A quick conversion calculation method for aircraft center of gravity data

Abstract

The application discloses a kind of quick conversion calculation method of aircraft center of gravity data, comprising the following steps: step one, according to the geometric relationship diagram of center of gravity conversion, the geometric relationship between the height h of aircraft center of gravity coordinate, the height of center of gravity when landing gear is fully extended, the distance a between the projection of aircraft center of gravity coordinate to ground point and front wheel contact point and the distance b between rear wheel contact point is established;Step two, the geometric relationship is packaged into Excel software;Step three, input the front wheel coordinate parameters and rear wheel coordinate parameters of the model that needs to be calculated, and then input the center of gravity coordinate, and the corresponding h, a, b value can be automatically converted;The application is aimed at the drawbacks of drawing method, combined with commonly used Excel software can automatically process a large number of formulas, realize the calculation of aircraft h, a, b value in each state, data processing speed is fast, solve the problem of low efficiency and easy to make mistake of traditional drawing method manual reading data.

Description

Technical Field

[0001] This invention relates to the field of aircraft weight engineering technology, specifically to a method for rapid conversion and calculation of aircraft center of gravity data. Background Technology

[0002] During the aircraft development process, according to GJB 67.4A-2008 "Structural Strength Specifications for Military Aircraft Part 4: Ground Load", the weight specialist needs to provide the strength specialist with center of gravity data for multiple states, such as normal takeoff weight, maximum ground weight, maximum landing weight, landing design weight, and minimum flight weight, for use in landing gear strength design and verification. The center of gravity data for each state needs to be converted into h, a, and b values, where h is the height of the center of gravity above the ground when the landing gear is fully extended, a is the distance between the aircraft's center of gravity coordinates projected onto the ground and the nose wheel contact point, and b is the distance between the aircraft's center of gravity coordinates projected onto the ground and the rear wheel contact point.

[0003] Previously, the values ​​of h, a, and b were generally obtained by plotting on the three-view diagram of the aircraft, such as... Figure 1 As shown, reading relevant data from the graph with the naked eye and copying it into the corresponding table can be crowded and chaotic when multiple sets of data are displayed on the graph. Manual reading is also prone to misjudgment, and data verification is very inconvenient. Moreover, from the design of a model to the final design evaluation, the center of gravity of the aircraft in various states often needs to go through multiple iterations. Such data conversion also needs to be carried out many times, which will consume a lot of time and energy. Summary of the Invention

[0004] This invention addresses the problem of complex and error-prone graphs when obtaining the coordinates h, a, and b of an aircraft's center of gravity using graphical methods. By employing mathematical analytical methods and encapsulating the corresponding algorithms in Excel software, an accurate and efficient tool for calculating h, a, and b values ​​has been developed.

[0005] This invention discloses a rapid conversion and calculation method for aircraft center of gravity data, comprising the following steps:

[0006] Step 1: Based on the geometric relationship diagram of the center of gravity conversion, construct the geometric relationship between the aircraft's center of gravity coordinates (X, Y), the height h of the center of gravity above the ground when the landing gear is fully extended, the distance a between the aircraft's center of gravity coordinates projected onto the ground and the front wheel contact point, and the distance b between the rear wheel contact point;

[0007] Step 2: Encapsulate the geometric formulas into Excel software;

[0008] Step 3: Input the front wheel coordinate parameters (X1, Y1) and rear wheel coordinate parameters (X2, Y2) of the model to be calculated, and then input the center of gravity coordinates (X, Y). The corresponding h, a, and b values ​​will be automatically converted.

[0009] Step four, input the state of gravity center coordinates, namely, the h, a, b values in each state can be obtained.

[0010] Further, the geometric relationship is as follows:

[0011] h=L1*sin(alpha2)

[0012] a=L1*cos(alpha2)

[0013] b=L0-a

[0014]

[0015]

[0016] alpha2=alpha0-alpha1

[0017]

[0018]

[0019] Wherein: h - the height of the gravity center from the ground when the landing gear is fully extended;

[0020] a - the distance between the projection of the aircraft gravity center to the ground point and the front wheel contact point;

[0021] b - the distance between the projection of the aircraft gravity center to the ground point and the rear wheel contact point;

[0022] L0 - the distance between the front and rear wheel contact points;

[0023] L1 - the distance between the aircraft gravity center and the front wheel contact point;

[0024] alpha0 - the angle between L1 and the horizontal reference line;

[0025] alpha1 - the angle between the ground line in the fully extended state of the landing gear and the horizontal reference line;

[0026] alpha2 - the angle between L1 and the ground line;

[0027] (X1, Y1) - the front wheel contact point coordinates;

[0028] (X2, Y2) - the rear wheel contact point coordinates;

[0029] (X, Y) - the aircraft gravity center coordinates.

