[aerohead]

This will be the second talking point from Vman455's thread, ' R H Barnard on template ( 10-10-2020 ), presently at the bottom of page-2, here at the Aero Forum.
This topic was brought by Julian Edgar, it's a good point. You can read the original quotes at Vman's thread.
--------------------------------------------------------------------------------------Pararaphrasing:
the ASTs aerohead presents as if it could be 'used to try to 'achieve' all sorts of things- to achieve setting rear spoiler height.'
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Collecting automotive blueprints and conducting dimensional analysis for 45-years now, comparisons of vehicle roof apex-to-tearing edge geometries with those of the 'templates' are indicated for vehicles designed by:
Acura
Alberto Morelli
Alfa Romeo
Alpine
Audi
BMW
Bugatti
GM-Cadillac
Jim Hall
GM-Chevrolet
DeLorean
De Tomaso
Dodge
Ferrari
Ford
General Motors concept cars
Honda
Hyundai
ItalDesign
Jaguar
Lamborghini
Lightyear
Lotus
Lucid
Maserati
Mercedes-Benz
GM-Pontiac
Porsche
Renault
Rivian
Shelby American Racing
Sunbeam
Volkswagen
Volvo
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So far, my only conclusion as to 'why' these 'contours/ silhouettes' are repeatedly employed for 'halo' cars, high performance supercars, and dedicated race cars, is that the pressure recovery capability of these contours are an open secret, hiding in plain view, within the charts and tables of the fluid mechanics literature, generated from empirical testing, long ago; and qualify as a tool for design strategies, showing how existing single results can be combined to provide general solutions as well as theoretical models for guiding and supporting tests.