A method for calculating power distribution of a main tail rotor of a helicopter

Abstract

The application belongs to the technical field of helicopter design, and discloses a kind of helicopter main tail propeller power distribution calculation method, first calculate the main reduction input power of helicopter, then use foot pedal displacement to calculate tail propeller power, then the main rotor power is obtained by the main reduction input power of helicopter minus tail propeller power and accessory consumption power.The application can calculate the main rotor power and tail propeller power of helicopter in different flight states, including can calculate instantaneous maneuvering state, and the calculation error is small, obviously solves the disadvantages that the current calculation method can only calculate the main rotor power and tail propeller power of helicopter in stable state, greatly improves the monitoring strength of main rotor power and tail propeller power of helicopter, and through obtaining more instantaneous maneuvering state data, the design ability of helicopter can be further improved, and the abnormal alarm method is given when the numerical value of main rotor power and tail propeller power exceeds the limit of corresponding maximum output power, which can more effectively guarantee the flight safety of helicopter.

Description

Technical Field

[0001] This invention belongs to the field of helicopter design technology, and relates to a method for calculating the power of a helicopter's main and tail rotors, specifically a method for calculating the power distribution of a helicopter's main and tail rotors. Background Technology

[0002] The power limits of a helicopter's transmission system's main gearbox include the maximum input power limit of the main gearbox, the output power limit of the main rotor shaft, and the output power limit of the tail shaft. Currently, helicopters are equipped with engine torque displays, and the torque value can be used to determine whether the main gearbox has exceeded its maximum input power limit. However, helicopter displays, both domestically and internationally, do not yet provide the power value of the helicopter's main and tail rotors during flight.

[0003] The traditional method for calculating helicopter main and tail rotor power is as follows: The main rotor power is calculated based on the main rotor pitch during stable flight, and the tail rotor power is calculated based on the tail rotor pitch during stable flight. This method can only calculate the main and tail rotor power under stable flight conditions. During helicopter flight, the tail rotor power accounts for a very small proportion of the helicopter's total power, at most not exceeding 20%, and less than 10% in most flight conditions, while the main rotor power accounts for more than 80% of the helicopter's total power. Both theoretical calculations and parameter measurements have errors; even small changes in the main rotor pitch can cause significant fluctuations in main rotor power. Therefore, it is impossible to accurately determine the power margin between the main rotor shaft power and the main rotor shaft limit power. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a method for calculating the power distribution of a helicopter's main and tail rotors. The tail rotor power is calculated based on the tail rotor pitch, and then the main rotor shaft power is obtained by subtracting the tail rotor power from the main rotor input power. This calculation method can calculate the main and tail rotor power not only in stable flight conditions but also in instantaneous maneuvering conditions, with minimal calculation error. If the calculated main and tail rotor power exceeds the maximum output power limit of the main rotor shaft or tail output shaft, an alarm for abnormal power in the transmission system is issued.

[0005] The technical solution of the present invention is as follows:

[0006] A method for calculating the power distribution of a helicopter's main rotor and tail rotor involves first calculating the main rotor input power, then using pedal displacement to calculate the tail rotor power, and finally subtracting the tail rotor power and accessory power consumption from the main rotor input power to obtain the main rotor power.

[0007] Furthermore, the helicopter's main input power reduction The calculation method is as follows:

[0008]

[0009] Among them, Q 实测It is the actual measured total engine torque. This refers to the main reduction input power at the reference rotor speed. It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

[0010] Furthermore, the method for calculating tail rotor power using pedal displacement is as follows: first, calculate tail rotor pitch from pedal displacement; then, calculate tail rotor power at sea level and under standard atmospheric conditions from tail rotor pitch; finally, calculate tail rotor power at current pressure altitude, atmospheric temperature, and rotor speed from tail rotor power at sea level and under standard atmospheric conditions.

[0011] Furthermore, the method for calculating the tail rotor pitch (pedal) using the pedal displacement (wz) is as follows:

[0012] ;

[0013] Among them, k and b are calculated from the correspondence between the tail rotor pitch and the pedal displacement of the helicopter.

