The nonlinear model of a novel ducted-fan uninhabited aerial vehicle is presented, where the aerodynamic coefficients are determined by numerical analysis of the flowfield about the airframe. The model is used to investigate performance and stability characteristics and to gain a sound physical understanding of dynamic behavior of this unconventional design. Finally, the influence of uncertainty in the aerodynamic derivatives on the open-loop dynamics is discussed as a result of significant approximations in the aerodynamic analysis