[aerohead]

Originally Posted by aardvarcus

Freebeard,
Those designs look nice, but it looks like a wind tunnel or powerful simulation would be needed to pull those off effectively. Might be a stretch for my calibrated thumb.

All,
After much thought I have been contemplating a new idea, a cross between the full body chop and the rear kamm extension. First I would do a very small roof chop at the very back of the suburban, dropping a few inches in a few feet to start getting some taper, but stopping above the rear door gaskets and not affecting the rear side windows, pillars, ect for simplicity. Second I would replace the rear barn doors (which are now too tall) with a custom rear single door. Third I would build a fixed kamm onto the back of the rear door, coming out to the bumper. Fourth I would build a secondary kamm hinged off the door that would fold out extending the length past the bumper several feet, but with an electric actuator to close it back within the first kamm for parking lots and other tight quarters.

This would allow for about five and a half foot worth of taper with no appreciable loss of cargo area nor additional permanent length to the vehicle. I believe hinging the second kamm would be too complicated without switching to a single door.

Thoughts and opinions?

Online,there was an image of a GM SUV model with a rather significant boat tail.They claimed 29% drag reduction with it.For simplicity,you'd be looking at close to 15% better highway mpg at the old double-nickel speed limit.A bit more at higher speed.