A method for calculating the remaining flight time of a helicopter

Abstract

The application belongs to the technical field of helicopters, and particularly relates to a helicopter residual flight time calculation method, which comprises the following steps: S1, calculating the output power of each engine on the helicopter; S2, calculating the engine hourly oil consumption of each engine according to the output power of the engine; and S3, calculating the residual flight time of the helicopter according to the total oil quantity of the helicopter and the engine hourly oil consumption of all the engines. The helicopter real-time residual flight range and time are calculated according to the engine hourly oil consumption, the engine oil quantity and the engine horizontal ground speed at a certain moment during the flight of the helicopter.

Description

Technical Field

[0001] This invention belongs to the field of helicopter technology, and in particular relates to a method for calculating the remaining flight time of a helicopter. Background Technology

[0002] Currently, most helicopter integrated displays only show the remaining fuel level, not the remaining range and flight time. Pilots can roughly estimate the remaining range and flight time based on the remaining fuel level displayed on the aircraft and their flight experience. In theoretical calculations of flight performance, factors affecting range and flight time include flight weight, atmospheric conditions, fuel level, cruising altitude, cruising speed, and engine fuel consumption data. Pilots cannot easily consider all these influencing factors during actual flight operations. Summary of the Invention

[0003] This invention presents a method for calculating the remaining flight time of a helicopter. Based on the engine's hourly fuel consumption, fuel quantity, and horizontal ground speed at a specific moment during flight, the method calculates the helicopter's real-time remaining flight time. This method can calculate the helicopter's real-time status with minimal error, ensuring that the pilot can see the remaining flight time in real-time on the integrated display during flight. This aids the pilot in making flight decisions and addresses the problem that pilots cannot easily consider all influencing factors during flight operations.

[0004] The present invention is implemented using the following technical solution.

[0005] A method for calculating the remaining flight time of a helicopter, the method comprising:

[0006] S1, calculates the output power of each engine on the helicopter;

[0007] S2, calculate the engine hour fuel consumption of each engine based on its output power;

[0008] S3 calculates the remaining flight time of the helicopter based on the total fuel of the helicopter and the engine hour fuel consumption of all engines.

[0009] Furthermore, the method also includes:

[0010] S4 calculates the remaining range of the helicopter based on the remaining flight time.

[0011] Furthermore, S1 specifically refers to:

[0012]

[0013] Among them, PW i The output power of the i-th engine at a certain moment during flight, in kW;

[0014] Qi The output shaft torque of the i-th engine at a certain moment during flight, expressed as a percentage.

[0015] PW 参考 For reference power, the engine power at 100% rotor speed and 100% engine torque, in kW;

[0016] NR 实测 The measured rotor speed is expressed in n / min.

[0017] NR 参考 Reference rotor speed, unit: n / min;

[0018] S 安装损失 This refers to the power loss after the engine is installed.

[0019] Furthermore, S2 specifically refers to:

[0020] WF i =a×PW i +b

[0021] Among them, WF i The hourly fuel consumption of the i-th engine at a certain moment during flight is expressed in kg / h.

[0022] PW i The output torque of the i-th engine at a certain moment during flight, in kW;

[0023] a and b are the engine fuel consumption-power coefficients under the corresponding air pressure altitude and temperature conditions at a certain moment.

[0024] Furthermore, S3 specifically refers to:

[0025]

[0026] Wherein, GF represents the total amount of fuel in all fuel tanks at a certain moment during flight.

[0027] Furthermore, S4 specifically refers to:

[0028] L 剩余航程 =T 剩余航时 ×V 地速

[0029] Among them, V 地速 The horizontal ground speed of the helicopter at a certain moment during flight is expressed in km / h.

[0030] Furthermore,

[0031] When the helicopter is hovering, V 地速 Calculated based on the long-distance flight speed of a helicopter.

[0032] Furthermore,

[0033] The engine fuel consumption-power coefficient is obtained under typical air pressure, altitude, and temperature conditions. If the helicopter is not in typical conditions at a certain moment, the current helicopter engine fuel consumption-power coefficient is obtained by linear interpolation.

[0034] This invention relates to the display of remaining range and flight time for helicopters. In addition to displaying remaining fuel, it provides pilots with more intuitive range and flight time information, replacing the experience-based assessment method. When the helicopter faces changes in atmospheric conditions, it can promptly respond with corresponding range and flight time adjustments. It intuitively presents the relationship between flight speed and flight range, providing pilots with a reference for making decisions on "arriving faster" or "arriving further." Furthermore, it considers the impact of wind speed on range and uses appropriate computing sources to calculate the range in the actual geographical coordinates. This patented method also considers range and flight time calculations when the helicopter is hovering. During the calculation process, the remaining range and flight time are calculated using the current real-time parameters of the helicopter. Detailed Implementation

[0035] The technical solution of the present invention will be described in detail below.

