Quote:
Originally Posted by UnicycleDan
Aerohead, I think I understand the concept of what you're saying. A question, though...I see that the Cd is decreasing as the tail of the wake is brought in closer toward the back of the car, but how do those angle drops in the second picture not produce a lot of turbulence, being so far away from the template? In your first picture, the template trajectories in the right column appear to be the same as their adjacent left column diagram. Do you have an explanation for why the steep angles in the left column produce a better Cd than their corresponding right column angles that follow the template more closely?
If my vehicle is 17ft long and I make a 2.5ft extension, then the kammback accounts for 13% of the total length, indicating I should use roughly a 14-degree decline according to the left column, which is not at all close to the template you advocate people superimposing over their car picture and following...I might be misunderstanding something.
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The point I wanted to make,is that for simplistic,sharp-edged slopes,the best angle would be dictated by how much of a rear end the car had.No cars are constructed this way.And you can see that the 'lowest' drag is quite high.
In this following example,you can see how the 1st-gen Golf/Rabbit achieves lowest drag when the roof is pushed up to the 'Template'
For all I've seen,we can't beat it.