PorKen

I didn't know there was a name for it, but I have been thinking ever since I took off my bumper covers, how cool it might look with a 'Kamm back'.



Even the front might look cool with a blunt tip, and there would be much more space for oil/intercooler radiators on the sides.



Like this Astin...



Fortunately ( ) I don't have any fiberglass (or whatever fancy plastic Msr. Ott is using) skillz... yet.

Normy

Pork-En! Chuck Z asked me a few weeks ago about the Aston Martin cars; I essentially told him to go for it, but tell us all about it.


N-

Normy

That Aston Martin and those exposed body parts:

Don't do it. YES you can cobble a body kit to kill the Porshe look.

I prefer my S2.

A car that will live in infamy.

N!

PorKen

I think body mods look odd on 928's partly because there are so few 928's. Perhaps more significant, there are no factory aero/racing body styles like the 911's have.

Fogey1

docmirror wrote:
"... Ex: Frontal plate area of 928 = 12.55 SqM ..."

I'm probably just displaying my ignorance, but ...

Twelve and half square meters!? How can that be? A brick wall 3 meters on a side has a frontal area of only 9 square meters and you could easily hide a 928 behind it. Ditto 2 X 3.

docmirror

The two letters at the front of the quote mean "EXAMPLE". In this context, that would let the reader know that the following is simply for reference, and not actual size.

Thanks Normy for the formula for D, which, although fun to have, wasn't what the focus of the post was about. Cd, can be derived, but I thought everyone already knew that drag increases at the square of speed. The crux of it as I meantioned is that the Cd is a measured caculation, not a formulaic one. That's why I put in that small blurb about the boundary layer, to account for seemingly irrational Cd numbers for cars that would seem to be somewhat bricklike.

Early attemps at aerodynamic cars include: Chrysler Airflow, Cord 810, Fuller's "Dymaxion" which got > 40MPG back in the '30s, while cruising at freeway speeds and carried up to 10 people.

As for the 747, what is the V# for max endurance or best L/D clean? I also wonder what the AoA is at that speed? It seems like those things are awfully nose up when just moseying around in holding patterns.

Doc

Bill Ball

Hey, Porken. You have something pretty close to a Kamm rear if you just leave the bumper cover off. Ugly, but conceptually close.

tomcat

I worked with several wind tunnels in college. Ford used our closed circuit, I think, 40 weeks/year. This was actually where NASCAR did research that implemented devices on the roof to inhibt "lift-off" when cars spun sideways. At least at that time, they seem to be more worried about the total pressure point (to locate openings for cooling) and yaw stability (mentioned earlier by Nicole) for driver's comfort. With speed limits at 55 and rush hour traffic, I wonder what impact Cd actually has on any car's fuel efficiency.