[0014] Furthermore, the tail rotor pitch is calculated using the platform to measure the tail rotor power at sea level and under standard atmospheric conditions. The calculation methods include hovering calculation method and forward flight calculation method. The hovering calculation method is used when hovering and accelerating to the optimal climb speed Vy; the forward flight calculation method is used when flying forward, i.e. when the speed is greater than or equal to Vy.

[0015] The hovering calculation method is as follows:

[0016]

[0017] The forward flight calculation method is:

[0018]

[0019] in, Obtained through rotor tower testing or flight testing.

[0020] Furthermore, the tail rotor power under sea level and standard atmospheric conditions... Calculate the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions. The calculation method is as follows:

[0021]

[0022] in, It is the density ratio. ,

[0023] It's the pressure ratio. Hp represents the current pressure level;

[0024] It's a temperature ratio. Th represents the current atmospheric temperature;

[0025] It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

[0026] Furthermore, the main input power of the helicopter... Subtract tail rotor power Power consumption of accessories To obtain the main rotor power The calculation method is as follows:

[0027] .

[0028] Furthermore, it also includes calculating the main rotor power at a reference rotor speed. :

[0029] ;

[0030] in, It is the main rotor power. It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed;

[0031] Then, the main rotor power at the reference rotor speed is compared with the main rotor shaft limit power to determine whether the main rotor power at the reference rotor speed exceeds the limit; if it does, it is recorded and an alarm is issued.

[0032] Furthermore, the tail rotor power at the reference rotor speed is calculated using the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions. Then, the main tail rotor output power is calculated using the tail rotor power at the reference rotor speed. Finally, the main tail rotor output power is compared with the main tail rotor output limit power to determine whether the main tail rotor output power exceeds the limit. If it does, it is recorded and an alarm is issued.

[0033] Furthermore, the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions... Calculate tail rotor power at reference rotor speed The method is:

[0034] ;

[0035] Tail rotor power at reference rotor speed Calculate the output power of the main tail reduction The method is:

[0036]

[0037] in, It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

[0038] The beneficial effects of this invention are:

[0039] 1. The helicopter main rotor and tail rotor power calculation method designed in this invention can calculate the main rotor power and tail rotor power of helicopters under different flight states, including instantaneous maneuvering states, and the calculation error is small. Obviously, it solves the drawback of the current calculation method that can only calculate the main rotor power and tail rotor power of helicopters under stable states, greatly improves the monitoring of helicopter main rotor power and tail rotor power, and can further improve the design capability of helicopters by obtaining more instantaneous maneuvering state data.

[0040] 2. The present invention also provides an abnormal alarm method for the main rotor power and tail rotor power values ​​exceeding the corresponding maximum output power limit, which has the advantages of being timely, accurate and reliable, and can more effectively ensure the flight safety of helicopters. Detailed Implementation

[0041] This section describes embodiments of the present invention, used to explain and illustrate the technical solutions of the present invention. Unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0042] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include more than one of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integrated connections; they can refer to mechanical connections or point connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] A method for calculating the power distribution of a helicopter's main rotor and tail rotor involves first calculating the main rotor input power, then using pedal displacement to calculate the tail rotor power, and finally subtracting the tail rotor power and accessory power consumption from the main rotor input power to obtain the main rotor power.

[0045] helicopter main input power reduction The calculation method is as follows:

[0046]

[0047] Among them, Q 实测 It is the actual measured total engine torque. This refers to the main reduction input power at the reference rotor speed. It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

[0048] The method for calculating tail rotor power using pedal displacement is as follows: First, calculate the tail rotor pitch from the pedal displacement; then calculate the tail rotor power under sea level and standard atmospheric conditions from the tail rotor pitch; finally, calculate the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions from the tail rotor power under sea level and standard atmospheric conditions.

[0049] Furthermore, the method for calculating the tail rotor pitch (pedal) using the pedal displacement (wz) is as follows:

[0050] ;

[0051] Among them, k and b are calculated from the correspondence between the tail rotor pitch and the pedal displacement of the helicopter.

[0052] Tail rotor pitch calculations based on tail rotor power at sea level and under standard atmospheric conditions. The calculation methods include hovering calculation method and forward flight calculation method. The hovering calculation method is used when hovering and accelerating to the optimal climb speed Vy; the forward flight calculation method is used when flying forward, i.e. when the speed is greater than or equal to Vy.

