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The new Mercedes-AMG SL: the aerodynamics
A major development focus of the new SL was high aero efficiency. That means a perfectly balanced relationship between low air resistance and reduced lift. Here the luxurious roadster benefits from the extensive motorsport expertise of Mercedes-AMG. The extensive active aerodynamic elements at the front and rear are seamlessly integrated into the exterior design. Further detailed measures reduce the drag coefficient down to cw 0,31 - a very good value for open sports cars. The good aerodynamics reduce consumption and stabilize driving behavior.
Driving stability, air resistance, cooling and wind noise: the SL's aerodynamics meet complex requirements. A balanced aerobalance can be used to defuse critical driving situations, such as sudden evasive maneuvers at high speed. At the same time, it contributes to easier drivability, high efficiency and low wind noise.
A particular challenge with a roadster is to keep the aerobalance balanced, regardless of whether the top is open or closed. The vehicle's character and driving characteristics should remain unchanged. In addition, the noise level should not vary too much if lowered side windows or the use of a wind deflector change the situation.
The three-dimensionally modeled front apron with jet wing and front splitter not only reduces lift to the required level, it also helps with the targeted flow in and out of the cooling modules. In addition, the flow of cooling air from the aerodynamically shaped brake air ducts brings about a targeted improvement in braking performance. The underbody, which is covered over a large area, guarantees both an optimal exhaust air flow from the oil cooler in the underbody area and an effective airflow towards the rear diffuser.
AIRPANEL air control system in two parts for the first time
Another technical highlight also improves the aerodynamics: the two-part, active air control system AIRPANEL. The first part operates with vertical fins that are hidden behind the radiator grille and the lower air intake in the front apron. The second part is located behind the upper air inlet and has horizontal fins. All slats are electronically controlled and can be opened and closed with servomotors in order to direct the air flow as required and thus improve the aeroperformance.
Usually the slats are closed - even at top speed. This position reduces air resistance and makes it possible to direct the air in a targeted manner towards the underbody in order to further reduce the front lift. Only when certain temperatures have been reached on predefined components and the cooling air requirement is particularly high do the fins open (the second part only from 180 km / h) and allow maximum cooling air to flow to the heat exchangers. This requires a highly intelligent and fast control.
Active rear spoiler with an intelligent operating strategy
The same applies to another active component of aerodynamics: the extendable rear spoiler, which is seamlessly integrated into the vehicle silhouette. It changes its position depending on the driving situation. The control software takes numerous parameters into account: It includes the driving speed, the longitudinal and lateral acceleration and the steering speed in the calculation.
From 80 km / h, the spoiler adopts five different angular positions, either to optimize driving stability or to reduce air resistance. If the system detects the driving dynamics, the spoiler moves to the steepest position, thus guaranteeing both dynamic and safe driving behavior.
- Position 0 (retracted), -11 degree angle, 0-80 km / h: The rear spoiler, which is fully integrated into the design of the trunk lid, enables a clean look when stationary and at low speed. The adjustment mechanism is protected from dirt or foreign objects when parking.
- Position 1, +6 degree angle, 80-140 km / h: In this position the new SL has the lowest air resistance (lower than in position 0), for the best possible efficiency and low fuel consumption.
- Position 2, + 11 degree angle, 140-160 km / h: optimal balance between low air resistance and driving stability from medium driving speed
- Position 3, +17 degree angle, 160 km / h Vmax: optimal balance between low air resistance and driving stability up to top speed
- Position 4, + 22-degree angle, dynamic position, 120 km / h-Vmax, with highly dynamic driving mode detected by the vehicle: maximum lateral dynamics through maximum downforce for best grip. At the same time maximum driving stability. The spoiler can extend into this position regardless of the driving situation if the driver presses the display button on the steering wheel.
A plus in downforce and efficiency: the optional aerodynamics package
This package not only sharpens the look: larger flics on the front and rear bumpers, a larger rear diffuser and an active aerodynamic profile in the underbody in front of the engine significantly improve the aerodynamic properties - both downforce and air resistance. This improves the driving characteristics at high speeds, especially the lateral acceleration, driving stability, braking stability and efficiency. The speed thresholds of the rear spoiler vary with the aerodynamic package. The rear spoiler extends 1 km / h earlier in position 2 and 10 and offers an improvement in balance with a steeper angle of 26,5 degrees in the dynamic position.
Active aerodynamic profile in the underbody
As part of the optional aerodynamics package, the active aerodynamics profile, which is almost invisible in the underbody in front of the engine, makes a significant contribution to improved driving behavior. The carbon element, which weighs only around two kilograms, reacts to the position of the AMG DYNAMICS and automatically extends downwards by around 100 millimeters at a speed of 80 km / h in Basic / Advanced or 40 km / h in Pro / Master. This significantly changes the air flow on the underbody. This creates the so-called Venturi effect, which also sucks the car against the road and reduces the lift on the front axle by around 250 kilograms at 50 km / h. The driver feels this positively in the steering, even at lower speeds: the SL can be steered even more precisely into bends and drives with even more stability. The roadster reacts much more agile and is always easy to control, especially when turning quickly and accelerating quickly. In addition, the drag coefficient is improved.
When the electrically driven profile extends, the exhaust air opening of the engine cooler in the front opens and directs the air flow in the direction of the rear diffuser. This is therefore optimally flown against. This also increases the driving stability of the rear axle and reduces the temperature level of the hotspots in the rear area. At the same time, the aerodynamic refinements of the new SL ensure optimized brake cooling by directing the cold air specifically to the wheel disks. To protect against damage, the active component is resiliently suspended and can therefore easily move upwards on bumps.
In addition, the active element reinforces the effect of the active air control system AIRPANEL: If the movable blinds are closed, the lift on the front axle is reduced even more. The aerodynamic profile on the underbody can be extended when the vehicle is stationary (to clean leaves, for example) and is then automatically retracted when driving off. When the speed threshold is reached, the profile extends again automatically.
Aero bikes reduce air resistance and weight
For the SL, there is also a range of aerodynamically optimized light alloy wheels with a diameter of 20 or 21 inches that reduce air resistance with less turbulence. The 20-inch wheels with aero rings made of plastic, which save weight, are particularly sophisticated.
The SL's low wind noise makes a significant contribution to the comfort that is typical of Mercedes on long journeys. Effective sealing systems and the sophisticated aero-acoustics guarantee a high level of suitability for everyday use. Keeping exterior mirrors, side windows and rear window dirt-free makes an important contribution to active safety.
