The paper presents the CFD analysis of the main rotor of the unmanned helicopter model with a maximum take-off mass of up to 150 kg. The calculations were performed in ANSYS Fluent software. The results of the work are the relationship between the lift force generated by the main rotor as a function of the blade angle of attack. The results are presented for the three considered rotational speeds i.e. 1400, 1600, 1800 rpm. As the angles of the blades of attack increases, an increase in the rotor lift force, torque, and power requirement of the tested main rotor was observed. Additionally, the power required to drive a carrier rotor for the three speeds in question was calculated. Examined changes in the power requirement of the main rotor also showed a percentage increase when changing the α and increasing the rotational speed. The result based on the numerical calculations for three blades main rotor model were presented in tables and diagrams.