[aerohead]

Originally Posted by JulianEdgar

Normal mix of Aerohead irrelevancies and the justifiable of the unjustifiable.

Fact 1: Aerohead cited the diagram and said of it:

The Cadillac poses only a small perturbation. It's virtual lack of rear lift is a testament to the pressure-producing capability of a streamlined shape.
If you'll revisit Figure 2.4, page 51 of Hucho, you can see how,over the last 14.5% of the body, local pressure rises all the way back to local barometric pressure. Depending on rear overhang, and low pressure under the body, due to a diffuser, rear lift can be zero, like the VSPORT's

Fact 2: The diagram is for an imaginary, viscous-free (inviscid) fluid. The accompanying body text says of the diagram:

On the rear part of the vehicle's upper surface a steep pressure rise occurs, and it is in this region where considerable differences exist between the real flow of a viscous fluid and the inviscid flow shown here.

Fact 3: Aerohead's description of what the diagram shows is completely contradicted by the text, which makes the clear point that the diagram does not apply to real cars, especially in terms of pressures on the rear half (exactly the area Aerohead references).

I posted a new thread dedicated to Hummel's Figure 2.4. Please check it out.
I agree with everything you've posted, however there's a context associated with everything I've posted. I'm glad you've brought this to the attention of the forum.