In this study the lateral loads of low aspect ratio wings are investigated at low Reynolds numbers. The purpose of this research is to better understand the stability characteristics of Micro Aerial Vehicles (MAVs) which experience flow conditions very different to those of a large wingspan aircraft. Wind tunnel testing is conducted to establish the relationships between sideslip and angle of attack variations with the roll and yaw moments of the models. The results show that the roll moment exhibits surprisingly linear behavior up to angles of attack near 20° at all sideslip angles for an aspect ratio of unity, at which point a 'roll stall' event occurs which has not previously been described in literature. The value of C_(t,max) increases with the sideslip angle, yielding a maximum of over 1.5 at a sideslip angle of β= 35°. An aspect ratio of 3 displays a significantly different plot although the stall angle and value are similar to the previous case. Measured yaw moments and side forces are significantly smaller than those of the roll moment. Flow visualization was conducted to explain this behavior, which was attributed to the asymmetric development of the wingtip vortices at increasing sideslip angles.
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