[0036] This invention presents a method for calculating the remaining range and flight time displayed on a helicopter integrated display. The method calculates the real-time remaining range and flight time based on the engine's hourly fuel consumption, fuel quantity, and horizontal ground speed at a specific moment during flight. This method can calculate the helicopter's real-time status with minimal error, ensuring that the pilot can see the remaining range and flight time on the integrated display in real time during flight, thus aiding in flight decision-making.

[0037] The real-time remaining range and flight time of the helicopter are calculated based on the engine hourly fuel consumption, engine fuel quantity, and engine horizontal ground speed at a certain moment during the helicopter's flight. The specific calculation involves the following: (1) Calculation of engine output power.

[0038] (1) Calculation of engine output power

[0039] In theoretical calculations, the helicopter engine output power is balanced with the helicopter's own power requirements. The helicopter's own power requirements are related to flight conditions such as flight weight, flight speed, cruising altitude, and atmospheric temperature. During actual helicopter flight, these influencing parameters are directly reflected in the engine output torque. Therefore, the real-time engine output power can be obtained directly from the engine output torque signal and rotor speed signal collected by the electromechanical system.

[0040] The engine output power can be obtained from the measured value of the engine output shaft torque at a certain moment. Taking a twin-engine helicopter as an example, considering installation losses, the engine output power is as follows:

[0041]

[0042] in:

[0043] PW and PW2 are the output power of each engine at a certain moment during flight, in kW.

[0044] Q1 and Q2 represent the engine output shaft torque at a certain moment during flight, in percentage (%).

[0045] PW 参考 The power corresponding to 100% rotor speed and 100% torque is the reference power, in kW; NR 实测 Measured rotor speed, unit n / min;

[0046] NR 参考 Reference rotor speed, i.e., the rated rotor speed, is expressed in n / min.

[0047] During helicopter flight, the real-time output power of the engine can be obtained from the engine output torque signal and rotor speed signal collected by the electromechanical system.

[0048] (2) Calculation of engine hourly fuel consumption

[0049] Most helicopters in the market are not equipped with fuel consumption sensors, and even those that are installed have questionable measurement accuracy. This paper proposes a method to generate a fuel consumption-power relationship formula for engines under different pressure altitudes and atmospheric static temperatures using data provided by engine bench tests.

[0050] In determining the engine hourly fuel consumption, the first step is to select a series of engine fuel consumption-power relationship formulas suitable for the current atmospheric conditions based on the pressure altitude and atmospheric static temperature signals collected by the atmospheric instrument during helicopter flight.

[0051] WF i =a×PW i +b

[0052] WF = a × PW + b

[0053] in:

[0054] WF represents the engine's hourly fuel consumption at a specific moment during flight, expressed in kg / h.

[0055] PW is the output torque of each engine at a certain moment during flight, measured in kW;

[0056] a and b are the coefficients corresponding to the air pressure, altitude, and temperature conditions.

[0057] Since the engine fuel consumption-power relationship formulas provided to the computer as input are based on typical demand and temperature conditions, if the helicopter is not in a typical state at a certain moment, the fuel consumption of each engine of the helicopter at that time is obtained through linear interpolation. Temperature and pressure altitude values ​​are taken at intervals according to the interpolation method that selects specific nearby values.

[0058] Assuming atmospheric conditions of 1600m altitude and 13℃, we select the coefficients a and b at nearby typical conditions of 1000m and 10℃, and 1000m and 20℃ respectively. Linear interpolation yields the coefficients a and b at 1000m and 13℃. Similarly, we obtain the coefficients a and b at 2000m and 13℃. Using the obtained coefficients a and b at 1000m and 13℃ and at 2000m and 13℃, we again perform linear interpolation to obtain the coefficients a and b at 1600m and 13℃.

[0059] (3) Calculation of remaining range and flight time

[0060] Conceptually, remaining flight time is the ratio of the helicopter's remaining fuel to its engine fuel consumption. In other words, it is calculated after obtaining the hourly fuel consumption of each helicopter engine.

[0061]

[0062] in:

[0063] PW1 and PW2 are the output power of each engine at a certain moment during flight, in kW;

[0064] Q1 and Q2 represent the engine output shaft torque at a certain moment during flight, in percentage (%).

