Methods for Determination of Dynamic Derivatives of Unsteady Moving Aircraft

Abstract

To reduce the aircraft development cost it is required to obtain information about the stability and control behavior of an aircraft at a very early stage in the design process. The reliability and accuracy of the pre-dicted data are of eminent importance with regard to cost effectiveness within the design process. The investigations presented in this report are concerned with the application and assessment of different methods for the determination of the steady and in particular unsteady behavior of a generic transport aircraft configuration (DLR-F12) with a high aspect ratio wing in subsonic speed range. The various methods such as wind tunnel measurement techniques, analytical and numerical methods and system identification tools can be used for aircraft configurations with high aspect ratio and also with low aspect ratio wings, where not only the linear aerodynamic behavior in the low alpha regime is of interest. The analysis and evaluation of nonlinear flow characteristics, such as vortex-dominated flows or flow separa-tion conditions, is also possible using these methods.