The file mfit_control.dat is a FORTRAN namelist file which is used to override the default settings of the control variables. These variables control the operation of WINGSPAN and MFIT, thereby allowing you to customize the program. If you wish to override the default settings, you can do so by copying /wingspan/mfit_control.dat, modifying it, and changing the logical MFIT_CONTROL_FILE in wing.pro to point to your copy. A description of the control variables and their default values is maintained in the file /wingspan/mfit_control_declare.incl located on the WINGSPAN directory. A list of control variables is provided in /wingspan/cv_list.dat to provide easy editing of your custom control file. Include cv_list.dat in mfit_control.dat, and edit as desired.