Ernie's wing
I located my photo of Ernie's New Beetle.It's in orthogonal projection,so nothings really in truelength,but the angle of the car allowed a cursory noodling.
It appears that the centerline of the backlight hits 22degrees about 1/2 a door handle length down the glass and I would suspect that the flow is very feeble,if not separating there.
Down at the bottom of the glass,the angle is on the order of 34degrees with the horizon.
A protractor reveals that Ernies wing relaxes that angle to about 19degrees,well within Mair's 22degree limit.
If you place a Frenchcurve over the car,with and without Ernie's wing,it looks like the wing 'doubles' the apparent length of the car's aftbody at centerline ,where the imaginary line would intersect the ground.
With respect to the streamlining template,at centerline,it would be the same as taking the Beetle with 30% of an aftbody,and extending it out
to about 80 %.
Of course the sides aren't done,but you can see how the wing could definitely help push Ernie into 50+ mpg territory.Sweet!
