Method for giving rear accelerator of three-engine propeller aircraft

Abstract

The invention discloses a three-engine propeller aircraft back-engine accelerator setting method, which comprises the following steps: S1, analyzing back-engine vibration test data and flight data in a combined manner to obtain a corresponding relationship between different back-engine accelerators and back-engine structural stress response, and determining a back-engine accelerator which cannot be used for a long time in combination with the tensile strength of a main structural material of a back engine; s2, calculating a later minimum takeoff accelerator according to the takeoff weight and the takeoff airport condition; s3, calculating a later minimum climbing accelerator according to the maximum flight height of the task; s4, calculating a later minimum cruise throttle according to the cruise height; and S5, according to the minimum later accelerator, the immeasurable minimum take-off accelerator, the minimum climbing accelerator and the minimum cruise accelerator, the range of the later accelerator based on the vibration limitation in the flight stage is given. On the premise that the lowest flight capability of the aircraft is met, the later vibration condition in the flight stage is relieved, the safety of the aircraft is guaranteed, and the aircraft can serve as an engine air test platform to accumulate more engine operation data.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft, and in particular to a method for setting a rear throttle of a three-engine propeller aircraft. Background Art

[0002] In recent years, aircraft have developed rapidly. For aircraft using propeller engines, they have the characteristics of low cost and long endurance. Vibration is an important monitoring parameter of propeller engines. Excessive vibration will accelerate the fatigue damage of engine components, shorten the engine life, and even affect flight safety.

[0003] For three-engine propeller aircraft with two wing-mounted and one tail-mounted, the engine on the left side of the wing is called the left engine, the engine on the right side of the wing is called the right engine, the left and right engines are collectively called the front engine, and the tail-mounted engine is called the rear engine. On the one hand, for this type of aircraft, due to the influence of factors such as the rear engine installation structure and the front engine propeller slipstream, the vibration of the rear engine is worse than that of the front engine. The possibility of structural fatigue damage failure of the rear engine during long-term flight increases, and even affects flight safety. On the other hand, this type of aircraft can be used as an aerial test platform for the engine. As a test object, the rear engine may need to undergo long-term flight tests under restricted working conditions due to vibration. Therefore, a method is needed that can not only meet the minimum flight capability requirements of the aircraft mission, but also reduce the vibration of the rear engine so that the fatigue life of the structural parts meets the requirements. Summary of the invention

[0004] In view of this, the present invention discloses a method for setting the after-engine throttle of a three-engine propeller aircraft, which aims to reduce the vibration of the after-engine in the main flight stage under the premise of meeting the minimum flight capability of the aircraft, ensure the three-engine propeller aircraft to carry out mission flight safely and for a long time, and also help the aircraft to accumulate more engine operation data as an engine aerial test platform.

[0005] The present invention discloses a method for setting a rear throttle of a three-engine propeller aircraft, comprising the following steps: S1, combine the vibration test data of the rear engine with the flight data for analysis, and determine that the rear engine cannot use the throttle for a long time; S2, calculate the minimum takeoff throttle based on the takeoff weight and takeoff airport conditions; S3, calculate the minimum climb throttle based on the mission maximum flight altitude; S4, calculate the minimum cruise throttle according to the cruise altitude; S5, the rear engine throttle range based on vibration limitations is given for the main flight phases based on the rear engine minimum, unusable, minimum takeoff, minimum climb, and minimum cruise throttles.

[0006] Further, in step S1, To screen out the stress of a certain post-engine material at a certain throttle according to the post-engine vibration test data and flight data simulation analysis. Does not exceed the material fatigue limit Maximum rear throttle , that is, the throttle that cannot be used for a long time corresponding to the post-production structural material.

[0007] Further, let is the minimum throttle of the engine, is the maximum throttle of the engine, then ≤ ≤ ,in, Use the throttle for the engine. Screen out the smallest throttle that cannot be used for a long time among all the evaluated structural materials and reserve a safety margin, which is the throttle that cannot be used for a long time. .

[0008] Further, in step S2, according to the available distance of the departure airport Determine the maximum takeoff run distance .in The safety factor for takeoff is 0< <1.

