[JulianEdgar]

Originally Posted by aerohead

1) I'm not interested.If you are, do your own work.You talk of wings. For wings, the plan-view area of chord and span is used.

Cars use frontal area in the calculation of coefficients of drag and lift. You were attempting to muddy the water by using plan area not frontal area.

2-3) The template was created to serve as a Go NoGo. It's derived from technology developed in the 1920s by NACA ( NASA). Its contour is incapable of producing flow separation ( that's why you'd want to use it).

Typical Aerohead non sequitur. I agree that the template (in 3D) is unlikely to have flow separation. That does not automatically lead to it being the best shaped body to use. A dog has four legs. Not all animals with four legs are dogs.

Your tuft study does not have scientific rigor. It's fraught with shortcomings. Automakers don't use it.

Are you serious? Carmakers have used tuft testing for getting on for a century. Every single professional aerodynamicist who reviewed my book complimented me on the quality of the tuft testing I show. One said it was the clearest he'd ever seen. Another Formula 1 aerodynamicist told me that only people who don't know anything about car aero deride tuft testing. Here's an example of a carmaker not using it:

4-5-6) Sometimes you appear to be obsessed with lift issues. Given the lift values reported for the Cadillac, Hucho's non-concern with lift was only reinforced. If you're a Princess and can feel a pea under a stack of mattresses, that's your problem. Lift is not associated with attached flow.

I am not obsessed with lift. It's just that it doesn't make good sense to utterly ignore it, as you do.

Lift is not associated with attached flow? You really believe that? Honestly, if you do, that is about a fundamental misunderstanding of aerodynamics as it's possible to get. Words fail me.

* revisit your polar diagrams for wing sections.( A. Silverstein, NACA Report 502, p. 15, 1934 will be a revelation ).

The report has only 13 pages.

* Hucho, p. 122 ( aspect ratio )

Aspect ratio is not relevant here. On the basis of what two professional car aerodynamicists have detailed to me, the description here of the relationship between induced drag and lift is now well outdated. (But from what I understand, this is an area of some disagreement between aerodynamicists.)

* Hucho, p. 151, Fig. 4.54 (attached flow= lower lift)

Fig 4.54 does not mention lift. Fig 4.55 does though. It shows exactly what I have stated many times. Lift is higher with a fastback shape than a squareback shape. In fact, it's such a clear diagram of what really happens, here it is:



As this diagram so clearly shows, I am afraid your understanding is completely backwards.

* Hucho, p. 217, Fig. 5.4, RAE 101 aerofoil @ 4-degrees offset flow pressure distribution, both sides.

Um, Fig 5.4 is showing aerodynamic side forces, not lift/downforce. Did you read the text?

* Hucho, p. 282, Fig. 7.34 ( attached flow = lower lift )

This diagram shows the presence of a spoiler that causes earlier separation, not better flow attachment. That's exactly what I wrote in my book, and when reviewing this part, Dr Thomas Wolf (the current head of Porsche aerodynamics) agreed with my analysis. But hey, what would he know?

So what I am finding, and as someone else here identified a while ago, is that when I spend the time to look up each of the references you cite, you are very often misquoting and/or misunderstanding them.