To investigate the flight characteristics of unmanned ducted vehicle

a full-scale ducted propeller wind tunnel test was conducted to build the aerodynamic model and analyze the aerodynamic characteristics of ducted propeller. On these foundations

the flight dynamic mathematical model of the vehicle was established to investigate the characteristics trimming and stability of unmanned ducted vehicle.The results indicate that the aerodynamic characteristics of the ducted-propeller are strongly influenced by the forward speed and attitude angle

leading to significant variations in stability and maneuverability of the unmanned ducted vehicle at different forward speeds. This unmanned ducted vehicle is an unstable body similar to inverted pendulum in hover and low forward speed. The aerodynamic damping is small

while the speed and attitude angle diverge quickly

with double amplitude in 0.5 s. The flight stability is improved due to the increase of aerodynamic damping at high forward speed. The reverse control brings difficulties to flight control the unmanned ducted vehicle.