I'm using the default C182 and I'm becoming aware of the effect that the throttle has on verticle speed or rate of climb but I'm still a little bit puzzled by the use of the propeller control. I can see the effect it has on RPM and I'm also aware that the aircraft "moves" when the control is used, but what is it for? I assume it's not the same as "feathering" the prob because when used on the ground I can still taxi normally.
Any advice would be appreciated but please keep it simple. The old grey cells arn't as good as they used to be

Zaphod.
ps
I did have a quick look at the learning center and couldn't find any mention. Perhaps I missed something?