[0009] ≤

[0010] Furthermore, according to the takeoff weight and maximum takeoff run distance , calculate the required thrust of the three engines for takeoff : ; .

[0011] In the above formula, is the required thrust of the three engines for takeoff. is the takeoff surface speed, True airspeed for takeoff, is the standard atmospheric density at sea level, is the standard atmospheric density corresponding to the altitude of the take-off airport, is the rolling friction coefficient, is the acceleration due to gravity, For takeoff roll lift, is the takeoff roll resistance.

[0012] Furthermore, according to the engine thrust calculation model, the speed is calculated as , height is the altitude of the take-off airport When the front engine is at maximum takeoff thrust .

[0013] Furthermore, the engine thrust calculation model: Calculate the power coefficient corresponding to the propeller according to the speed corresponding to the engine throttle and close ratio , and then calculate the power coefficient according to the propeller database and close ratio Interpolate to get the propeller thrust coefficient , and then calculate the thrust according to the tension coefficient : ; ; .

[0014] In the above formula, is the engine shaft power; APR is the engine intake total pressure recovery coefficient; is the standard atmospheric density corresponding to the altitude of the aircraft; RPM is the engine speed; is the transmission ratio between the engine and the propeller; D is the propeller diameter; V is the flight speed of the aircraft (true speed).

[0015] Furthermore, according to the thrust requirements of the three engines for takeoff , and the maximum takeoff thrust of the front engine , calculate the thrust required by the rear engine : .

[0016] Furthermore, according to the engine thrust calculation model, The corresponding engine speed, and the minimum takeoff throttle for the rear engine is determined based on the throttle-speed correspondence (like < ,make = ).

[0017] Furthermore, if > , the takeoff weight needs to be reduced , continue to step S2; < , execute step S3.

[0018] Further, in step S3, according to the takeoff weight , mission maximum altitude , take-off airport altitude , average climb rate , climb fuel consumption , calculate the flight weight to reach the maximum mission altitude .

[0019] .

[0020] Further, according to the flight weight Corresponding climb speed , and the sea level airport atmospheric density , Atmospheric density at mission altitude , calculate the true climbing speed corresponding to the maximum mission altitude . .

[0021] Further, according to the flight weight , minimum climb rate , climb true airspeed ,speed Corresponding aerodynamic resistance Calculate the three-engine thrust required for climbing .

[0022] .

[0023] Furthermore, the speed is calculated according to the engine thrust calculation model: , height is the mission height Maximum continuous climb thrust .

[0024] Furthermore, the three-engine thrust required for climbing , and the maximum continuous climb thrust of the front engine , calculate the thrust required by the rear engine .

[0025]

[0026] Furthermore, according to the engine thrust calculation model, The corresponding engine speed, and the minimum climbing throttle for the rear engine is determined according to the throttle-speed correspondence .

[0027] Furthermore, if > , the takeoff weight needs to be reduced , continue to step S3; if < ,make = , execute step S4; if < < , execute step S4.

[0028] Further, in step S4, according to the cruising weight of the aircraft , lift coefficient , wing area S, gravity acceleration g, cruising altitude The corresponding atmospheric density , calculate the cruising speed.

[0029]

[0030] Furthermore, according to the cruising speed of the aircraft , drag coefficient , wing area S, cruising altitude The corresponding atmospheric density , calculate the cruise resistance , and then get the cruise three-engine required thrust .

[0031]

[0032] Furthermore, the speed is calculated according to the engine thrust calculation model: , altitude is cruising altitude Maximum continuous climb thrust .

[0033] Furthermore, according to the cruise three-engine thrust requirements , and the maximum continuous climb thrust of the front engine , calculate the thrust required by the rear engine .

[0034]

[0035] Furthermore, according to the engine thrust calculation model, The corresponding engine speed, and the minimum cruise throttle is determined according to the throttle-speed correspondence .

[0036] Further, in step S5, the main flight phases of the aircraft include take-off, climb, cruise, descent, and landing. , Do not use the throttle for a long time .

