Engineering calculation method and device for length and weight of main landing gear

Abstract

The invention belongs to the technical field of aircraft design, and relates to an engineering calculation method and device for the length and weight of a main landing gear. The method comprises the following steps: S1, taking 80% of a minimum length estimated value of a main landing gear as a base point, and establishing a main landing gear length array according to a set step length; s2, calculating a take-off elevation angle, a mopping angle and a back-turning angle; s3, finding out the minimum main landing gear length of the attack angle, the grazing angle design value and the tip-back angle constraint value required by takeoff in the main landing gear length array; s4, interpolating a first main landing gear length corresponding to an attack angle required for minimum-speed takeoff, a second main landing gear length corresponding to a design value of a grazing angle, and a third main landing gear length corresponding to a retroverted angle constraint value respectively, wherein the first main landing gear length, the second main landing gear length and the third main landing gear length are required for minimum-speed takeoff; s5, determining the final length of the main landing gear; and S6, calculating the weight of the main landing gear according to the length of the main landing gear. According to the method, the optimal design length of the undercarriage can be accurately calculated.

Description

Technical Field

[0001] This application belongs to the field of aircraft design technology, and specifically relates to an engineering calculation method and apparatus for the length and weight of the main landing gear. Background Technology

[0002] Calculating the length and weight of the main landing gear is a key technology in its optimized design. Main landing gear optimization needs to consider the required angle of attack for minimum takeoff speed, the required tail strike angle of the fuselage, and the need to prevent rollover. The position of the tail skid relative to the hinge point between the main landing gear and the fuselage is closely related to the main landing gear length. Main landing gear length, main landing gear compression, maximum landing weight, landing speed, load distribution between the nose and main landing gear, and tire pressure are all sensitive parameters affecting the main landing gear weight. The length and weight of the main landing gear are also related to the maximum lift coefficient of the aircraft's takeoff and landing configuration. Therefore, constructing a calculation model for the main landing gear length and weight to guide main landing gear optimization is a technical problem that urgently needs to be solved. Summary of the Invention

[0003] To address the aforementioned issues, this application provides an engineering calculation method and apparatus for the length and weight of the main landing gear. This model reflects the aerodynamic characteristics of the aircraft's takeoff and landing configuration, performance requirements for takeoff and landing, and the influence of fuselage and tail skid parameters on the length and weight of the main landing gear. It can provide technical support for reducing aircraft weight, ensuring flight safety, and optimizing the design of the main landing gear. The main landing gear length and weight calculation method provided in this application is applicable to transport aircraft with main landing gear installed under the fuselage.

[0004] The first aspect of this application provides an engineering calculation method for the length and weight of the main landing gear, mainly including:

[0005] Step S1: Using 80% of the estimated minimum length of the main landing gear as the base point, establish the main landing gear length array according to the set step size;

[0006] Step S2: Calculate the takeoff pitch angle, ground contact angle, and roll angle for each main landing gear length;

[0007] Step S3: Using the following filtering conditions, the minimum main landing gear length is found in the main landing gear length array: the takeoff pitch angle is not less than the angle of attack required for takeoff at the minimum speed, the ground contact angle is not less than the ground contact angle design value, and the roll angle is not less than the roll angle constraint value.

[0008] Step S4: Interpolate the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff, the length of the second main landing gear corresponding to the design value of the ground scraping angle, and the length of the third main landing gear corresponding to the roll angle constraint value between the minimum main landing gear length and the length of the main landing gear preceding it.

[0009] Step S5: Determine the maximum value between the length of the first main landing gear and the length of the second main landing gear, and select the minimum value between the maximum value and the length of the third main landing gear as the final main landing gear length;

[0010] Step S6: Calculate the weight of the main landing gear based on its length.

[0011] Preferably, in step S1, the step size is set to 10cm.

