SBIR Phase I: Aerodynamic Drag Reduction with a Flexible Composite Surface De-Turbulator

A flexible composite surface de-turbulator (FCSD) tape has been developed which can be conveniently affixed to aerodynamic surfaces, such as aircraft wings, to reduce the combined skin-friction and form drag. This is due to the flow-FCSD interaction, which damps out most turbulent fluctuations through sub-micron amplitude flexural oscillations, thereby stabilizing a thin nearly stagnant sub-layer next to the aerodynamic surface in non-zero pressure gradient boundary layers. Preliminary flight evaluations on a Standard Cirrus sailplane have shown the externally un-powered Sinha-FCSD capable of reducing the local profile drag of a test section of the wing by 17- 27% over the entire operable airspeed range. The proposed SBIR Phase-I project is aimed at verifying, through flight and wind-tunnel tests if similar improvements can be obtained for the entire surface of the wing, so as to reduce the overall drag about 5-8%; a level currently not feasible through other simple externally un-powered modifications. The proposed work is primarily geared towards launching a U.S.-made glide-ratio enhancement device to the sailplane community worldwide with the next two years. Fuel savings resulting from drag reduction of commercial aircraft will not only help us better utilize fossil fuels for this purpose but also help reduce the injection of greenhouse gases into the atmosphere.