A method for setting the throttle of the rear engine of a three-engine propeller aircraft

Abstract

The present invention discloses a method for setting the throttle of the rear engine of a three-engine propeller aircraft. The steps are as follows: S1, combining and analyzing the rear engine vibration test data with the flight data to obtain the corresponding relationship between different throttles of the rear engine and the stress response of the rear engine structure, and combining the tensile strength of the main structural materials of the rear engine to determine the throttle that the rear engine cannot be used for a long time; S2, calculating the minimum takeoff throttle of the rear engine according to the takeoff weight and the situation of the departure airport; S3, calculating the minimum climb throttle of the rear engine according to the maximum flight altitude of the mission; S4, calculating the minimum cruise throttle of the rear engine according to the cruise altitude; S5, setting the throttle range of the rear engine based on vibration limitation in the flight phase according to the minimum, non-long-term usable, minimum takeoff, minimum climb, and minimum cruise throttles of the rear engine. The present invention reduces the vibration of the rear engine in the flight phase on the premise of meeting the minimum flight ability of the aircraft, ensures the safety of the aircraft, and is also conducive to the aircraft accumulating more engine operation data as an in-air engine test platform.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and particularly to a method for setting the throttle of the rear engine 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 strong endurance. Vibration is an important monitoring parameter of propeller engines. Excessive vibration will accelerate the fatigue damage of engine components, affect the engine life, and even affect flight safety.

[0003] For a three-engine propeller aircraft with two engines mounted on the wings and one engine mounted at the tail, the engine mounted on the left side of the wing is called the left engine, the engine mounted on the right side of the wing is called the right engine, and the left and right engines are collectively called the front engines, and the engine mounted at the tail is called the rear engine. On the one hand, for such aircraft, due to factors such as the installation structure of the rear engine and the propeller slipstream of the front engines, the vibration condition of the rear engine is worse than that of the front engines. During a long flight, the possibility of structural fatigue damage failure of the rear engine increases, and even affects flight safety. On the other hand, such aircraft can be used as an in-air test platform for engines. As the test object, the rear engine may need to conduct long-term flight tests under restricted operating conditions due to vibration reasons. Therefore, a method is needed that can not only meet the minimum flight ability requirements of the aircraft but also reduce the vibration of the rear engine and make the fatigue life of the structural components meet the requirements. Summary of the Invention

[0004] In view of this, the present invention discloses a method for setting the throttle of the rear engine of a three-engine propeller aircraft, aiming to reduce the vibration of the rear engine during the main flight stage on the premise of meeting the minimum flight ability of the aircraft, ensure the safe and long-term mission flight of the three-engine propeller aircraft, and also facilitate the aircraft to accumulate more engine operation data as an in-air test platform for engines.

[0005] The method for setting the throttle of the rear engine of a three-engine propeller aircraft disclosed by the present invention includes the following steps:

[0006] S1. Combine and analyze the rear engine vibration test data and flight data to determine the non-durable throttle of the rear engine;

[0007] S2. Calculate the minimum takeoff throttle of the rear engine according to the takeoff weight and the situation of the departure airport;

[0008] S3. Calculate the minimum climb throttle of the rear engine according to the maximum flight altitude of the mission;

[0009] S4. Calculate the minimum cruise throttle of the rear engine according to the cruise altitude;

[0010] S5, based on the vibration limit, determine the range of the rear engine throttle for the main flight phases according to the minimum afterburner, non-permanent use, minimum takeoff, minimum climb, and minimum cruise throttle settings.

[0011] Furthermore, in step S1, For a certain rear engine material under a certain throttle stress magnitude obtained from the simulation analysis of the rear engine vibration test data and flight data, select the maximum rear engine throttle that does not exceed the fatigue limit of the material , which is the non-permanent use throttle corresponding to the rear engine structural material.

[0012] Furthermore, let be the minimum throttle of the engine, be the maximum throttle of the engine, then ≤ ≤ , where is the throttle used by the engine. Select the minimum non-permanent use throttle among all the evaluated structural materials and reserve a safety margin, which is the rear engine non-permanent use throttle .

[0013] Furthermore, in step S2, determine the maximum takeoff roll distance according to the available distance at the departure airport . Among them, is the takeoff safety factor, 0 < <1.