[0053] The hovering calculation method is as follows:

[0054]

[0055] The forward flight calculation method is:

[0056]

[0057] in, Obtained through rotor tower testing or flight testing.

[0058] Tail rotor power under sea level and standard atmospheric conditions Calculate the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions. The calculation method is as follows:

[0059]

[0060] in, It is the density ratio. ,

[0061] It's the pressure ratio. Hp represents the current pressure level;

[0062] It's a temperature ratio. Th represents the current atmospheric temperature;

[0063] It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

[0064] The main input power of the helicopter Subtract tail rotor power Power consumption of accessories To obtain the main rotor power The calculation method is as follows:

[0065] .

[0066] It also includes calculating the main rotor power at the reference rotor speed. :

[0067] ;

[0068] in, It is the main rotor power. It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed;

[0069] Then, the main rotor power at the reference rotor speed is compared with the main rotor shaft limit power to determine whether the main rotor power at the reference rotor speed exceeds the limit; if it does, it is recorded and an alarm is issued.

[0070] The tail rotor power at the reference rotor speed is calculated using the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions. Then, the main tail rotor output power is calculated using the tail rotor power at the reference rotor speed. Finally, the main tail rotor output power is compared with the main tail rotor output limit power to determine whether the main tail rotor output power exceeds the limit. If it does, it is recorded and an alarm is issued.

[0071] Tail rotor power under current pressure altitude, atmospheric temperature, and rotor speed conditions Calculate tail rotor power at reference rotor speed The method is:

[0072] ;

[0073] Tail rotor power at reference rotor speed Calculate the output power of the main tail reduction The method is:

[0074]

[0075] in, It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

[0076] The following is another embodiment of the present invention.

[0077] 1. Calculation of main rotor shaft power

[0078] When calculating the main rotor shaft power, the tail rotor power is first determined from the pedal displacement. Then, the main rotor input power is obtained by subtracting the tail rotor power and accessory power consumption from the main rotor input power. The power value at a certain speed reflects whether the transmission system torque exceeds the limit. The detailed calculation steps are as follows:

[0079] (1) Calculate the main reduction input power of the helicopter:

[0080]

[0081] (2) Calculate the tail rotor power:

[0082] a) Calculate tail rotor pitch from pedal displacement:

[0083]

[0084] b) Calculate the tail rotor power at sea level and under standard atmospheric conditions from the tail rotor pitch:

[0085] The tail rotor power corresponds to the same tail rotor pitch when hovering and when flying forward. Therefore, when calculating the tail rotor power of a helicopter, it is calculated in two flight states: hovering and accelerating to the optimal climb speed (Vy); and flying forward, i.e., when the speed is greater than or equal to Vy.

[0086] Hovering and accelerating to the optimal climb rate Vy, i.e., when the indicated airspeed is less than Vy:

[0087]

[0088] When flying forward, i.e. when the indicated airspeed is greater than or equal to Vy:

[0089]

[0090] c) Calculate the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions based on the tail rotor power at sea level and under standard atmospheric conditions. The calculation method for δ is shown in Table 1:

[0091]

[0092] (3) Calculate the main rotor power:

[0093]

[0094] (4) Calculate the main rotor power at the reference rotor speed:

[0095]

[0096] (5) The main rotor shaft limiting power at the reference rotor speed is ,if This indicates that the main rotor shaft power is less than the main rotor shaft limit power; if This indicates that the main rotor shaft power exceeds the main rotor shaft power limit. Inspection should be performed according to the relevant provisions in the maintenance manual.

[0097] 2. Calculation of main reduction tail output power

[0098] (1) The tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions is calculated from the tail rotor power under sea level and standard atmospheric conditions. The calculation method of δ is shown in Table 1:

[0099]

[0100] (2) Calculate the tail rotor power at the reference rotor speed:

[0101]

[0102] (3) Calculate the main tail output power at the reference rotor speed:

[0103]

[0104] (4) The main tail output limiting power at the reference rotor speed is: ,if This indicates that the output power of the main reduction tail is less than the output limit power of the main reduction tail; if This indicates that the output power of the main reducer exceeds the output limit of the main reducer, and an inspection should be carried out in accordance with the relevant provisions of the maintenance manual.

