A matching test method for variable pitch propeller and engine

Abstract

The present invention relates to the technical field of aero-engines, and discloses a matching test method for a variable-pitch propeller and an engine, comprising: an idle feathering function check, verification of the propeller's minimum constant speed, verification of the propeller's maximum constant speed, and a vibration check. By performing an idle feathering function check, it is verified whether the propeller's feathering function and forward propeller function are normal under the drive of the engine. Then, by measuring the propeller's actual minimum constant speed and determining whether it is less than or equal to a preset minimum speed, it is verified whether the propeller's minimum constant speed is qualified. Then, by measuring the propeller's actual maximum constant speed and determining whether it is equal to the propeller's rated speed, it is verified whether the propeller's maximum constant speed is qualified. Finally, by detecting the engine's vibration during slow acceleration and deceleration, it is verified whether the engine's vibration is qualified. This allows the matching between the propeller and the engine to be fully verified during ground testing, eliminating potential safety hazards.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation engines, and in particular to a matching test method for a variable-pitch propeller and an engine. Background Art

[0002] Variable-pitch propellers and engines are crucial components of an aircraft. Variable-pitch propellers vary the output torque by changing the pitch angle of each propeller blade, while the engine provides the power for the propeller's rotation. The variable-pitch propeller is switched between different operating modes using a selector lever, while the engine speed is adjusted using the engine throttle lever. The engine must be matched to the propeller to ensure flight safety. However, currently, variable-pitch propellers and engines are typically assembled directly onto aircraft and immediately put into operation or flight verification. Ground testing fails to fully verify the compatibility between the propeller and engine. Consequently, subsequent flight verification may be affected by insufficient understanding of the propeller-engine matching characteristics, potentially impacting flight safety and posing a significant safety hazard. Summary of the Invention

[0003] In view of this, the present invention provides a matching test method for a variable pitch propeller and an engine, so as to solve the problem that the matching between the propeller and the engine cannot be fully verified during ground testing.

[0004] The present invention provides a matching test method for a variable pitch propeller and an engine, wherein the variable pitch propeller is adjusted by a speed regulating device, and the speed regulating device includes a speed selector lever. The method comprises:

[0005] An idle feathering function check includes sequentially adjusting the propeller to a feathered state and a propeller aligning state, and continuously operating the propeller in the feathered state and the propeller aligning state for a first preset time. If the propeller can switch from the feathered state to the propeller aligning state and can rotate smoothly in the feathered state and the propeller aligning state, the idle feathering function is qualified.

[0006] Verifying the minimum constant speed of the propeller, including measuring the actual minimum constant speed of the propeller and determining whether the actual minimum constant speed is less than or equal to a preset minimum speed. If the actual minimum constant speed is less than or equal to the preset minimum speed, the minimum constant speed of the propeller is qualified.

[0007] Verifying the maximum constant speed of the propeller, including measuring an actual maximum constant speed of the propeller and determining whether the actual maximum constant speed is equal to the rated speed of the propeller; if the actual maximum constant speed is equal to the rated speed, the maximum constant speed of the propeller is qualified, and calibrating the position of the propeller selector lever as the maximum constant speed position;

[0008] The vibration check includes adjusting the propeller selector lever to the maximum constant speed position, gradually increasing the engine speed, and then gradually decreasing the engine speed, detecting the vibration of the engine, and determining whether the engine has abnormal vibration. If the engine does not have abnormal vibration, the propeller and the engine are qualified.

[0009] In an optional embodiment, the determining the actual minimum constant speed of the propeller specifically includes the following steps:

[0010] placing the speed selector lever in a first preset position to place the propeller in a feathering state;

[0011] Starting the engine, and after the engine reaches an idle speed, maintaining the engine speed constant and continuing to operate for a first preset time;

[0012] Slowly pushing the speed selector lever upward to a second preset position to adjust the propeller to a forward propeller state;

[0013] Pushing the engine throttle lever to adjust the engine speed, thereby adjusting the current speed of the propeller, until the current speed of the propeller remains unchanged;

[0014] The engine throttle lever is fixed, and the speed selector lever is slowly retracted until the current speed of the propeller decreases by a first preset speed difference, and then the speed selector lever is stopped from being retracted, and it is determined whether the current speed of the propeller continues to automatically decrease;

[0015] If the current speed of the propeller stops decreasing, recording the current speed of the propeller as the actual minimum constant speed, and calibrating the position of the speed selector lever as the minimum constant speed position;

[0016] If the current speed of the propeller continues to automatically decrease, the speed selector lever is pushed upward until the current speed of the propeller stops automatically decreasing, and the speed selector lever is slowly retracted until the current speed of the propeller decreases significantly, and then the speed selector lever is stopped and it is determined whether the current speed of the propeller continues to decrease.

[0017] retracting the engine throttle lever to allow the engine to reach an idle speed, and the engine maintains the idle speed for a second preset time;

[0018] The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to work for a third preset time, the engine is controlled to stop.

[0019] In an optional embodiment, the idle feathering function check specifically includes the following steps:

[0020] The engine feathering is started, and after the engine reaches an idle speed, the engine speed is maintained unchanged, and the propeller remains in the feathered state for a first preset time;

[0021] Adjusting the speed selector lever to a second preset position to adjust the propeller to a forward propeller state, wherein the propeller maintains the forward propeller state for a first preset time;

[0022] adjusting the speed selector lever to a first preset position to adjust the propeller to a feathered state, and the propeller remains in the feathered state for a first preset time;

[0023] Adjusting the speed selector lever to a second preset position to adjust the propeller to a forward propeller state, wherein the propeller maintains the forward propeller state for a first preset time;

[0024] The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to operate for a third preset time, the engine is controlled to stop.

[0025] In an optional embodiment, the speed regulating device further includes a limiter, the limiter is spaced apart from the speed selector lever, and the determining the actual maximum constant speed of the propeller specifically includes the following steps:

[0026] feathering the engine, and after the engine reaches an idle speed, maintaining the engine speed constant and continuing to operate for a first preset time;

[0027] Adjusting the speed selector lever until the speed selector lever abuts against the limiting member;

[0028] Slowly pushing the engine throttle lever until the speed of the propeller remains constant, and continuing to operate for a third preset time, recording the current speed of the propeller as the actual maximum constant speed, and recording the current power of the engine as the minimum constant speed power;

[0029] Slowly pulling down the engine throttle lever to make the engine reach an idle speed, and the engine maintains the idle speed for a second preset time;

[0030] The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to work for a third preset time, the engine is controlled to stop.

[0031] In an optional embodiment, after determining whether the actual maximum constant speed is equal to the rated speed of the propeller, the following steps are specifically included:

[0032] When the actual maximum constant speed is equal to the rated speed of the propeller, the maximum constant speed of the propeller is qualified;

[0033] When the actual maximum constant speed is greater than or less than the rated speed, after the engine is stopped, the position of the limiter is adjusted, and the process returns to the step of measuring the actual maximum constant speed of the propeller.