[0037] Furthermore, according to the minimum takeoff throttle of the rear engine , Do not use the throttle for a long time Given the throttle range for launch, To use the throttle for the engines after the aircraft takes off: ; Furthermore, according to the minimum climbing throttle of the rear engine , Do not use the throttle for a long time Given the rear-end climb throttle range, where To use the throttle for the engines after the vehicle climbs: .

[0038] Furthermore, according to the minimum cruise throttle of the rear engine , Do not use the throttle for a long time Given the cruise throttle range, To use the throttle for the engines after the vehicle cruise phase: .

[0039] Furthermore, the power requirements for the descent and landing phases are not high, and the minimum descent throttle and the minimum landing throttle are the minimum throttle . According to the minimum descent throttle and minimum landing throttle , Do not use the throttle for a long time Given the after launch descent and landing throttle range, To use the throttle for the engines after the vehicle cruise phase: .

[0040] The beneficial effects of the present invention are: The invention provides a method for determining a throttle of a rear engine of a three-engine propeller aircraft that cannot be used for a long time through rear engine vibration test data and fatigue limit of rear engine structural materials.

[0041] The present invention innovatively provides a method for determining the minimum throttle of a three-engine propeller-powered aircraft during take-off, climbing and cruising stages.

[0042] The present invention can provide a post-engine throttle range for a three-engine propeller aircraft in a main flight phase, and provide data support for alleviating post-engine vibration under the premise of ensuring the minimum flight capability of the aircraft, which is in line with actual conditions.

[0043] The present invention can be applied to an aerial test platform of an engine in the form of a three-engine propeller aircraft, and a safe and reliable flight test outline with rich test conditions can be formulated according to the calculation of the post-engine throttle range. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a flow chart of the method of the present invention; Figure 2 A stress response versus engine throttle variation trend diagram in the second embodiment of the present invention; Figure 3 This is a throttle-speed relationship diagram of a new type of engine in Example 2 of the present invention. DETAILED DESCRIPTION

[0045] The specific implementation modes of the present invention are described in detail below in conjunction with the embodiments so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and clarified by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0046] Embodiment 1

[0047] like Figure 1 As shown, a method for setting the rear throttle of a three-engine propeller aircraft includes the following steps: S1, combine the vibration test data of the rear engine with the flight data for analysis, and determine that the rear engine cannot use the throttle for a long time; S2, calculate the minimum takeoff throttle based on the takeoff weight and takeoff airport conditions; S3, calculate the minimum climb throttle based on the mission maximum flight altitude; S4, calculate the minimum cruise throttle according to the cruise altitude; S5, the rear engine throttle range based on vibration limitations is given for the main flight phases based on the rear engine minimum, unusable, minimum takeoff, minimum climb, and minimum cruise throttles.

[0048] In this embodiment, specifically, in step S1, the fatigue limit of the rear-stage structural parts of different materials is used as a restriction condition to limit the size of the rear-stage throttle, so that when the stress of the rear-stage structure during the flight of the aircraft meets the restriction, fatigue damage of the rear-stage structure can be avoided.

[0049] The step S1 comprises: is the stress of a certain material of the rear engine at a certain throttle obtained based on the rear engine vibration test data and flight data simulation analysis, DT is the engine throttle, j is the different structural materials of the rear engine; is the fatigue limit of the subsequent structural material j, when ≥ When the fatigue life of the structural parts is limited, fatigue failure may occur during the service life. ≤ Maximum rear throttle That is the throttle that cannot be used for a long time corresponding to the post-structural material j.

[0050] In this embodiment, specifically, the step S1 further includes: is the minimum throttle of the engine, is the maximum throttle of the engine, then ≤ ≤ , where DT is the engine throttle. The smallest throttle that cannot be used for a long time among all the evaluated structural materials is selected and a safety margin is reserved, which is the throttle that cannot be used for a long time. .

[0051] In this embodiment, specifically, step S2 includes: determining the maximum takeoff run distance according to the available distance L of the takeoff airport .in The safety factor for takeoff is 0< <1.

