Propeller-induced effects on the aerodynamics of a small unmanned aerial vehicle

Abstract

The present paper has discussed investigations about the propeller slipstream effects on the aerodynamics of a generic unmanned air vehicle platform in the wind tunnel for a broad advance ratio range. The propeller-induced effects for small unmanned air vehicles are more significantly pronounced than general aviation aircraft, because of their high propeller-diameter-to-wing-span-ratio. The stall angle of attack of the small unmanned air vehicle is generally delayed under slipstream effects. The study evaluated the shift in stall angle of attack as a function of propeller-diameter-to-wing-span and advance ratios of the propeller. The aerodynamics of the unmanned air vehicle platform is estimated through wind-tunnel experiments. The study reported in this paper is part of an effort to develop the framework for the analysis of propeller-wing interaction for small/micro unmanned air vehicles at an early design stage. Specifically, the slipstream effects on the aerodynamics of a generic small unmanned air vehicle are studied in the wind tunnel for the shift in the aircraft stall angle of attack. The lift-curve slope of the aircraft is independent from the variation of advance ratio. The stall characteristics show strong dependence on the advance ratio. Therefore, the relationship is modeled accurately using inverse-quadratic relationship. This empirical trend of the stall behavior with advance ratio can be useful in the analysis and simulation of the resulting flight and estimation of performance envelopes.