[0034] In an optional embodiment, the engine is provided with a vibration detection device for detecting the vibration of the engine in real time, and adjusting the propeller speed selector lever to the maximum constant speed position, gradually increasing the engine speed, and then gradually decreasing the engine speed specifically comprises the following steps:

[0035] feathering the engine, and after the engine reaches an idle speed, maintaining the engine speed constant and continuing to operate for a first preset time;

[0036] adjusting the speed selector lever until the speed selector lever contacts the limiter, fixing the speed selector lever, and causing the propeller to continuously operate for a third preset time;

[0037] Pushing the engine throttle lever to gradually increase the engine speed to a maximum state of the engine, and the engine maintains the maximum state and continues to operate for a first preset time;

[0038] retracting the engine throttle lever, gradually reducing the engine speed until the engine reaches an idle speed, and the engine maintains the idle speed for a second preset time;

[0039] The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to work for a third preset time, the engine is controlled to stop.

[0040] In an optional embodiment, gradually increasing the engine speed is specifically: increasing the engine speed by a second preset speed difference; gradually reducing the engine speed is specifically: gradually reducing the engine speed by a second preset speed difference.

[0041] In an optional embodiment, the propeller further has a reverse propeller state, and the speed control device further includes a reverse propeller joystick, which is suitable for adjusting the propeller to switch between the reverse propeller state and the feathering state. After verifying the maximum constant speed of the propeller, a reverse propeller function check is further included, which specifically includes the following steps:

[0042] The engine feathering is started, and after the engine reaches an idle speed, the engine speed is maintained unchanged, and the propeller remains in the feathered state for a first preset time;

[0043] adjusting the speed selector lever until the speed selector lever contacts the limiter, fixing the speed selector lever, and causing the propeller to continuously operate for a third preset time;

[0044] Pushing up the reverse propeller joystick to determine whether the propeller has entered the reverse propeller state;

[0045] When the propeller enters the reverse propeller state, continue to push up the reverse propeller joystick until the reverse propeller speed of the propeller no longer increases, and then stop pushing up the reverse propeller joystick;

[0046] pushing the engine throttle lever until the rotation speed of the propeller reaches a maximum reverse propeller rotation speed, fixing the engine throttle lever, and continuing to operate for a fourth preset time;

[0047] retracting the engine throttle lever to allow the engine to reach an idle speed, and then pulling down the reverse propeller lever to an initial position to determine whether the propeller has exited the reverse propeller state;

[0048] When the propeller exits the reverse propeller state, the reverse propeller function is qualified, and the propeller maintains the forward propeller state and continues to work for a second preset time;

[0049] The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state, and after the propeller continues to work for a third preset time, the engine is controlled to stop.

[0050] In an optional embodiment, after determining whether the propeller enters the reverse state, the method further includes: when the propeller does not enter the reverse state, pulling the reverse joystick back to the initial position and stopping the machine for inspection; and / or, after determining whether the propeller exits the reverse state, the method further includes: when the propeller does not exit the reverse state, stopping the machine for inspection.

[0051] In an optional embodiment, a first detection device is provided on the engine near the propeller, and the first detection device is used to detect the rotational speed of the propeller; and / or a second detection device is provided on the engine, and the second detection device is used to detect the rotational speed of the engine.

[0052] Beneficial effects:

[0053] By performing an idle feathering function check, it is verified whether the feathering and propeller functions of the propeller are normal under the drive of the engine. Then, by measuring the actual minimum constant speed of the propeller and judging whether it is less than or equal to the preset minimum speed, it is verified whether the minimum constant speed of the propeller is qualified. Then, by measuring the actual maximum constant speed of the propeller and judging whether it is equal to the rated speed of the propeller, it is verified whether the maximum constant speed of the propeller is qualified. Finally, by detecting the vibration of the engine during slow acceleration and slow deceleration and judging whether the engine vibration is normal, it is verified whether the engine vibration is qualified. When the idle feathering function check is passed, the minimum constant speed of the propeller is passed, the maximum constant speed of the propeller is passed, and the vibration check is passed, it means that the propeller and engine are matched well. The matching between the propeller and the engine is fully verified during the ground test, avoiding flight safety problems caused by insufficient understanding of the matching characteristics of the propeller and the engine during subsequent flight verification, and eliminating safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 This is a flow chart of a matching test method for a variable pitch propeller and an engine according to an embodiment of the present invention;

[0056] Figure 2 Schematic diagram of the structure of the experimental test system according to an embodiment of the present invention.

[0057] Description of reference numerals:

[0058] 1. Engine; 2. Propeller; 3. Test bench mounting device; 4. First detection device; 5. Vibration detection device; 6. Second detection device. DETAILED DESCRIPTION

[0059] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0060] The following combination Figures 1 to 2 , describing embodiments of the present invention.

[0061] According to an embodiment of the present invention, a matching test method for a variable pitch propeller and an engine is provided, using Figure 2 The test system shown is used for testing. The test system includes: an engine 1, a propeller 2 and a test bench mounting device 3. The engine 1 is fixedly mounted on the test bench mounting device 3, the propeller 2 is connected to the engine 1, and the engine 1 drives the propeller 2 to rotate.

[0062] Among them, propeller 2 is a variable pitch propeller, which includes at least the working states of feathering state and forward propeller state. The torque-variable propeller changes the output torque by changing the inclination angle of each propeller blade, thereby realizing switching between different working states, and then realizing the speed adjustment of propeller 2 in cooperation with engine 1; engine 1 is a turboprop engine, which can improve the power and torque of the engine, matches the variable pitch propeller, and is often used as an aircraft engine.

[0063] It should be noted that the variable-pitch propeller is regulated by a speed control device, which includes a selector lever and a stopper. The stopper is spaced apart from the selector lever. By pushing or retracting the selector lever, propeller 2 can be adjusted between feathering and forward propeller positions. The stopper is used to limit the maximum upward position of the selector lever, thereby further cooperating with engine 1 to limit the maximum constant speed that propeller 2 can achieve. The speed of engine 1 is regulated by the engine throttle lever.

[0064] like Figure 1 As shown in FIG, the matching test method of the variable pitch propeller and the engine includes the following steps:

[0065] Step S100: Checking the feathering function at slow speed, including adjusting the propeller 2 to the feathering state and the propeller state in sequence, and continuously operating the propeller 2 in the feathering state and the propeller state for a first preset time respectively. If the propeller 2 can be switched from the feathering state to the propeller state and can rotate smoothly in the feathering state and the propeller state respectively, the feathering function at slow speed is qualified.

[0066] The idle feathering function check checks propeller 2's feathering and spur gear positions while engine 1 is at idle. This checks propeller 2's ability to rotate normally at engine 1's idle speed, thereby verifying the matching performance between engine 1 and propeller 2 at idle. Idle speed refers to the lowest speed at which engine 1 can operate stably, and the specific speed varies depending on the engine model. The pass criterion for the idle feathering function check is that the propeller's spur gear and feathering functions are normal. If the test fails, the aircraft will be shut down for inspection and repair.

