Load-carrying voyage model research method of transport aircraft

Abstract

The invention belongs to the technical field of aircraft performance design, and particularly relates to a load range model research method for a transport aircraft, which comprises the following steps of: firstly, constructing a weight parameter model for aircraft load range evaluation by combining a typical mission profile according to the maximum takeoff weight of a transport aircraft and aircraft weight statistical data; then developing a flight distance performance model for load range evaluation based on the specific range parameter of each task section of the transport plane; and finally, inputting data of different load conditions of the transport aircraft by taking the load voyage calculation model as a carrier, and calculating a corresponding voyage result and an operation efficiency result. In this way, construction of a transport aircraft load range model and evaluation of a load range result are achieved. Through an overall weight model, a mission profile model and a flight performance model of the transport aircraft, a set of mathematical relationship between key design parameters and core capability indexes of the transport aircraft is established, and the mathematical relationship is used for evaluating voyage and operation efficiency results under different load conditions. The method is visual and clear, and the calculation process is convenient.

Description

Technical Field

[0001] This application belongs to the technical field of aircraft performance design, and specifically relates to a research method for a load-range model of a transport aircraft. Background Technology

[0002] Transport aircraft are aircraft that perform air transport missions, capable of carrying out long-distance transport of a certain number of personnel or supplies. As a means of transportation with high speed and large transport capacity, transport aircraft effectively expand the transport range of the military and airlines, and improve transport efficiency. Major military powers around the world attach great importance to the development of their air transport systems, investing huge resources to maintain and improve their air transport support capabilities; airlines invest heavily in purchasing various types of transport aircraft from companies such as Airbus and Boeing to expand their air transport business.

[0003] Transport aircraft typically operate by loading various payloads as needed and then flying along a designed route to land at the target airport.

[0004] Based on the operational methods of transport aircraft, payload range is a core capability indicator, meaning the aircraft can transport a load of x tons of cargo to a target airport y kilometers away from its takeoff airport. Aircraft designers typically use payload range charts to illustrate this capability. Data affecting the aircraft's payload range include aerodynamic characteristics, dynamic characteristics, overall weight parameters, and mission profile parameters. At various stages of aircraft development, this data is provided by engineers from multiple disciplines, and finally, flight performance engineers compile, summarize, and calculate it to obtain the payload range result.

[0005] Currently, there are shortcomings in the rapid assessment of core capability indicators for transport aircraft by overall aircraft designers. Firstly, assessing the payload and range of transport aircraft requires coordination among multiple disciplines, resulting in a lengthy calculation cycle. Secondly, this assessment involves a large amount of data, and overall aircraft designers are more focused on the core design parameters and the relationships between them. Therefore, developing an intuitive, clear, and convenient method for assessing the payload and range of transport aircraft is crucial. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a method for studying the payload range model of transport aircraft, thereby resolving the problem in the prior art of effectively assessing the payload range of transport aircraft.

[0007] The technical solution of this application is: a method for studying the payload-range model of a transport aircraft, including:

[0008] Based on the maximum takeoff weight and aircraft weight statistics of transport aircraft, a weight parameter model for evaluating aircraft payload range is constructed in combination with typical mission profiles.

[0009] A flight distance performance model for payload range evaluation is established based on the specific range parameters of each mission segment of the transport aircraft.

[0010] Based on the weight parameter model for aircraft payload range assessment and the flight distance performance model for aircraft payload range assessment, data of different payload conditions of transport aircraft are input to calculate the corresponding range results and operational efficiency results.

[0011] Preferably, the aircraft weight statistics include the aircraft's empty weight, maximum fuel weight, maximum payload weight, takeoff weight, and maximum takeoff weight.

[0012] The takeoff weight W0 includes:

[0013] ;

[0014] In the formula: Woe is the empty weight of the aircraft; Wfuel is the weight of the aircraft fuel; Wpl is the loaded weight.

[0015] Preferably, the method for constructing the weight parameter model for aircraft payload range assessment is as follows:

[0016] The formula for calculating the weight of the aircraft in each mission segment is as follows:

[0017] ;

[0018] In the formula, W1 is the starting weight of the climb, W2 is the starting weight of the cruise, W3 is the starting weight of the descent, W4 is the starting weight of the landing, W5 is the starting weight of the taxiing, and W6 is the ending weight of the taxiing.

