Quote:
Originally Posted by JulianEdgar
a few posts later....
Gosh it's hard to keep up. One moment a spoiler will add drag, and the next moment, it won't!
Soon we will be back to your completely incorrect theory of how rear spoilers work on modern cars.
Ah, here it is.
How did you go with the reference I cited on how spoilers reduce drag and lift on fastbacks? I can tell you one thing: it is not at all as (you think) Hucho stated it back in the 1980s.
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*On line 1) I prefaced my comments with respect to context.
* Whether a 'fastback' is a 'pseudo-Jaray', or 'Kamm-back' is the context.
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A) on a 'pseudo-Jaray' body, a rear spoiler would have to address lift-due-to-separation, as well as 'direct lift' if that was desirable.
B) on a 'Kamm-back' fastback, no lift-due-to-separation would exist.
C) adding a spoiler to a Kamm-back would cause the streamlines to re-converge, the flow to accelerate up to a higher velocity, lower pressure, increasing the size of the wake, lowering base pressure, raising overall drag.
The 'active' spoiler attempts to navigate the dilemma. They don't obstruct rearwards vision when 'parked', can limit the hit to rear visibility at low speeds, ( Tesla Model-X original, 3-position wing ), then go for downforce at high speed, where one needs to pay close attention to what's ahead of the car.