Winglets have been shown to significantly reduce the lift induced drag. Different parametric studies have identified important winglet characteristics, but none have examined effects on drag from varying winglet twist and toe angle. The purpose of this research report is to examine the drag reducing effect of winglet twist and toe angle on a transport type high aspect ratio wing.
By using a cost-effective three dimensional vortex-lattice program which included two dimensional profile drag, the effect of winglet twist was found to have a moderate drag reduction against an untwisted winglet for the same toe angle. For the wing-winglet configuration studied, a minimum total drag was obtained when the winglet has 2.8 degrees toe out and 2.5 degrees wash-in twist.
A more sophisticated computer program was used to find areas of boundary layer separation, which were evident from the output results. If the winglet has a large enough toe out to prevent interference drag caused by separated flow at the wing-winglet juncture, winglet twist can be varied to reduce the total drag compared to an untwisted winglet.
Master of Science (M.S.)
College of Engineering
Length of Campus-only Access
Masters Thesis (Open Access)
Moore, Thomas T., "The Effect of Winglet Twist and Toe Angle on the Drag of a High Aspect Ratio Wing" (1986). Retrospective Theses and Dissertations. 4983.