Gravity racers, the fancy title for streamlined soapboxes. It is obvious when you want to win a downhill race, without any other propulsion then gravity, there are only two playing fields :
Aerodynamic resistance.
Rolling resistance.
Aerodynamic resistance is proportional to the square of the velocity (V), the frontal surface area (A) and the drag coefficient (Cd).
The values that can be influenced by the designer are the frontal area (hence very narrow and low racers) and the dag coefficient (hence very flowing designs)
Rolling resistance, technically more complex, but basically getting the wheels to turn as freely as possible ie. no or very fluid lubricants in the bearing and secondly losing as little energy as possible from the contact with the road, ie. hard tires.
Why is this page in the Wind & Water website.
Looking at the pictures it seems obvious that some car makers take this competition very seriously indeed. Should be a great starting point for these companies in doing something for the aerodynamics of our normal household car, which are terribly inefficient energy users. I personally would not mind driving around in teh Bentley with a small electric motor fitted.
Gravity racers
