The shape of vehicles greatly affects their efficiency, stability, and handling.
The air flowing above and below the car also acts to turn the car into a 'wing', usually lifting the body upward as speed increases unless aerodynamic parts, like a rear spoiler, are present to force the body down by redirecting air upward.
The Tesla Roadster uses active rear and side wings to generate downward force to help keep the vehicle on the road, a common design element seen on Porsches to Corvettes, ensuring the tires have sufficient grip for control at faster speeds. But slower speeds generate smaller downforce, which can also be interrupted with changing direction, causing a reduction in tire grip.
To further counteract these issues and generate more downforce on demand, the Tesla Roadster is equipped with a multi-mode fan that can suck the air out from underneath the car while lowering itself closer to the ground, creating a suction effect that allows the car to hold itself onto surfaces while upside down, according to the company.
The fan was demonstrated to generate around 4,700 kg of force, so the maximum possible weight of the Roadster is likely 10-20% less than this. This amount of force helps the car corner at over 2 g's, exceeding that of many sports cars.