Body and aerodynamics: Less weight for more dynamic performance

Nov 17, 2014
Mercedes-AMG has employed an intelligent material mix for the body of the GT. Chassis including greenhouse and body are produced in light alloy, the boot lid of steel and the front deck in magnesium. Over 90 percent of the weight-optimised spaceframe consists of aluminium components, leading to a low kerb weight of 1540 kilograms. Painstakingly refined aerodynamics ensure good balance and effective cooling.
Bodyshell and structural development for the GT was carried out entirely in-house by Mercedes-AMG GmbH. The GT uses the technological DNA of the Mercedes-Benz SLS AMG, one of the most successful sports cars of recent years. The GT is a systematic further development in terms of vehicle dynamics, lightweight design and quality, while the latest legal requirements and in-house Daimler standards relating to passive safety are reflected in state-of-the-art technology.
The bodyshell weight of the GT is 231 kilograms – a benchmark figure in the sports car segment. There was one overriding objective during the design and development of the bodyshell structure: to achieve a very lightweight but also very rigid structure – ideal requirements for the use of aluminium. It is not only the car's low centre of gravity and the high static and dynamic flexural and torsional rigidity that play a key role, but also the induction and transfer of extreme longitudinal and lateral forces from the powertrain and suspension. Unwanted flexibility is thus reduced, with the vehicle responding rigidly and directly. As a result, the driver experiences a sports car with maximum dynamism that responds with excellent precision.
The aluminium spaceframe of the GT consists of cast aluminium components and aluminium sections. Cast components are used at the nodal points where forces come together or where functions are highly integrated, i.e. where large forces require to be transferred. Cast components have the advantage of enabling the specific discharge of forces, and make it possible to vary wall thicknesses locally according to the loads encountered. Areas of greater rigidity can therefore be incorporated where required, for example at the chassis connections. Moreover, only the necessary wall thickness is provided at any point of the structure, which saves weight in the areas subject to lower forces.
With the help of so-called topology optimisation, the cast components are specifically weight-optimised: ribbed structures precisely follow the force paths, while wall thicknesses are reduced to a minimum in less highly stressed areas.
A spaceframe structure of aluminium sections and cast components is used in the roof area. This meets the stringent requirements for rollover resistance. At the same time this solution reduces weight in the upper body area, with positive effects on the vehicle's centre of gravity. The torque tube connecting the engine to the dual clutch transmission at the rear axle is made of sand-cast aluminium.
Front deck in magnesium, boot lid in steel
The extremely lightweight front deck made of magnesium reduces the inertia ahead of the front axle, improving the agility of the GT. The boot lid is made of steel. This was a deliberate choice: to achieve the same level of torsional rigidity, a comparable aluminium boot lid would be considerably heavier. All the aerials for radio, telephone and navigation reception are invisibly located in the boot lid and rear window.
Panoramic roof – better view and more light
On request the sports car is also available with a panoramic roof. This one-piece glass module connecting directly with the windscreen spans the entire roof area. It gives the driver and passenger the best possible view, and creates a bright, friendly atmosphere in the interior. A manual roller sunblind provides shade in bright sunshine. The continuous, homogeneous glass surface gives the vehicle exterior an even more lightweight appearance.
Carbon-fibre roof exclusively for "Edition 1"
The GT is given even more of a racing touch and greater individuality by the striking carbon-fibre roof, which is available exclusively for the "Edition 1". The roof features a carbon-look finish, as used in motorsport.
Exclusive production for optimum product quality
The aluminium spaceframe and body of the GT are produced to the most stringent quality standards. Highly qualified specialists join the aluminium components using cutting-edge methods. The most appropriate joining technique is used depending on requirements – riveting, bonding, welding and bolting.
The production shop applies a mixture of manual and automated processes. The bonding adhesive for the body is applied completely automatically, for example, and the welding studs, body bolts and a major proportion of the riveted connections are also placed fully automatically. At the end of bodyshell production a portal milling machine precisely positions around 130 functional and access apertures – e.g. for lights, major assemblies or the front and rear apron. And as a matter of course for a new model bearing the Mercedes star, the utmost precision and process reliability are mandatory during production, as only this guarantees optimum product quality.
