Here is an update removing the tangent points and adding the point I previously omitted on purpose. The ler and ter definition points are still the last four. I tried burrman's method and it works fine. In this case you can use all the naca points and the ter definition but ignore the ler definition. I don't really care which way you go here. I am keeping the ler and ter and loosening the data point definition. The difference I have been allowing is small. However, if you want to redefine the ler, its fine by mean. Comparing the leading edge you get with burrman's method and using the naca defined radius, the difference is small. I'll let brian and whoever else works on the actual script to decide how they want to do it. I don't plan on using this myself. I just wanted it for others. I have finished all my work on PROP_DESIGN, this was just a loose end I thought could be improved. Either way you go, its about the same for all intensive purposes. The data points, as defined now, should allow you to create the airfoil spline however you like. The main thing is to create a blade that transitions smoothly and follows the naca file i'm referencing as close as possible, since PROP_DESIGN utilizes the performance data for this specific airfoil.

Edit; Latest version is available in a later post.