[0052] ≤ In this embodiment, specifically, step S2 further includes: according to the takeoff weight and maximum takeoff run distance , calculate the required thrust of the three engines for takeoff :

[0053]

[0054] In the above formula, is the required thrust of the three engines for takeoff. is the takeoff surface speed, True airspeed for takeoff, is the standard atmospheric density at sea level, is the standard atmospheric density corresponding to the altitude of the take-off airport, is the rolling friction coefficient, is the acceleration due to gravity, For takeoff roll lift, is the takeoff roll resistance.

[0055] In this embodiment, specifically, step S2 further includes: calculating the speed according to the engine thrust calculation model: , height is the altitude of the take-off airport When the front engine is at maximum takeoff thrust .

[0056] In this embodiment, specifically, in step S2, the engine thrust calculation model is: the power corresponding to the propeller is calculated according to the speed corresponding to the engine throttle and distance ratio , and then calculate the power coefficient according to the propeller database and close ratio Interpolate to get the propeller thrust coefficient , and then calculate the thrust according to the tension coefficient : ; ; .

[0057] In the above formula, is the engine shaft power; APR is the engine intake total pressure recovery coefficient; is the standard atmospheric density corresponding to the altitude of the aircraft; RPM is the engine speed; is the transmission ratio between the engine and the propeller; D is the propeller diameter; V is the flight speed of the aircraft (true speed).

[0058] In this embodiment, specifically, step S2 further includes: according to the thrust requirement of the three engines for takeoff, , and the maximum takeoff thrust of the front engine , calculate the thrust required by the rear engine .

[0059] .

[0060] In this embodiment, specifically, step S2 further includes: calculating according to the engine thrust calculation model The corresponding engine speed, and the minimum takeoff throttle for the rear engine is determined based on the throttle-speed correspondence (like < ,make = ).

[0061] In this embodiment, specifically, step S2 further includes: if > , the takeoff weight needs to be reduced , continue to step S2; < , execute step S3.

[0062] In this embodiment, specifically, step S3 includes: according to the takeoff weight , mission maximum altitude , take-off airport altitude , average climb rate , climb fuel consumption , calculate the flight weight to reach the maximum mission altitude .

[0063] .

[0064] In this embodiment, specifically, step S3 further includes: according to the flight weight Corresponding climb speed , and the sea level airport atmospheric density , Atmospheric density at mission altitude , calculate the true climbing speed corresponding to the maximum mission altitude .

[0065] .

[0066] In this embodiment, specifically, step S3 further includes: according to the flight weight , minimum climb rate , climb true airspeed ,speed Corresponding aerodynamic resistance Calculate the three-engine thrust required for climbing .

[0067] .

[0068] In this embodiment, specifically, step S3 further includes: calculating the speed according to the engine thrust calculation model: , height is the mission height Maximum continuous climb thrust .

[0069] In this embodiment, specifically, step S3 further includes: climbing three-engine required thrust , and the maximum continuous climb thrust of the front engine , calculate the thrust required by the rear engine .

[0070]

[0071] In this embodiment, specifically, step S3 further includes: calculating according to the engine thrust calculation model The corresponding engine speed, and the minimum climbing throttle for the rear engine is determined according to the throttle-speed correspondence .

[0072] In this embodiment, specifically, step S3 further includes: if > , the takeoff weight needs to be reduced , continue to step S3; if < ,make = , execute step S4; if < < , execute step S4.

[0073] In this embodiment, specifically, step S4 includes: according to the cruising weight of the aircraft , lift coefficient , wing area S, gravity acceleration g, cruising altitude The corresponding atmospheric density , calculate the cruising speed.

[0074]

[0075] In this embodiment, specifically, step S4 further includes: according to the cruising speed of the aircraft , drag coefficient , wing area S, cruising altitude The corresponding atmospheric density , calculate the cruise resistance , and then get the cruise three-engine required thrust .

[0076]

[0077] In this embodiment, specifically, step S4 further includes: calculating the speed according to the engine thrust calculation model: , altitude is cruising altitude Maximum continuous climb thrust .

[0078] In this embodiment, specifically, step S4 further includes: according to the cruise three-engine thrust requirement , and the maximum continuous climb thrust of the front engine , calculate the thrust required by the rear engine .