[0067] Step S200: Verify the minimum constant speed of the propeller, including measuring the actual minimum constant speed of propeller 2 and judging whether the actual minimum constant speed is less than or equal to the preset minimum speed. If the actual minimum constant speed is less than or equal to the preset minimum speed, the minimum constant speed of the propeller is qualified.

[0068] It should be noted that the purpose of verifying the minimum constant speed of the propeller is to verify whether the minimum constant speed of propeller 2 meets the design requirements. If the minimum constant speed of propeller 2 meets the design requirements, the test passes. The minimum constant speed is the minimum speed at which propeller 2 can rotate smoothly. When the speed of propeller 2 is less than the minimum constant speed, propeller 2 cannot rotate smoothly. The lower the minimum constant speed, the larger the operating range between the minimum and maximum speeds of propeller 2 and the better the operating performance of propeller 2. The preset minimum speed is the minimum constant speed that propeller 2 must achieve during the design process of propeller 2. Meeting the design requirements means that the measured actual minimum constant speed is less than or equal to the preset minimum speed. If the actual minimum constant speed is less than or equal to the preset minimum speed, it means that propeller 2 can meet the pre-designed operating range when driven by engine 1. When the propeller operates at the minimum constant speed, the matching performance between engine 1 and propeller 2 is good, and the test passes. If the actual minimum constant speed is greater than the preset minimum speed, it means that propeller 2 cannot reach the preset minimum constant speed, the test fails, and the engine needs to be shut down for inspection and adjustment.

[0069] Before determining whether the actual minimum constant speed is less than or equal to the preset minimum speed, the step of comparing the actual minimum constant speed with the preset minimum speed is included. The test system also includes a control device configured to compare and determine the relationship between the actual minimum constant speed and the preset minimum speed.

[0070] Step S300: Verify the maximum constant speed of the propeller, including measuring the actual maximum constant speed of the propeller and judging whether the actual maximum constant speed is equal to the rated speed of propeller 2. If the actual maximum constant speed is equal to the rated speed, the maximum constant speed of the propeller is qualified, and the position of the speed selector lever of propeller 2 is calibrated as the maximum constant speed position.

[0071] It should be noted that the purpose of verifying the maximum constant speed of the propeller is to verify whether the maximum constant speed of the propeller 2 meets the design requirements. If the maximum constant speed of the propeller 2 meets the design requirements, the test is passed. Among them, before judging whether the actual maximum constant speed is equal to the rated speed of the propeller 2, it also includes a step of comparing the actual maximum constant speed with the rated speed of the propeller 2. The rated speed is the maximum speed that the propeller 2 can reach when the propeller 2 is designed. Whether the maximum constant speed of the propeller 2 meets the design requirements refers to whether the measured actual maximum constant speed of the propeller 2 is equal to the rated speed. If the actual maximum constant speed is equal to the rated speed, it means that under the drive of the engine 1, the propeller 2 can meet the design requirements, and when the propeller is running at the rated speed, the matching performance of the engine 1 and the propeller 2 is good, and the test is passed; if the actual maximum constant speed is not equal to the rated speed, the test fails and it is necessary to stop the machine for inspection and adjustment.

[0072] Step S400: Vibration check, including adjusting the speed selector lever of the propeller 2 to the maximum constant speed position, gradually increasing the speed of the engine 1, and then gradually reducing the speed of the engine 1, detecting the vibration of the engine 1, and determining whether the engine 1 has abnormal vibration. If the engine 1 does not have abnormal vibration, the propeller and engine 1 are matched properly.

[0073] It should be noted that engine 1 will vibrate during operation. Mild, regular vibration is normal, but since propeller 2 also vibrates during operation, resonance between propeller 2 and engine 1 is possible. Resonance can damage the equipment or even lead to more serious accidents. Therefore, the purpose of a vibration check is to verify whether propeller 2 and engine 1 are compatible and resonate during operation. If engine 1 vibrates normally and no resonance occurs, the propeller 2 and engine 1 are properly matched. When changing the speed of engine 1, the speed of propeller 2 also changes accordingly. By first adjusting the propeller 2 selector lever to the maximum constant speed position, a sufficient range of variation is provided for the speed change of engine 1. Specifically, gradually increasing the speed of engine 1 and then gradually decreasing it achieves a slow acceleration and deceleration process. During this process, the vibration of engine 1 is detected and determined to be normal. If the vibration of engine 1 is normal, the propeller and engine 1 are properly matched. If abnormal resonance occurs, the propeller and engine 1 are not properly matched.

[0074] The variable-pitch propeller and engine matching test method of this embodiment verifies whether the feathering and propeller functions of propeller 2 are normal when driven by engine 1 by performing an idle feathering function check. The minimum constant speed of propeller 2 is then measured to determine whether it is less than or equal to a preset minimum speed to verify whether the minimum constant speed of the propeller is qualified. The maximum constant speed of propeller 2 is then measured to determine whether it is equal to the rated speed of propeller 2 to verify whether the maximum constant speed of the propeller is qualified. Finally, the vibration of engine 1 is tested during slow acceleration and deceleration to determine whether the vibration of engine 1 is normal to verify whether the vibration of engine 1 is qualified. If the idle feathering function check, the minimum constant speed of propeller 2, the maximum constant speed of propeller 2, and the vibration check are all qualified, it indicates that the propeller and engine 1 are matched properly. This fully verifies the matching between propeller 2 and engine 1 during ground testing, avoids flight safety issues caused by insufficient understanding of the matching characteristics of propeller 2 and engine 1 during subsequent flight verification, and eliminates safety hazards.

[0075] It should be noted that before applying the variable pitch propeller and engine matching test method of this embodiment to conduct test verification, the following preparations and settings need to be made:

[0076] First, the engine 1 needs to complete the acceptance test to ensure that the engine 1 can operate normally; secondly, the propeller 2 and the engine 1 are installed normally; then, the speed selector lever of the propeller 2 needs to be calibrated. Specifically, the speed selector lever is calibrated with a first preset position and a second preset position. The first preset position corresponds to the propeller 2 being in the feathering state, and the second preset position corresponds to the propeller 2 being in the forward propeller state.

[0077] In one embodiment, determining the actual minimum constant speed of the propeller in step S200 specifically includes the following steps:

[0078] Step S201: placing the speed selector lever in a first preset position to put the propeller 2 in a feathering state.

[0079] It should be noted that the variable pitch propeller is switched between different working states by adjusting the speed selector lever. The first preset position of the speed selector lever corresponds to the feathering state of the propeller 2. This step is to ensure that the propeller 2 is in the feathering state.

[0080] Step S202: starting the engine 1. After the engine 1 reaches an idling speed, the speed of the engine 1 is kept constant and continues to operate for a first preset time.

