[aerohead]

Originally Posted by Madact

I've always wondered if an airfoil in the opposite of 'downforce' mode could provide a virtual boat-tail - not enough to cause much extra lift to speak of, mind you, just enough to encourage the wake to converge a little quicker - possibly at the sides as well. It would be a fairly small airfoil with very mild camber and a very gentle angle of attack, placed just behind and 'out' from the separation point on a station wagon or similar - just far enough out to catch a little bit of the free stream without impacting on the frontal area...

No idea if it would work or pay off in drag of course - just one of those random thoughts .

Hucho says nothing has worked except boat tails and box-cavities.