Natural laminar flow techniques have long been sought after as a means of improving racing sailplane performance. Slotted, natural-laminar-flow airfoils have the potential to be the next great technological advance in sailplanes because of their mechanical simplicity and ability to reduce wing profile drag. Wing and horizontal stabilizer areas are resized for a standard-class glider in this study to take advantage of the increased Cl,max seen with the S414 airfoil as compared to current airfoils, Cl,max = 1.842 vs. 1.183 at R = 1 x 106, respectively, while maintaining similar climb rates in thermals. An SNLF airfoil-based sailplane outperforms a competitive standard-class glider at thermal strengths above 2.5 m/s and having an average thermal radius of 150m. These results motivate future work in designing an SNLF airfoil specifically optimized for sailplane lift coefficient ranges, with the potential to increase the performance gains outlined in this study.