Selection and Optimization of Motor KV Values for Multi-Blade and High-Load Ratio UAVs

This paper proposes a method to enhance the load capacity and reduce the volume of an Unmanned Aerial Vehicle (UAV) by optimizing the motor’s KV value (a measure of RPM per volt) to match the specific aerodynamic characteristics of a multi-blade propeller system. Given the fixed maximum output power of the motor when its volume and weight are determined, a higher-power-density motor structure can maximize blade lift by optimizing its output torque and speed. The electromagnetic structure of the motor is initially designed based on the aerodynamic characteristics of a 29-inch, four-blade model. Different motor Voltage-Turns (KV) value schemes are obtained by altering the number of winding turns and the wire diameter. Subsequently, the torque–speed output performance of the motor is calculated under constant power conditions. This data, in conjunction with the blade load, allow for a comparison of the motor’s output lift at different KV values. The optimal KV value for the motor is determined to be 116, resulting in a rated lift of 11.57 kg. This paper correctly analyzes the motor and blade as an integrated system, which is crucial for meaningful optimization in aerospace application.