[0065] PW 参考 The power corresponding to 100% rotor speed and 100% torque is the reference power, in kW; NR 实测 Measured rotor speed, unit n / min;

[0066] NR 参考 Reference rotor speed, i.e., the rated rotor speed, is expressed in n / min.

[0067] During helicopter flight, the real-time output power of the engine can be obtained from the engine output torque signal and rotor speed signal collected by the electromechanical system.

[0068] (2) Calculation of engine hourly fuel consumption

[0069] Most helicopters in the market are not equipped with fuel consumption sensors, and even those that are installed have questionable measurement accuracy. This paper proposes a method to generate a fuel consumption-power relationship formula for engines under different pressure altitudes and atmospheric static temperatures using data provided by engine bench tests.

[0070] In determining the engine hourly fuel consumption, the first step is to select a series of engine fuel consumption-power relationship formulas suitable for the current atmospheric conditions based on the pressure altitude and atmospheric static temperature signals collected by the atmospheric instrument during helicopter flight.

[0071] WF i =a×PW i +b

[0072] WF = a × PW + b

[0073] in:

[0074] WF represents the engine's hourly fuel consumption at a specific moment during flight, expressed in kg / h.

[0075] PW is the output torque of each engine at a certain moment during flight, measured in kW;

[0076] a and b are the coefficients corresponding to the air pressure, altitude, and temperature conditions.

[0077] Since the engine fuel consumption-power relationship formulas provided to the computer as input are based on typical demand and temperature conditions, if the helicopter is not in a typical state at a certain moment, the fuel consumption of each engine of the helicopter at that time is obtained through linear interpolation. Temperature and pressure altitude values ​​are taken at intervals according to the interpolation method that selects specific nearby values.

[0078] Assuming atmospheric conditions of 1600m altitude and 13℃, we select the coefficients a and b at nearby typical conditions of 1000m and 10℃, and 1000m and 20℃ respectively. Linear interpolation yields the coefficients a and b at 1000m and 13℃. Similarly, we obtain the coefficients a and b at 2000m and 13℃. Using the obtained coefficients a and b at 1000m and 13℃ and at 2000m and 13℃, we again perform linear interpolation to obtain the coefficients a and b at 1600m and 13℃.

[0079] (3) Calculation of remaining range and flight time

[0080] Remaining flight time, conceptually speaking, is the ratio of the helicopter's remaining fuel to its engine fuel consumption. In other words, it's calculated after obtaining the hourly fuel consumption of each helicopter engine.

[0081]

[0082] in:

[0083] GF represents the total fuel volume of the two fuel tanks at a certain moment during flight (taken from the electromechanical management computer), in kg.

[0084] WF represents the engine's hourly fuel consumption at a specific moment during flight, expressed in kg / h.

[0085] Remaining range is the product of remaining flight time and the current helicopter speed. Common helicopter speeds can be categorized as indicated airspeed, vacuum speed, and ground speed. Indicated airspeed is the speed displayed on the helicopter's airspeed gauge; vacuum speed is equivalent to the speed of undisturbed air; and ground speed is the helicopter's speed relative to the ground.

[0086] Indicated airspeed is the speed indicator commonly used by pilots. Indicated airspeed can be calculated to obtain the corresponding vacuum speed through density ratio conversion. Vacuum speed is often used in theoretical calculations for range calculations, assuming no wind conditions. Based on the relationship between vacuum speed, wind speed, and ground speed:

[0087]

[0088] It can be seen that the ground speed is the result of considering the wind speed effect on the helicopter speed. In the helicopter avionics system's inertial navigation, the measured ground speed can be directly extracted as the input for calculating the helicopter's remaining range.

[0089] L 剩余航程 =T 剩余航时 ×V 地速

[0090] Flight distance = Flight time × V 地速

[0091] in:

[0092] V 地速 The horizontal ground speed of the helicopter at a certain moment during flight (taken from the inertial navigation system), in km / h.

[0093] (4) Calculate the integer part of the value

[0094] Considering that the input parameters for the remaining range and flight time calculation method in this paper are all data collected from onboard equipment, and since the data characteristics of parameters such as ground speed, total fuel quantity GF, and instantaneous fuel consumption are inherently volatile, in order to facilitate the pilot's observation of the data, a method of rounding the range and flight time down to the tenth place is proposed, and the result is displayed to the pilot on the integrated display.

