From the
link posted by Fabio:
"A whole range of measures were necessary in order to attain the excellent
drag coefficient," explains Dr Teddy Woll, Daimler's head of aerodynamics at
Daimler AG. "Apart from an aerodynamically efficient basic design, these
include numerous optimisation measures on points of detail, such as the air
flow around the front wheels, the underbody design and the flow of cooling
air."
The aerodynamics of the 2012 B-class were optimised using complex
computer calculations and flow simulations which required more than 275,000
CPU hours. Models and prototypes spent around 1100 hours in the wind
tunnel.
I take it this means it will be difficult to duplicate/transfer the subtle
aerodynamic "optimisations" with Coroplast, duct tape and a box cutter.
