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Method for identifying balanced polar curve of two-engine airplane through ground taxiing test

A ground taxiing and taxiing test technology, which is applied in the direction of aircraft component testing, etc., can solve the problems of high risk and high cost of air flight test, and achieve the effect of shortening the cycle, reducing the risk of flight test, and good practicability

Active Publication Date: 2020-02-21
CHENGDU AIRCRAFT INDUSTRY GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] 3) Air flight tests are expensive and risky;

Method used

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  • Method for identifying balanced polar curve of two-engine airplane through ground taxiing test
  • Method for identifying balanced polar curve of two-engine airplane through ground taxiing test
  • Method for identifying balanced polar curve of two-engine airplane through ground taxiing test

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Embodiment 1

[0083] A method of identifying the balance pole curve of a twin-engine aircraft through ground taxiing tests, ignoring the change in intake distortion caused by engine speed changes; the test runway is horizontal, and the angle of attack and pitch angle are the same; figure 1 As shown in Fig. 1, select two sliding state points with different pitch angles to carry out the sliding tests of synchronous acceleration / deceleration and asynchronous acceleration / deceleration of the two engines at different speeds, respectively, and calculate the acceleration / deceleration through the acceleration / deceleration motion graph; thus The model resistance and lift-induced resistance factors are calculated, such as Figure 9 As shown, the aircraft equilibrium pole curve CD-CL is obtained by fitting. In order to facilitate the calculation of the correction amount of the aircraft balance pole curve, two taxiing state points with different pitch angles are selected for testing.

[0084] The inve...

Embodiment 2

[0086] This embodiment is optimized on the basis of embodiment 1, such as figure 1 Shown, the present invention comprises the following steps:

[0087] 1) Select working conditions, namely weight, speed and pitch angle;

[0088] 2) Under two different pitch angles, carry out the sliding tests in different states of synchronous acceleration / deceleration of the two engines at different speeds and asynchronous acceleration / deceleration of the two engines;

[0089] 3) Calculate the acceleration / deceleration in the same speed range during different taxiing processes;

[0090] 4) Through the taxiing process in different states, the drag coefficient, lift-induced drag factor and form resistance are respectively solved, and the aircraft equilibrium pole curve under this working condition (speed point) is identified;

[0091] 5) Change the speed, repeat steps 2) to 4), and identify the balance pole curves of the aircraft at different speeds.

[0092] As shown in Table 1, two state p...

Embodiment 3

[0098] This embodiment is optimized on the basis of embodiment 1 or 2, as figure 2 As shown, the calculation formula of the acceleration / deceleration motion in the sliding test is as follows:

[0099] L+N=G (1)

[0100] T-D-f=ma (2)

[0101]

[0102]

[0103] f=μN (5)

[0104] Among them, L is the lift of the aircraft, N is the support force of the aircraft tires, G is the gravity of the aircraft, T is the total thrust of the two engines, D is the drag of the aircraft, f is the friction force on the aircraft, and m is the mass of the aircraft , a is the acceleration / deceleration of the aircraft, ρ is the density, V is the velocity, S is the reference area, CL is the lift coefficient, and CD is the drag coefficient.

[0105] Other parts of this embodiment are the same as those of Embodiment 1 or 2 above, so details are not repeated here.

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Abstract

The invention discloses a method for identifying the balanced polar curve of a two-engine airplane through a ground taxiing test. The variable quantity of inlet distortion caused by change of the rotation speeds of engines is ignored; a runway for the test is horizontal, and the angle of attack and the angle of pitch are the same in size; taxiing state points of two different angles of pitch are selected to be subjected to synchronous accelerating / decelerating and asynchronous accelerating / decelerating taxiing tests when the two engines are at the different rotation speeds, and the accelerating / decelerating speed is worked out through accelerating / decelerating motion graph lines; and accordingly, profile drag and lift-to-drag factors are worked out, and the balanced polar curve CD-CL of the airplane is obtained through fitting. According to the method, inaccuracy of data of an engine bed test is overcome, the true balanced polar curve of the airplane is obtained, meanwhile, the aerialflight test cost is reduced, and the test flight risk of maiden flight is reduced; and the balanced polar curve of the airplane is identified on the basis that the data of the engine bed test are notutilized, a foundation is built for reasonably making a test flight plane of maiden flight in the later period, and the good practicality is achieved.

Description

technical field [0001] The invention belongs to the technical field of aircraft testing, and in particular relates to a method for identifying the balance pole curve of a twin-engine aircraft through a ground taxiing test. Background technique [0002] At present, the known balance pole curve data of the aircraft are obtained through wind tunnel tests, and some corrections are made to the test data. The wind tunnel test is to obtain the aerodynamic characteristics of the real aircraft after the aerodynamic characteristics of the wind tunnel model are corrected. This requires similarity, interference correction and other links. Therefore, it is still difficult to obtain the aerodynamic parameters of the real aircraft. There are relatively mature methods for hole wall interference correction and Reynolds number correction for test data, but the accuracy of the correction results still needs to be further improved. [0003] In addition, due to the influence of factors such as ...

Claims

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Application Information

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IPC IPC(8): B64F5/60
CPCB64F5/60
Inventor 冯宇鹏李锐李阳周伟
Owner CHENGDU AIRCRAFT INDUSTRY GROUP
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