Aerodynamic analysis of a ducted fan VTOL UAV for transition manoeuvre

The development of a dynamic model for a new ducted fan VTOL UAV is presented to analyze the transition maneuver from vertical to horizontal flight. The objective is to ensure that the UAV can achieve a smooth transition from vertical climb or hover ing to horizontal flight by using conventional control surfaces which are affected by the propeller exit flow behind the duct. As a pan of the development of the dynamics model, this paper presents a simplified duct design methodology based on an annular wing theory and explains how the slipstream affects control surface and generates high efficiency lift force. The theoretical results are to be compared with CFD analysis. Computational fluid dynamics was used to evaluate the aerodynamic coefficients at different speeds and angles of attack. The interaction between the fan flow and duct causes complex flow structures depending on the flight condition. To evaluate the aerodynamic characteristics of the duct, 3D analytical models were used. The full-scale model of UAV with due ted fan rotating is also simulated using computational fluid dynamics approach in hopes of analyzing the process of UAV in full flow field.