[0019] The average flight weight during the climb is as follows:

[0020] ;

[0021] The average flight weight during descent is as follows:

[0022] ;

[0023] The average flight weight during cruise is as follows:

[0024] ;

[0025] The formula for calculating the fuel weight Wfuel during flight is as follows:

[0026] ;

[0027] The maximum payload capacity of the transport aircraft, Wpl,max, is:

[0028] ;

[0029] The values ​​of Wfuel, Wpl, and W0 are obtained. Based on the determined values ​​of Wfuel, Wpl, and W0, the final weight Wi and the initial weight Wi-1 of the transport aircraft in each mission segment of the mission profile are calculated.

[0030] Preferably, the flight distance performance model for payload range assessment includes a comparative range assessment model for each mission segment of the transport aircraft and a flight distance assessment model for each mission segment of the transport aircraft.

[0031] The cruise segment's specific range (SRcruise) refers to the cruising distance achieved per unit weight of fuel consumed, calculated as follows:

[0032] ;

[0033] Where LCruise is the cruising distance, and Wfuel, cruise is the fuel consumption weight during the cruise flight.

[0034] Referring to the method for setting the relative range concept of the cruise segment, the relative range of the climb and descent segments is set as follows:

[0035] ;

[0036] .

[0037] Preferably, the method for establishing the comparative range evaluation model for each mission segment of the transport aircraft is as follows:

[0038] Based on different cruise modes, the flight speed V, lift-to-drag ratio K, fuel consumption rate Sfc, and flight weight m are obtained during the cruise flight. The specific range under different cruise weight conditions is evaluated as follows:

[0039] ;

[0040] in The cruise factor cr is referred to as the cruise factor during the cruise flight of a transport aircraft.

[0041] Record the maximum cruise factor cr_max and the corresponding cruise weight m_cr_max under each cruise weight condition; then extract the cruise factors of the maximum cruise weight mcruise_max and the minimum cruise weight mcruise_min. If the maximum cruise weight and m_cr_max are the same, then extract the maximum cruise weight recommended for the service ceiling altitude.

[0042] The cruise factor under the weight condition m_cr_max is called cr_max, and the cruise factor for other weights is represented by k_sr × cr_max, where k_sr is a correction coefficient, resulting in:

[0043] ;

[0044] Based on the correction factor and the relative range under different cruise weight conditions, calculate the relative range of the cruise segment under any weight condition;

[0045] By determining the flight mode, flight weight, and cr_m1 value for each mission segment, the corresponding specific range results are obtained, and a specific range evaluation model for each mission segment of the transport aircraft is established.

[0046] Preferably, the specific range of the aircraft during the climb and descent phases is positively correlated with the specific range during the cruise phase, as follows:

[0047] ;

[0048] .

[0049] Preferably, the method for establishing the flight distance assessment model for each mission segment of the transport aircraft is as follows:

[0050] The climb phase data is obtained to calculate the average flight weight of the climb phase. The climb phase specific range under different cruise weight conditions is calculated based on the correction factor and the specific range calculation formula. The horizontal distance LClimb of the climb phase is calculated by multiplying the fuel consumption weight of the climb phase by the specific range.

[0051] The cruise segment data is obtained to calculate the average flight weight during the cruise process. The descent segment specific range under different cruise weight conditions is calculated based on the correction factor and the specific range calculation formula. The horizontal distance of the cruise segment, LCruise, is calculated by multiplying the fuel consumption weight of the cruise segment by the specific range.

[0052] The average flight weight during the descent phase is calculated by acquiring descent phase data. The descent phase specific range under different cruise weight conditions is calculated based on the correction factor and the specific range calculation formula. The horizontal distance LDecline during the descent phase is calculated by multiplying the fuel consumption weight and specific range during the descent phase.

[0053] The flight distance L is calculated based on the horizontal distances of the climb, cruise, and descent phases:

[0054] .

[0055] Preferably, based on the payload range results obtained from the range evaluation model and the operational efficiency results obtained from the flight distance evaluation model, independent input parameters are input, and finally, different payload Wpl and fuel Wfuel results are loaded to calculate the range results under different conditions.

