Experimental study on methods of measuring lift in coaxial rotor engine

Unmanned aerial vehicles (UAVs) with coaxial rotor configurations are increasingly employed due to their ability to enhance lift within limited spatial constraints. This paper presents an experimental study on a 15×4 coaxial rotor configuration to evaluate the effect of power distribution on lift characteristics. The results indicate that, at maximum power, the lift of the coaxial system decreases by approximately 30% compared to two independently operating rotors, owing to the turbulent airflow from the upper rotor impinging on the lower one. Based on the measured data, nonlinear regression functions were developed to describe the relationships among lift, power, current, and rotational speed. These findings clarify the performance limitations of coaxial rotor systems and provide an experimental basis for optimizing UAV propulsion system design.