Aerodynamic Drag

Aerodynamic Drag: How it affects the vehicle performance?

What is Aerodynamic Drag?

An Aerodynamic Drag is a force which the oncoming air applies on a moving body. It is the resistance offered to the movement of the body by the air. So, when a car is moving; it displaces the air. However, it affects the car’s speed and performance. Technically, it is the aerodynamic drag or the friction offered by air to a vehicle.

Aerodynamic Drag
Aerodynamic Drag

Ideal Drag:

Manufacturers always try to keep the Aerodynamic Drag to the minimum possible. This is because it has a negative effect on vehicle’s performance and efficiency. The upright stance of some vehicles gives it a drag coefficient of 1.30 while a raindrop design has the least amount of drag.

Nowadays, the cars have an average drag coefficient of 0.40 and some car have as low as 0.26. Such vehicles are said to have the best aerodynamic design. Also, the power you need while moving a body through the air goes up with the speed. So, above 60 km/h, you need a lot of power to push the car to overcome the aerodynamic drag.

The reduction in drag can help to decrease the wind/air resistance of a vehicle. Thus, it helps to increase the fuel efficiency to some extent. It also improves other performance characteristics os the car such as handling and acceleration. The vehicle’s frontal area and the drag coefficient are the two main factors which have an impact on the overall drag effect.

How to reduce the Aerodynamic Drag?

Firstly, you can lower the drag coefficient by streamlining the exterior body of the vehicle. Streamlining the body requires the characteristic use of the lines and precise calculation of the surrounding airspeed. In some high-speed cars, the manufacturers install a rear spoiler onto the boot. It helps to reduce the drag to a great extent.

To reduce the aerodynamic drag further, the manufacturers use character lines on the exteriors of the body right from the concept. These lines help the air to pass smoothly over the body and thus, reducing the air resistance.

Mercedes-Benz CLA 200 character lines
Mercedes-Benz CLA 200 with character lines to reduce the aerodynamic drag

For eliminating the aerodynamic-drag, the manufacturers typically work on the external components. These include the roof rack, mud flaps, rear spoiler, side mirrors, radio antenna and windshield wipers etc. They also employ crucial design bits such as the partial front grille, redesigned under-body trays and fender skirts, modified front bumper, redesigned wheel covers, and boat-tail shaped rear boot etc.

Boat Tail Boot
Boat Tail Boot

Read more about how the aerodynamic drag affects the fuel economy here.

Watch the testing of aerodynamic boat tail here:

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