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Originally Posted by Pendragon
I am pretty much in agreement, but I do believe that placement of the max height of the roof line further aft than is commonplace (such as the Daytona Coupe) is something we should be seeing more of from the car designers.
I have my doubts about the wind tunnel smoke visualizations shown in commercials...I suspect that the positioning of the smoke wand is chosen to look good rather than show the problem areas. I suppose you can't blame them too much for turning the marketers loose.
As an aside, I have seen several things that the designers are "tweaking" that are probably beyond what is reasonable for all but the most committed modders. The shape of the headlight area of the nose of some cars has been shaped to modify airflow to try to reduce drag from the outside mirrors. The mirrors themselves have been seeing more attention to lower drag shapes as well. There are some other flow modifiers on the front fenders of some cars which attempt to reduce drag from the wheel well and wheel. I doubt that we will see the wind tunnel work for these items on commercials, but we should...it would demonstrate the attention to detail that helps make more efficient cars.
Cheers
P.S. When are we going to see flush mounted windshields and "hidden" windshield wipers?
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I GOOGLED the Shelby Daytona coupe.State of the art would suggest that this shape would do better 'backwards,' as Chrysler attempted to illustrate in 1934 with their Airflow series.
The 1984 Ford Probe-IV concept was the last car I can recall which relied primarily on the fore-body for drag reduction.The car achieved Cd 0.154,pretty good.
Then Ford pushed the roof forward,extended the tail to create the Probe-V which came in at Cd 0.137.
'Pumpkin seeds,' like the 1922 Jaray,1933 Lay,1957 MG EX-181,1987 Sunraycer,and lately,NUNA-3 demonstrate Cd 0.13,0.12,0.12/0.089,0.077 respectively.
All these cars respect the basic aerodynamic streamlining tenant,that for low drag,a car must use its 1st 1/3rd of body for penetration,and the last 2/3rds for pressure recovery.
I've tried to illustrate this with the Aerodynamic Streamlining Template.It's based on sound empirical science borne out of the best wind tunnels over the last century of investigations.
Of course,automakers are free to produce whatever they want,within DOT and EPA guidelines,but for low drag and maximum mpg,the 'Template' demonstrates the lowest drag form.
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As to the wind tunnel photos( Madison Ave. aside ),the images at 'Flow-Images' appear unadulterated to me.
Since this sort of thing is peer-reviewed there is no reason why an automaker would risk loss of credibility within the auto community by fudging on the photographs,knowing,that like 'cold-fusion,' other tunnels would be duplicating the tests for verification.
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And yes,we see subtle massaging of the fore-body.And that's good.As long as they don't forget the elephant in the living room( the tail ).
As far as the windshield mounting and wipers,these were looked at during development of GM's Precept PNGV car ( CD 0.163 ).In the wind tunnel,they demonstrated no measurable drag,so things may be okay as the are with respect to contemporary manufacturing technology.
