Variable scissor angle mechanism for tail rotor test

Abstract

The invention discloses a variable scissor angle mechanism for a tail rotor test, which comprises a mounting table, a propeller hub fairing, a first propeller hub connected with the propeller hub fairing, a second propeller hub connected with the first propeller hub and a plurality of propeller clamps, and is characterized in that the propeller clamps comprise a first propeller clamp, a second propeller clamp, a third propeller clamp and a fourth propeller clamp; according to the invention, the first propeller hub is mounted on the angle adjusting holes in the different second propeller hubs through the screws II, so that the relative mounting angle of the first propeller hub can be changed, the purpose of changing the scissor angle is achieved, and the requirements of a scissor type tail rotor test on different scissor angle working conditions are met through the simple mode. Therefore, when related scissor angle analysis and research tests are carried out, more test mechanisms do not need to be machined, the efficiency of the scissor type tail rotor test is improved, the complexity of the test is reduced, and the test cost is saved. Meanwhile, due to the design of the two layers of propeller hubs, control over the axial distance between the upper propeller disc and the lower propeller disc of the scissor type tail rotor is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of tail rotors, and in particular to a variable scissor angle mechanism for tail rotor testing. Background Art

[0002] With the development of urban air mobility (UAM) and the low-altitude economy, noise pollution from traditional helicopters faces severe challenges. The tail rotor is the primary source of noise for single-rotor helicopters with a tail rotor, so reducing tail rotor aerodynamic noise is crucial for overall helicopter noise reduction. The scissor-type tail rotor, an unconventional helicopter tail rotor configuration, exhibits considerable noise reduction capabilities and has been implemented on several aircraft, making it a valuable research topic. However, its unique configuration makes its aerodynamic and noise characteristics more complex than those of traditional tail rotors, making research more challenging.

[0003] The rational design of the scissor angle and axis spacing is the core element of optimizing the performance of a scissor tail rotor. Its significance lies in the fact that precise design can further enhance the aerodynamic performance of the tail rotor and effectively reduce the noise generated by the tail rotor rotation, creating a quieter flight environment for pilots and ground personnel. It can also improve the helicopter's maneuverability and flight stability to a certain extent. Currently, aerodynamic testing of scissor tail rotors requires the fabrication of multiple sets of tail rotor hub test structures to meet the test requirements of different operating conditions.

[0004] Changes in the scissor angle and the axis spacing will have a certain impact on the performance of the scissor tail rotor. In order to make the scissor tail rotor have excellent aerodynamic performance and a low noise level, a reasonable design is required. However, when conducting scissor tail rotor tests with different parameter configurations, different hub structures need to be used accordingly. This will result in complex working condition tests requiring the processing of more test mechanisms, increasing the test cost. Replacing the test piece requires shutdown, disassembly, installation, and re-debugging, which extends the test cycle. At the same time, frequent replacement of test pieces will also cause wear and tear on equipment and components, shortening their service life. Multiple disassembly and assembly may change the initial state of the test equipment, requiring frequent calibration, increasing the risk of error, and affecting data quality. Therefore, a mechanism with a variable scissor angle for tail rotor testing is needed to solve the above problems. Summary of the Invention

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0006] The present invention is proposed in view of the above-mentioned problem of a variable scissor angle mechanism for tail rotor testing.

[0007] Therefore, the purpose of the present invention is to provide a mechanism with a variable scissor angle for tail rotor testing, which is used to solve the problems that "when conducting scissor-type tail rotor tests with different parameter configurations, different hub structures need to be used accordingly, which will result in complex working condition tests requiring the processing of more test mechanisms, increasing the test cost; and complex disassembly and assembly causing wear of equipment and parts."

[0008] To solve the above technical problems, the present invention provides the following technical solutions: A variable scissor angle mechanism for tail rotor testing, comprising: a mounting platform, a propeller hub fairing, a first propeller hub connected to the propeller hub fairing, a second propeller hub connected to the first propeller hub, and a plurality of propeller clamps; The propeller clamp is used to fix the propeller blade, and the propeller clamp includes a first propeller clamp, a second propeller clamp, a third propeller clamp and a fourth propeller clamp; The first propeller clamp and the second propeller clamp are fixed on the first propeller hub, and the third propeller clamp and the fourth propeller clamp are fixed on the second propeller hub.

