Ok, I'll be serious. the difference is this: a belt driven fan has potential to move MUCH more cfm's because the fan is NOT driven by a belt, but a 400 hp motor (for example). An electric fan has a 1/4 horse motor, which limits the amount of air it is able to move.
- Put a belt driven 7 blade clutch fan on the end of the peewey electric motor and see if it has the ability to turn it enough to make a breeze. The air it would be trying to pull would all but stop the stomper 4x4 motor.
- That is why propeller airplanes have a combustion engine turning them. To move enough air, takes more than a bench grinder motor to get the plane off the ground. Besides, it would take a long extension cord to make it across a few states :D