well then my friend u need to look up the venturi effect it is when a mass of air flows through a convergent duct causing the velocity to increase or you could go on you tube and watch a video on a venturi tube.
the fan does not keep up the the engines induction through the entire rev range but does help a little in the lower revs if you look at the graphs that guy had earlier to over come the fan being an obstruction at high revs then all that needs to be done is fit a simple trap door valve it works by when the fan is no longer producing enough thrust to keep valve closed then it opens and lets the engine suck in air freely.
cheers gregor
the fan does not keep up the the engines induction through the entire rev range but does help a little in the lower revs if you look at the graphs that guy had earlier to over come the fan being an obstruction at high revs then all that needs to be done is fit a simple trap door valve it works by when the fan is no longer producing enough thrust to keep valve closed then it opens and lets the engine suck in air freely.
cheers gregor