Mercedes designers have brought their aerodynamic knowledge and experience to
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bear on the new trailer. Numerous individual measures have been combined to drastically lower the wind resistance of the entire tractor-trailer combination. For instance, a front airdam on the trailer reduces the distance to the tractor unit and lowers the wind resistance by 1%. Side trim panels contribute an 8% improvement. These are slightly drawn-in at the front and characterised by an opening at the rear. This steers the air in the direction of the rear diffuser. The diffuser has the shape of a parallelogram and links up with the underbody panelling. This improves wind resistance by a further 1%-2%. A rear end taper measuring slightly more than 400mm in length forms a crucial part of the aerodynamic concept. It features folding elements to facilitate access to the load compartment. The rear end taper improves wind resistance by a further 7%.
Reduced fuel consumption
Together these measures reduce the wind resistance of the combination by approximately 18%, which results in a reduction in fuel consumption amounting to almost 5% in real-life road trafic according to Mercedes.
The aero trailer’s only current restriction is the fact that its length measurement exceeds the currently permissible limit by almost half a metre, due to the tail-end extension, and would require a legislative change in order to be legal on European roads.
According to tests carried out by Mercedes along with others in the VDA, the German automotive association, the rear extension is by far the most effective fuel-saving device, while modiications to the cab such as a supposedly aerodynamic nose job extension result in minimal improvements so far as wind resistance is concerned. n
NEW AXLES DRIVE FURTHER GAINS
Saving space and weight In addition to the new aerodynamic design, Mercedes has also further developed its trailer axle range with the unveiling of the new DCA Airmaster. This uses the axle housing as the compressed air tank for the trailer. Each axle has a storage capacity of up to 40 litres of compressed air, removing the need for conventional compressed air tanks on the trailer.
This supplementary function saves space underneath the trailer as well as up to 50kg in weight. Despite the integral compressed air reservoir, the Airmaster axle weighs no more than the familiar lightweight Weightmaster trailer axle from the same manufacturer: in its lightest version for standard trailers, it tips the scales at just 395kg.