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Old 01-08-2021, 04:06 PM   #133 (permalink)
aerohead
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Hucho

Quote:
Originally Posted by Vman455 View Post
I've mentioned this before here, but when I emailed Hucho directly last year and asked him what he would recommend to reduce the drag of my car, he said nothing about any sort of template, tapered tail, half-body of revolution, or extension at all.

Be sure you're differentiating between what Hucho has actually recommended, and what you recommend as pathways to low drag. He is by far not the only author to treat low-drag idealized shapes--although some others do at much more length--but all of them that I have read consider streamlined half-bodies as shapes which can be, in Hucho's words, "progressively transformed into a car." (He wrote this in a section which does not appear in the 2nd edition).
1) ' [I]t is very important to design a rear body surface which brings the divided streamlines smoothly together. Optimum shapes are 'streamlined' bodies having a very slender rear part.' Hucho, page- 61.
2) ' [L[ow drag can only be achieved when the separation at the rear is eliminated.' Hucho, page- 16
3) ' [T]he optimum shape in terms of drag is a half-body, which forms a complete body of revolution together with its mirror image - produced through reflection from the roadway.' Hucho, page-16.
4) ' [T]he drag of the basic body is achievable. To what extent this can be approached in the development of a production vehicle is therefore more a question of the balance of the requirements of the specification, than of technical feasibility.' Hucho, page-209
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