DATCOM 's input method for Fin
 

Now, i have trouble in define the fin's parameter in missile DATCOM 97. The body is a typical cone-flare configuration. the Wing is located at the conical and flare part. I am confused in define the sspan(1), xle(1)。 IN the manual, 1997 Fortran 90VERSION, it suggest we select th root chord span station such that the center of the exposed root chord is on the surface mold line. For a straight mold line ,it is easy to do .but for a multi-line with discontinous slope, how to do it .