Estimation Methods for Determination of Drag Characteristics of Fly - by - Wire Aircraft

In this paper, several parameterlslate estimation approaches for the determination ofdragpolars from flight data are described and evaluated for a fly-by-wire (FBW) aircraft. Bolh model-based approaches (MBAs) and non-model-based approaches (NMBAs) are considered. Dynamic.response data from roller coaster and windupturn manoeuvres are generated in a FBW aircraft flight simulator at different flight conditions and the typical performance resulls are presented. A novel approach to estimate the drag polar has been evaluated. It has been found that Ihe NMBAs perform better than the MBAs. Classically, the MBAs have been used for the determination of drag polan. The merits of an NMBAare that it does not require specification of the detailed model of the aerodynamic coefficients and it can be suitably used for online estimation of drag polm from the flight data of aerospace vehicles.