Winglets and Aspect Ratio: Induced Drag Reduction for Balsa Wood Gliders

Description: Induced drag is more and more a parameter that is examined for efficiency gains in aircraft design. One common method for induced drag reduction is lengthening wingspan to increase the wing’s aspect ratio. Another involves altering the shape of the wing at the wingtips, typically by using vertical extensions called winglets. In this study, three balsa wood gliders are constructed, keeping lift-generating area, tail and fuselage dimensions, and mass constant. The results of both increasing aspect ratio on the first glider and adding winglets to the second are compared against a third baseline glider. To nullify variations in the launching process, the experimental method uses video software to track the center-of-mass position and orientation of the gliders in flight. This allows data to be exported for analysis and direct calculation of aerodynamic forces and coefficients. Results show that increasing aspect ratio does reduce induced drag, but there is an increase in overall drag caused by the presence of extra frontal area from lengthening the wings. The addition of winglets, however, caused a 35% reduction of induced drag, 20% reduction of overall drag, and a lift-coefficient increase of 28%. Winglets are shown to be the best method for achieving enhanced performance associated with induced drag reduction