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Old 08-26-2020, 07:41 PM   #64 (permalink)
JulianEdgar
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Quote:
Originally Posted by California98Civic View Post
Wow. A lot there and more than I can digest. Let me redirect and try and be clearer on a narrower point. You had written that with a "proper fastback roof contour, the effective static pressure acting over the rear of the greenhouse is at the highest pressure of all roof profiles." I think Figure 7 in the article I linked supports that claim: at the rear of the roof, just ahead of the backlight, the coefficient of pressure is greater on the fastback than on the notchback. Nonetheless, the same article shows that the fastback produces a little more body lift (Fig. 5). For this specific comparison, both your claim and Julian's appear to be true. Isn't that right?
It's an interesting paper - thanks for linking to it.

For my money, this is the key graph:



It's what we're interested in in terms of lift (ie it integrates the effect of all the pressures), and it shows greater lift for the fastback compared to the notchback at all angles of yaw. What a surprise (not).

Note though the graph is a bit confusing, showing negative coefficients. (The paper says: "Hence, the maximum lift force is claimed at a yaw angle of β=10°" and yet a negative CL would normally indicate downforce.) So higher up graph = greater lift.

Anyway, so much for Aerohead's oft-repeated point that fastbacks have low lift!

Last edited by JulianEdgar; 08-26-2020 at 07:58 PM..
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