Application of a Slotted, Natural-Laminar-Flow Airfoil to an 18-Meter High-Performance Sailplane

A flapped, slotted, natural-laminar-flow airfoil was recently wind-tunnel tested. Given that its design specifications and the Reynolds number range of the experimental results closely match those required for the FAI 18-Meter class of racing sailplanes, this airfoil, the S702, was evaluated in a design and performance study of such an aircraft and compared with a current competitive sailplane in this class. The S702 design had significantly better climb and cross-country performance. While specific to this application, it is felt that this work can provide insight into the use of this or similar airfoils on other aircraft in this operating regime, such as general aviation, unmanned air vehicles, and so forth.