[0095] (5) Hovering status range and time display calculation

[0096] When a helicopter is hovering, the engine's power demand and fuel consumption are relatively high, while the ground speed is near zero. Following the above method, this would result in a shorter range and flight time. However, logically, a helicopter cannot remain hovering indefinitely.

[0097] This method proposes that when the helicopter is determined to be in a hovering state, the remaining range and flight time are calculated based on the helicopter's long-range speed and atmospheric conditions, which means that the displayed value is the theoretical calculation of the helicopter's range.

[0098]

[0099] in:

[0100] PW1 and PW2 are the output power of each engine at a certain moment during flight, in kW;

[0101] Q1 and Q2 represent the engine output shaft torque at a certain moment during flight, in percentage (%).

[0102] PW 参考 The power corresponding to 100% rotor speed and 100% torque is the reference power, in kW; NR 实测 Measured rotor speed, unit n / min;

[0103] NR 参考 Reference rotor speed, i.e., the rated rotor speed, is expressed in n / min.

[0104] During helicopter flight, the real-time output power of the engine can be obtained from the engine output torque signal and rotor speed signal collected by the electromechanical system.

[0105] (2) Calculation of engine hourly fuel consumption

[0106] Most helicopters in the market are not equipped with fuel consumption sensors, and even those that are installed have questionable measurement accuracy. This paper proposes a method to generate a fuel consumption-power relationship formula for engines under different pressure altitudes and atmospheric static temperatures using data provided by engine bench tests.

[0107] In determining the engine hourly fuel consumption, the first step is to select a series of engine fuel consumption-power relationship formulas suitable for the current atmospheric conditions based on the pressure altitude and atmospheric static temperature signals collected by the atmospheric instrument during helicopter flight.

[0108] WF i =a×PW i +b

[0109] WF = a × PW + b

[0110] in:

[0111] WF represents the engine's hourly fuel consumption at a specific moment during flight, expressed in kg / h.

[0112] PW is the output torque of each engine at a certain moment during flight, measured in kW;

[0113] a and b are the coefficients corresponding to the air pressure, altitude, and temperature conditions.

[0114] Since the engine fuel consumption-power relationship formulas provided to the computer as input are based on typical demand and temperature conditions, if the helicopter is not in a typical state at a certain moment, the fuel consumption of each engine of the helicopter at that time is obtained through linear interpolation. Temperature and pressure altitude values ​​are taken at intervals according to the interpolation method that selects specific nearby values.

[0115] Assuming atmospheric conditions of 1600m altitude and 13℃, we select the coefficients a and b at nearby typical conditions of 1000m and 10℃, and 1000m and 20℃ respectively. Linear interpolation yields the coefficients a and b at 1000m and 13℃. Similarly, we obtain the coefficients a and b at 2000m and 13℃. Using the obtained coefficients a and b at 1000m and 13℃ and at 2000m and 13℃, we again perform linear interpolation to obtain the coefficients a and b at 1600m and 13℃.

[0116] (3) Calculation of remaining range and flight time

[0117] Remaining flight time, conceptually speaking, is the ratio of the helicopter's remaining fuel to its engine fuel consumption. In other words, it's calculated after obtaining the hourly fuel consumption of each helicopter engine.

[0118]

[0119] in:

[0120] GF represents the total fuel volume of the two fuel tanks at a certain moment during flight (taken from the electromechanical management computer), in kg.

[0121] WF represents the engine's hourly fuel consumption at a specific moment during flight, expressed in kg / h.

[0122] Remaining range is the product of remaining flight time and the current helicopter speed. Common helicopter speeds can be categorized as indicated airspeed, vacuum speed, and ground speed. Indicated airspeed is the speed displayed on the helicopter's airspeed gauge; vacuum speed is equivalent to the speed of undisturbed air; and ground speed is the helicopter's speed relative to the ground.

[0123] Indicated airspeed is the speed indicator commonly used by pilots. Indicated airspeed can be calculated to obtain the corresponding vacuum speed through density ratio conversion. Vacuum speed is often used in theoretical calculations for range calculations, assuming no wind conditions. Based on the relationship between vacuum speed, wind speed, and ground speed:

[0124]

[0125] It can be seen that the ground speed is the result of considering the wind speed effect on the helicopter speed. In the helicopter avionics system's inertial navigation, the measured ground speed can be directly extracted as the input for calculating the helicopter's remaining range.

[0126] L 剩余航程 =T 剩余航时 ×V 地速

[0127] Flight distance = Flight time × V 地速

[0128] in:

[0129] V 地速 The horizontal ground speed of the helicopter at a certain moment during flight (taken from the inertial navigation system), in km / h.

