more papers (aerodynamics links)
 

Here are couple of papers that might be of some interest to you.

Micro-vortex generators

Trailer aerodynamics

SAE pneumatic aerodynamics

Drafting and more trailers aero

Boundary layer separation

AIAA VG

SAE pickup tailgate paper (same principle as a spoiler)

Contribution to drag

We need to collect the aerodynamic articles links on this and previous threads onto a dedicated sticky thread for quick reference so they don't get lost or buried.

Yeah, I was just thinkin the same thing.

I concur on the sticky-icky of the aero stuff. Maybe Ben (SVOboy) woud have some time for that. If not, then I could find some time to lump them together I guess.

Rear Aero
 

here is a picture. Of what a good rear of the car should look like for low drag.

The diffuser is way to short and it's angle to steep on this picture. It's far from optimal.

I agree, way to steep....

Angle will greatly depend on height and length...

Check and see if your library has this book

Race Car Aerodynamics: Designing for Speed by Joseph Katz. While some of that won't apply to your typical car... There's interesting discussion on height/length ratios and front/rear shapes....

Another problem with saying that rear end is ideal (I know it wasn't explicitly stated) is that there's a lot of interaction between the side and bottom. Yes, ideally a cone is what you want - but you're not going to find the same flow speed under and next to a car... To deal with that, you'd add vertical winglets that extend the side of the car while the diffuser does it's magic under the car.

The wing strakes and side portion in this diffuser is close to what I'm getting at...
http://www.revozport.com/webpics/FER...s-diffuser.jpg

Good find, tas. I've used the tailgate paper to enlighten three different masses.

Here's a REALLY good one.

The Influence of Aerodynamics on the Design of High-Performance Road Vehicles - Part 1

The Influence of Aerodynamics on the Design of High-Performance Road Vehicles - Part 2