[0012] Preferably, step S2 further includes: calculating the takeoff pitch angle using the following formula. :

[0013] ;

[0014] in, The angle between the line connecting the main landing gear and the wheel axle hinge point and the tail skid contact point and the horizontal plane. The angle between the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle and the horizontal plane;

[0015] ;

[0016] ;

[0017] ;

[0018] ;

[0019] ;

[0020] ;

[0021] in, The length of the main landing gear in its uncompressed state. This refers to the compression of the main landing gear during takeoff. The height of the main landing gear hinge point to the fuselage from the wheel axle at the takeoff angle of attack. This refers to the horizontal distance from the bottom of the tail skid to the hinge point between the main landing gear and the fuselage. The height of the bottom of the tail skid from the hinge point between the main landing gear and the fuselage; The height of the bottom of the tail skid from the main landing gear and wheel axle. The height of the bottom of the tail skid from the ground above the main landing gear; The diameter of the main landing gear wheels. Compression of the main landing gear tires. It is the length of the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle.

[0022] Preferably, step S2 further includes: calculating the rubbing angle using the following formula. :

[0023] ;

[0024] in, The height of the bottom of the tail skid from the ground above the main landing gear;

[0025] .

[0026] Preferably, step S2 further includes: calculating the back-flip angle using the following formula. :

[0027] ;

[0028] in, This is the horizontal distance between the aircraft's rear center of gravity and the main landing gear. The height of the rear center of gravity from the ground;

[0029] ;

[0030] in, This refers to the height of the rear center of gravity from the hinge point between the main landing gear and the fuselage.

[0031] Preferably, in step S4, interpolating the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff includes: interpolating the angle of attack required for minimum speed takeoff as the takeoff pitch angle.

[0032] The angle of attack required for minimum speed takeoff is calculated using the following formula. :

[0033] ;

[0034] in, The lift coefficient at takeoff is the coefficient of force applied when the aircraft leaves the ground. The lift coefficient at zero angle of attack. The average slope of the lift line;

[0035] ;

[0036] ;

[0037] in, The maximum lift coefficient for takeoff configuration. Minimum takeoff speed Takeoff stall speed The ratio of .

[0038] Preferably, in step S6, the weight of the main landing gear is calculated using the following formula. :

[0039] ;

[0040] in, For maximum landing weight, For landing speed, The uncompressed length of the main landing gear Compression of the main landing gear during landing. The pressure of the main landing gear tires. The distance from the center of gravity to the main landing gear. This is the distance between the nose landing gear and the main landing gear.

[0041] Preferably, the landing speed is calculated using the following formula. :

[0042] ;

[0043] in, The stall speed at landing;

[0044] ;

[0045] in, The maximum lift coefficient for the landing configuration. For wing reference area, This refers to air density.

[0046] The second aspect of this application provides an engineering calculation device for the length and weight of the main landing gear, mainly comprising:

[0047] The main landing gear length array construction module is used to build a main landing gear length array with 80% of the minimum estimated value of the main landing gear length as the base point and according to the set step size.

[0048] The parameter calculation module is used to calculate the takeoff pitch angle, ground contact angle, and roll angle for each main landing gear length.

[0049] The minimum main landing gear length query module is used to find the minimum main landing gear length in the main landing gear length array by filtering conditions such as the takeoff pitch angle not being less than the angle of attack required for takeoff at minimum speed, the ground contact angle not being less than the ground contact angle design value, and the roll angle not being less than the roll angle constraint value.

[0050] The interpolation calculation module is used to interpolate the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff, the length of the second main landing gear corresponding to the design value of the ground scraping angle, and the length of the third main landing gear corresponding to the roll angle constraint value, respectively, between the minimum main landing gear length and the length of the main landing gear preceding it.

[0051] The main landing gear length selection module is used to determine the maximum value between the first main landing gear length and the second main landing gear length, and select the minimum value between the maximum value and the third main landing gear length as the final main landing gear length.

[0052] The main landing gear weight calculation module is used to calculate the weight of the main landing gear based on its length.

[0053] Preferably, the step size is set to 10cm in the main landing gear length array construction module.

