[KWTrucker]

Greetings,

I run a KW T600 truck and step deck trailer. It is not practical to skin the underbody of the truck, though perhaps it might be for the trailer. I would like to pursue an air dam for the truck and have continuous tool boxes to install down each side of the trailer to provide storage and skirting.

The issues raised in "Aerodynamics of Road Vehicles" conclude that an air dam will help up to a certain "height" (they discuss the height in relation to how far it hangs down from the bumper) but after it exceeds that height (i.e. gets too close to the ground) the effect becomes detrimental.

Further, there is reference to the work of W. H. Hucho, et al, where it was demonstrated that an air dam by itself (properly designed) reduced drag by 2%. They then added sort of a mustache dropping down just slightly from the from lip of the hood. This also achieved a 2% drag reduction. However, when these two mods were combined, a total dray reduction of 8% was achieved. (Lift was also reduced, though this is little concern for my truck).

Is anyone familiar with this combination or concept? The references in the book include 4 basic drawings (dimensionless) and sort of a fleeting reference to "properly designed" being necessary.

Any help in reducing the learning curve would be appreciated.