Tool options

Check the Fluids Mechnics cehckbox to turn on, the Prandtl Number display within the Atmosphere tab

Check the Include Non Si Units to show, feet alongside the Altitude text box. The Flight Velocity is also shown in Km /H and knots

Check the Debug checkbox to display the Text file contents when opening a file.
The iterations to calculate Gamma will also be displayed when the Nozzle calculation is performed.

The Clear Picklist on new defines the behavior of new Pick Lists, either a new picklist is added to the current pick list in a combo box or the combo box list is cleared on the application of a new pick list.

Select the radio button to correspond to the engine cycle to be calculated within the Engine Tab
Within the Nozzle tab rather than entering a Stagnation temperature the Polytropic temperature rise can automatically be calculated from the Pressure ratio.

Within the Options panel, check the Calculate Temperature Rise checkbox and enter an efficiency.
The Stagnation Temperature box will grey out on the Nozzle tab and be automatically calculated.