[0054] Preferably, the parameter calculation module includes a takeoff pitch angle calculation unit, used to calculate the takeoff pitch angle using the following formula. :

[0055] ;

[0056] in, The angle between the line connecting the main landing gear and the wheel axle hinge point and the tail skid contact point and the horizontal plane. The angle between the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle and the horizontal plane;

[0057] ;

[0058] ;

[0059] ;

[0060] ;

[0061] ;

[0062] ;

[0063] in, The length of the main landing gear in its uncompressed state. This refers to the compression of the main landing gear during takeoff. The height of the main landing gear hinge point to the fuselage from the wheel axle at the takeoff angle of attack. This refers to the horizontal distance from the bottom of the tail skid to the hinge point between the main landing gear and the fuselage. The height of the bottom of the tail skid from the hinge point between the main landing gear and the fuselage; The height of the bottom of the tail skid from the main landing gear and wheel axle. The height of the bottom of the tail skid from the ground above the main landing gear; The diameter of the main landing gear wheels. Compression of the main landing gear tires. It is the length of the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle.

[0064] Preferably, the parameter calculation module includes a rubbing angle calculation unit, used to calculate the rubbing angle using the following formula. :

[0065] ;

[0066] in, The height of the bottom of the tail skid from the ground above the main landing gear;

[0067] .

[0068] Preferably, the parameter calculation module includes a back-turn angle calculation unit, used to calculate the back-turn angle using the following formula. :

[0069] ;

[0070] in, This is the horizontal distance between the aircraft's rear center of gravity and the main landing gear. The height of the rear center of gravity from the ground;

[0071] ;

[0072] in, This refers to the height of the rear center of gravity from the hinge point between the main landing gear and the fuselage.

[0073] Preferably, in the interpolation calculation module, interpolating the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff includes: interpolating the angle of attack required for minimum speed takeoff as the takeoff pitch angle;

[0074] The angle of attack required for minimum speed takeoff is calculated using the following formula. :

[0075] ;

[0076] in, The lift coefficient at takeoff is the coefficient of force applied when the aircraft leaves the ground. The lift coefficient at zero angle of attack. The average slope of the lift line;

[0077] ;

[0078] ;

[0079] in, The maximum lift coefficient for takeoff configuration. Minimum takeoff speed Takeoff stall speed The ratio of .

[0080] Preferably, in the main landing gear weight calculation module, the main landing gear weight is calculated using the following formula. :

[0081] ;

[0082] in, For maximum landing weight, For landing speed, The uncompressed length of the main landing gear Compression of the main landing gear during landing. The pressure of the main landing gear tires. The distance from the center of gravity to the main landing gear. This is the distance between the nose landing gear and the main landing gear.

[0083] Preferably, the landing speed is calculated using the following formula. :

[0084] ;

[0085] in, The stall speed at landing;

[0086] ;

[0087] in, The maximum lift coefficient for the landing configuration. For wing reference area, This refers to air density.

[0088] A third aspect of this application provides a computer device including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the engineering calculation method for the length and weight of the main landing gear as described above.

[0089] A fourth aspect of this application provides a readable storage medium storing a computer program that, when executed by a processor, is used to implement the engineering calculation method for the length and weight of the main landing gear as described above.

[0090] This application can accurately calculate the optimal design length of the landing gear. Attached Figure Description

[0091] Figure 1 This is a flowchart of a preferred embodiment of the engineering calculation method for the length and weight of the main landing gear in this application.

[0092] Figure 2 This is a schematic diagram showing the relevant parameters for calculating the length of the main landing gear.

[0093] Figure 3 This is a schematic diagram of the structure of a computer device suitable for implementing the embodiments of this application. Detailed Implementation

[0094] 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 creative 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.

[0095] The first aspect of this application provides an engineering calculation method for the length and weight of the main landing gear, such as... Figure 1 As shown, it mainly includes:

[0096] Step S1: Using 80% of the estimated minimum length of the main landing gear as the base point, establish the main landing gear length array according to the set step size;

[0097] Step S2: Calculate the takeoff pitch angle, ground contact angle, and roll angle for each main landing gear length;

[0098] Step S3: Using the following filtering conditions, the minimum main landing gear length is found in the main landing gear length array: the takeoff pitch angle is not less than the angle of attack required for takeoff at the minimum speed, the ground contact angle is not less than the ground contact angle design value, and the roll angle is not less than the roll angle constraint value.

[0099] Step S4: Interpolate the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff, the length of the second main landing gear corresponding to the design value of the ground scraping angle, and the length of the third main landing gear corresponding to the roll angle constraint value between the minimum main landing gear length and the length of the main landing gear preceding it.