[0014] ≤

[0015] Furthermore, according to the takeoff weight and the maximum takeoff roll distance , calculate the required thrust of the three engines for takeoff :

[0016] ;

[0017] .

[0018] In the above formula, is the required thrust of the three engines for takeoff, is the takeoff speed from the ground, is the takeoff true airspeed, is the standard atmospheric density at sea level, is the standard atmospheric density corresponding to the altitude of the departure airport, is the rolling friction coefficient, is the acceleration due to gravity, is the lift during takeoff roll, is the takeoff roll resistance.

[0019] Further, according to the engine thrust calculation model, calculate the speed as , the altitude is the elevation of the departure airport , and the maximum takeoff thrust of the forward engine in the maximum state .

[0020] Further, the engine thrust calculation model: Calculate the power coefficient corresponding to the propeller according to the engine throttle corresponding speed and the proximity ratio , then interpolate the power coefficient and the proximity ratio through the propeller database to obtain the propeller thrust coefficient , and then calculate the thrust according to the thrust coefficient :

[0021] ;

[0022] ;

[0023] .

[0024] In the above formula, is the engine shaft power; APR is the total pressure recovery coefficient of the engine inlet; is the standard atmospheric density corresponding to the altitude where the aircraft is located; RPM is the engine speed; is the transmission ratio corresponding to the engine and the propeller; D is the propeller diameter; V is the true airspeed of the aircraft.

[0025] Further, according to the takeoff three-engine required thrust , and the maximum takeoff thrust of the forward engine , calculate the thrust that the rear engine needs to provide:

[0026] .

[0027] Further, calculate the engine speed corresponding to according to the engine thrust calculation model, and determine the minimum takeoff throttle of the rear engine according to the throttle-speed correspondence relationship (if < , let = ).

[0028] Further, if > , then it is necessary to reduce the takeoff weight , and continue to execute step S2; < , perform step S3.

[0029] Further, in step S3, according to the takeoff weight , the maximum mission altitude , the elevation of the departure airport , the average climb rate , the climb fuel consumption , calculate the flight weight at the maximum mission altitude .

[0030] .

[0031] Further, according to the climb indicated airspeed corresponding to the flight weight , and the atmospheric density at sea-level airport 、the atmospheric density at mission altitude , calculate the climb true airspeed at the maximum mission altitude . .

[0032] Further, according to the flight weight , the minimum climb rate , the climb true airspeed , the speed corresponding to the aerodynamic drag calculate the three-engine required thrust for climb .

[0033] .

[0034] Further, calculate the maximum continuous climb thrust of the forward engine at the speed of and the altitude of the mission altitude according to the engine thrust calculation model.

[0035] Further, the three-engine required thrust for climb , and the maximum continuous climb thrust of the forward engine , calculate the thrust that the rear engine needs to provide.

[0036]

[0037] Further, calculate the engine speed corresponding to according to the engine thrust calculation model, and determine the minimum climb throttle of the rear engine according to the throttle-speed correspondence.

[0038] Further, if > , the takeoff weight needs to be reduced , continue to step S3; if < ,make = , execute step S4; if < < , execute step S4.

[0039] Further, in step S4, according to the aircraft cruising weight , lift coefficient , wing area S, gravitational acceleration g, cruising altitude The corresponding atmospheric density , calculate the cruising speed.

[0040]

[0041] 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 required thrust of the cruise three engines .

[0042]

[0043] Furthermore, the speed is calculated based on the engine thrust calculation model as , altitude is cruising altitude Maximum continuous climb thrust .

[0044] 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 .

[0045]

[0046] 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 .

[0047] Furthermore, in step S5, the main flight phases of the aircraft include takeoff, climb, cruise, descent, and landing. , The throttle should not be used for a long time .

[0048] Furthermore, according to the minimum takeoff throttle of the rear engine , The throttle that should not be used for a long time A rear engine takeoff throttle range is given, where is the throttle used by the rear engine during the takeoff phase of the aircraft:

[0049] ;

[0050] Furthermore, according to the minimum climb throttle of the rear engine , The throttle that should not be used for a long time A rear engine climb throttle range is given, where is the throttle used by the rear engine during the climb phase of the aircraft:

[0051] .

[0052] Furthermore, according to the minimum cruise throttle of the rear engine , The throttle that should not be used for a long time A rear engine cruise throttle range is given, where is the throttle used by the rear engine during the cruise phase of the aircraft:

[0053] .

[0054] Furthermore, the power demand during the glide phase and the landing phase is not high, and the minimum glide throttle and the minimum landing throttle are the minimum throttle . According to the minimum glide throttle and the minimum landing throttle of the rear engine , The throttle that should not be used for a long time A rear engine glide and landing throttle range is given, where is the throttle used by the rear engine during the cruise phase of the aircraft:

[0055] .

[0056] The beneficial effects of the present invention are:

[0057] The present invention provides a method for determining the non - durable throttle of the rear engine of a three - engine propeller aircraft through the rear engine vibration test data and the fatigue limit of the rear engine structural material.

[0058] The present invention innovatively provides a method for determining the minimum throttle of the rear engine of a three - engine propeller - powered aircraft during the takeoff, climb, and cruise phases.

[0059] The present invention can give the rear engine throttle range during the main flight phases of a three - engine propeller aircraft, and provide data support for reducing the rear engine vibration on the premise of ensuring the minimum flight ability of the aircraft, which is in line with the actual situation.

[0060] The present invention can be applied to an air test platform for an engine in the form of a three-engine propeller aircraft. According to the calculation of the throttle range of the rear engine, a flight test outline with safety, reliability, and rich test conditions is formulated. Description of the Drawings

[0061] Figure 1 is a flowchart of the method of the present invention;

[0062] Figure 2 is a graph showing the trend of stress response with engine throttle in the second embodiment of the present invention;

[0063] Figure 3 is a throttle-rotation speed relationship diagram of a certain new engine in the second embodiment of the present invention. Detailed Embodiments

[0064] The following describes in detail the specific embodiments of the present invention in conjunction with the embodiments, so that those skilled in the art of the present technology can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of the present technology, as long as various changes are within the scope defined by the appended claims and the spirit of the present invention clearly defined, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0065] Embodiment 1

[0066] As Figure 1 shown, a method for giving the throttle of the rear engine of a three-engine propeller aircraft includes the following steps:

[0067] S1. Combine and analyze the rear engine vibration test data and flight data to determine the non-permanent-use throttle of the rear engine;

[0068] S2. Calculate the minimum takeoff throttle of the rear engine according to the takeoff weight and the situation of the departure airport;

[0069] S3. Calculate the minimum climb throttle of the rear engine according to the maximum flight altitude of the mission;

[0070] S4. Calculate the minimum cruise throttle of the rear engine according to the cruise altitude;

[0071] S5. Give the throttle range of the rear engine based on vibration limitation for the main flight phases according to the minimum, non-permanent-use, minimum takeoff, minimum climb, and minimum cruise throttles of the rear engine.

[0072] In this embodiment, specifically, in step S1, taking the fatigue limits of different material structural components of the rear engine as limiting conditions to limit the throttle size of the rear engine, so that the rear engine structural stress during the flight of the aircraft all meets the limits, the failure of rear engine structural fatigue damage can be avoided.

[0073] The step S1 includes: is the throttle stress of a certain material in the rear engine obtained from the simulation analysis of the rear engine vibration test data and flight data. DT is the engine throttle, and j is the different structural materials of the rear engine; is the fatigue limit of the rear engine structural material j. When ≥ , the fatigue life of the structural member is limited, and fatigue failure may occur during use. When ≤ , the maximum throttle of the rear engine is the non-durable throttle corresponding to the rear engine structural material j.

[0074] In this embodiment, specifically, the step S1 further includes: setting as the minimum throttle of the engine, as the maximum throttle of the engine. Then ≤ ≤ , where DT is the throttle used by the engine. Screen out the minimum non-durable throttle among all the evaluated structural materials and reserve a safety margin, which is the non-durable throttle of the rear engine .

[0075] In this embodiment, specifically, the step S2 includes: determining the maximum takeoff roll distance according to the available distance L at the departure airport. Where is the takeoff safety factor, 0 < < 1.

[0076] ≤

[0077] In this embodiment, specifically, the step S2 further includes: calculating the takeoff three-engine required thrust and the maximum takeoff roll distance : :

[0078]

[0079]

[0080] In the above formula, is the takeoff three-engine required thrust, is the takeoff ground speed, is the takeoff true airspeed, is the standard atmospheric density at sea level, is the standard atmospheric density corresponding to the altitude of the departure airport, is the rolling friction coefficient, is the acceleration due to gravity, is the takeoff roll lift, is the takeoff roll resistance.