[0056] Preferably, the independent input parameters include:

[0057] 1. W0,max — Maximum takeoff weight, kg;

[0058] 2. A and B – Two parameters relating to the relationship between Woe and W0;

[0059] 3. Vcruise_m1 — Cruise speed under weight condition m1;

[0060] 4. K_m1 — Cruise lift-to-drag ratio under weight condition m1;

[0061] 5. Sfc_m1 — Cruise fuel consumption rate under weight m1 condition;

[0062] 6. —The ratio of the distance traveled during climb to the distance traveled during cruise;

[0063] 7. —The ratio of the distance traveled during descent to the distance traveled during cruise;

[0064] 8. SW – Wing Area;

[0065] 9. CLcruise – Cruise lift coefficient;

[0066] 10. Hcruise, max — Maximum cruising altitude;

[0067] 11. c, d — parameters of the correction function for the cruising weight m ∈ [weight interval 1];

[0068] 12. e, f — parameters of the correction function for the cruising weight m ∈ [weight interval 2];

[0069] 13. Wi / Wi-1 — Task segment weight ratio.

[0070] Preferably, a line graph is plotted with the voyage distance L as the independent variable and the load weight as the dependent variable, and the result is the load-range graph.

[0071] Preferably, the calculation result of the operational efficiency of the transport aircraft during loaded flight is as follows:

[0072] ;

[0073] Where W0-W6 is the weight of fuel consumed by the aircraft during the entire mission, L is the aircraft's range, Wpl is the aircraft's payload weight, and j is the range weight correction, j≥1; when j=1, the result of SL calculation is equal to the aircraft's fuel efficiency.

[0074] The method for studying the payload-range model of transport aircraft in this application has the following advantages:

[0075] By using the overall weight model, mission profile model, and flight performance model of a transport aircraft, a mathematical relationship between key design parameters and core capability indicators is established to evaluate the range and operational efficiency under different payload conditions. This method focuses on the key design parameters for evaluating the payload range of transport aircraft; the method is intuitive, clear, and the calculation process is convenient. Attached Figure Description

[0076] Figure 1 This is a schematic diagram of the overall process of this application;

[0077] Figure 2 This is a schematic diagram showing the transport aircraft model and the calculated payload range of this application.

[0078] Figure 3 The results of the transport aircraft's payload range and operational efficiency in this application are plotted. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0080] The first aspect of this application provides a method for researching a payload-range model for transport aircraft. First, based on statistical data of the transport aircraft's maximum takeoff weight and total weight, and combined with typical mission profiles, a weight parameter model for evaluating the aircraft's payload-range is constructed. Then, based on the specific range parameters of each mission segment of the transport aircraft, a flight distance performance model for evaluating the payload-range is developed. Finally, using the payload-range calculation model as a carrier, data from different payload conditions of the transport aircraft are input to calculate the corresponding range results and operational efficiency results. This achieves the task of constructing a payload-range model for transport aircraft and evaluating payload-range results.

[0081] like Figure 1 Specifically, it includes the following steps:

[0082] Step S100: Construct a weight parameter model for aircraft payload range assessment. The design methods mainly include the overall weight data model construction method for transport aircraft and the mission profile weight data model construction method.

[0083] The overall weight data model for transport aircraft is constructed based on the maximum takeoff weight of the transport aircraft and combined with weight statistics of similar aircraft. The overall weight data for transport aircraft includes the aircraft's empty weight, maximum fuel weight, maximum payload weight, and maximum takeoff weight.

[0084] Weight data affects aircraft flight performance, with the key data being takeoff weight W0, which is composed of the following:

[0085] (1)

[0086] In the formula: Woe – empty weight of the aircraft; Wfuel – weight of the aircraft fuel; Wpl – payload weight. The weight referred to in this article is mass, in kg, and the same applies below.

[0087] An aircraft's empty weight (Woe) is related to both its maximum takeoff weight (W0,max) and its design and production capabilities. For aircraft of the same type and at similar levels, a functional relationship between Woe and W0,max can be constructed using statistical data. The relationship for transport aircraft is as follows:

[0088] (2)

[0089] Aircraft design literature provides values ​​for parameters A and B under different conditions. For example, statistical data for transport aircraft that widely use composite materials shows A = 0.09907 and B = 1.0411. Of course, the values ​​of A and B can be adjusted based on the actual design results of the transport aircraft. Thus, by using W0,max, A, and B as independent variables, Woe can be calculated.

