Testing and research on acoustic characteristics of low small slow drones

In order to study the acoustic characteristics of low-speed and slow speed drones, different drone models were selected in anechoic chambers and outdoor urban environments, and test states such as single engine hovering, multi aircraft hovering, wing variation, drone wings, and low altitude scanning were used to test the acoustic characteristics of drones. By analyzing the total sound pressure level, FFT, and noise distribution, the acoustic characteristics of weak slow targets were obtained. The results indicate that the acoustic characteristics of "weak yet slow" drones are related to the aerodynamic noise generated by engine speed and wing rotation. As the motor speed of low-speed and slow speed drones changes, their sound frequency characteristics and flight speed synchronously change. That is, as the motor speed increases, the frequency of the sound speed characteristics of low-speed and slow speed drones increases, and the flight speed accelerates. At the same time, due to the rotation of the wings, aerodynamic noise is generated in the air near the driven wings as the wing speed changes.