[0100] Step S5: Determine the maximum value between the length of the first main landing gear and the length of the second main landing gear, and select the minimum value between the maximum value and the length of the third main landing gear as the final main landing gear length;

[0101] Step S6: Calculate the weight of the main landing gear based on its length.

[0102] Step S1 in this application is used to construct the main landing gear length array.

[0103] In some alternative implementations, in step S1, the step size is set to 10cm.

[0104] Assuming the base point is 0.85m, the array constructed from this is: =0.85:0.1:1.35.

[0105] In step S2, this application analyzes the effects of aircraft takeoff and landing performance requirements, the relative positions of the main landing gear and tail skid, the main landing gear compression, and tire pressure and compressibility on the length and weight of the main landing gear. Based on a large amount of experimental data, a calculation model for the length and weight of the main landing gear is established. In step S3, design constraints for the main landing gear are set to ensure aircraft takeoff and landing safety.

[0106] In some alternative implementations, step S2 further includes: calculating the takeoff pitch angle using the following formula. :

[0107] ;

[0108] like Figure 2 As shown, The angle between the line connecting the main landing gear and the wheel axle hinge point and the tail skid contact point and the horizontal plane. The angle between the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle and the horizontal plane;

[0109] ;

[0110] ;

[0111] ;

[0112] ;

[0113] ;

[0114] ;

[0115] in, The length of the main landing gear in its uncompressed state. This refers to the compression of the main landing gear during takeoff. The height of the main landing gear hinge point to the fuselage from the wheel axle at the takeoff angle of attack. This refers to the horizontal distance from the bottom of the tail skid to the hinge point between the main landing gear and the fuselage. The height of the bottom of the tail skid from the hinge point between the main landing gear and the fuselage; The height of the bottom of the tail skid from the main landing gear and wheel axle. The height of the bottom of the tail skid from the ground above the main landing gear; The diameter of the main landing gear wheels. Compression of the main landing gear tires. It is the length of the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle.

[0116] In some alternative implementations, step S2 further includes: calculating the rubbing angle using the following formula. :

[0117] ;

[0118] in, The height of the bottom of the tail skid from the ground above the main landing gear;

[0119] .

[0120] In some alternative implementations, step S2 further includes: calculating the back flap angle using the following formula. :

[0121] ;

[0122] in, This is the horizontal distance between the aircraft's rear center of gravity and the main landing gear. The height of the rear center of gravity from the ground;

[0123] ;

[0124] in, This refers to the height of the rear center of gravity from the hinge point between the main landing gear and the fuselage.

[0125] Based on the above calculation method, the reference area of ​​the aircraft wing in the example is 300m². 2 The maximum landing weight is 165 tons. The main landing gear is mounted on the lower fuselage, located at 58% of the wing's mean aerodynamic chord. A tail skid is installed under the rear fuselage to prevent tail scrambling; the skid is 8.1 meters from the hinge point between the main landing gear and the fuselage, and 15 centimeters above the hinge point. The rear center of gravity is 0.78 meters from the main landing gear, and 78.75 centimeters above the hinge point. The example aircraft has a maximum lift coefficient of 2.3 in takeoff configuration, a zero angle-of-attack lift coefficient of 0.79, a lift line slope of 0.098° at 0.2 meters, and a maximum lift coefficient of 3.0 in landing configuration. The calculation results are shown in Table 1.

[0126] Table 1. Calculation data of design constraint parameters corresponding to the main landing gear length array.

[0127]

[0128] In step S3, the main landing gear design constraints are obtained, such as the minimum takeoff speed of 1.06 km / h. The tail angle should be no less than 13°; the rollover angle should be no less than 17°.

[0129] As can be seen from Table 1, the landing gear length of 1.25m meets the design requirements. Therefore, the two rows of data with landing gear lengths of 1.25m and 1.15m are used for interpolation calculation in step S4.

[0130] In some optional implementations, in step S4, interpolating the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff includes: interpolating the angle of attack required for minimum speed takeoff as the takeoff pitch angle.