[0090] The maximum payload weight Wpl,max of the transport aircraft is related to the maximum takeoff weight W0,max, and the maximum fuel weight Wfuel,max is related to the takeoff weight W0,max. The calculation is based on the following relationship. The value of formula (3) can also be adjusted according to the actual design results of the transport aircraft.

[0091] (3)

[0092] Where: Wpl, fuelmax — maximum load weight under maximum fuel conditions, kg.

[0093] The formula for calculating the fuel weight Wfuel during flight is shown below:

[0094] (4)

[0095] The overall weight data model of the transport aircraft has been completed. Using the determined values ​​of W0,max, the values ​​of Woe, Wpl,max, Wfuel,max, and Wpl,fuelmax can be calculated. A specific W0 can be calculated using specific Wfuel and Wpl values.

[0096] The mission profile weight data model for transport aircraft is constructed based on the typical usage patterns of such aircraft. The transport aircraft in this paper employs a high-high-high mission profile (see Table 1), where the aircraft operates in its most efficient flight mode. During the payload-range assessment, the weight results are calculated using the ratio and difference between the final weight Wi and the initial weight Wi-1 for each mission segment, referencing the weight ratio Wi / Wi-1 provided in the statistical data (see Table 1).

[0097] Table 1. Weight ratios of each mission segment in the high-altitude mission profile of transport aircraft

[0098]

[0099] The landing weight is W5. The fuel reserve assessment in this paper is 10% of the fuel weight of the route. Therefore, W5 = Woe + Wpl + 0.1Wfuel.

[0100] The formulas for W0 and W5 are given above. Combining them with the data in Table 1, the formulas for calculating the weight of each task segment can be obtained as follows:

[0101] (5)

[0102] The average flight weight during the climb is as follows:

[0103] (5.1)

[0104] The average flight weight during descent is as follows:

[0105] (5.2)

[0106] The average flight weight during cruise is as follows:

[0107] (5.3)

[0108] The mission profile weight data model for the transport aircraft has been completed. Using the determined values ​​of Wfuel, Wpl, and W0, the final weight Wi and initial weight Wi-1 of each mission segment within the mission profile can be calculated.

[0109] Thus, the weight parameter model for assessing the payload range of transport aircraft is completed.

[0110] Step S200: Construct a flight distance performance model for evaluating the aircraft's payload range. The design methods mainly include the comparative range evaluation method for each mission segment of the transport aircraft and the flight distance evaluation method for each mission segment of the transport aircraft.

[0111] The methods for evaluating the relative range of transport aircraft in each mission segment include cruise segment relative range evaluation and climb / descent segment relative range evaluation. The relative range (SRcruise) of the cruise segment refers to the cruising distance consumed per unit weight of fuel, calculated as follows:

[0112] (6)

[0113] Among them, LCruise is the cruise distance, Wfuel is the fuel consumption weight during cruise flight. The ratio of the cruise segment to the descent segment is set according to the concept of cruise segment to range.

[0114] (7)

[0115] (8)

[0116] Table 1 shows the fuel consumption for the cruise, climb, and descent segments. Therefore, by obtaining the relative range results for these three mission segments, the horizontal distance of these three mission segments can be calculated.

[0117] First, we study the specific range of transport aircraft during the cruise phase. Common cruise flight modes for transport aircraft are as follows: a) When the cruise altitude is below the service ceiling, the recommended cruise speed and lift coefficient remain constant. The recommended cruise altitude varies with the cruise weight; the lower the weight, the higher the cruise altitude. b) When the cruise altitude reaches the service ceiling, the aircraft flies at the service ceiling. The cruise speed and lift coefficient vary with the cruise weight; the lower the weight, the lower the cruise speed and lift coefficient. Based on these cruise flight modes, we evaluate the specific range under different cruise weight conditions, which is mainly related to the flight speed V, lift-to-drag ratio K, fuel consumption rate Sfc, and flight weight m during the cruise flight.

[0118] (9)

[0119] in The cruise factor cr is referred to as the cruise factor during the transport aircraft's cruise flight. The maximum cruise factor cr_max and the corresponding cruise weight m_cr_max are recorded for each cruise weight condition. Then, the cruise factors for the maximum cruise weight mcruise_max and the minimum cruise weight mcruise_min are extracted. If the maximum cruise weight and m_cr_max are the same, then the maximum cruise weight recommended for the service ceiling is extracted. Three typical sets of parameters are extracted within this cruise weight range, as shown in Table 2.

