The props change pitch to keep them running a fairly constant speed. In a light wind, they take a big bite of wind for maximum speed. In a heavy wind they take a small bite.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250