[0131] The angle of attack required for minimum speed takeoff is calculated using the following formula. :

[0132] ;

[0133] in, The lift coefficient at takeoff is the coefficient of force applied when the aircraft leaves the ground. The lift coefficient at zero angle of attack. The average slope of the lift line;

[0134] ;

[0135] ;

[0136] in, The maximum lift coefficient for takeoff configuration. Minimum takeoff speed Takeoff stall speed The ratio of .

[0137] In this embodiment, the minimum takeoff speed of the simulated aircraft is 1.06. Pitch angle at minimum takeoff speed The angle of attack is the same, and the calculated result is 12.826°.

[0138] The interpolation model in step S4 is shown below:

[0139] ;

[0140] ;

[0141] ;

[0142] As mentioned earlier, the first two parameters in the interpolation function `interp1`, which have the suffix "sz", represent arrays. These two parameters use known data from the array (i.e., Table 1). The third parameter, given the design or constraint value from step S3, interpolates the corresponding landing gear length from Table 1. This is the length of the first main landing gear. This is the length of the second main landing gear. This refers to the length of the third main landing gear.

[0143] Then, in step S5, take and The minimum value in the range is the main landing gear length, of which yes and The maximum value in. The calculation model is as follows:

[0144] ;

[0145] .

[0146] In the calculation results of the above example, the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff. The design value for the ground-touching angle is 1.199m, corresponding to the length of the second main landing gear. The length of the third main landing gear is 1.214m, corresponding to the rear tilt angle constraint value. The initial length was 1.285m. The final determined length of the main landing gear was 1.214m.

[0147] Finally, calculate the weight of the main landing gear.

[0148] In some alternative implementations, in step S6, the weight of the main landing gear is calculated using the following formula. :

[0149] ;

[0150] in, For maximum landing weight, For landing speed, The uncompressed length of the main landing gear Compression of the main landing gear during landing. The pressure of the main landing gear tires. The distance from the center of gravity to the main landing gear. This is the distance between the nose landing gear and the main landing gear.

[0151] In some alternative implementations, the landing speed is calculated using the following formula. :

[0152] ;

[0153] in, The stall speed at landing;

[0154] ;

[0155] in, The maximum lift coefficient for the landing configuration. For wing reference area, This refers to air density.

[0156] The weight of the main landing gear, calculated based on the final determined main landing gear length of 1.214m, is 6.671t.

[0157] The second aspect of this application provides an engineering calculation device for the length and weight of the main landing gear corresponding to the above method, mainly comprising:

[0158] The main landing gear length array construction module is used to build a main landing gear length array with 80% of the minimum estimated value of the main landing gear length as the base point and according to the set step size.

[0159] The parameter calculation module is used to calculate the takeoff pitch angle, ground contact angle, and roll angle for each main landing gear length.

[0160] The minimum main landing gear length query module is used to find the minimum main landing gear length in the main landing gear length array by filtering conditions such as the takeoff pitch angle not being less than the angle of attack required for takeoff at minimum speed, the ground contact angle not being less than the ground contact angle design value, and the roll angle not being less than the roll angle constraint value.

[0161] The interpolation calculation module is used to interpolate the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff, the length of the second main landing gear corresponding to the design value of the ground scraping angle, and the length of the third main landing gear corresponding to the roll angle constraint value, respectively, between the minimum main landing gear length and the length of the main landing gear preceding it.

[0162] The main landing gear length selection module is used to determine the maximum value between the first main landing gear length and the second main landing gear length, and select the minimum value between the maximum value and the third main landing gear length as the final main landing gear length.

[0163] The main landing gear weight calculation module is used to calculate the weight of the main landing gear based on its length.

[0164] In some alternative implementations, the step size is set to 10cm in the main landing gear length array construction module.

[0165] In some optional embodiments, the parameter calculation module includes a takeoff pitch angle calculation unit, used to calculate the takeoff pitch angle using the following formula. :

[0166] ;

[0167] in, The angle between the line connecting the main landing gear and the wheel axle hinge point and the tail skid contact point and the horizontal plane. The angle between the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle and the horizontal plane;

[0168] ;

[0169] ;

[0170] ;

[0171] ;

[0172] ;

[0173] ;

[0174] in, The length of the main landing gear in its uncompressed state. This refers to the compression of the main landing gear during takeoff. The height of the main landing gear hinge point to the fuselage from the wheel axle at the takeoff angle of attack. This refers to the horizontal distance from the bottom of the tail skid to the hinge point between the main landing gear and the fuselage. The height of the bottom of the tail skid from the hinge point between the main landing gear and the fuselage; The height of the bottom of the tail skid from the main landing gear and wheel axle. The height of the bottom of the tail skid from the ground above the main landing gear; The diameter of the main landing gear wheels. Compression of the main landing gear tires. It is the length of the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle.