[0120] Table 2 Cruise Weight and Cruise Factor Values

[0121]

[0122] The cruise factor under the weight condition m_cr_max is called cr_max, and the cruise factor for other weights is represented by k_sr×cr_max, where k_sr is a correction coefficient.

[0123] (10)

[0124] Formulas (9) and (10) can be used to calculate the cruise segment to distance ratio under any weight condition.

[0125] The relative range of an aircraft during climb and descent is positively correlated with the relative range during cruise. It is usually calculated according to the following relationship, but the values ​​of formulas (11) and (12) can also be adjusted according to the actual design results of the transport aircraft.

[0126] (11)

[0127] (12)

[0128] The method for evaluating the comparative range of each mission segment of the transport aircraft has been developed. By determining the flight mode, flight weight, and cr_m1 value for each mission segment, the corresponding comparative range results are obtained through adjustments.

[0129] The flight distance assessment methods for each mission segment of a transport aircraft include flight distance assessment for the climb, cruise, and descent segments.

[0130] First, calculate the horizontal distance of the climb phase. Use formula (5.1) to calculate the average flight weight of the climb phase, and use formulas (9), (10), and (11) to calculate the climb phase relative range under this weight condition. Multiply the fuel consumption weight of the climb phase by the relative range to calculate the horizontal distance LClimb of the climb phase.

[0131] Then calculate the horizontal distance of the cruise segment. Use formula (5.3) to calculate the average flight weight of the cruise segment, use formulas (9) and (10) to calculate the cruise segment specific range under this weight condition, and multiply the fuel consumption weight of the cruise segment by the specific range to calculate the horizontal distance of the cruise segment LCruise.

[0132] Then calculate the horizontal distance of the descent phase. Use formula (5.2) to calculate the average flight weight of the descent phase, use formulas (9), (10), and (12) to calculate the descent phase specific range under this weight condition, and multiply the fuel consumption weight of the descent phase by the specific range to calculate the horizontal distance LDecline of the descent phase.

[0133] Note that in the above calculation process, if the weight of the mission segment crosses m2, i.e., Wi-1 < m2 < Wi, then the calculation is completed using the segmented calculation method. That is, the horizontal distances from Wi-1 to m2 and from m2 to Wi are calculated separately.

[0134] The flight range L is as follows:

[0135] (13)

[0136] The ferry range refers to the flight range result of the aircraft under the conditions of no payload and maximum fuel. The calculation method of the ferry range is similar to the flight range calculation method described above and will not be elaborated here.

[0137] The method for evaluating the flight distances of each mission segment of the transport aircraft is completed. Through the specific range of the average flight weight of each mission segment and the fuel consumption of the mission segment, the flight distance results of the transport aircraft in each mission segment can be calculated.

[0138] In this way, the construction of the flight distance performance model for evaluating the payload range of the transport aircraft is completed.

[0139] Step S300, the operation calculation model obtains the payload range result and the operation efficiency result. The design method mainly includes the development method of the payload range calculation model and the operation efficiency design method for the payload flight of the transport aircraft.

[0140] The development of the payload range calculation model is based on the weight parameter model for evaluating the payload range of the aircraft and the flight distance performance model for evaluating the payload range of the aircraft, and the independent input parameters are sorted out, as follows:

[0141] 1. W0,max - Maximum takeoff weight, kg

[0142] 2. A, B - Two parameters related to the relationship between Woe and W0

[0143] 3. Vcruise_m1 - Cruise speed under the condition of weight m1

[0144] 4. K_m1 - Cruise lift-to-drag ratio value under the condition of weight m1

[0145] 5. Sfc_m1 - Cruise fuel consumption rate under the condition of weight m1

[0146] 6. - Ratio of the specific range during climb to the specific range during cruise

[0147] 7. - Ratio of the specific range during descent to the specific range during cruise

[0148] 8. SW - Wing area

[0149] 9. CLcruise – Cruise Lift Coefficient

[0150] 10. Hcruise, max — Maximum cruising altitude

[0151] 11. c, d — Parameters of the correction function for the cruising weight m ∈ [weight interval 1].

[0152] 12. e, f — Parameters of the correction function for the cruising weight m ∈ [weight interval 2].

