Introduction
The NACA 4- and 5-Series Mod airfoils provide additional control over the leading edge radius index and the location of maximum thickness. The naming convention follows the usual method for 4- and 5-series airfoils with the extension of two additional digits indicating these new values. The leading edge radius index ranges from 0.0 (sharp) to 9.0 (semicircular) with a default of 6.0 corresponding to the traditional series.