Experimental investigation of aerodynamic characteristic for a coaxial rotor aircraft

In this paper, the aerodynamic characteristics of coaxial rotor aircraft during hover flight are studied, in order to find out the relationship between several controllable parameters that affect aerodynamic characteristics, so as to improve the performance of the aircraft from the design and parameter configuration stage. By using computational fluid dynamics simulation and hovering experimental equipment, the performance measurement (thrust, torque, and power consumption) and design parameters (rotor spacing, rotational speed, and angle of attack) of the coaxial rotor aircraft were obtained. By CFD simulation of thrust characteristics at different rotor spacing, it can be seen that different rotor spacing leading to different thrusts. When the rotor spacing is set around: h/R=0.35, the thrust of the system is greater than that under other rotor spacings. Based on this, The Semi-physical experiment test device was used to test the characteristics of the coaxial rotor aircraft. Then the data obtained by fluid simulation is compared with the data obtained by experimental tests, telling that the aerodynamic performance was well predicted. To analyze the underlying principles behind the test data, an orthogonal L
₁₆
(4
³
) test design had been applied, then the design parameters of the aircraft are optimized. By analyzing the data obtained from the experiment, it can be seen that the design parameters influenced thrust, torque, and power consumption reduced in the order: angle of attack > rotational speed > rotor spacing, rotational speed >rotor spacing > angle of attack, and rotational speed > angle of attack > rotor spacing, respectively. The optimal rotor spacing and attack angle were determined to maximize the aerodynamic performance considering increased thrust, reduced torque and reduced power consumption.