[0130] (4) Calculate the integer part of the value

[0131] Considering that the input parameters for the remaining range and flight time calculation method in this paper are all data collected from onboard equipment, and since the data characteristics of parameters such as ground speed, total fuel quantity GF, and instantaneous fuel consumption are inherently volatile, in order to facilitate the pilot's observation of the data, a method of rounding the range and flight time down to the tenth place is proposed, and the result is displayed to the pilot on the integrated display.

[0132] (5) Hovering status range and time display calculation

[0133] When a helicopter is hovering, the engine's power demand and fuel consumption are relatively high, while the ground speed is near zero. Following the above method, this would result in a shorter range and flight time. However, logically, a helicopter cannot remain hovering indefinitely.

[0134] This method proposes that when the helicopter is determined to be in a hovering state, the remaining range and flight time are calculated based on the helicopter's long-range speed and atmospheric conditions, which means that the displayed value is the theoretical calculation of the helicopter's range.

[0135] This invention applies to the display of remaining range and flight time for helicopters. In addition to displaying remaining fuel, it provides pilots with more intuitive range and flight time information, replacing the experience-based assessment method. When the helicopter faces changes in atmospheric conditions, it can promptly respond with corresponding range and flight time adjustments. It intuitively presents the relationship between flight speed and flight range, providing pilots with a reference for making decisions on "arriving faster" or "arriving further." It considers the impact of wind speed on range and uses an appropriate computing source to calculate the range in the actual geographical coordinates. It also considers the method for calculating range and flight time when the helicopter is hovering. During the calculation process, it utilizes the current real-time parameters of the helicopter to calculate the remaining range and flight time, without considering the impact of reduced fuel consumption due to the decrease in helicopter weight caused by fuel consumption; therefore, the calculated numerical results have a certain degree of conservatism. When considering the stability of the data display, it uses a method of rounding down to the nearest ten, which also has a certain degree of conservatism.

Claims

1. A method for calculating the remaining flight time of a helicopter, characterized in that, The method includes: S1, calculates the output power of each engine on the helicopter; S2, calculate the engine hour fuel consumption of each engine based on its output power; S3 calculates the remaining flight time of the helicopter based on the total fuel of the helicopter and the engine hour fuel consumption of all engines.

2. The method for calculating the remaining flight time of a helicopter according to claim 1, characterized in that, The method further includes: S4 calculates the remaining range of the helicopter based on the remaining flight time.

3. The method for calculating the remaining flight time of a helicopter according to claim 2, characterized in that, S1 specifically refers to: Among them, PW i The output power of the i-th engine at a certain moment during flight, in kW; Q i The output shaft torque of the i-th engine at a certain moment during flight, expressed as a percentage. PW 参考 For reference power, the engine power at 100% rotor speed and 100% engine torque, in kW; NR 实测 The measured rotor speed is expressed in n / min. NR 参考 Reference rotor speed, unit: n / min; S 安装损失 This refers to the power loss after the engine is installed.

4. The method for calculating the remaining flight time of a helicopter according to claim 3, characterized in that, S2 specifically refers to: WF i =a×PW i +b Among them, WF i The hourly fuel consumption of the i-th engine at a certain moment during flight is expressed in kg / h. PW i The output torque of the i-th engine at a certain moment during flight, in kW; a and b are the engine fuel consumption-power coefficients under the corresponding air pressure altitude and temperature conditions at a certain moment.

5. The method for calculating the remaining flight time of a helicopter according to claim 4, characterized in that, S3 specifically refers to: Wherein, GF represents the total amount of fuel in all fuel tanks at a certain moment during flight.

6. The method for calculating the remaining flight time of a helicopter according to claim 4, characterized in that, S4 specifically refers to: L 剩余航程 =T 剩余航时 ×V 地速 Among them, V 地速 The horizontal ground speed of the helicopter at a certain moment during flight is expressed in km / h.

7. The method for calculating the remaining flight time of a helicopter according to claim 6, characterized in that, When the helicopter is hovering, V 地速 Calculated based on the long-distance flight speed of a helicopter.

8. The method for calculating the remaining flight time of a helicopter according to claim 4, characterized in that, The engine fuel consumption-power coefficient is obtained under typical air pressure, altitude, and temperature conditions. If the helicopter is not in typical conditions at a certain moment, the current helicopter engine fuel consumption-power coefficient is obtained by linear interpolation.

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