EXPERIMENTAL ASSESSMENT OF PROPELLER-DOWNWASH EFFECTS ON THE WING’S AERODYNAMIC CHARACTERISTICS AT LOW REYNOLDS NUMBER

Abstract

Unmanned aerial vehicles (UAVs) and micro air vehicles (MAVs), which are often referred to as drones, are among the advancing technologies that are utilized to secure remote surveillance. The propeller technology used by these aircraft has a considerable impact on their wing’s aerodynamics. It has been shown that the propeller slipstream affects the pressure distribution over the wing surfaces in both chordwise and spanwise directions, influencing the distribution of wing loading especially during low-speed cruising. This study is done to examine the effects of propeller slipstream at low Reynolds numbers on several airfoils, namely NACA 0012, NACA 4415 and NACA 6712, concentrating on four key factors: type of airfoil, propeller diameter, propeller speed and distance between the propeller and the rectangular wing. Specifically, in the context of employing propellers for UAV applications, the goal is to evaluate if these parameters result in improvements and to analyze their impacts on lift, drag and lift-to-drag ratio. On the whole, the results imply that the propeller effect reduces lift and drag on most parameters discussed. However, the lift-to-drag ratio appears to increase on specific parameters. In this case, reducing the distance between the wing and the propeller leads to noticeable improvement in the lift-to-drag ratio. However, if the distance becomes extremely small, lift-to-drag ratio starts to decrease again.