[0030] The present application aims at the drawbacks of the drawing method, and a large number of formulas can be automatically processed by combining with commonly used Excel software, so that the aircraft gravity center h, a, b values in each state are directly calculated in the Excel software, which has the advantages of fast data processing speed, and solves the problems of low efficiency and easy error of the traditional drawing method. Attached Figure Description

[0031] Figure 1 Traditional graphical methods are used to determine the values ​​of h, a, and b;

[0032] Figure 2 Geometric analysis of the centroid transformed into h, a, b;

[0033] Figure 3 Encapsulation of input / output geometric relationships;

[0034] Figure 4 The required values ​​of centroid h, a, and b for each state are calculated. Detailed Implementation

[0035] The present invention can be further described through the following embodiments; however, the scope of the present invention is not limited to the following embodiments.

[0036] Example: The following, with reference to the accompanying drawings, uses a set of center of gravity (X, Y) values ​​of an aircraft as an example to further illustrate the rapid conversion and calculation method for aircraft center of gravity data according to the present invention.

[0037] First, based on the definitions of h, a, and b values, construct as follows: Figure 2 The diagram shown illustrates the geometric relationship between the aircraft's center of gravity coordinates (X, Y) and the values ​​of h, a, and b. The geometric formula is as follows:

[0038] h = L1●sin(α2)

[0039] a = L1·cos(α2)

[0040] b=L0-a

[0041]

[0042]

[0043] α2=α0-α1

[0044]

[0045]

[0046] Where: h——the height of the center of gravity above the ground when the landing gear is fully extended, in meters;

[0047] a——Distance between the aircraft's center of gravity projection onto the ground and the point where the nose wheel touches down, in meters;

[0048] b—Distance between the aircraft's center of gravity projection onto the ground and the rear wheel contact point, in meters;

[0049] L0—Distance between the front and rear wheel contact points, in meters;

[0050] L1—Distance from the aircraft's center of gravity to the point where the nose wheel touches down, in meters;

[0051] α0 — Angle between L1 and the horizontal baseline, in radians;

[0052] α1—Angle between the ground line and the horizontal baseline when the landing gear is fully extended, in radians;

[0053] α2 — Angle between L1 and the ground line, in radians;

[0054] (X1,Y1)——Coordinates of the front wheel contact point, in meters;

[0055] (X2,Y2)——Coordinates of the rear wheel contact point, in meters;

[0056] (X,Y)——Coordinates of the aircraft's center of gravity, in meters.

[0057] Secondly, the geometric relationships are encapsulated in Excel software, such as... Figure 3 As shown.

[0058] Finally, input the front wheel coordinate parameters (X1, Y1) and rear wheel coordinate parameters (X2, Y2) of the target aircraft model, and then input the coordinate values ​​of the aircraft's center of gravity (X, Y) to be calculated. The corresponding h, a, and b values ​​will be automatically obtained.

[0059] By inputting the center-of-gravity data for each state, you can obtain the following: Figure 4 The values ​​of the centroid h, a, and b for each state are shown.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0061] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for rapid conversion and calculation of aircraft center of gravity data, characterized in that: The process includes the following steps: Step 1: Based on the center of gravity conversion geometric relationship diagram, construct the geometric relationship between the aircraft's center of gravity coordinates (X, Y), the height h of the center of gravity above the ground when the landing gear is fully extended, the distance a between the aircraft's center of gravity coordinates projected onto the ground and the contact point of the front wheel, and the distance b between the contact point of the rear wheel and the contact point of the front wheel; Step 2: Encapsulate the geometric relationship into Excel software; Step 3: Input the front wheel coordinate parameters (X1, Y1) and rear wheel coordinate parameters (X2, Y2) of the aircraft model to be calculated, and then input the center of gravity coordinates (X, Y), and the corresponding h, a, and b values ​​will be automatically obtained; Step 4: Input the center of gravity coordinates for each state to obtain the h, a, and b values ​​for each state; The geometric relationship is as follows: h = L1·sin(α2) a = L1·cos(α2) b=L0-a α2＝α0-α1 Where: h—height of the center of gravity above the ground when the landing gear is fully extended; a—distance between the ground point projected from the aircraft's center of gravity coordinates and the contact point of the nose wheel; b—distance between the ground point projected from the aircraft's center of gravity coordinates and the contact point of the rear wheel; L0—distance between the contact points of the front and rear wheels; L1—distance between the aircraft's center of gravity coordinates and the contact point of the nose wheel; α0—angle between L1 and the horizontal baseline; α1—angle between the ground line and the horizontal baseline when the landing gear is fully extended; α2—angle between L1 and the ground line; (X1, Y1)—coordinates of the nose wheel contact point; (X2, Y2)—coordinates of the rear wheel contact point; (X, Y)—coordinates of the aircraft's center of gravity.

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