Once upon a time the aerodynamics of a racing car were a black art. Cars

were created with shapes the designer thought would slice through the air, but without exact science to back up those ideas.

In Formula One, even with the introduction of wings in the late 1960s and

ground effects a decade later, aerodynamic design was often still a hit-or-miss operation.

These days, with high-tech wind tunnels and Computational Fluid Dynamics

(CFD) and sophisticated computers and intricate scale models of the car to

be used in the wind tunnel, aerodynamics is a true science.

"Aerodynamics has been steadily gaining importance in recent years,

accounting for roughly three quarters of the performance of a F1 car

today," said team owner Peter Sauber.

Every year, F1 designers find ways to increase the downforce of their cars

while adding the minimum of drag.

And practically every year, the FIA comes up with new rules to reduce

downforce trying to slow cars down.

In 2005, major new aerodynamic rules are part of the FIA trilogy of drastic

regulation changes to reduce speeds for safety reasons.

Parts one and two of that trilogy -- drivers limited to one engine for two

entire Grand Prix weekends, and drivers limited to a single set of tires

for qualifying and the race -- have already been covered by ESPN.com.

While the aerodynamic rule changes have not been controversial like the

other two aspects, they are still very significant.

"When we put a 2005 package on the wind tunnel model we lost nearly 30

percent [of downforce]," said Ferrari's technical director Ross Brawn.

"We're gradually getting that back. We would be pleased if we get to 15

percent of where we are now."

The basics of the new rules are as follows:

The distance between the bottom of the front wing and the ground has been

increased by 50 mm (1.97 inches).

The overhang of the rear wing has been decreased, so the wing must now be

located 100 mm (3.94 inches) closer to the back of the car.

The size of the rear diffuser (the tail edge of the floor of the car that

sculpts upwards behind the rear axle line) has been reduced.