Design Tools for Advanced Low Noise Rotors for Small VTOL UAS

A major innovative thrust in Army tactical operations is routine use of small Group 1 UAS for surveillance and sensing missions. However, for effective and stealthy use of such assets, low acoustic signature is critical. At present, capabilities for designing such vehicles for minimum noise is extremely limited, especially when combined with the challenge of designing to meet critical mission requirements. The proposed Phase I/Phase II effort will fill this technology gap by enhancing state-of-the-art rotary-wing aerodynamic and aeroacoustic analysis with additional modeling capabilities needed for accurate acoustic prediction of small UAS noise and then developing a small UAS design optimization tool inclusive of acoustic signature using reduced order surrogate models generated from this enhanced analysis. The new design optimization tool will provide fast, accurate prediction of both the acoustic and aerodynamic characteristics associated with small UAS, including (1) noise generated by multiple, variable RPM proprotors, (2) interacting propeller/airframe noise (e.g., strut noise and prop/wing interaction noise), and (3) electric motor noise. Phase I will demonstrate the feasibility of the proposed approach. Phase II will develop and demonstrate a Group 1 multirotor UAS design optimization tool. All modeling and design capabilities will be validated through acoustic testing.