Design + Aerodynamics

The technology of a single line
that goes against the wind

sonata exterior

All the things that move – from birds and airplanes that fly in the sky to the cars and trains that run on the ground – are destined to stand against the wind. The design elements in a vehicle, which many deem as an element for aesthetics, is in fact the essential factor for a vehicle to move faster, quicker and yet retain stability.

The excellence in function depends on the direction of the wind; however, the aesthetical sense shall not be discarded for the function. This is why it is interesting and meaningful to see how the designers battle against the wind in adhering to the initial design concept, while providing good functionality.

A vehicle that rides on the wind, not going against the wind


The wind and air that blow from all directions when a car drives on the road is an important factor in terms of the car’s fuel efficiency, power performance and driving stability. We call the power of air “aerodynamics.” Since more than 70% of the air resistance a vehicle comes across is determined by the vehicle’s exterior styling, the design is the starting point for aerodynamics technology. Not taking the aerodynamics into account will entail reduction in fuel efficiency, huge noise and low driving stability. Generally, it is said that a 10% reduction in the air resistance coefficient will result in a 2.5% increase in fuel efficiency. This is not that low a figure. On the contrary, if one only thinks about the aerodynamics, the vehicles on the road will all end up looking same. For that reason, the Hyundai Motor’s designers contemplate on developing unique designs that still have a high level of aerodynamics force.

A differentiated design with high level of aerodynamics force and unique styling


The approach of the Hyundai Motor towards optimal aerodynamics force is to make a smooth line so that the wind can flow smoothly on the rear side of the car. The vehicle’s side profile and surface are all relevant to aerodynamics. Among them, the side profile, which goes from the lower front bumper, radiator, grill, hood, wind shield glass, roof, trunk lid and to the rear bumper, is the core part of the car design and the aerodynamics itself.

The air resistance that effects a vehicle is usually divided into drag, lift and side force. The drag, which blocks an object’s movement forward, is the factor relevant to its fuel efficiency, outrunning acceleration and driving performance. The lift that helps the planes to fly in the air determines the driving stability, as it is connected to the automotive levitation force and wing force. In addition, if one fails to properly measure side force, stability cannot be retained during driving. Likewise, a car can either drive fast or slow depending on the leverage of the wind that blows from different directions.

Avante grill

Grill and undercover design, the most sensible elements to the aerodynamics force

The front surface design, where the running vehicle comes into contact with the wind, is the part that impacts the aerodynamics forces the most. Whether the wind forms a big whirlpool in the starting point of the hood or makes a curve line determines the extent of drag and lift; designing the entire surface in a curve line so that it will have inclination angle will be effective.
The undercover that embraces the rear part is also important. If the under body is not flat, the lower part velocity will be reduced and the air resistance will be increased. So, the Hyundai Motor has applied an undercover on the entire surface that covers the center floor and fuel tank. In addition, the undercover is applied on the lower rear bumper to prevent the lower air flow concentration on the bumper.

LF Sonata

Boat shaped side design for smooth air flow

In order to have the air from the grill and hood to smoothly pass the side of the car body, the side of the bumper needs a curve line as an air flow guide. The boat shape where the middle part of the right and left side sticks out and becomes narrow is better for the aerodynamics. For this, you need to take into account the length of the bumper side and fender. This is because there may be a possibility of an excessive whirlpool in the front of the wheel house that covers the upper part of the front wheels, reducing the aerodynamics force. In addition, like a convertible car which stays close to the ground, the lesser the gap there is between the wheelhouse and the tire, lesser the whirlpool, giving a more effective aerodynamics and more stable stance in design.

Avante wheels

Ongoing wheels: the wheel design that has reduced air inflow

The side of the tire - in other words the wheel - has a great part in air resistance as well. Unlike the unchanged car body, the tire wheel, which moves on and on from the left to right, often changes the direction of the wind or even creates a new wind depending on the curve angle. For this reason, the wheels should be designed by taking into account various aerodynamics technology. In order to improve the wheels so that they would ride well on the wind, the Hyundai Motor made a wind guide on the lower part of the side bumper so that the tire would have less space where it hits the wind directly. In addition, the wheel deflector shape and size have been optimized to reduce the resistance against the air that comes into the wheel arch. In addition, in case of the environmentally friendly cars, which are more sensitive to fuel effectiveness, the wheel shape is flat so that the openness rate where the wind moves in and out is reduced. This, in the end, extensively reduces the air resistance that flows inside the wheel.

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