from the center of rotation to the tip, the blade sequentially includes a root portion, a body portion, and a tip portion, with the recessed structure located at the tip portion.

19. The paddle of claim 18, wherein, B represents the distance between the second peak point and the second intersection point of the recessed structure. The second intersection point represents the intersection of the chord at the second peak point and the second extension line. The second extension line represents the extension line that starts from the first rear edge portion in the rear edge and passes through the second starting point of the recessed structure. The first rear edge portion represents the portion of the rear edge outside the recessed structure and close to the second starting point.

20. The paddle of claim 15, wherein, The recessed structure includes a third connecting segment and a fourth connecting segment. Along the radial direction of the blade, the third connecting segment corresponds to a portion of the recessed structure extending from the second starting point to the second peak point, and the fourth connecting segment corresponds to another portion of the protruding structure extending from the second peak point to the second ending point.

21. The paddle of claim 20, wherein, The third connecting section is relatively far from the propeller tip, and the fourth connecting section is relatively close to the propeller tip.

22. The paddle of claim 21, wherein, Viewed radially from the center of rotation to the tip of the propeller, the third connecting section shows an upward trend, while the fourth connecting section shows a downward trend.

23. The paddle of claim 14, wherein, The portion of the trailing edge corresponding to the protruding structure is continuously and gently sloped.

24. The paddle of claim 23, wherein, The slope of the portion of the trailing edge corresponding to the protruding structure is approximately the same.

25. The paddle of claim 23, wherein, The portion of the trailing edge between the first position point and the second position point represents the portion corresponding to the protruding structure. The first position point represents the intersection of the chord line containing the first starting point of the protruding structure on the trailing edge, and the second position point represents the intersection of the chord line containing the first ending point of the protruding structure on the trailing edge.

26. The paddle of claim 25, wherein, The extension line between the first position point and the third position point passes through the blade tip, and the third position point represents the intersection of the chord line containing the first peak point of the protrusion structure on the trailing edge.

27. The paddle of claim 1, wherein, The blades are made of lightweight materials.

28. The paddle of claim 27, wherein, The blade is made of any of the following materials: plastic, fiber, alloy, or fiber composite.

29. The paddle of claim 27, wherein, Along the radial direction of the blade, from the center of rotation to the tip, the blade sequentially includes a root, a body, and a tip.

30. The paddle of claim 29, wherein, From the center of rotation to the blade tip, there is at least one region at the blade root where the corresponding chord length gradually increases.

31. The paddle of claim 30, wherein, From the center of rotation to the blade tip, the chord length at the blade root gradually increases.

32. The paddle of claim 31, wherein, From the center of rotation to the tip of the blade, there is at least one region in the blade body where the corresponding chord length gradually decreases.

33. The paddle of claim 32, wherein, From the center of rotation to the blade tip, the chord length of the blade gradually decreases.

34. A paddle, characterized by The propeller blades are used in an aircraft, and the propeller blades include: Leading edge, the leading edge including an outwardly projecting protrusion located at one end of the leading edge relatively close to the tip of the blade; and, A trailing edge disposed opposite to the leading edge, the trailing edge including a specific portion corresponding to the protrusion structure, the specific portion being located at one end of the trailing edge relatively close to the tip of the blade; The smoothness of the specific portion is greater than the smoothness of the protruding structure.

35. A propeller, characterized by The propeller includes: paddle mount; and, The blade according to any one of claims 1 to 34, wherein the root of the blade is connected to the blade seat.

36. The propeller of claim 35, wherein, The number of the blades is at least two, each of the blades is connected with the hub, and at least two of the blades are uniformly arranged around the center of the hub, which is the rotation center.

37. A power module, characterized by The power module comprises: The propeller of claim 35 or claim 36; and A driver connected with the propeller, the driver being used to drive the propeller to rotate.

38. An aircraft characterized by: The aircraft comprises the power module of claim 37.

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