[0105] Table 1. Symbol Explanation Table

[0106]

[0107] The key point of this invention is:

[0108] The test parameters used in this calculation method are simple, and they are all data recorded from the helicopter flight recorder.

[0109] This calculation method is not limited by the helicopter's flight state; it can calculate both stable flight states and instantaneous maneuver states.

[0110] This calculation method can calculate the main rotor shaft output power and tail shaft output power of a helicopter in real time.

[0111] This calculation method can promptly issue alarms for abnormal power in the transmission system.

[0112] The method of the present invention is implemented in software form, which is installed in the flight control computer of the helicopter.

[0113] The above description is merely a specific embodiment of the present invention, providing a detailed description of the invention. Parts not covered herein are conventional techniques. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for calculating the power distribution of a helicopter main and tail rotor, characterized in that, First, calculate the main rotor input power of the helicopter, then use the pedal displacement to calculate the tail rotor power, and finally subtract the tail rotor power and accessory power consumption from the main rotor input power to obtain the main rotor power. The method for calculating tail rotor power using pedal displacement is as follows: First, calculate the tail rotor pitch from the pedal displacement; then calculate the tail rotor power at sea level and under standard atmospheric conditions from the tail rotor pitch; finally, calculate the tail rotor power at the current pressure altitude, atmospheric temperature, and rotor speed from the tail rotor power at sea level and under standard atmospheric conditions. Tail rotor pitch calculations based on tail rotor power at sea level and under standard atmospheric conditions. The calculation methods include hovering calculation method and forward flight calculation method. The hovering calculation method is used when hovering and accelerating to the optimal climb speed Vy; the forward flight calculation method is used when flying forward, i.e. when the speed is greater than or equal to Vy. The hovering calculation method is as follows: ； The forward flight calculation method is: ； in, Obtained through rotor tower testing or flight testing.

2. The method for calculating the power distribution of a helicopter main and tail rotor according to claim 1, characterized in that, helicopter main input power reduction The calculation method is as follows: ； Among them, Q is the measured total torque of the engine. This refers to the main reduction input power at the reference rotor speed. It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

3. The method for calculating the power distribution of a helicopter main and tail rotor according to claim 1, characterized in that, The method for calculating the tail rotor pitch using the pedal displacement wz is as follows: ； Among them, k and b are calculated from the correspondence between the tail rotor pitch and the pedal displacement of the helicopter.

4. The method for calculating the power distribution of a helicopter main and tail rotor according to claim 1, characterized in that, Tail rotor power under sea level and standard atmospheric conditions Calculate the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions. The calculation method is as follows: ； in, It is the density ratio. , It's the pressure ratio. Hp represents the current pressure level; It's a temperature ratio. Th represents the current atmospheric temperature; It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

5. The method for calculating the power distribution of a helicopter main and tail rotor according to claim 1, characterized in that, The main input power of the helicopter Subtract tail rotor power Power consumption of accessories To obtain the main rotor power The calculation method is as follows: 。 6. The method for calculating the power distribution of a helicopter main and tail rotor according to claim 1, characterized in that, It also includes calculating the main rotor power at the reference rotor speed. : ； in, It is the main rotor power. It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed; Then, the main rotor power at the reference rotor speed is compared with the main rotor shaft limit power to determine whether the main rotor power at the reference rotor speed exceeds the limit; if it does, it is recorded and an alarm is issued.

7. The method for calculating the power distribution of a helicopter main and tail rotor according to claim 1, characterized in that, Also includes: The tail rotor power at the reference rotor speed is calculated using the tail rotor power under the current pressure altitude, atmospheric temperature, and rotor speed conditions. Then, the main tail rotor output power is calculated using the tail rotor power at the reference rotor speed. Finally, the main tail rotor output power is compared with the main tail rotor output limit power to determine whether the main tail rotor output power exceeds the limit. If it does, it is recorded and an alarm is issued.

8. The method for calculating the power distribution of a helicopter main and tail rotor according to claim 7, characterized in that, Tail rotor power under current pressure altitude, atmospheric temperature, and rotor speed conditions Calculate tail rotor power at reference rotor speed The method is: ； Tail rotor power at reference rotor speed Calculate the output power of the main tail reduction The method is: in, It is the actual measured rotor speed. It is the reference rotor speed, i.e., the rated rotor speed.

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