Flight Tests of Parameter Estimation and Validation Applying to FTD

Jung Hoon Lee, Principal Researcher, Korea Aerospace Research Institute, Daejeon, Korea

Abstract

The flight tests of a light aircraft named ChangGong-91 in the normal category, were conducted. The tests were
aimed at producing the flight parameters and verifying the Flight Training Device (FTD) simulation models
which were constructed from the parameters. First, in order to produce the flight parameters, proper control
inputs were applied to separate the longitudinal motions from the lateral-directional motions via the flight test.
The longitudinal motions include short period motions excited by a rapid triple-step input to the stabilator,
performed during trimmed level flights. For the lateral-directional motions, the flights were induced by a rapid
triple-step control input to the rudder and followed input to the aileron which produced a dutch-roll motion. The
Output Error Method was used to produce aerodynamic coefficients, stability and control derivatives. The
second part of the flight tests measured the control force, take-off, climb, trim, short period, phugoid, roll, spiral,
dutch-roll, stall, landing, and ground effects during various flights. Body, wind, stability and inertial axes allow
6 second-order linear differential equations for translational and rotational motions. The equations of motion
were integrated with the time measurement, resulting in good agreement with the flight tests.