To use this calcultor, enter your VBar governor's Max. Headspeed value (on the VStabi software's Gov II tab), then click Calculate.
The calculator will show you the headspeeds determined by your transmitter's percent throttle setting.
For example, if you set Max. Headspeed to 3500 but want a headspeed of 3,000, you would set your thottle to 93% (3010 RPM).