[0081] In this embodiment, specifically, step S2 further includes: calculating, according to the engine thrust calculation model, the maximum takeoff thrust of the front engine in the maximum state when the speed is and the altitude is the altitude of the departure airport . .

[0082] In this embodiment, specifically, in step S2, the engine thrust calculation model is: calculating the power corresponding to the propeller according to the engine throttle corresponding speed and the advance ratio , then interpolating the power coefficient and the close ratio through the propeller database to obtain the propeller thrust coefficient , and then calculating the thrust :

[0083] ;

[0084] ;

[0085] .

[0086] In the above formula, is the engine shaft power; APR is the total pressure recovery coefficient of the engine inlet; is the standard atmospheric density corresponding to the altitude where the aircraft is located; RPM is the engine speed; is the transmission ratio corresponding to the engine and the propeller; D is the propeller diameter; V is the true airspeed of the aircraft.

[0087] In this embodiment, specifically, step S2 further includes: calculating the thrust required for takeoff with three engines, and the maximum takeoff thrust of the front engine in the maximum state, and calculating the thrust that the rear engine needs to provide.

[0088] .

[0089] In this embodiment, specifically, step S2 further includes: calculating the engine speed corresponding to according to the engine thrust calculation model, and determining the minimum takeoff throttle of the rear engine according to the throttle-speed correspondence (if < , let = ).

[0090] In this embodiment, specifically, the step S2 further includes: if > , the takeoff weight needs to be reduced , continue to step S2; < , execute step S3.

[0091] In this embodiment, specifically, step S3 includes: according to the takeoff weight , maximum mission altitude , take-off airport altitude , average rate of climb , climb fuel consumption , calculate the flight weight to reach the maximum mission altitude .

[0092] .

[0093] In this embodiment, specifically, the step S3 further includes: according to the flight weight Corresponding climb speed indicator , and the sea-level airport atmospheric density , mission altitude atmospheric density , calculate the climb true airspeed corresponding to the maximum mission altitude .

[0094] .

[0095] In this embodiment, specifically, the 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 .

[0096] .

[0097] In this embodiment, specifically, the step S3 further includes: calculating the speed according to the engine thrust calculation model , height is mission height Maximum continuous climb thrust .

[0098] 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 .

[0099]

[0100] In this embodiment, specifically, the step S3 further includes: calculating according to the engine thrust calculation model The corresponding engine speed, and the minimum climbing throttle is determined according to the throttle-speed correspondence .

[0101] In this embodiment, specifically, the 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.

[0102] In this embodiment, specifically, step S4 includes: according to the cruising weight of the aircraft , lift coefficient , wing area S, gravitational acceleration g, cruising altitude The corresponding atmospheric density , calculate the cruising speed.

[0103]

[0104] In this embodiment, specifically, the 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 required thrust of the cruise three engines .

[0105]

[0106] In this embodiment, specifically, the step S4 further includes: calculating the speed according to the engine thrust calculation model , altitude is cruising altitude Maximum continuous climb thrust .

[0107] In this embodiment, specifically, the 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 .

[0108]

[0109] In this embodiment, specifically, step S4 further includes: calculating the engine speed corresponding to the engine thrust according to the engine thrust calculation model, and determining the minimum cruise throttle of the rear engine according to the throttle-speed correspondence . .

[0110] In this embodiment, specifically, in step S5, the main flight phases of the aircraft include takeoff, climb, cruise, descent, and landing. The minimum throttle of the rear engine is , and the non-durable throttle is .

[0111] In this embodiment, specifically, step S5 includes: giving the takeoff throttle range of the rear engine according to the minimum takeoff throttle of the rear engine , the non-durable throttle , where is the throttle used by the engine after the takeoff phase of the aircraft:

[0112] ;

[0113] In this embodiment, specifically, step S5 further includes: giving the climb throttle range of the rear engine according to the minimum climb throttle of the rear engine , the non-durable throttle , where is the throttle used by the engine after the climb phase of the aircraft:

[0114] .

