Hello GasTurb, GSP, PROOSIS and NPSS users!
You need turbine maps for your performance studies? I can generate them for you!
The source of your map may be a figure from a publication, calculated or measured data as text file, and input data from your favourite performance program. Extending the map down to 1% spool speed and to pressure ratios less than unity - as needed for starting and windmilling simulations - is not a problem.
Here are maps that have been extended down to 1% of the design spool speed: