Aerodynamic and aeroacoustic design of small unmanned aircraft system propellers at low Reynolds numbers.

The Small Unmanned Aircraft System (sUAS) has become an overwhelmingly important asset for military intelligence, surveillance, and reconnaissance in addition to a multitude of needs in the commercial industry. More research should investigate sUAS propulsion systems and specifically the propellers, largely responsible for noise generation and inefficiencies in power consumption at low Reynolds numbers. Experimental noise data compared stock, modified, and five bladed propellers reducing tip vortex strength and noise generation. Results showed measurable far field sound decay and five bladed noise reductions of 5 dBA. Three motors compared propeller power consumption and resulted in increased electrical efficiencies of 14.5% and 31.3%. An airfoil study showed the GOE358 as the most aerodynamically efficient airfoil tested. A Prandtl bell-shaped lift distribution, minimum induced loss design, was applied to a propeller resulting in decreased power consumption and improved electrical efficiency by 18.51% with a SPL reduction of 11.15 dBA compared against the Baseline propeller. The Baseline propeller used an industry standard minimum loss propeller design.