You may have seen spoilers on the back of a vehicle and thought they added a cool look. But what does a spoiler actually do?
Spoilers, which also include air dams and fascia on the front of a car, are designed to improve aerodynamics by redirecting airflow under, over and around the body. This reduces drag, which helps the vehicle travel more quickly and efficiently. It also minimizes "skid" or slip (a slipping of the tires due to road conditions) and can help reduce the amount of energy the vehicle expends to travel forward at high speeds.
Most cars with spoilers feature a rear wing to generate downforce, which helps to maintain traction during high-speed driving and cornering. This is especially true for race and sports cars, which require increased stability at high speed. However, for passenger vehicles that typically don't reach racing speeds, spoilers are primarily aesthetic accessories.
A spoiler, on the other hand, is positioned to disrupt the flow of air over the vehicle to reduce lift. They are often angled, which increases their effectiveness at higher speeds. Spoilers can also be shaped to create more downforce or to improve high-speed handling and braking.
In addition, spoilers reduce skin friction drag – which is the result of air rubbing against the surface of the body as it passes over and around it. This can be reduced by polishing and smoothing the surface of the spoiler to eliminate friction. This can significantly increase the fuel efficiency of a vehicle.