[0115] In this embodiment, specifically, step S5 further includes: giving the cruise throttle range of the rear engine according to the minimum cruise throttle of the rear engine , the non-durable throttle , where is the throttle used by the engine after the cruise phase of the aircraft:

[0116] .

[0117] In this embodiment, specifically, in step S5, the power demand in the descent and landing phases is not high, and the minimum descent throttle and the minimum landing throttle are the minimum throttle . According to the minimum descent throttle and the minimum landing throttle of the rear engine , the non-durable throttle give the descent and landing throttle ranges of the rear engine, where For the engine to use the throttle during the cruise phase of the aircraft:

[0118] 。

[0119] Embodiment 2

[0120] Embodiment 2 is a specific application of a method for setting the throttle of the rear engine of a three - engine propeller aircraft proposed based on Embodiment 1, and the steps are the same as those in Embodiment 1.

[0121] In this embodiment, specifically, in step S1, an engine is installed at the tail of a three - engine propeller aircraft. The installation bracket is made of GH1140 alloy ( ), and the connecting bolt is made of 304 stainless steel ( ). According to the simulation of the rear - engine vibration test data and flight data, the stress response trends of the two structural components with the change of the engine throttle are as Figure 2 shown. It can be analyzed that the non - durable throttle of the bracket is 98%, and the non - durable throttle of the bolt is 89%. Considering the results of both and the safety margin, the non - durable throttle of the rear engine is set as 。

[0122] In this embodiment, specifically, in step S1, according to the design specification of this type of engine, the throttle - speed correspondence is shown in Figure 3 , the minimum throttle of the engine is , and the maximum throttle of the engine is 。

[0123] In this embodiment, specifically, in step S2, an airport with an altitude of 0m is selected, and the take - off safety factor = 0.75, and the take - off weight = 3000kg. By calculating through the method in Embodiment 1, the minimum take - off throttle of the rear engine is obtained as = 60%. Since < , step S3 is continued. The calculation process parameters for step S2 are shown in Table 1.

[0124] Table 1 Calculation process parameter table for step S2

[0125]

[0126] In this embodiment, specifically, in step S3, the maximum flight altitude of the mission = 7000m. By calculating through the method in Embodiment 1, the minimum climb throttle of the rear engine is obtained as = 63%. Since < < , continue to execute step S4. The calculation process parameters of step S3 are shown in Table 2.

[0127] Table 2 Calculation Process Parameter Table of Step S3

[0128]

[0129] In this embodiment, specifically, in step S4, let the cruise altitude = 6000m. Through the method of Embodiment 1, the minimum cruise throttle of the rear engine can be calculated as = 26%. The calculation process parameters of step S4 are shown in Table 3.

[0130] Table 3 Calculation Process Parameter Table of Step S4

[0131]

[0132] In this embodiment, specifically, in the said step S5, the takeoff throttle range of the rear engine is given by the method of Embodiment 1: 60% < < 85%; the climb throttle range of the rear engine is given: 63% < < 85%; the cruise throttle range of the rear engine is given: 26% < < 85%; the glide and landing throttle range of the rear engine is given: 20% < < .

[0133] The above embodiments only represent the specific implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several deformations and modifications can still be made, and these all belong to the protection scope of the present application.

