Some more work on the tail today. I had a couple trips to Kansas in the last month, and just to try out the cargo carrier I installed a box temporarily on back:
Now that I've been home this week, I got some 2" foam board and cut a piece large enough to be the platform for the streamlined tail:
Since I frequently carry bikes in back and use the car for sleeping in on road trips, I wanted to preserve hatch access. The tail is spaced 6" away from the bumper edge to facilitate this, just enough so I can stand between the tail and bumper, and exactly enough clearance for the hatch to swing upward and clear the box.
I took the plan taper from the rear bumper cover--which turned out to be more aggressive than I thought, 12 degrees--and extended it with a straightedge onto the tail platform:
Then, I gradually tapered the angle to 21 degrees at the end of the tail.
Cut out one side:
And then the other:
You'll barely be able to see it coming down the road:
The tail itself is 36" long, giving the car a total 42" extension from the rear bumper edge for a total length of 218", 9" longer than a regular cab 6.5-foot bed F-150. Length/depth ratio of the vehicle system will be 3.81:1, up from the stock 2.99:1, and the width of the tail at the back is 35", a little more than half the width of the car at the rear bumper.