Mutilcopters or multirotors have become standouts because they have the ability to hover and vertically take off and land. When they are in action, multirotors may needshrouds to protect their blades from impact and protect human from being wounded. However, the effects of shrouds to the aerodynamic characteristics of rotors must be considered. This paper will use computational fluid dynamics (CFD) to investigate the effects of a shroud to the thrust and power of a 9.5 inch rotor. The results show that at the same rpm, a shrouded rotor produces 20% more thrust than a free rotor. The power also increases but only by 6%. These results agree with Baeder’s results (2011).
