The recommended optimal twist angles were determined for particular sections of the prototype rotor blade dedicated to an unmanned helicopter with a maximum take-off weight of 150 kg. The main rotor diameter is 2m. The main rotor blade was tested in the GUNT HM 170 tunnel for four different air flow velocities and variable angles of attack. The blade model was divided into sections, each of them was made in 3D printing technology. For all the sections, the maximum lift force and drag force were determined and then converted to dimensionless values. Aerodynamic characteristics were calculated for each section and different air flow velocities in the wind tunnel. Due to the division of the blade into sections, it was possible to define the most favorable angles of attack along the rotor radius. Aerodynamic excellence was identified for each blade section and air flow velocities.