[0175] In some optional embodiments, the parameter calculation module includes a rubbing angle calculation unit for calculating the rubbing angle using the following formula. :

[0176] ;

[0177] in, The height of the bottom of the tail skid from the ground above the main landing gear;

[0178] .

[0179] In some optional embodiments, the parameter calculation module includes a backflip angle calculation unit for calculating the backflip angle using the following formula. :

[0180] ;

[0181] in, This is the horizontal distance between the aircraft's rear center of gravity and the main landing gear. The height of the rear center of gravity from the ground;

[0182] ;

[0183] in, This refers to the height of the rear center of gravity from the hinge point between the main landing gear and the fuselage.

[0184] In some optional implementations, in the interpolation calculation module, interpolating the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff includes: interpolating the angle of attack required for minimum speed takeoff as the takeoff pitch angle;

[0185] The angle of attack required for minimum speed takeoff is calculated using the following formula. :

[0186] ;

[0187] in, The lift coefficient at takeoff is the coefficient of force applied when the aircraft leaves the ground. The lift coefficient at zero angle of attack. The average slope of the lift line;

[0188] ;

[0189] ;

[0190] in, The maximum lift coefficient for takeoff configuration. Minimum takeoff speed Takeoff stall speed The ratio of .

[0191] In some alternative implementations, the main landing gear weight calculation module calculates the main landing gear weight using the following formula. :

[0192] ;

[0193] in, For maximum landing weight, For landing speed, The uncompressed length of the main landing gear Compression of the main landing gear during landing. The pressure of the main landing gear tires. The distance from the center of gravity to the main landing gear. This is the distance between the nose landing gear and the main landing gear.

[0194] In some alternative implementations, the landing speed is calculated using the following formula. :

[0195] ;

[0196] in, The stall speed at landing;

[0197] ;

[0198] in, The maximum lift coefficient for the landing configuration. For wing reference area, This refers to air density.

[0199] In a third aspect of this application, a computer device is provided, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the engineering calculation method for the length and weight of the main landing gear as described above.

[0200] In a fourth aspect, this application provides a readable storage medium storing a computer program that, when executed by a processor, implements the engineering calculation method for the length and weight of the main landing gear as described above. This computer-readable storage medium may be included in the apparatus described in the above embodiments; or it may exist independently and not incorporated into the apparatus. The aforementioned computer-readable storage medium carries one or more programs that, when executed by the apparatus, process data according to the method described above.

[0201] The following is for reference. Figure 3 It shows a schematic diagram of the structure of a computer device 400 suitable for implementing the embodiments of this application. Figure 3 The computer device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments described in this application.

[0202] like Figure 3As shown, the computer device 400 includes a central processing unit (CPU) 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 402 or a program loaded from a storage section 408 into a random access memory (RAM) 403. The RAM 403 also stores various programs and data required for the operation of the device 400. The CPU 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0203] The following components are connected to I / O interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to I / O interface 405 as needed. A removable medium 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 410 as needed so that computer programs read from it can be installed into storage section 408 as needed.

[0204] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by central processing unit (CPU) 401, it performs the functions defined in the methods of this application. It should be noted that the computer storage medium of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on a computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0205] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0206] The modules or units described in the embodiments of this application can be implemented in software or hardware. The described modules or units can also be located in a processor, and the names of these modules or units do not necessarily constitute a limitation on the module or unit itself.

