Small and medium Unmanned Aerial Vehicles use piston engines with different kind of propulsion systems, that incorporate propeller concept. Existed design and optimization methods give possibility to find optimal solution for certain application. Usage appropriately shaped circular housing or duct around propeller in some case sufficiently increase performance, compared to typical propeller. This study aimed made design of ducted fan propulsion system by complex design methods with thrust about 300 kg. Complex method described here incorporate panel-vortex method as design tools, and finite volume analysis for performance calculation.General parameters and geometry of propulsor was determined at first stage. Assumed that propulsor should generate 300 kg of thrust with 136 hp engine power. Input data for propeller design was circular housing geometry. Clark-Y airfoil data used for geometry of circular housing around propeller. After parameters calculation complete propulsor geometry was generated.Propeller have four blades, after propeller installed static contra-propeller for recovering wake energy with five blades. Blade shape specified by planform and four control section with appropriate airfoil and twist. With this geometry data perfomance calculation was made at second stage.Second stage calculations are carried out in CFD codes, which implements finite-volume analysis. Results are thrust and speed/pressure spatial distribution at two differ flight condition – zero speed at ground and 50 m/s at sea level.Concluded that circular housing add 15…20% extra thrust with same power of engine. Rotation speed should not increase for propeller with 1.5 m diameter, because blade tip have supersonic speed, drag dramatically increased, vibration occurs, as result a significant loss of thrust.Obtained speed and pressure spatial distribution around propulsor given information about stall region, and help with further improvement of propulsor.