[0081] It should be noted that after executing step S201, step S202 is executed to start engine 1 while propeller 2 is feathered, i.e., engine feathering is performed. The engine 1 speed is adjusted by the engine throttle lever. The first preset time is a time set based on experience to ensure that engine 1 maintains a stable idle speed for a period of time, thereby further ensuring the smooth operation of subsequent operations. Preferably, the first preset time is 3 minutes. Therefore, after the engine feathers and reaches idle, the engine speed is maintained constant and stable for 3 minutes.

[0082] Step S203: slowly push the selector lever upward to the second preset position to adjust the propeller 2 to the forward propeller state.

[0083] It should be noted that when the speed selector lever is in the second preset position, it corresponds to the propeller 2 in the forward propeller state. The minimum constant speed of propeller 2 refers to its minimum constant speed in the forward propeller state. This step is to adjust propeller 2 to the forward propeller state in preparation for subsequent operations. It should be noted that when pushing up the speed selector lever, it is necessary to push up the speed selector lever slowly. Slowly pushing up the speed selector lever refers to pushing the speed lever at the first preset speed. It is generally believed that if the time taken to push the speed selector lever from the first preset position to the second preset position is greater than 15 seconds, it is considered a slow push up. The slow push up is to ensure the smoothness of the propeller 2 when switching between different working states. Usually, the second preset position is located relatively above the first preset position. Therefore, the speed selector lever needs to be pushed up when switching from the first preset position to the second preset position.

[0084] Step S204: Push the engine throttle lever to adjust the speed of the engine 1 to adjust the current speed of the propeller 2 until the current speed of the propeller 2 remains unchanged.

[0085] That is, after the propeller 2 is switched to the forward propeller state, the engine throttle lever is pushed to adjust the speed of the engine 1, and the change in the speed of the engine 1 drives the change in the current speed of the propeller 2 until the current speed of the propeller 2 remains unchanged, and then the engine throttle lever is stopped to keep the propeller 2 rotating at the current speed. A first detection device 4 is provided on the engine 1 near the propeller 2 for detecting the speed of the propeller 2. The first detection device 4 can detect whether the current speed of the propeller 2 is stable. Optionally, the first detection device 4 is a speed sensor, which is electrically connected to a display screen, and the speed data detected by the speed sensor is displayed on the display screen.

[0086] Step S205: Fix the engine throttle lever and slowly retract the speed selector lever until the current speed of the propeller 2 decreases by a first preset speed difference. Then, stop retracting the speed selector lever and determine whether the current speed of the propeller 2 continues to automatically decrease.

[0087] Among them, slowly retracting the speed selector lever refers to slowly switching the speed selector lever from the second preset position to the first preset position at a first preset speed, specifically retracting the speed lever at a speed that takes more than 15s to slowly switch from the second preset position to the first preset position; during the process of slowly retracting the speed selector lever, the current speed of the propeller 2 slowly decreases; the specific value of the first preset speed difference is greater than or equal to 20r / min / s. When the current speed of the propeller 2 decreases at the first preset speed difference, it is manifested as a significant decrease in the current speed of the propeller 2, indicating that the current speed of the propeller 2 has reached or is less than the minimum constant speed. At this time, the speed selector lever is stopped from being retracted. By judging whether the current speed of the propeller 2 continues to automatically decrease, it can be judged whether the propeller 2 can be in a stable state, thereby judging whether the minimum constant speed of the propeller is qualified.

[0088] Step S206: If the current rotation speed of the propeller 2 stops decreasing, the current rotation speed of the propeller 2 is recorded as the actual minimum constant speed, and the position of the speed selector lever is calibrated as the minimum constant speed position.

[0089] It should be noted that if the current speed of propeller 2 stops decreasing, it means that propeller 2 can maintain stability at the current speed, and the current speed is the actual minimum constant speed, thereby testing the actual minimum constant speed of propeller 2. Further, the position of the selector lever corresponding to the actual minimum constant speed is calibrated as the minimum constant speed position, which is convenient for operation after the aircraft is put into use.

[0090] Step S207: If the current speed of propeller 2 continues to automatically decrease, the speed selector lever is pushed upward until the current speed of propeller 2 stops automatically decreasing, and the process returns to the above-mentioned step S205 in which the speed selector lever is slowly retracted until the current speed of propeller 2 decreases significantly. Thereafter, the speed selector lever is stopped from being retracted, and it is determined whether the current speed of propeller 2 continues to decrease.

[0091] It should be noted that if the current speed of propeller 2 continues to automatically decrease, that is, if propeller 2 cannot maintain steady rotation, it indicates that the current speed of propeller 2 is less than the minimum constant speed required to maintain stable rotation. The process must return to step S205, where the selector lever is slowly retracted, and the subsequent steps to readjust the current speed of propeller 2 and determine whether the current speed of propeller 2 continues to automatically decrease. This process is repeated until the current speed of propeller 2 stops decreasing. Finally, the actual minimum constant speed and the corresponding minimum constant speed position of the selector lever are determined. It should be noted that during this adjustment process, the engine throttle lever remains fixed.

[0092] Step S208: retracting the engine throttle lever to make the engine 1 reach an idling speed, and the engine 1 maintains the idling speed for a second preset time.

[0093] That is, after determining the actual minimum constant speed of propeller 2, the engine throttle lever is adjusted to reduce the speed of engine 1 to an idle speed and stabilize it for a certain period of time, thereby driving the speed of propeller 2 to reduce and stabilize for a certain period of time, thereby ensuring the stability of the operating mode switching process. The second preset time is less than the first preset time, and preferably, the second preset time is 2 minutes.

[0094] Step S209: adjusting the speed selector lever to the first preset position to adjust the propeller 2 to the feathering state. After the propeller 2 keeps working in the feathering state for a third preset time, the engine 1 is controlled to stop.

[0095] By adjusting the selector lever to the first preset position, propeller 2 is adjusted to its original feathered state. After propeller 2 maintains the feathered state and operates stably for a certain period of time, engine 1 is controlled to stop in a stable state, which is beneficial to protecting propeller 2 and engine 1. The test ends when engine 1 stops. The third preset time is less than the second preset time. Preferably, the third preset time is 1 minute.

[0096] By executing steps S201 to S209, the actual minimum constant speed of the propeller 2 is determined. During this process, while the propeller 2 remains in the feathered state and the speed of the engine 1 remains unchanged, the actual minimum constant speed of the propeller 2 is determined by repeatedly adjusting the position of the selector lever in combination with the detection of the current speed of the propeller 2 by the first detection device 4. This facilitates subsequent comparison of the actual minimum constant speed with the preset minimum speed, thereby determining whether the minimum constant speed of the propeller meets the design requirements. In addition, the corresponding position of the selector lever is determined at the same time, which facilitates operation of the aircraft after it is put into use.

[0097] In one embodiment, the above step S100 specifically includes the following steps:

[0098] Step S101: The engine starts feathering. After the engine 1 reaches an idling speed, the speed of the engine 1 is kept unchanged, and the propeller 2 keeps feathering for a first preset time.

