A Design Tool for Minimizing the Acoustic Signature of Small Rotors

An innovative modeling utility is proposed for designing rotor blades for Unmanned Aerial Systems (UAS) with reduced acoustic signatures. Emphasis will be placed on modeling the performance and noise characteristics of small propellers and rotors operating at low tip speeds and low Reynolds numbers; typical of the platforms that fall under the Group 1 UAS category defined by the US Department of Defense. Published performance and acoustic data will be used to access the accuracy of the proposed utility in predicting the frequency power spectrum and directivity characteristics of Group 1 UAS rotors. The proposed model will be used to perform parametric studies to investigate the effects of rotor design parameters including rotor size, RPM, and disk loading on the harmonic noise radiation of the rotor. While the initial model will focus specifically on minimizing the rotational harmonic noise (i.e. loading noise and thickness noise), modeling techniques for broadband noise will also be considered.