[0207] 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. An engineering calculation method for the length and weight of the main landing gear, characterized in that, include: Step S1: Using 80% of the estimated minimum length of the main landing gear as the base point, establish the main landing gear length array according to the set step size; Step S2: Calculate the takeoff pitch angle, ground contact angle, and roll angle for each main landing gear length; Step S3: Using the following filtering conditions, the minimum main landing gear length is found in the main landing gear length array: the takeoff pitch angle is not less than the angle of attack required for takeoff at the minimum speed, the ground contact angle is not less than the ground contact angle design value, and the roll angle is not less than the roll angle constraint value. Step S4: Interpolate the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff, the length of the second main landing gear corresponding to the design value of the ground scraping angle, and the length of the third main landing gear corresponding to the roll angle constraint value between the minimum main landing gear length and the length of the main landing gear preceding it. Step S5: Determine the maximum value between the length of the first main landing gear and the length of the second main landing gear, and select the minimum value between the maximum value and the length of the third main landing gear as the final main landing gear length; Step S6: Calculate the weight of the main landing gear based on its length.

2. The engineering calculation method for the length and weight of the main landing gear as described in claim 1, characterized in that, In step S1, the step length is set to 10cm.

3. The engineering calculation method for the length and weight of the main landing gear as described in claim 1, characterized in that, Step S2 further includes: calculating the takeoff pitch angle using the following formula. : ； in, The angle between the line connecting the main landing gear and the wheel axle hinge point and the tail skid contact point and the horizontal plane. The angle between the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle and the horizontal plane; ； ； ； ； ； ； in, The length of the main landing gear in its uncompressed state. This refers to the compression of the main landing gear during takeoff. The height of the main landing gear hinge point to the fuselage from the wheel axle at the takeoff angle of attack. This refers to the horizontal distance from the bottom of the tail skid to the hinge point between the main landing gear and the fuselage. The height of the bottom of the tail skid from the hinge point between the main landing gear and the fuselage; The height of the bottom of the tail skid from the main landing gear and wheel axle. The height of the bottom of the tail skid from the ground above the main landing gear; The diameter of the main landing gear wheels. Compression of the main landing gear tires. It is the length of the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle.

4. The engineering calculation method for the length and weight of the main landing gear as described in claim 3, characterized in that, Step S2 further includes: calculating the rubbing angle using the following formula. : ； in, The height of the bottom of the tail skid from the ground above the main landing gear; 。 5. The engineering calculation method for the length and weight of the main landing gear as described in claim 3, characterized in that, Step S2 further includes: calculating the back-flip angle using the following formula. : ； in, This is the horizontal distance between the aircraft's rear center of gravity and the main landing gear. The height of the rear center of gravity from the ground; ； in, This refers to the height of the rear center of gravity from the hinge point between the main landing gear and the fuselage.

6. The engineering calculation method for the length and weight of the main landing gear as described in claim 1, characterized in that, In step S4, interpolating the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff includes: interpolating the angle of attack required for minimum speed takeoff as the takeoff pitch angle. The angle of attack required for minimum speed takeoff is calculated using the following formula. : ； in, The lift coefficient at takeoff is the coefficient of force applied when the aircraft leaves the ground. The lift coefficient at zero angle of attack. The average slope of the lift line; ； ； in, The maximum lift coefficient for takeoff configuration. Minimum takeoff speed Takeoff stall speed The ratio of .

7. The engineering calculation method for the length and weight of the main landing gear as described in claim 1, characterized in that, In step S6, the weight of the main landing gear is calculated using the following formula. : ； in, For maximum landing weight, For landing speed, The uncompressed length of the main landing gear Compression of the main landing gear during landing. The pressure of the main landing gear tires. The distance from the center of gravity to the main landing gear. This is the distance between the nose landing gear and the main landing gear.

8. The engineering calculation method for the length and weight of the main landing gear as described in claim 7, characterized in that, Calculate the landing speed using the following formula. : ； in, The stall speed at landing; ； in, The maximum lift coefficient for the landing configuration. For wing reference area, This refers to air density.