[0079]

[0080] In this embodiment, specifically, step S4 further includes: calculating according to the engine thrust calculation model The corresponding engine speed, and the minimum cruise throttle is determined according to the throttle-speed correspondence .

[0081] In this embodiment, specifically, in step S5, the main flight phases of the aircraft include take-off, climb, cruise, descent, and landing. , Do not use the throttle for a long time .

[0082] In this embodiment, specifically, step S5 includes: according to the minimum takeoff throttle of the rear engine , Do not use the throttle for a long time Given the throttle range for launch, To use the throttle for the engines after the aircraft takes off: ; In this embodiment, specifically, step S5 further includes: according to the minimum climbing throttle of the rear engine, , Do not use the throttle for a long time Given the rear-end climb throttle range, where To use the throttle for the engines after the vehicle climbs: .

[0083] In this embodiment, specifically, step S5 further includes: according to the minimum cruise throttle of the rear engine, , Do not use the throttle for a long time Given the cruise throttle range, To use the throttle for the engines after the vehicle cruise phase: .

[0084] In this embodiment, specifically, step S5 further includes: the power demand in the descent stage and the landing stage is not high, and the minimum descent throttle and the minimum landing throttle are the minimum throttle. . According to the minimum descent throttle and minimum landing throttle , Do not use the throttle for a long time Given the after launch descent and landing throttle range, To use the throttle for the engines after the vehicle cruise phase: .

[0085] Embodiment 2 Embodiment 2 is a specific application of a method for setting a rear throttle of a three-engine propeller aircraft proposed in Embodiment 1, and the steps are the same as those in Embodiment 1.

[0086] In this embodiment, specifically, in step S1, a certain engine is installed at the tail of a three-engine propeller aircraft, and the mounting bracket material is GH1140 alloy ( ), the connecting bolts are 304 stainless steel ( ), according to the post-vibration test data and flight data simulation, the stress response of the two structural parts changes with the engine throttle as shown in the following figure: Figure 2 The analysis shows that the unusable throttle of the bracket is 98%, and the unusable throttle of the bolt is 89%. Combining the results of the two and taking into account the safety margin, the unusable throttle of the latter is .

[0087] In this embodiment, specifically, in step S1, according to the design specification of the engine, the throttle-speed correspondence relationship is shown in Figure 3 , minimum engine throttle , engine maximum throttle .

[0088] In this embodiment, specifically, in step S2, a certain altitude is selected. For an airport with a takeoff safety factor of 0m, =0.75, takeoff weight =3000kg, the minimum takeoff throttle for the rear engine can be calculated by the method in Example 1. = 60%, due to < , and continue to step S3. The calculation process parameters of step S2 are shown in Table 1.

[0089] Table 1 Parameters of step S2 calculation process

[0090] In this embodiment, specifically, in step S3, the maximum flight altitude of the mission is =7000m, the minimum climbing throttle for the rear launch can be calculated by the method of Example 1 = 63%, due to < < , and continue to step S4. The calculation process parameters of step S3 are shown in Table 2.

[0091] Table 2 Calculation process parameters of step S3

[0092] In this embodiment, specifically, in step S4, the cruising altitude is set to =6000m, the minimum cruise throttle for the rear engine can be calculated by the method in Example 1. =26%. The calculation process parameters of step S4 are shown in Table 3.

[0093] Table 3 Calculation process parameters of step S4

[0094] In this embodiment, specifically, in step S5, the throttle range for the subsequent launch is given by the method of embodiment 1: 60%< <85%; given rear-end climb throttle range: 63%< <85%; given cruise throttle range: 26%< <85%; given after-glide, landing throttle range: 20%< < .

[0095] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and modifications can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A method for setting the rear throttle of a three-engine propeller aircraft, characterized in that: The following steps are involved: S1, analyze the vibration test data of the rear engine and the flight data, and determine that the throttle of the rear engine cannot be used for a long time. ; S2, calculate the minimum takeoff throttle for the rear engine based on the takeoff weight and takeoff airport conditions ; S3, calculate the minimum climb throttle based on the mission maximum flight altitude ; S4, calculate the minimum cruise throttle based on the cruise altitude ; S5, according to the minimum throttle of the rear engine , Do not use the throttle for a long time after starting , minimum takeoff throttle for the rear engine , minimum climbing throttle for rear launch , Minimum cruise throttle for rear engine The aft throttle range for a given aircraft during the primary flight phase.

