A Method for Predicting the Flight Trajectory of a Wind Tunnel Free Flight Test Model

Abstract

The invention provides a method for estimating the flight trajectory of a wind tunnel free flight test model, which includes, step 1, obtaining the angle of attack-mechanical coefficient table of the flight model; step 2, setting the initial angle of attack value θ0 and launch of the free flight test Position, initial launch speed, use the linear interpolation method to obtain the mechanical coefficient under the initial angle of attack value θ0, and record the initial angle of attack value θ0 and the corresponding mechanical coefficient as the initial launch parameter D0; Step 3, use the Runge-Kutta method Calculate the estimated flight trajectory data after taking off at the launch position; step 4, when the estimated flight trajectory data does not meet the test requirements, repeat steps 2 and 3 to obtain a new estimated flight trajectory until the new estimated flight trajectory Meet the test requirements. This method predicts the flight trajectory of the model flying freely in the wind tunnel, and enables the flight trajectory to stay in the observation window area for a long time, so that the test can obtain more effective information.

Description

technical field [0001] The invention belongs to the field of wind tunnel flight tests, in particular to a method for predicting the flight trajectory of a wind tunnel free flight test model. Background technique [0002] Wind tunnel free flight test is an important method in the study of aircraft dynamic characteristics. The test principle is to truly reproduce the dynamic characteristics of the aircraft under the action of unsteady aerodynamic forces in the free flight state under the condition that the wind tunnel test is similar to the dynamics of the flight state, and directly record the motion characteristics of the aircraft through high-speed photography At the same time, based on the aerodynamic parameter identification technology, according to the angular displacement and linear displacement data of the model captured and recorded by the high-speed camera in the test, the static and dynamic stability derivative coefficients of the aircraft, as well as the drag and li...

AI Technical Summary

Problems solved by technology

However, if the launch speed and launch position are repeatedly adjusted through the actual wind tunnel free flight test results again and again, it will also cause a large waste of wind tunnel blowing times and test models. Therefore, if certain launch parameters and launch positions can be adjusted before the test Under normal circumstances, the model flight trajectory passing through the observation window area is estimated, and then by adjusting the launch parameters and launch position, it is estimated that the model flight trajectory passing through the observation window area can meet the launch parameters and launch position required by the test. It is of great significance to ensure the test effect and greatly reduce the cost of the wind tunnel free flight test

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