9. An engineering calculation device for the length and weight of the main landing gear, characterized in that, include: The main landing gear length array construction module is used to build a main landing gear length array with 80% of the minimum estimated value of the main landing gear length as the base point and according to the set step size. The parameter calculation module is used to calculate the takeoff pitch angle, ground contact angle, and roll angle for each main landing gear length. The minimum main landing gear length query module is used to find the minimum main landing gear length in the main landing gear length array by filtering conditions such as the takeoff pitch angle not being less than the angle of attack required for takeoff at minimum speed, the ground contact angle not being less than the ground contact angle design value, and the roll angle not being less than the roll angle constraint value. The interpolation calculation module is used to interpolate the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff, the length of the second main landing gear corresponding to the design value of the ground scraping angle, and the length of the third main landing gear corresponding to the roll angle constraint value, respectively, between the minimum main landing gear length and the length of the main landing gear preceding it. The main landing gear length selection module is used to determine the maximum value between the first main landing gear length and the second main landing gear length, and select the minimum value between the maximum value and the third main landing gear length as the final main landing gear length. The main landing gear weight calculation module is used to calculate the weight of the main landing gear based on its length.

10. The engineering calculation device for the length and weight of the main landing gear as described in claim 9, characterized in that, In the main landing gear length array construction module, the step size is set to 10cm.

11. The engineering calculation device for the length and weight of the main landing gear as described in claim 9, characterized in that, The parameter calculation module includes a takeoff pitch angle calculation unit, used to calculate the takeoff pitch angle using the following formula. : ； in, The angle between the line connecting the main landing gear and the wheel axle hinge point and the tail skid contact point and the horizontal plane. The angle between the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle and the horizontal plane; ； ； ； ； ； ； in, The length of the main landing gear in its uncompressed state. This refers to the compression of the main landing gear during takeoff. The height of the main landing gear hinge point to the fuselage from the wheel axle at the takeoff angle of attack. This refers to the horizontal distance from the bottom of the tail skid to the hinge point between the main landing gear and the fuselage. The height of the bottom of the tail skid from the hinge point between the main landing gear and the fuselage; The height of the bottom of the tail skid from the main landing gear and wheel axle. The height of the bottom of the tail skid from the ground above the main landing gear; The diameter of the main landing gear wheels. Compression of the main landing gear tires. It is the length of the line connecting the bottom of the tail skid and the hinge point of the main landing gear and the wheel axle.

12. The engineering calculation device for the length and weight of the main landing gear as described in claim 11, characterized in that, The parameter calculation module includes a floor rubbing angle calculation unit, used to calculate the floor rubbing angle using the following formula. : ； in, The height of the bottom of the tail skid from the ground above the main landing gear; 。 13. The engineering calculation device for the length and weight of the main landing gear as described in claim 11, characterized in that, The parameter calculation module includes a back-turn angle calculation unit, used to calculate the back-turn angle using the following formula. : ； in, This is the horizontal distance between the aircraft's rear center of gravity and the main landing gear. The height of the rear center of gravity from the ground; ； in, This refers to the height of the rear center of gravity from the hinge point between the main landing gear and the fuselage.

14. The engineering calculation device for the length and weight of the main landing gear as described in claim 9, characterized in that, In the interpolation calculation module, interpolating the length of the first main landing gear corresponding to the angle of attack required for minimum speed takeoff includes: interpolating the angle of attack required for minimum speed takeoff as the takeoff pitch angle; The angle of attack required for minimum speed takeoff is calculated using the following formula. : ； in, The lift coefficient at takeoff is the coefficient of force applied when the aircraft leaves the ground. The lift coefficient at zero angle of attack. The average slope of the lift line; ； ； in, The maximum lift coefficient for takeoff configuration. Minimum takeoff speed Takeoff stall speed The ratio of .

15. The engineering calculation device for the length and weight of the main landing gear as described in claim 9, characterized in that, In the main landing gear weight calculation module, the main landing gear weight is calculated using the following formula. : ； in, For maximum landing weight, For landing speed, The uncompressed length of the main landing gear Compression of the main landing gear during landing. The pressure of the main landing gear tires. The distance from the center of gravity to the main landing gear. This is the distance between the nose landing gear and the main landing gear.

16. The engineering calculation device for the length and weight of the main landing gear as described in claim 15, characterized in that, Calculate the landing speed using the following formula. : ； in, The stall speed at landing; ； in, The maximum lift coefficient for the landing configuration. For wing reference area, This refers to air density.

17. A computer device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, the processor executing the computer program to implement the engineering calculation method for the length and weight of the main landing gear as described in any one of claims 1-8.

18. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the engineering calculation method for the length and weight of the main landing gear as described in any one of claims 1-8.

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