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Old 11-14-2020, 12:46 AM   #11 (permalink)
aardvarcus
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Quote:
Originally Posted by JulianEdgar View Post
I don't even know what "aerodynamics works off" means....

If it means "aerodynamic drag" then yes, a reduction in wake size (usually giving less drag) is one of the things that needs to be balanced in the rear extension design against the created lift-induced drag component (that gives more drag).

In the case of the photographed Roomster, too steep an extension angle (note: still with attached flow) gave higher measured drag, despite the smaller wake.

Incidentally, that Roomster example is in my aero book, and was specifically cited by three of the professional aerodynamicists who reviewed the book as a good example. In fact Dr Hucho liked the Roomster wake pics so much that he asked me for high res versions.
I see you are ignoring the part of my post about not using the AST-II template, which fits several of your example cars in your video per my overlay.

Apologies I did not precisely define all terms in my question.

I do not understand your correlation of a photographed wake size to drag, as a photograph can not lend insight into how the airflows that become the wake are exerting pressure on the vehicle.

I realize that your post acknowledges the effects of the steep extension not aligning with this expected result of smaller wake equals lower drag.

I am aware of what is in your aero book, seeing as how I own a copy. Care to comment on why there are so many examples of modifications made to match "the template" in the DIY section?

 
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