[brucepick]

cfg83 - I had one sorta like that for a few months last summer, coroplast and duct tape. Couldn't document that mine helped but I'm sure that if its built well, it will help. Reading on the Kamm topic in wikipedia makes me think you could/should slope it down a bit steeper. The idea is to have a smaller cross section at the point where the airflow finally leaves the body. Taper it downwards a bit. Curve it down if you can, but making a curve there will probably get you a compound curve that's tough to build. Taper it in sideways too.

diesel_john - Very neat - it made its own Kamm back!