Claims

1. A method for setting the throttle of the rear engine of a three-engine propeller aircraft, characterized in that including the following steps: S1. Combine and analyze the vibration test data after the event with the flight data to determine that the non-durable throttle after the event is ; S2. Calculate the minimum takeoff throttle of the rear engine based on the takeoff weight and the situation of the departure airport ; S3. Calculate the minimum climb throttle of the after - takeoff based on the maximum flight altitude of the mission ; S4. Calculate the minimum cruise throttle of the rear engine based on the cruise altitude ; S5, according to the minimum afterburner throttle , the non-durable afterburner throttle , the minimum takeoff afterburner throttle , the minimum climb afterburner throttle , the minimum cruise afterburner throttle to determine the afterburner throttle range of the aircraft in the main flight phases; The said step S1 includes: Based on the simulation of the vibration test data of the later-developed engine and the flight data, analyzing a certain later-developed engine material at a certain throttle stress magnitude of ; Screening out the maximum later-developed engine throttle that does not exceed the fatigue limit of the material , which is the non-durable throttle of the later-developed engine corresponding to this later-developed engine material; ​ The step S1 further includes: For the minimum throttle of the engine that starts later, For the maximum throttle of the engine, then , where Is the throttle used by the engine; Screen out the minimum non-durable throttle among all the evaluated structural materials as the non-durable throttle for the later start ; The step S2 includes: determining the maximum takeoff roll distance according to the available distance of the departure airport ; and then calculating the three-engine takeoff required thrust according to the takeoff weight ;​ The step S3 includes: According to the takeoff weight , the maximum mission altitude , the elevation of the departure airport , the average climb rate , the climb fuel consumption , calculate the flight weight to reach the maximum mission altitude ; Furthermore, according to the climb indicated airspeed corresponding to the flight weight , and the atmospheric density at sea level airport , the atmospheric density at mission altitude , calculate the climb true airspeed corresponding to the maximum mission altitude ; Furthermore, according to the flight weight , the minimum climb rate , the climb true airspeed , corresponding aerodynamic drag , calculate the three-engine required thrust for climb ; The step S3 further includes: calculating, according to an engine thrust calculation model, the maximum continuous state climb thrust of the front engine at a speed of and an altitude of the mission altitude ; and then calculating the thrust to be provided by the rear engine and the corresponding engine speed, and determining the minimum climb throttle of the rear engine according to the throttle-speed correspondence ; ; The step S4 includes: according to the cruising weight of the aircraft , lift coefficient , wing area , acceleration due to gravity , cruising altitude the corresponding atmospheric density , calculate the cruising speed , cruising drag , and then obtain the required thrust of three engines for cruising ; The step S4 further includes: calculating the maximum continuous state cruise thrust of the front engine at a speed of and an altitude of the cruise altitude , and then calculating the thrust that the rear engine needs to provide, and the corresponding engine speed, and determining the minimum cruise throttle of the rear engine according to the throttle-speed correspondence relationship . .

2. The method for setting the throttle of the rear engine 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, calculate the maximum takeoff thrust of the front engine of the aircraft when the altitude is the elevation of the departure airport ; and then calculate the thrust that the rear engine needs to provide as and the corresponding engine speed, and determine the minimum takeoff throttle of the rear engine according to the throttle-speed correspondence relationship , if < , then let = .​ 3. The method for setting the throttle of the rear engine of a three-engine propeller aircraft according to claim 1, characterized in that, If > , the takeoff weight needs to be reduced , and then continue to execute step S2; until < , then execute step S3.

4. The method for setting the throttle of the rear engine of a three-engine propeller aircraft according to claim 1, characterized in that, If > , the takeoff weight needs to be reduced , and step S3 is continued; if < , then let = , and step S4 is executed; if < < , step S4 is executed.

5. A method for setting the throttle of the rear engine of a three-engine propeller aircraft according to claim 1, characterized in that The step S5 includes: The flight phases of the aircraft include takeoff, climb, cruise, descent, and landing; the minimum throttle of the rear engine is , and the non-durable throttle is .

6. The method for setting the throttle of the rear engine of a three-engine propeller aircraft according to claim 5, characterized in that, According to the minimum takeoff throttle for afterburner and the non - sustainable throttle a given afterburner takeoff throttle range is provided, where is the throttle used by the engine during the takeoff phase of the aircraft: ＜ ＜ 。 7. A method for setting the throttle of the rear engine of a three-engine propeller aircraft according to claim 5, characterized in that: According to the minimum climb throttle of the rear engine and the non - durable throttle Given the rear - engine climb throttle range, where is the throttle used by the rear engine during the climb phase of the aircraft: ＜ ＜ 。 8. A method for setting the throttle of the rear engine of a three-engine propeller aircraft according to claim 5, characterized in that: According to the minimum cruise throttle of the rear engine and the non - durable throttle a rear - engine cruise throttle range is given, where is the throttle used by the rear engine during the cruise phase of the aircraft: ＜ ＜ 。 9. A method for setting the throttle of the rear engine of a three-engine propeller aircraft according to claim 5, characterized in that: The power demand during the gliding phase and the landing phase is not high, and the minimum gliding throttle and the minimum landing throttle are the minimum throttle ; According to the minimum throttle , the non-durable throttle is given to set the range of the throttle for the afterburner during gliding and landing. Among them, is the throttle used by the engine during the cruise phase of the aircraft: ＜ ＜ 。

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