2. A method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S1 comprises: According to the post-vibration test data and flight data simulation, a post-material At a certain throttle stress ; Filter out Does not exceed the material fatigue limit Maximum rear throttle , that is, the throttle of the rear engine corresponding to the rear engine structural material cannot be used for a long time.

3. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S1 further includes: The minimum throttle for the rear engine, is the maximum throttle of the engine, then ,in, Use the throttle for the engine; select the smallest throttle that cannot be used for a long time among all the evaluated structural materials, which is the throttle that cannot be used for a long time after the engine is launched .

4. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S2 comprises: Determine the maximum takeoff run distance based on the distance available at the takeoff airport ; Then according to the takeoff weight Calculate the required thrust of three engines for takeoff .

5. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S2 further includes: According to the engine thrust calculation model, the calculated altitude is the altitude of the take-off airport. When the aircraft sends out the maximum takeoff thrust ; Then calculate the thrust required by the rear engine as and the corresponding engine speed, and determine the minimum takeoff throttle based on the throttle-speed correspondence ,like < , then let = .

6. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: like > , the takeoff weight needs to be reduced Then, continue to execute step S2; until < , then execute step S3.

7. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S3 comprises: According to take-off weight , mission maximum altitude , take-off airport altitude , average climb rate , climb fuel consumption , calculate the flight weight to reach the maximum mission altitude ; And then according to the flight weight Corresponding climb speed , and the sea level airport atmospheric density , Atmospheric density at mission altitude , calculate the true climbing speed corresponding to the maximum mission altitude ; And then according to the flight weight , minimum climb rate , climb true airspeed , Corresponding aerodynamic resistance , calculate the three-engine thrust required for climbing .

8. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S3 further includes: The speed is calculated based on the engine thrust calculation model: , height is the mission height Maximum continuous climb thrust ; Then calculate the thrust required by the rear engine And the corresponding engine speed, and determine the minimum climbing throttle according to the throttle-speed correspondence .

9. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: like > , the takeoff weight needs to be reduced , continue to step S3; if < , then let = , execute step S4; if < < , execute step S4.

10. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S4 comprises: According to the cruising weight of the aircraft , lift coefficient , wing area , the acceleration due to gravity , cruising altitude The corresponding atmospheric density , calculate the cruising speed , Cruise resistance , and then get the required thrust of the cruise three engines .

11. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S4 further includes: The speed is calculated based on the engine thrust calculation model: , altitude is cruising altitude Maximum continuous cruise thrust , and then calculate the thrust required by the rear engine And the corresponding engine speed, and determine the minimum cruise throttle according to the throttle-speed correspondence .

12. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 1, characterized in that: The step S5 comprises: The flight phases of the aircraft include take-off, climb, cruise, descent, and landing; the minimum throttle for the rear launch is , Do not use the throttle for a long time .

13. A method for setting the rear throttle of a three-engine propeller aircraft according to claim 12, characterized in that: According to the minimum takeoff throttle , Do not use the throttle for a long time Given the throttle range for launch, To use the throttle for the engines after the aircraft takes off: ＜ ＜ 。 14. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 12, characterized in that: According to the minimum climbing throttle , Do not use the throttle for a long time Given the rear-end climb throttle range, To use the throttle for the engines after the vehicle climbs: ＜ ＜ 。 15. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 12, characterized in that: According to the minimum cruise throttle , Do not use the throttle for a long time Given the cruise throttle range, To use the throttle for the engines after the vehicle cruise phase: ＜ ＜ 。 16. The method for setting the rear throttle of a three-engine propeller aircraft according to claim 12, characterized in that: The power demand during the descent and landing phases is not high, and the minimum descent throttle and the minimum landing throttle are the minimum throttle. ; Based on minimum throttle , Do not use the throttle for a long time Given the after launch descent and landing throttle range, To use the throttle for the engines after the vehicle cruise phase: ＜ ＜ 。

Images