Benjamin H's Senior Project Blog

Project Title: Going subsonic: Why drones have their distinctive hum and how propeller design can help fix it. BASIS Advisor: Josh Smith Internship Location: Pilot Institute Onsite Mentor: Greg Reverdiau

Project Abstract

Drone technology has been “the future” for more than a decade, but only recently have drones become strong and quiet enough to find widespread use. Small quadcopters now appear in the fields of surveying, videography, Search-and-Rescue, and even active combat. For each of these purposes, noise and power are the key determinants of performance. For use in residential areas, for instance, a drone must be quiet to avoid noise pollution, and for heavier applications, a drone must have enough thrust to carry itself and its cargo. Drone noise, and thus inefficiency, is invariably caused by miniature vortices on propeller tips, making propeller optimization a compelling avenue for performance improvement. Design changes such as wing swooping promise better performance, and theoretical designs such as toroidal shaping offer unique air interactions, so I studied the effect of design on sound and power performance. I compiled theoretical and practical designs for propellers, then tested them to determine the best propeller design for hobbyist-level flight. For my final product, I completed a document detailing my findings and produced a drone incorporating the best propeller design.