When I first saw this image, I thought that we were looking at a bird's-eye view of the car, rather than a side view. I trust y'all on the forum, especially after the "what do you do for a living" thread! So, what I mean is, I believe you that it's actually referring to the side-view. End of preface, lol

I'm confusing myself since I keep flipping the perspective in my head. I'd imagine that the guy who wrote the book knows his 'ish and would say that it's preferable to figure boat tail measurements based on the side view, duh, anyone knows that, rather than bird's-eye. But it doesn't hurt to ask, y'know?? Anyone ever compare the above-type thing in that way? Why the side view rather than bird's-eye? Say I have a car that's waaaaay wider than it is tall, could the difference in "d" be negligible? Or "d"-bird's-eye is not as aerodynamically awesome as "d"-side-view? L-script and the 22-degree angle (assuming the end of the boat tail is circular) would be the same regardless of the POV. "d" would be the only difference in the equation based on the above diagram. Set me straight!