[0153] 13. Wi / Wi-1 — Task segment weight ratio

[0154] Based on the weight parameter model for aircraft payload-range assessment and the flight distance performance model for aircraft payload-range assessment, and by loading the aforementioned independent input parameters, a payload-range calculation tool was developed. Finally, by loading different payload (Wpl) and fuel (Wfuel) results, the range results under different conditions were calculated. It should be noted that some conditions in the payload-range chart are special and necessary for plotting the payload-range chart, as shown in Table 3.

[0155] Table 3 Design points for commercial payload range of transport aircraft (partial)

[0156]

[0157] Using the voyage distance L as the independent variable and the load weight as the dependent variable, a line graph is plotted, and the result is the load-range graph.

[0158] A payload-range calculation model for transport aircraft has been developed. Based on core design parameters from the overall aircraft design, as well as weight parameter models and flight distance performance models for payload-range evaluation, a complete payload-range calculation tool for transport aircraft has been developed. By loading the payload (Wpl) and fuel (Wfuel) results, the range can be calculated.

[0159] The payload-range parameters of a transport aircraft serve as input conditions for evaluating its operational efficiency. A method for evaluating the operational efficiency of a transport aircraft is designed. Clearly, operational efficiency is positively correlated with payload weight (Wpl) and range (L), and negatively correlated with fuel consumption. The operational efficiency of a transport aircraft flying with its payload is calculated as follows.

[0160] (14)

[0161] Where W0-W6 represent the total weight of fuel consumed by the aircraft during the entire mission, L is the aircraft's range, Wpl is the aircraft's payload weight, and j is the range weighting correction, where j≥1. When j=1, the calculated SL result equals the aircraft's fuel efficiency.

[0162] The operational efficiency of transport aircraft with loaded flight has been developed. Based on the calculation results of the loaded range, the operational efficiency is obtained according to the formula.

[0163] Thus, the calculation model for the payload and range of transport aircraft was completed.

[0164] In summary, this application has the following advantages:

[0165] By using the overall weight model, mission profile model, and flight performance model of a transport aircraft, a mathematical relationship between key design parameters and core capability indicators is established to evaluate the range and operational efficiency under different payload conditions. This method focuses on the key design parameters for evaluating the payload range of transport aircraft; the method is intuitive, clear, and the calculation process is convenient.

[0166] As one specific implementation method, the following is an illustration using a concrete example:

[0167] The method for assessing the payload range of this transport aircraft includes the following steps:

[0168] S1, the subject of the study is a subsonic jet transport aircraft.

[0169] S2, construct the functional relationship between the total weight data of the transport aircraft and the independent variables. The independent variables include the maximum takeoff weight W0,max, and weight statistics A and B. For example, W0 = 130000 kg, A = 0.09907, B = 1.0411. Use equation (2) to calculate Woe = 65599 kg. Calculate the maximum load weight Wpl,max = 40045 kg according to equation (3), the maximum load weight Wpl,fuelmax = 14416 kg under maximum fuel conditions, and the maximum fuel weight Wfuel,max = 49985 kg. The range of the transport aircraft's load weight is set to 0 kg to 40045 kg, and the range of fuel weight is set to 0 kg to 49985 kg. See Figure 2 Upper and middle sections.

[0170] S3. Construct the functional relationship between weight data and independent variables for each stage of the transport aircraft flight mission profile. The transport aircraft mission profile is divided into 6 mission segments, with the starting weight of each segment being Wi-1 and the ending weight being Wi, as shown in Table 1. Note that the ratio of the ending weight to the starting weight does not change much in some mission segments, such as the takeoff, climb, descent, landing, and taxiing segments. Based on the statistical results, Wi / Wi-1 is given. Combining the formulas W0 = Woe + Wfuel + Wpl and W5 = Woe + Wpl + 0.1Wfuel, the expressions for W1 to W6 are given, as shown in Equation (5). The calculation results for W0 to W6 are obtained. See Figure 1 Central region.

[0171] S4, construct the functional relationship between flight capability and independent variables for each stage of the transport aircraft's flight mission profile. Calculate the cr_max of the transport aircraft's cruise flight process. For example, if Vcruise = 830 km / h, K = 15, and Sfc = 0.700 kg / kgf / h, then cr_max = 17786. Referring to the concept of cruise-specific range SRCruise = cr_max / m, set the climb-specific range and descent-specific range, which are the ratios of horizontal flight distance to fuel consumption weight during climb and descent. See... Figure 1 upper part.

