From the games entry here on the Geek:
TIME SCALE: One month per turn.
MAP SCALE: Twenty-five miles per hex.
UNIT SCALE: Corps, armies, fleets, and flotillas.
PLAYING TIME: From two to eighteen hours, depending on the scenario and rules used.
Ah, sorry, I wanted to know the measures (in cm) of one hex . In need them to scale my extension maps to the right size ..