[0099] Engine feathering refers to starting engine 1 while propeller 2 is feathered. Specifically, the process includes placing the selector lever in the first preset position to feather propeller 2, and then starting engine 1. After the engine feathers and reaches idle speed, engine 1 drives propeller 2 in a stable feathered state for 3 minutes to verify proper operation.

[0100] Step S102: adjusting the speed selector lever to a second preset position to adjust the propeller 2 to a forward propeller state, and the propeller 2 maintains the forward propeller state for a first preset time;

[0101] At this time, engine 1 has been at an idle speed. After adjusting propeller 2 to the forward propeller state, engine 1 drives propeller 2 to work stably in the forward propeller state for 3 minutes to verify whether it can work normally.

[0102] Step S103: adjusting the speed selector lever to a first preset position to adjust the propeller 2 to a feathering state, and the propeller maintains the feathering state for a first preset time.

[0103] It should be noted that since the propeller feathering verification in step S101 is performed immediately after engine startup, achieving smooth operation is difficult during the initial startup, potentially leading to unstable operation. Therefore, testing is performed after a cycle of feathering and forward propellers for greater stability and reliability. In step S103, propeller 2 is again adjusted to feathering and operated stably for 3 minutes to verify the matching between engine 1 and propeller 2 under these operating conditions, thereby improving the reliability of the test verification.

[0104] Step S104: adjusting the speed selector lever to a second preset position to adjust the propeller 2 to a forward propeller state, and the propeller 2 maintains the forward propeller state for a first preset time.

[0105] This step is the same as the above-mentioned step S102 and is used to verify the matching performance between the engine 1 and the propeller 2 when the propeller 2 is in the forward propeller state, and can improve the reliability of the test verification.

[0106] Step S105: adjusting the speed selector lever to the first preset position to adjust the propeller 2 to the feathering state. After the propeller 2 keeps working in the feathering state for a third preset time, the engine is controlled to stop.

[0107] This step has the same operation and effect as the above-mentioned step S209, both of which are to realize controlling the engine 1 to stop in a stable state, and will not be repeated here.

[0108] It should be noted that after the above step S104, the cycle of steps S103 and S104 may be repeated one or more times, and multiple cycle verifications may be performed before entering step S105, which can further improve the reliability of the test verification.

[0109] By executing the above steps S101 to S105, it is verified whether the propeller 2 can rotate smoothly in the feathering state and the propeller state respectively, and the feathering function and the propeller state of the propeller 2 are checked respectively when the engine 1 is at the idle speed, and whether the propeller 2 can switch smoothly between the feathering state and the propeller state is completed, thereby realizing the verification of the matching performance of the engine 1 and the propeller 2.

[0110] In one embodiment, the speed regulating device further includes a limiter, and the limiter is spaced apart from the speed selector lever. The determining of the actual maximum constant speed of the propeller in step S300 specifically includes the following steps:

[0111] Step S301: Engine feathering start: After the engine 1 reaches an idle speed, the speed of the engine 1 is maintained constant and continues to operate for a first preset time, thereby completing the start of the engine 1 and the propeller 2.

[0112] Step S302: Adjust the speed selector lever until the speed selector lever contacts the limiting member.

[0113] It should be noted that the stopper is a component incorporated into the propeller design and serves to limit the selector lever. When the selector lever is adjusted to abut the stopper, propeller 2 can reach its maximum speed. When the selector lever abuts the stopper, propeller 2 is in a certain position in the forward propeller state. Preferably, the stopper is a stopper.

[0114] Step S303: Slowly push the engine throttle lever until the speed of the propeller 2 remains constant, and continue to work for a third preset time, record the current speed of the propeller 2 as the actual maximum constant speed, and record the current power of the engine 1 as the minimum constant speed power.

[0115] It should be noted that when the speed selector lever is in contact with the limiter, the engine throttle lever is pushed to increase the speed of engine 1, and engine 1 drives the speed of propeller 2 to increase until the speed of propeller 2 remains unchanged and can work stably for a certain period of time, that is, the speed of propeller 2 reaches its maximum value. The speed of propeller 2 at this time is the actual maximum constant speed, and the power of engine 1 at this time is the minimum constant speed power. Among them, the minimum constant speed power refers to the minimum power that engine 1 can use to meet the actual maximum constant speed; slowly pushing the engine throttle lever refers to pushing the engine throttle lever at a second preset speed. Specifically, when the time taken for engine 1 to switch from slow speed to the corresponding engine 1 speed when the speed of propeller 2 remains unchanged is greater than 15 seconds, it is considered that the engine throttle lever is slowly pushed, and the switching speed of the engine throttle lever during the entire process is the second preset speed.

[0116] Step S304: slowly pull down the engine throttle lever to make the engine 1 reach the idling speed, and the engine maintains the idling speed for a second preset time.

[0117] Among them, slowly pulling down the engine throttle lever refers to pulling down the engine throttle lever at a second preset speed. Specifically, when the time taken for the speed of the engine 1 to switch from the speed corresponding to the maximum speed of the propeller 2 in step S303 to the idling speed of the engine 1 is greater than 15 seconds, the operation of the engine throttle lever is considered as slowly pulling down the engine throttle lever.

[0118] Step S305: adjusting the speed selector lever to the first preset position to adjust the propeller to the feathering state, and after the propeller keeps working in the feathering state for a third preset time, the engine is controlled to stop.

[0119] By executing the above steps S301 to S305, the actual maximum constant speed of the propeller is determined. In this process, the speed selector lever is first adjusted to abut against the limit member, and then the speed of the engine 1 is adjusted to increase the speed of the propeller 2 so that the propeller 2 reaches the maximum constant speed. The reliability of the adjustment process is high.

[0120] In one embodiment, after determining whether the actual maximum constant speed is equal to the rated speed of the propeller in step S300, the following steps are specifically included:

[0121] Step S306: When the actual maximum constant speed is equal to the rated speed of the propeller, the maximum constant speed of the propeller is qualified.

[0122] It should be noted that the maximum constant speed is the designed rated speed of propeller 2 and should be the speed of propeller 2 when the selector lever rests on the stop pin. That is, the actual maximum constant speed measured in step S303 should be equal to the rated speed. At this point, the selector lever is in the maximum constant speed position.

[0123] Step S307: When the actual maximum constant speed is greater than or less than the rated speed, after the engine is stopped, the position of the limiter is adjusted, and the process returns to the step of measuring the actual maximum constant speed of the propeller.

[0124] That is, when the actual maximum constant speed is not equal to the rated speed, it means that the maximum constant speed of the propeller is unqualified, and the vehicle is stopped to adjust the position of the stop pin to achieve the purpose of adjusting the actual maximum speed of the propeller 2.

[0125] In one embodiment, after the above step S307, the above steps S301 to S305 are re-entered to verify again whether the adjusted maximum constant speed of the propeller is qualified.

