On the effect of popular additive manufacturing technologies on the performance and noise emission of UAV propellers

Noise remains a major concern for the widespread employment of Unmanned Air Vehicles (UAVs) operations, especially in urban environments. Moreover, not only must overall noise levels be considered when analyzing the acoustic impact of UAVs, but noise quality based on the spectral content of the acoustic signal must also be considered due to the psycho-acoustic effect on the listeners. Additionally, as UAVs become widespread, the ability to perform field replacement of propellers using additive manufacturing (AM) is of increased interest to many operators. However, as different AM techniques become popular, their impact on performance and noise must be assessed. In this investigation, the effect of manufacturing characteristics, such as surface roughness and flexibility, on the propeller thrust, torque, and acoustic signature is explored through an experimental campaign, revealing differences depending on the selected technique. A numerical experiment is then performed to isolate the effect of flexibility and roughness on these characteristics.