[0172] S5 calculates the flight distances of the transport aircraft during the climb, descent, and cruise phases. Using a calculation model with a payload of 31588 kg and a fuel load of 32813 kg as an example, the average weight, specific range, and fuel consumption for each mission phase are calculated, and finally, the flight distance is calculated, as shown in the table below.

[0173] Table 4 Calculation of Flight Distance for Each Mission Segment

[0174] The distance calculated using formula (13) is 232+226+3628=4087km.

[0175] S6, calculate the flight distance under different load conditions. Repeat step S5, setting the target Wpl for the load distance to 40045kg, 35816kg, 27231kg, 22874kg, 18645kg, 14416kg, and 0kg respectively. The calculated flight distances are 2850km, 3460km, 4752km, 5438km, 6125km, 6834km, and 7653km respectively. Plot a line graph with flight distance as the independent variable and load weight as the dependent variable, see [link to graph]. Figure 2 .

[0176] S7, calculate the operational efficiency of the transport aircraft under load. Substitute the range and fuel consumption results under different load conditions into equation (14), where j=1.5, to calculate the operational efficiency SL. Plot a line graph with range as the independent variable and operational efficiency as the dependent variable, see [reference needed]. Figure 3 .

[0177] S8, calculate the payload range for other takeoff weights and fuel weights. Change the takeoff weight settings in step S2, calculate the payload range for 90% of the maximum takeoff weight, and repeat steps S3 to S7. Plot a line graph with range as the independent variable and payload weight and operational efficiency as the dependent variables, see [link to graph]. Figure 3 .

[0178] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for studying the payload-range model of a transport aircraft, characterized in that, include: Based on the maximum takeoff weight and aircraft weight statistics of transport aircraft, a weight parameter model for evaluating aircraft payload range is constructed in combination with typical mission profiles. A flight distance performance model for payload range evaluation is established based on the specific range parameters of each mission segment of the transport aircraft. Based on the weight parameter model for aircraft payload range assessment and the flight distance performance model for aircraft payload range assessment, data of different payload conditions of transport aircraft are input to calculate the corresponding range results and operational efficiency results.

2. The method for studying the payload-range model of a transport aircraft as described in claim 1, characterized in that, Aircraft weight statistics include empty weight, maximum fuel weight, maximum payload, takeoff weight, and maximum takeoff weight. The takeoff weight W0 includes: ； In the formula: Woe is the empty weight of the aircraft; Wfuel is the weight of the aircraft fuel; Wpl is the loaded weight.

3. The method for studying the payload-range model of a transport aircraft as described in claim 2, characterized in that, The method for constructing the weight parameter model for aircraft payload-range assessment is as follows: The formula for calculating the weight of the aircraft in each mission segment is as follows: ； In the formula, W1 is the starting weight of the climb, W2 is the starting weight of the cruise, W3 is the starting weight of the descent, W4 is the starting weight of the landing, W5 is the starting weight of the taxiing, and W6 is the ending weight of the taxiing. The average flight weight during the climb is as follows: ； The average flight weight during descent is as follows: ； The average flight weight during cruise is as follows: ； The formula for calculating the fuel weight Wfuel during flight is as follows: ； The maximum payload capacity of the transport aircraft, Wpl,max, is: ； The values ​​of Wfuel, Wpl, and W0 are obtained. Based on the determined values ​​of Wfuel, Wpl, and W0, the final weight Wi and the initial weight Wi-1 of the transport aircraft in each mission segment of the mission profile are calculated.