[0126] In one embodiment, the step of adjusting the propeller speed selector lever to the maximum constant speed position, gradually increasing the current speed of the engine 1, and then gradually decreasing the current speed of the engine 1 in step S400 specifically includes the following steps:

[0127] S401: The engine starts feathering. After the engine reaches an idle speed, the speed of the engine 1 is kept constant and continues to operate for a first preset time.

[0128] S402: The speed selector lever is adjusted until it contacts the limiter, the speed selector lever is fixed, and the propeller 2 continues to operate for a third preset time.

[0129] Among them, by adjusting the speed selector lever until it abuts against the limiter and fixing the speed selector lever, the speed selector lever is placed at the 100% propeller speed position, that is, the position where the speed of propeller 2 is the maximum. The propeller 2 works stably for 1 minute to ensure smooth operation.

[0130] S403: Pushing the engine throttle lever to gradually increase the speed of the engine 1 to the maximum state of the engine, and the engine 1 maintains the maximum state and continues to operate for a first preset time.

[0131] The maximum constant speed refers to the maximum speed at which propeller 2 can stably rotate when the selector lever abuts the limiter, and should be equal to the actual maximum constant speed measured in step S303. The maximum state of the engine refers to the state at which the engine speed reaches the maximum speed of the engine. By accelerating the engine to the maximum state, engine 1 can be fully verified within its available operating range. By gradually increasing the speed of engine 1, engine 1 is slowly accelerated from slow to maximum speed. During the slow acceleration of engine 1, engine 1 drives propeller 2 to accelerate, thereby verifying whether resonance occurs between engine 1 and propeller 2 during the acceleration process.

[0132] It should be noted that the engine 1 is provided with a second detection device 6 for detecting the real-time speed of the engine 1. Optionally, the second detection device 6 is a speed sensor, which is electrically connected to the display screen, and the speed data detected by the speed sensor is displayed on the display screen.

[0133] S404: retracting the engine throttle lever, gradually reducing the speed of the engine 1 until the engine 1 reaches an idling speed, and the engine 1 maintains the idling speed for a second preset time.

[0134] By gradually reducing the speed of the engine 1, the engine 1 is gradually reduced from its maximum speed to the slow speed, and the engine 1 is slowly decelerated from the maximum state to the slow speed. The engine 1 drives the propeller 2 to decelerate, thereby fully verifying whether resonance occurs between the engine 1 and the propeller 2 during the slow deceleration process within the working range that the engine 1 can provide.

[0135] S405: Adjusting the selector lever to a first preset position to adjust the propeller to a feathering state, and after the propeller maintains the feathering state for a third preset time, controlling the engine to stop.

[0136] It should be noted that the vibration detection device 5 is provided on the engine 1, and the vibration of the engine 1 is detected by the vibration detection device 5. During the execution of the above steps S401 to S405, the vibration detection device 5 always detects the vibration of the engine 1 in real time, so as to judge at any time whether the engine has abnormal vibration. Among them, the vibration of the engine 1 has a limit value, and the limit value of different models of products is different. When the vibration of the engine 1 detected by the vibration detection device 5 exceeds the limit value, it indicates that the vibration of the engine 1 is abnormal and the vehicle should be stopped immediately. Preferably, the vibration detection device 5 is a vibration sensor, which is electrically connected to a display screen, and the vibration amplitude detected by the vibration sensor is displayed on the display screen.

[0137] By executing the above steps S401 to S405, the engine 1 performs regular slow acceleration and slow deceleration, and the speed variation range of the engine 1 is relatively large, which can fully verify whether the propeller 2 and the engine 1 resonate during the slow acceleration and slow deceleration process, thereby further improving the understanding of the matching performance between the propeller 2 and the engine 1 and further improving the safety of subsequent use.

[0138] In one embodiment, the step of gradually increasing the speed of the engine 1 in S404 is specifically: increasing the speed of the engine 1 by a second preset speed difference; the step of gradually decreasing the speed of the engine 1 in S405 is specifically: gradually decreasing the speed of the engine 1 by a second preset speed difference. The acceleration of the engine 1 during slow acceleration is equal to the acceleration during slow deceleration, both of which are the second preset speed difference. The second preset speed difference is a constant value set based on experience. The engine 1 performs slow acceleration and slow deceleration at a constant acceleration, and the acceleration process is smooth, avoiding the influence of the vibration detection result due to the uneven acceleration process, thereby improving the reliability of the vibration detection. Preferably, the second preset speed difference △n g =50r / min / s, which can achieve slow acceleration / slow deceleration of the engine 1.

[0139] In one embodiment, propeller 2 further has a reverse propeller state. The thrust generated in the reverse propeller state is in the opposite direction to that generated in the forward propeller state, and is used to assist braking. The speed control device further includes a reverse propeller lever, which is suitable for adjusting the propeller 2 between the reverse propeller state and the feathering propeller state. Between steps S300 and S400, step S500 is further included: a reverse propeller function check. The reverse propeller function check is used to check whether the reverse propeller function of propeller 2 is qualified. If propeller 2 can normally enter and exit the reverse propeller state and can operate stably in the reverse propeller state for a certain period of time, the propeller reverse propeller function is qualified.

[0140] Specifically, the above step S500 includes the following steps:

[0141] S501: Engine feathering is started. After the engine 1 reaches an idle speed, the speed of the engine 1 is kept unchanged, and the propeller 2 keeps feathering for a first preset time.

[0142] S502: The speed selector lever is adjusted until the speed selector lever contacts the limiter, the speed selector lever is fixed, and the propeller continues to operate for a third preset time.

[0143] S503: Push up the reverse propeller joystick to determine whether propeller 2 enters the reverse propeller state.

[0144] It should be noted that pushing up the reverse propeller lever specifically refers to slowly pushing up the reverse propeller lever, that is, pushing up the reverse propeller lever at a third preset speed, specifically referring to pushing the reverse propeller lever at a speed such that the time taken to push the reverse propeller lever from the initial position to the highest position is greater than 15 seconds. Since the propeller 2 is in the forward propeller state after executing step S502, the initial position of the reverse propeller lever corresponds to the forward propeller state of the propeller 2, and the highest position of the reverse propeller lever corresponds to the reverse propeller state of the propeller 2. During the process of pushing up the reverse propeller lever, it is determined whether the propeller 2 has entered the reverse propeller state, thereby verifying whether the propeller 2 can successfully enter the reverse propeller state. Since the thrust generated by the propeller 2 in the reverse propeller state is opposite in direction to the thrust generated in the forward propeller state, the determination of whether the propeller 2 has entered the reverse propeller state from the forward propeller state is based on the operator's intuitive feeling.

[0145] S504: When propeller 2 enters the reverse state, the reverse propeller lever is continuously pushed upward until the reverse propeller speed of propeller 2 stops increasing, and then the reverse propeller lever is stopped from being pushed upward.

[0146] It should be noted that when propeller 2 enters the reverse state, it means that propeller 2 can enter the reverse state normally and the function of entering the reverse state is qualified; continue to push up the reverse propeller joystick until the reverse propeller speed of propeller 2 no longer increases, then propeller 2 reaches the maximum state of the reverse state, and fix the reverse propeller joystick to keep it stationary for subsequent operation.