[0009] As a preferred solution of the variable scissor angle mechanism for tail rotor testing described in the present invention, wherein: a plurality of conical countersunk holes are provided on the hub fairing, a plurality of threaded holes corresponding to the conical countersunk holes are provided on the first hub, the hub fairing and the first hub are fixed by screw one, and screw one passes through the conical countersunk hole and is threadedly connected to threaded hole one.

[0010] As a preferred solution of the variable scissor angle mechanism for tail rotor testing described in the present invention, the first hub and the second hub are fixed by screw 2, a plurality of circular countersunk holes are provided on the first hub, and the difference between adjacent circular countersunk holes is 60°, and thirty-six angle adjustment holes are provided on the second hub, and the difference between adjacent angle adjustment holes is 10°, and the screw 2 passes through the circular countersunk holes and is connected with the angle adjustment holes.

[0011] As a preferred solution of the variable scissor angle mechanism for tail rotor testing described in the present invention, wherein: a plurality of mounting holes are provided on the second hub, a plurality of through holes corresponding to the mounting holes are provided on the mounting platform, the second hub and the mounting platform are fixed to the mounting platform by bolts and nuts, and the bolts pass through the mounting holes and the through holes.

[0012] As a preferred solution of the variable scissor angle mechanism for tail rotor testing described in the present invention, wherein: multiple propeller clamps are provided with connecting holes for installing blades, and multiple propeller clamps are provided with multiple fixing holes.

[0013] As a preferred solution of the variable scissor angle mechanism for tail rotor testing described in the present invention, wherein: a plurality of threaded holes 2 are opened on the first propeller hub and the second propeller hub, and the plurality of propeller clamps are respectively fixed to the first propeller hub and the second propeller hub by screws 3, and the screws 3 pass through the fixing holes and are threadedly connected to the threaded holes 2.

[0014] As a preferred solution of the variable scissor angle mechanism for tail rotor testing described in the present invention, the first hub is installed on different angle adjustment holes by screw 2, which is used to change the relative installation angle of the first hub.

[0015] The beneficial effects of the present invention are as follows: by installing the first hub on the angle adjustment hole on the different second hubs through screw 2, the relative installation angle of the first hub can be changed to achieve the purpose of changing the scissor angle. This simple method can meet the requirements of the scissor tail rotor test for different scissor angle working conditions. Therefore, when conducting relevant scissor angle analysis and research tests, there is no need to process more test mechanisms, which helps to improve the efficiency of the scissor tail rotor test, reduce the complexity of the test, and save test costs. At the same time, the two-layer hub design of the present invention realizes the control of the axial spacing between the upper and lower rotor discs of the scissor tail rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them: Figure 1 The figure is a schematic diagram of the three-dimensional structure of a mechanism with a variable scissor angle for tail rotor testing according to the present invention.

[0017] Figure 2 It is a partial structural diagram of the first hub in the present invention.

[0018] Figure 3 It is a partial structural diagram of the second hub in the present invention.

[0019] Figure 4 It is a partial structural diagram of the second hub in the present invention.

[0020] Figure 5 It is a schematic diagram of the installation structure of the mechanism in the present invention.

[0021] Figure 6 Schematic diagram of adjusting the scissor angle in the present invention.

[0022] Description of the drawings: 100, propeller hub fairing; 100a, tapered countersunk hole; 200, first propeller hub; 200a, threaded hole 1; 200b, circular countersunk hole; 300, second propeller hub; 300a, angle adjustment hole; 300b, mounting hole; 400, mounting platform; 500, first propeller clamp; 600, second propeller clamp; 700, third propeller clamp; 800, fourth propeller clamp. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0026] Furthermore, the present invention is described in detail with reference to schematic diagrams. For ease of illustration, when describing the embodiments of the present invention, cross-sectional views illustrating device structures may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, the three-dimensional dimensions of length, width, and depth should be included.

