Identification of dynamic derivatives with a controlled wind tunnel model of the spaceplane-configuration PHOENIX

Abstract

A method for the experimental investigation of unsteady aerodynamic effects in a wind tunnel based on the method of free oscillation is presented. The wind tunnel model is mounted on a free oscillation rig and is equipped with electrically driven control surfaces that allow to excite the model in different frequency ranges. Because of the unstable behaviour of the investigated spaceplane configuration PHOENIX a controller was used to stabilize the model. Two types of aerodynamic models are investigated. It is shown that the identified parameters of classical steady aerodynamic models depend on the frequency of motion. In a second step aerodynamic models are used that include first order transfer functions to consider the unsteady aerodynamic effects. A method for the iterative determination of the unknown parameters is presented. The identified parameters of these models are shown to be independent from the frequency of motion.