[0147] S505: Push the engine throttle lever until the rotation speed of propeller 2 reaches the maximum reverse propeller rotation speed, fix the engine throttle lever, and continue working for a fourth preset time.

[0148] Among them, the fourth preset time is less than the third preset time. Since the working time required for the reverse propeller function of the propeller 2 is generally short, the fourth preset time can be set to a shorter time. Preferably, the fourth preset time is 30s. It should be noted that the maximum reverse propeller speed is the maximum speed that the propeller 2 can reach in the reverse propeller state. After executing the above step S504, the reverse propeller joystick has been placed in a position where the propeller 2 can reach the maximum reverse propeller speed. Therefore, by pushing the engine throttle lever, the speed of the propeller 2 can be increased to the maximum reverse propeller speed. At this time, stabilize the engine throttle lever and keep the propeller 2 working stably at the maximum reverse propeller speed for the fourth preset time. It can be verified whether the propeller 2 can work stably in the reverse propeller state under the drive of the engine 1. That is, if the propeller 2 can maintain the maximum reverse propeller speed and work stably for the fourth preset time, then the rotation function of the life-threatening propeller 2 in the reverse propeller state is qualified.

[0149] S506: Retract the engine throttle lever to allow engine 1 to reach an idle speed, then pull down the reverse propeller lever to the initial position to determine whether propeller 2 has exited the reverse propeller state.

[0150] By retracting the engine throttle lever, the speed of engine 1 is reduced until the engine reaches the idle speed, thereby driving the speed of propeller 2 to reduce, making it easier to perform subsequent operations at low speed; by pulling down the reverse propeller joystick value to the initial position, and judging whether propeller 2 can switch from the reverse propeller state to the forward propeller state, it can be verified whether propeller 2 can smoothly exit the reverse propeller state, that is, whether the ability of propeller 2 to exit the reverse propeller state is qualified.

[0151] S507: When the propeller 2 exits the reverse propeller state, the reverse propeller function is qualified, and the propeller 2 maintains the forward propeller state and continues to operate for a second preset time.

[0152] If the propeller 2 can smoothly exit the reverse state, the ability of the propeller 2 to exit the reverse state is qualified. Further combined with the fact that the function of the propeller 2 entering the reverse state in step S504 is qualified, and the function of the propeller 2 rotating in the reverse state in step S505 is qualified, it can be concluded that the reverse function of the propeller 2 is qualified.

[0153] S508: Adjust the selector lever to the first preset position to adjust the propeller to the feathering state, and after the propeller continues to work for a third preset time, control the engine to stop.

[0154] By first executing step 507 to keep the propeller 2 in the forward propeller state and stably operate for the second preset time, and then executing step S508 to adjust the propeller 2 to the feathered propeller state and stably operate for the third preset time, and then controlling the engine to stop, the transition is gradual, which can improve the smoothness of the operation process.

[0155] By executing the above steps S501 to S508, it is verified that the function of the propeller 2 entering the reverse state is qualified, the function of the propeller 2 rotating in the reverse state is qualified, and the ability of the propeller 2 to exit the reverse state is qualified, thereby verifying that the reverse function of the propeller 2 is qualified, indicating that the matching performance of the engine 1 and the propeller 2 is good for the reverse function of the propeller 2.

[0156] In one embodiment, after determining whether the propeller has entered the reverse state in S503, the method further includes: when the propeller 2 has not entered the reverse state, pulling the reverse control lever back to the initial position and stopping the machine for inspection.

[0157] It should be noted that if the propeller 2 cannot enter the reverse propeller state, that is, the function of the propeller 2 to enter the reverse propeller state is unqualified, the reverse propeller joystick should be pulled back to the initial position to switch the propeller 2 to the forward propeller state, and then step S508 should be executed. After shutdown, an inspection should be carried out to find out the cause of the fault and make adjustments and repairs.

[0158] In one embodiment, after determining whether the propeller has exited the reverse state in S506 , the method further includes: when the propeller 2 has not exited the reverse state, stopping the machine for inspection.

[0159] It should be noted that if the propeller 2 cannot exit the reverse state normally, that is, the function of the propeller 2 exiting the reverse state is unqualified, step S508 is executed to shut down the propeller 2, and then inspection and adjustment are performed after the shutdown.

[0160] In one embodiment, a first detection device 4 is provided on the engine 1 near the propeller 2. The first detection device is used to detect the rotational speed of the propeller 2. It should be noted that the engine 1 provides power for the rotation of the propeller 2, which is connected to the output shaft of the engine 1 via a transmission mechanism. The first detection device 4 is provided at the end of the transmission mechanism. The first detection device 4 directly detects the rotational speed at the end of the transmission mechanism, which is equal to the rotational speed of the propeller 2. The real-time rotational speed of the propeller 2 is detected by the first detection device 4, and the detected rotational speed data is displayed on a display screen, which is highly reliable and relatively intuitive.

[0161] In one embodiment, the engine 1 is provided with a second detection device 6 for detecting the rotational speed of the engine 1. The second detection device 6 is used to detect the rotational speed of the output shaft of the engine 1. The real-time rotational speed of the engine 1 detected by the second detection device 6 is displayed on a display screen, which is intuitive and highly reliable. The rotational speed of the output shaft of the engine 1 and the rotational speed of the propeller 2 have a certain ratio to ensure normal rotation of the propeller 2.

[0162] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A matching test method for a variable pitch propeller and an engine, characterized in that: The variable pitch propeller is adjusted by a speed regulating device, the speed regulating device includes a speed selector lever, and the method includes: An idle feathering function check includes sequentially adjusting the propeller to a feathered state and a propeller aligning state, and continuously operating the propeller in the feathered state and the propeller aligning state for a first preset time. If the propeller can switch from the feathered state to the propeller aligning state and can rotate smoothly in the feathered state and the propeller aligning state, the idle feathering function is qualified. Verifying the minimum constant speed of the propeller, including measuring the actual minimum constant speed of the propeller and determining whether the actual minimum constant speed is less than or equal to a preset minimum speed. If the actual minimum constant speed is less than or equal to the preset minimum speed, the minimum constant speed of the propeller is qualified. Verifying the maximum constant speed of the propeller, including measuring an actual maximum constant speed of the propeller and determining whether the actual maximum constant speed is equal to the rated speed of the propeller; if the actual maximum constant speed is equal to the rated speed, the maximum constant speed of the propeller is qualified, and calibrating the position of the propeller selector lever as the maximum constant speed position; The vibration check includes adjusting the propeller selector lever to the maximum constant speed position, gradually increasing the engine speed, and then gradually decreasing the engine speed, detecting the vibration of the engine, and determining whether the engine has abnormal vibration. If the engine does not have abnormal vibration, the propeller and the engine are qualified.