[0027] Example 1 Reference Figures 1-4 , which is an embodiment of the present invention, provides a variable scissor angle mechanism for tail rotor testing. The mechanism controls the axis spacing between the upper and lower propeller discs through a double-layer propeller hub structure. The mechanism includes: a mounting platform 400, a propeller hub fairing 100, a first propeller hub 200 connected to the propeller hub fairing 100, a second propeller hub 300 connected to the first propeller hub 200, and a plurality of propeller clamps. It should be noted that the hub is a precision component that connects the blades to the main shaft in the helicopter rotor system. Its structure must withstand centrifugal force, aerodynamic loads, and dynamic alternating stress. It is the core load-bearing and movement hub of the rotor system, directly affecting flight safety and control stability. The paddle clamps are used to fix the paddle blades, and the paddle clamps include a first paddle clamp 500, a second paddle clamp 600, a third paddle clamp 700, and a fourth paddle clamp 800; The first propeller clamp 500 and the second propeller clamp 600 are fixed on the first propeller hub 200 , and the third propeller clamp 700 and the fourth propeller clamp 800 are fixed on the second propeller hub 300 .

[0028] When in use, the first propeller clamp 500 and the second propeller clamp 600 are installed on the first propeller hub 200, and the third propeller clamp 700 and the fourth propeller clamp 800 are installed on the second propeller hub 300, thereby forming a double-layer propeller hub structure. By replacing one layer of the propeller hub, the axis spacing between the upper and lower propeller discs of the scissor-type tail rotor can be controlled; It should be noted that the tail rotor is a propeller device located at the tail of a helicopter, usually perpendicular or approximately perpendicular to the main rotor plane. It generates lateral thrust to balance the counter-torque caused by the rotation of the main rotor, ensuring fuselage stability, while allowing the pilot to achieve directional control by adjusting the tail rotor thrust. The scissor tail rotor is a special tail rotor configuration that uses a cross-blade tail rotor system with a non-equidistant blade arrangement and non-zero axis spacing. It offsets air resistance vibrations by counter-rotating blades and is widely used on some high-speed helicopters. The axis spacing is the vertical distance between the upper and lower rotor disc planes measured along the axis of rotation of the tail rotor. The above are all existing mature technologies and will not be elaborated here.

[0029] Example 2 Reference Figures 1-6 , which is the second embodiment of the present invention. Different from the previous embodiment, the hub fairing 100 is provided with a plurality of tapered countersunk holes 100a, and the first hub 200 is provided with a plurality of threaded holes 200a corresponding to the tapered countersunk holes 100a. The hub fairing 100 and the first hub 200 are fixed by screws 1, and the screws 1 pass through the tapered countersunk holes 100a and are threadedly connected to the threaded holes 200a. Figure 2 The first hub 200 and the hub fairing 100 are fixedly installed by a pair of screws.

[0030] Among them, the first hub 200 and the second hub 300 are fixed by screw 2. A plurality of circular countersunk holes 200b are provided on the first hub 200, and the difference between adjacent circular countersunk holes is 60°. Thirty-six angle adjustment holes 300a are provided on the second hub 300, and the difference between adjacent angle adjustment holes 300a is 10°. The second screw passes through the circular countersunk hole 200b and is connected with the angle adjustment hole 300a. Figure 3 The first propeller hub 200 is mounted on different angle adjustment holes 300 a by screw 2, so as to change the relative installation angle of the first propeller hub 200 .

[0031] Among them, the second hub 300 is provided with a plurality of mounting holes 300b, and the mounting platform 400 is provided with a plurality of through holes corresponding to the mounting holes 300b. The second hub 300 and the mounting platform 400 are fixed by bolts and nuts, and the bolts pass through the mounting holes 300b and the through holes. Figure 4 The second hub 300 and the mounting platform 400 are fixedly installed by bolts and nuts.

