The word spoilers comes from the idea that the structures disrupt or spoil the natural flow of air over the car. Technically spoilers and wings are different, although they are lumped together here. Wings are aerodynamic devices whose purpose is to move air. In airplanes they push air downward so the plane has lift. In cars, wings are upside down so they push the car down to give it better traction. 30 A F I E L D G U I D E TO A U TO M OT I V E T E C H N O LO G Y Race cars have them over | Spoiler BEHAVIOR On passenger cars and trucks the chief purpose of having a spoiler is to make the car look cooler. In race cars spoilers wings push the rear of the car downward to increase the traction to improve both acceleration and braking. HABITAT Spoilers generally are found on the rear of the car body. However some cars NASCAR race cars for example and trucks have spoilers on their roofs. Less noticeable are spoilers beneath the front of passenger cars. HOW IT WORKS The word spoilers comes from the idea that the structures disrupt or spoil the natural flow of air over the car. Technically spoilers and wings are different although they are lumped together here. Wings are aerodynamic devices whose purpose is to move air. In airplanes they push air downward so the plane has lift. In cars wings are upside down so they push the car down to give it better traction. 30 A FIELD GUIDE TO AUTOMOTIVE TECHNOLOGY Race cars have them over the rear or driving wheels to provide better traction. NASCAR cars now have safety wings called spoilers on the roof to provide downward force when the car is moving backward at high speed. You might wonder why race cars need downward force when moving opposite to the normal direction of driving. NASCAR cars have a tendency to fly when traveling backward after a collision or spin out. A car moving backward at high speeds generates so much lift that it lifts off the ground making it uncontrollable. Roof spoilers apply downward force to reduce the chance of lift-offs after accidents. Passenger cars use devices to cover parts of the car to make them more aerodynamic reducing drag. A belly pan under a car can smooth the air flow and keep it away from uneven surfaces. Trucks use spoilers to divert air up and over their trailers. The flat front surface of a trailer presents a large drag surface. The spoiler pushes air up and over this surface. Stylistic spoilers don t have aerodynamic or wing shapes. They sit on the rear of red sporty cars .