2. The matching test method of a variable pitch propeller and an engine according to claim 1, characterized in that: Determining the actual minimum constant speed of the propeller specifically includes the following steps: placing the speed selector lever in a first preset position to place the propeller in a feathering state; Starting the engine, and after the engine reaches an idle speed, maintaining the engine speed constant and continuing to operate for a first preset time; Slowly pushing the speed selector lever upward to a second preset position to adjust the propeller to a forward propeller state; Pushing the engine throttle lever to adjust the engine speed, thereby adjusting the current speed of the propeller, until the current speed of the propeller remains unchanged; The engine throttle lever is fixed, and the speed selector lever is slowly retracted until the current speed of the propeller decreases by a first preset speed difference, and then the speed selector lever is stopped from being retracted, and it is determined whether the current speed of the propeller continues to automatically decrease; If the current speed of the propeller stops decreasing, recording the current speed of the propeller as the actual minimum constant speed, and calibrating the position of the speed selector lever as the minimum constant speed position; If the current speed of the propeller continues to automatically decrease, the speed selector lever is pushed upward until the current speed of the propeller stops automatically decreasing, and the speed selector lever is slowly retracted until the current speed of the propeller decreases significantly, and then the speed selector lever is stopped and it is determined whether the current speed of the propeller continues to decrease. retracting the engine throttle lever to allow the engine to reach an idle speed, and the engine maintains the idle speed for a second preset time; The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to work for a third preset time, the engine is controlled to stop.

3. The matching test method of a variable pitch propeller and an engine according to claim 1, characterized in that: The idle feathering function check specifically includes the following steps: The engine feathering is started, and after the engine reaches an idle speed, the engine speed is maintained unchanged, and the propeller remains in the feathered state for a first preset time; Adjusting the speed selector lever to a second preset position to adjust the propeller to a forward propeller state, wherein the propeller maintains the forward propeller state for a first preset time; adjusting the speed selector lever to a first preset position to adjust the propeller to a feathered state, and the propeller remains in the feathered state for a first preset time; Adjusting the speed selector lever to a second preset position to adjust the propeller to a forward propeller state, wherein the propeller maintains the forward propeller state for a first preset time; The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to operate for a third preset time, the engine is controlled to stop.

4. The matching test method of a variable pitch propeller and an engine according to claim 1, characterized in that: The speed regulating device further includes a limiter, wherein the limiter is spaced apart from the speed selector lever. The measuring of the actual maximum constant speed of the propeller specifically includes the following steps: feathering the engine, and after the engine reaches an idle speed, maintaining the engine speed constant and continuing to operate for a first preset time; Adjusting the speed selector lever until the speed selector lever abuts against the limiting member; Slowly pushing the engine throttle lever until the speed of the propeller remains constant, and continuing to operate for a third preset time, recording the current speed of the propeller as the actual maximum constant speed, and recording the current power of the engine as the minimum constant speed power; Slowly pulling down the engine throttle lever to make the engine reach an idle speed, and the engine maintains the idle speed for a second preset time; The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to work for a third preset time, the engine is controlled to stop.

5. The matching test method of a variable pitch propeller and an engine according to claim 4, characterized in that: After determining whether the actual maximum constant speed is equal to the rated speed of the propeller, the following steps are specifically included: When the actual maximum constant speed is equal to the rated speed of the propeller, the maximum constant speed of the propeller is qualified; When the actual maximum constant speed is greater than or less than the rated speed, after the engine is stopped, the position of the limiter is adjusted, and the process returns to the step of measuring the actual maximum constant speed of the propeller.

6. The matching test method of a variable pitch propeller and an engine according to claim 4, characterized in that: The engine is provided with a vibration detection device for detecting the vibration of the engine in real time. The adjusting the propeller speed selector lever to the maximum constant speed position, gradually increasing the engine speed, and then gradually decreasing the engine speed specifically comprises the following steps: feathering the engine, and after the engine reaches an idle speed, maintaining the engine speed constant and continuing to operate for a first preset time; adjusting the speed selector lever until the speed selector lever contacts the limiter, fixing the speed selector lever, and causing the propeller to continuously operate for a third preset time; Pushing the engine throttle lever to gradually increase the engine speed to a maximum state of the engine, and the engine maintains the maximum state and continues to operate for a first preset time; retracting the engine throttle lever, gradually reducing the engine speed until the engine reaches an idle speed, and the engine maintains the idle speed for a second preset time; The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state. After the propeller maintains the feathering state and continues to work for a third preset time, the engine is controlled to stop.

7. The matching test method of a variable pitch propeller and an engine according to claim 6, characterized in that: The step of gradually increasing the engine speed specifically includes: increasing the engine speed by a second preset speed difference; The stepwise reduction of the engine speed specifically includes: stepwise reduction of the engine speed by a second preset speed difference.

8. The matching test method of a variable pitch propeller and an engine according to claim 4, characterized in that: The propeller further has a reverse propeller state, and the speed control device further includes a reverse propeller joystick, which is suitable for adjusting the propeller to switch between the reverse propeller state and the feathering state. After verifying the maximum constant speed of the propeller, a reverse propeller function check is also included, which specifically includes the following steps: The engine feathering is started, and after the engine reaches an idle speed, the engine speed is maintained unchanged, and the propeller remains in the feathered state for a first preset time; adjusting the speed selector lever until the speed selector lever contacts the limiter, fixing the speed selector lever, and causing the propeller to continuously operate for a third preset time; Pushing up the reverse propeller joystick to determine whether the propeller has entered the reverse propeller state; When the propeller enters the reverse propeller state, continue to push up the reverse propeller joystick until the reverse propeller speed of the propeller no longer increases, and then stop pushing up the reverse propeller joystick; pushing the engine throttle lever until the rotation speed of the propeller reaches a maximum reverse propeller rotation speed, fixing the engine throttle lever, and continuing to operate for a fourth preset time; retracting the engine throttle lever to allow the engine to reach an idle speed, then pulling down the reverse propeller lever to an initial position to determine whether the propeller has exited the reverse propeller state; When the propeller exits the reverse propeller state, the reverse propeller function is qualified, and the propeller maintains the forward propeller state and continues to work for a second preset time; The speed selector lever is adjusted to a first preset position to adjust the propeller to a feathering state, and after the propeller continues to work for a third preset time, the engine is controlled to stop.

9. The matching test method of a variable pitch propeller and an engine according to claim 8, characterized in that: After determining whether the propeller enters the reverse state, the method further includes: when the propeller does not enter the reverse state, pulling the reverse control lever back to the initial position and stopping the machine for inspection; And / or, after determining whether the propeller has exited the reverse state, the method further includes: when the propeller has not exited the reverse state, stopping the machine for inspection.

10. The matching test method of a variable pitch propeller and an engine according to any one of claims 1 to 9, characterized in that: A first detection device is provided on the engine near the propeller, and the first detection device is used to detect the rotation speed of the propeller; And / or, the engine is provided with a second detection device, and the second detection device is used to detect the rotational speed of the engine.

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