[0032] Among them, multiple propeller clips are provided with connection holes for installing blades, multiple propeller clips are provided with multiple fixing holes, multiple threaded holes 2 are provided on the first propeller hub 200 and the second propeller hub 300, and multiple propeller clips are fixed to the first propeller hub 200 and the second propeller hub 300 respectively by screws 3, and the screws 3 pass through the fixing holes and are threadedly connected to the threaded holes 2. Figure 2 , multiple propeller clips are used to install the propeller blades.

[0033] When in use, the specific shape and installation method of each component refer to Figure 5 When conducting tests under different scissor angle conditions, refer to Figure 6 As shown in FIG. 1 , by mounting the first propeller hub 200 on the angle adjustment hole 300a of a different second propeller hub 300 using screw 2, the relative installation angle of the first propeller hub 200 can be changed, thereby changing the scissor angle. When adjusting the center-to-center distance, the center-to-center distance can be changed by simply replacing the first propeller hub 200.

[0034] It should be noted that the scissor angle is the angle between the two oppositely crossed blades in the helicopter's scissor-type tail rotor.

[0035] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A variable scissor angle mechanism for tail rotor testing, characterized in that: include: A mounting platform (400), a propeller hub fairing (100), a first propeller hub (200) connected to the propeller hub fairing (100), a second propeller hub (300) connected to the first propeller hub (200), and a plurality of propeller clamps; The paddle clamp is used to fix the paddle blade, and the paddle clamp includes a first paddle clamp (500), a second paddle clamp (600), a third paddle clamp (700) and a fourth paddle clamp (800); The first propeller clamp (500) and the second propeller clamp (600) are fixedly arranged on the first propeller hub (200), and the third propeller clamp (700) and the fourth propeller clamp (800) are fixedly arranged on the second propeller hub (300).

2. The variable scissor angle mechanism for tail rotor testing according to claim 1, characterized in that: The hub fairing (100) is provided with a plurality of conical countersunk holes (100a), and the first hub (200) is provided with a plurality of threaded holes (200a) corresponding to the conical countersunk holes (100a). The hub fairing (100) and the first hub (200) are fixed by screws, and the screws pass through the conical countersunk holes (100a) and are threadedly connected to the threaded holes (200a).

3. The variable scissor angle mechanism for tail rotor testing according to claim 1, characterized in that: The first propeller hub (200) and the second propeller hub (300) are fixed by screw No.

2. The first propeller hub (200) is provided with a plurality of circular countersunk holes (200b), and the difference between adjacent circular countersunk holes is 60°. The second propeller hub (300) is provided with thirty-six angle adjustment holes (300a), and the difference between adjacent angle adjustment holes (300a) is 10°. The screw No. 2 passes through the circular countersunk holes (200b) and is connected in cooperation with the angle adjustment holes (300a).

4. The variable scissor angle mechanism for tail rotor testing according to claim 1, characterized in that: The second propeller hub (300) is provided with a plurality of mounting holes (300b), and the mounting platform (400) is provided with a plurality of through holes corresponding to the mounting holes (300b). The second propeller hub (300) and the mounting platform (400) are fixed by bolts and nuts, and the bolts pass through the mounting holes (300b) and the through holes.

5. The variable scissor angle mechanism for tail rotor testing according to claim 1, characterized in that: The plurality of blade clamps are each provided with a connection hole for installing the blades, and the plurality of blade clamps are each provided with a plurality of fixing holes.

6. The variable scissor angle mechanism for tail rotor testing according to claim 1, characterized in that: The first propeller hub (200) and the second propeller hub (300) are provided with a plurality of threaded holes 2, and the plurality of propeller clamps are fixed to the first propeller hub (200) and the second propeller hub (300) respectively by screws 3, and the screws 3 pass through the fixing holes and are threadedly connected to the threaded holes 2.

7. The variable scissor angle mechanism for tail rotor testing according to claim 1, characterized in that: The first propeller hub (200) is mounted on different angle adjustment holes (300a) by means of screw 2, and is used to change the relative installation angle of the first propeller hub (200).

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