[aerohead]

Originally Posted by arcosine

With 4 people aboard? We can find a special plane that gets better than that, not just an old Cessna 172 rg. Whats the point? 45 mpg at 207 mph.

Hypermiling Plane Gets 45 MPG at 207 MPH, Capable of 100 MPG (That's Better Than Most Cars!) : TreeHugger

A plane with better fuel economy than your car - Technology & science - Innovation - NBCNews.com

*We're streamlining a Saturn,yes?
*Abbott and von Doenhoff tell us not to attempt to use any flight value of any aircraft structure at any place other than under flight conditions.
*Jaray,Prandtl,and Rumpler all were aware that drag coefficients of free-flying forms doubles when in ground proximity.
*Aircraft design presumes fully attached flow.
*Aircraft drag is dominated by skin friction.
*Automobile design is challenged with respect to attached flow.
*Automobile drag is dominated by pressure drag which is a function of flow separation.
*Hucho warns us about attempting to translate the flow efficiencies of 2-dimensional free-flow structures to the 3-dimensional flow of bluff body structures in ground proximity,especially the wake,which cannot be easily modeled as with aircraft.