Aerodynamics for good balance and effective cooling
Vehicle proportions, weight distribution and drive configuration, handling stability, drag, cooling and wind noise: the aerodynamics of the GT fulfil complex requirements. The high-performance vehicle has been developed aerodynamically with one clear objective in mind: transferring the high power to the road to enhance driving dynamics and handling safety at medium and high speeds. Thanks to the aerodynamic configuration, critical driving situations can be avoided – such as with a sudden evasive manoeuvre at high speed.
The design of the front apron with A-wing and front splitter not only reduces lift to the desired level, but also helps route air directly to and from the cooling modules. The flow of cooling air from the aerodynamically shaped brake cooling ducts also specifically improves brake performance.
The large area of underbody cladding ensures an optimum exhaust airflow from the oil cooler in the underfloor area, and effective airflow to the rear diffuser. As an active component of the aerodynamics, the Mercedes-AMG GT comes with an extendable rear aerofoil that is integrated into the design silhouette. The aerofoil extends at 120 km/h and retracts when the speed falls below 80 km/h. When the "RACE" driving mode (GT S only) specially configured for the racetrack is active, the speed thresholds are 70 and 30 km/h. Alternatively, the driver is able to extend or retract the rear aerofoil by pressing a button. In combination with rear diffuser without air deflectors, the vehicle's roadholding is enhanced in the aerodynamically relevant speed range. This improves lateral acceleration and handling stability at high speeds.
A drag coefficient (Cd figure) of 0.365 and a frontal area (A) of 2.13 m2 results in a wind resistance (Cd x A) of 0.78 m2. The GT S and GT have identical wind resistance.
The low wind noises of the GT considerably contribute to the long-distance comfort that is a hallmark of Mercedes-Benz. Effective sealing systems and sophisticated aero-acoustics ensure a high level of day-to-day suitability. The anti-soiling measures for the exterior mirrors, side windows and rear window make an important contribution to active safety.
Aerodynamic package reserved exclusively for the "Edition 1"
The Aerodynamic package is reserved exclusively for the "Edition 1" (also see section Interior and appointments): A large front splitter ending in the flics on the air inlets, a fixed rear aerofoil and flics at the front wheel arches increase the downforce. This improves the driving characteristics at high speeds, especially lateral acceleration, handling stability and braking distance. The Aerodynamic package is rounded off by special side sill features ensuring a strikingly sporty look.
High level of safety and numerous assistance systems from the new S-Class
The new AMG sports car also meets the very high active and passive safety standards that are traditional at Mercedes-Benz. Right from the outset, the specified lightweight construction and outstanding crash characteristics were designed to be in line with the car's low centre of gravity and the best possible distribution of force and load paths. The latter are specifically routed around the occupants – this applies to front, rear-end and lateral collisions, as well as to roof impacts.
The standard-fit restraint systems not only include three-point seat belts with belt tensioners and belt force limiters, but also front airbags, combined thorax/pelvis sidebags, windowbags and kneebags, for the driver and front passenger respectively.
The Mercedes-AMG GT adopts numerous Mercedes-Benz Intelligent Drive assistance systems that are familiar from the new S-Class. Standard equipment includes COLLISION PREVENTION ASSIST PLUS, ADAPTIVE BRAKE, ATTENTION ASSIST and the tyre pressure monitoring system. Optional extras available include:
  • Adaptive Highbeam Assist
  • PRE-SAFE® system
  • Reversing camera
  • Lane Tracking package including Lane Keeping Assist and Blind Spot Assist
  • Blind Spot Assist
  • Traffic Sign Assist (included in COMAND Online)
Mercedes-AMG GT, testing
Mercedes-AMG GT, testing
Mercedes-AMG GT, testing
Mercedes-AMG GT, testing
Mercedes-AMG GT, testing
Mercedes-AMG GT, testing