Identification of Engine Thrust and Aerodynamic Drag Force According to Flight Test Data with Smoothing of Random Measurement Errors

In this paper, an approach is proposed to identify the thrust force of engines and the aerodynamic drag force of aircraft according to flight test data. To obtain separate estimates of thrust and drag forces, measurements of longitudinal and normal load factors, angle of attack, true airspeed and barometric altitude are used. The advantage of the proposed approach is that it does not require the use of gas-dynamic models of the engine, flying laboratories, force measurements in the engine mounting points, or the installation of additional sensors in the engine. Despite these advantages, in practice, such an approach is usually not used, since it leads to a poorly conditioned or incorrect identification problem due to the high degree of linear relationship between the vectors of thrust and drag forces. This article suggests ways to solve the problem of poor conditionality, consisting of the development of a special test maneuver that improves the degree of conditionality of the problem, as well as the use of the special smoothing of random measurement errors using the equations of motion of the aircraft.