The design and implementation of a autonomous navigation and control system for UAV, mandates simulating the system before in-flight testing. These simulations require a computational model of the aircraft, that can be obtained from the computation of aerodynamic parameters such as the drag polar. In this paper we present the identification of these parameters using two methods: one by flight testing techniques; the other by a combination of semi-empirical methods and computational fluid dynamics, dubbed the hybrid method. The hybrid method, which produces a parabolic polar drag, had the same qualitative trend compared to experiments. However, a detailed analysis of the parameters that shapes the polar drag, had significant differences, particularly in the parasite drag. This is probably due to propeller effects, low Reynolds Number and limitations of the piloting technique.
Keywords: Drag polar, flight testing, parasite drag, UAV, VLM