Experimental Model of Effects of Large Upstream Obstructions on Drone Scale Propellers

Abstract

Recent improvements in computer and electrical energy storage technologies among others have made small Unmanned Aerial Vehicles practical and economical across many design spaces. Recently, designs blending fixed wing and multi-copter elements have become popular as commercial products and research platforms. This configuration has a number of understudied aerodynamic interactions particularly between the rotors and other aerodynamic surfaces. Studying these interactions is key to creating effective designs and developing good models for other aspects of the system such as control and performance evaluation. This paper seeks to understand the effect of occluding the upstream of a propeller at varying distances and varying amounts. The experiments are meant to provide useful guidelines on how far one should position lifting rotors from obstructions such as wings or the fuselage or what the associated trade offs might be. The data indicate that, for large obstructions, the combined effect is significant on performance, but is also predictable regardless of propeller size and pitch, reducing to negligible at roughly one-half propelled diameter.