Quote:
Originally Posted by Frank Lee
The simplest way to think of it is, it takes energy input to cause an unpowered fan to spin. That energy is coming from the vehicle's forward motion hence it must increase drag.
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Thanks to you all for the replies, rather than ignoring the question, or saying "Your en idiot !".
I remain the idiot, and don't learn if people keep it to themselves, without explaining what makes the question idiotic.
I understand that the motion produced by the fan blade is a result of forward motion from burning fuel.
I'm just trying to find out if any additional air can be added to the cars wake purely by a free spinning fan.( To reduce the cars wake )
My guess is that it most certainly would not add any additional airflow - ( unless the fan had left over momentum after the airflow slowed.)
But I just don't know.
I have some NACA ducts installed on my cars box cavity / aero extension-do-ma-hitchee
The airflow through them is surprisingly good.
( I tuft tested them )
The idea is to channel air into the dead zone in the cars wake, and hopefully reduce its size.
I think adding small fan blades behind the ducts would be a waste of time, but it did make me curious about what they would do.