4. The method for studying the payload-range model of a transport aircraft as described in claim 3, characterized in that, The flight distance performance model for payload range assessment includes the comparative range assessment model for each mission segment of the transport aircraft and the flight distance assessment model for each mission segment of the transport aircraft. The cruise segment's specific range (SRcruise) refers to the cruising distance achieved per unit weight of fuel consumed, calculated as follows: ； Where LCruise is the cruising distance, and Wfuel, cruise is the fuel consumption weight during the cruise flight. Referring to the method for setting the relative range concept of the cruise segment, the relative range of the climb and descent segments is set as follows: ； 。 5. The method for studying the payload-range model of a transport aircraft as described in claim 4, characterized in that, The method for establishing the comparative range evaluation model for each mission segment of a transport aircraft is as follows: Based on different cruise modes, the flight speed V, lift-to-drag ratio K, fuel consumption rate Sfc, and flight weight m are obtained during the cruise flight. The specific range under different cruise weight conditions is evaluated as follows: ； in The cruise factor cr is referred to as the cruise factor during the cruise flight of a transport aircraft. Record the maximum cruise factor cr_max and the corresponding cruise weight m_cr_max under each cruise weight condition; then extract the cruise factors of the maximum cruise weight mcruise_max and the minimum cruise weight mcruise_min. If the maximum cruise weight and m_cr_max are the same, then extract the maximum cruise weight recommended for the service ceiling altitude. The cruise factor under the weight condition m_cr_max is called cr_max, and the cruise factor for other weights is represented by k_sr × cr_max, where k_sr is a correction coefficient, resulting in: ； Based on the correction factor and the relative range under different cruise weight conditions, calculate the relative range of the cruise segment under any weight condition; By determining the flight mode, flight weight, and cr_m1 value for each mission segment, the corresponding specific range results are obtained, and a specific range evaluation model for each mission segment of the transport aircraft is established.

6. The method for studying the payload-range model of a transport aircraft as described in claim 5, characterized in that, The specific range of an aircraft during climb and descent is positively correlated with the specific range during cruise, as follows: ； 。 7. The method for studying the payload-range model of a transport aircraft as described in claim 5, characterized in that, The method for establishing the flight distance assessment model for each mission segment of a transport aircraft is as follows: The climb phase data is obtained to calculate the average flight weight of the climb phase. The climb phase specific range under different cruise weight conditions is calculated based on the correction factor and the specific range calculation formula. The horizontal distance LClimb of the climb phase is calculated by multiplying the fuel consumption weight of the climb phase by the specific range. The cruise segment data is obtained to calculate the average flight weight during the cruise process. The descent segment specific range under different cruise weight conditions is calculated based on the correction factor and the specific range calculation formula. The horizontal distance of the cruise segment, LCruise, is calculated by multiplying the fuel consumption weight of the cruise segment by the specific range. The average flight weight during the descent phase is calculated by acquiring descent phase data. The descent phase specific range under different cruise weight conditions is calculated based on the correction factor and the specific range calculation formula. The horizontal distance LDecline during the descent phase is calculated by multiplying the fuel consumption weight and specific range during the descent phase. The flight distance L is calculated based on the horizontal distances of the climb, cruise, and descent phases: 。 8. The method for studying the payload-range model of a transport aircraft as described in claim 7, characterized in that, Based on the payload range results obtained from the range comparison evaluation model and the operational efficiency results obtained from the flight distance evaluation model, independent input parameters are input, and finally, different payload Wpl and fuel Wfuel results are loaded to calculate the range results under different conditions.

9. The method for studying the payload-range model of a transport aircraft as described in claim 8, characterized in that, Independent input parameters include:

1. W0,max — Maximum takeoff weight, kg; 2. A and B – Two parameters relating to the relationship between Woe and W0; 3. Vcruise_m1 — Cruise speed under weight condition m1; 4. K_m1 — Cruise lift-to-drag ratio under weight condition m1; 5. Sfc_m1 — Cruise fuel consumption rate under weight m1 condition; 6. —The ratio of the distance traveled during climb to the distance traveled during cruise; 7. —The ratio of the distance traveled during descent to the distance traveled during cruise; 8. SW – Wing Area; 9. CLcruise – Cruise lift coefficient; 10. Hcruise, max — Maximum cruising altitude; 11. c, d — parameters of the correction function for the cruising weight m ∈ [weight interval 1]; 12. e, f — parameters of the correction function for the cruising weight m ∈ [weight interval 2]; 13. Wi / Wi-1 — Task segment weight ratio.

10. The method for studying the payload-range model of a transport aircraft as described in claim 8, characterized in that, Using the voyage distance L as the independent variable and the load weight as the dependent variable, a line graph is plotted, and the result is the load-range graph.

11. The method for studying the payload-range model of a transport aircraft as described in claim 8, characterized in that, The results of calculating the operational efficiency of transport aircraft flying with a full load are as follows: ； Where W0-W6 is the weight of fuel consumed by the aircraft during the entire mission, L is the aircraft's range, Wpl is the aircraft's payload weight, and j is the range weight correction, j≥1; when j=1, the result of SL calculation is equal to the aircraft's fuel efficiency.

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