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Old 02-10-2018, 02:13 PM   #17 (permalink)
aerohead
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attached airflow

Quote:
Originally Posted by Vman455 View Post
I'm going to stop you right there: if you put tufts on the rear window and go for a drive, you'll see that there is attached airflow already over the back of the Prius. There's no need to build it up to meet a theoretical template; rather, you should change the angle of the spoiler, which currently sticks out nearly parallel to the ground (to combat rear lift). The tail extension you'll have to test to see if it can continue the same angle as the window (somewhere around 17 degrees from horizontal) or if it needs to relax that to avoid flow separation, like the EV1 LSR tail cone. The cargo carrier I'm building right now relaxes that angle, because I didn't want to mess with the spoiler for now and I want to ensure flow attachment of the air coming off of it. In a future iteration I might try something more aggressive.
I agree.If it's not to the 'template',it does satisfy Rolf Buchheim's 23-degree maximum angle,which Hucho shared.On the 1981 VW 'flow' body,Buchheim et al. measured Cd 0.14,so it can't be bad.
Also,I don't think the photo of the Prius is true-length,as in a blueprint.The camera appears to be looking from a forward-biased location,which would throw off any template alignment.
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