Application of Bio-Inspired Dihedral Wingtip Attachments on a Flat-Plate Wing for Micro Aerial Vehicles

This study explores the aerodynamic performance of flat-plate wings equipped with dihedral wingtip attachments (winglets) meant for micro aerial vehicle (MAV) applications that operate at low Reynolds number (Re). The investigations are performed for the lift and drag forces on wings with dihedral attachments, for different aspect ratios (ARs) of 1.0 and 1.5, and the results are compared with the base wing (without winglets) and wings with planar wingtip attachments. The experiments have been conducted in a subsonic wind tunnel to measure the aerodynamic forces across a range of angles of attack and Re. The findings reveal that dihedral modifications can enhance the lift characteristics significantly. It is also observed that one of the configurations, for an AR=1.0 wing, consistently exhibits superior lift force values, particularly at lower Re, making it a promising candidate for MAV applications. This particular configuration showed improvements in lift coefficients over a base wing of AR=2.0, with a maximum average improvement of 21% at Re=15×104. Despite the lift improvements, the wings with dihedral attachments experienced higher drag forces for both the ARs, as the extra attachments introduced additional aerodynamic resistance. The Oswald’s efficiency factor (e) analysis showed that while dihedral attachments do not surpass the planar wingtip attachments, they still provide significant improvements over the base wings. The dihedral arrangement for the AR=1.0 wing demonstrated the highest e values, ranging between 0.48 and 0.72, indicating an enhanced aerodynamic efficiency.