Quote:
Originally Posted by JulianEdgar
Excellent aerodynamic testing and development can occur on the road or track, at little or no cost.
You know that, but you pretend otherwise so that interest is maintained in simplistic and incorrect notions like using templates - ie making guesses from drawings.
To put that another way, you deliberately choose to continue to mislead people here.
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1) I don't know that within the context with which you imply.
2) A 'Kamm-back' based fastback, of any length, would already have the smallest wake, highest base pressure, lowest lift, and lowest drag. A spoiler wouldn't alter that situation. A spoiler could add 'direct downforce,' however, historically, would come at the expense of higher drag, or danger to pedestrians if not thoughtfully conceived.
3) I'm in total agreement that a pseudo-Jaray 'fastback' could certainly benefit from a rear spoiler, as the flow would already be compromised. A perfect environment for a spoiler.
4) And I also fully agree that for a high-performance vehicle, of which its specification would easily provide for high-speed operation, that the incorporation of a rear spoiler would not only be beneficial, it would be a safety requirement.
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From Hucho's 2nd-Edition, page-23, Figure 1.26, 2nd from bottom, the 'template' of Lay's multi-element, multi-configurational, wind tunnel test model, allows prediction of Cd, in a range from Cd 0.30, to Cd 0.13., as a function of body elongation, with which Hucho discusses in the context of future vehicles design as of December, 1986. ( The actual research presented by Baron Koenig-Fachsenfeld indicated Cd 0.12 as the minimum ).
Hucho himself presented dozens of 'templates' in his chapter on detail optimization. Hoerner's book is also full of them. Both recommended reading.
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Finally, another aspect of vehicle aerodynamics and design, often mentioned here at EcoModder, which could explain WHY anything like a 'template' would never be expressed in vehicle design, and worthy of its own dedicated thread is, 'styling'.
As early as page-6, Hucho wrote: ' [M]inimizing the drag of a passenger vehicle must be accomplished with less conspicuous methods which conform to current styles.' ( Law of the Paris Dressmakers, 1927 )