View Single Post
Old 07-28-2019, 09:33 AM   #4 (permalink)
Master EcoModder
Join Date: May 2010
Location: Illinois
Posts: 452

Oh Deer - '03 Ford Ranger XL
90 day: 33.16 mpg (US)
Thanks: 54
Thanked 79 Times in 63 Posts
Originally Posted by aerohead View Post
As viewed from the rear,the perimeter of the box would be inset from that of the body 'slice' onto which it's attached.
When viewed from the side,the trailing edge of the box would fall where an imaginary 'template' line would intersect that point in space.
Rather than a gentle curving surface,you'd just a rearward-facing step.
The flow would separate from the body as the downslope hit 22-23 degrees from horizontal,but re-attach right at the end of the step,capturing a vortex of circulating air.
I'm assuming the trailing edge would be sloped about 12 (to be in-line with the template). But viewed from the top, would the rearward taper be the same 12 or something closer to 7? I think I remember when I was attempting my aerocap for my old Ranger, something had been said about the angle from front to back being more like 7 instead of 12. Or does the template keep curving more aggressively as you move rearward. Seems like I had planned my old aerocap at 3 down at the cab out for a foot. Then another 4 (7 total) for another 2 feet, and another 5 (12 total) for the remaining 3 feet. Or does the template keep curving more aggressively beyond about 12 as it moves rearward?

I guess I'm still not seeing how 12 down angle from the template would would ever intersect with 22 to give a point for the trailing edge of the box.

Last edited by hat_man; 07-28-2019 at 09:38 AM..
  Reply With Quote