Mercedes aero engineer: Cd of .20 feasible in production cars within 10 yrs

[aerohead]

I just read Mr. Voll's article,thanks Darin!
If he is referring to the GM Aero( which used to reside at the GM exhibit at Epcot Center,Orlando,Florida),it had a higher Cd than the Citation.
The Citation never had a bellypan,hence it's higher Cd than Probe.
As far as gaps,every real car has got to have "cut lines" for the hood,doors,trunklid,fuel door/charging port,etc..He may have been referring to a development model.I don't know.
GM's Program For New Generation Vehicle(PNGV) 80-mpg car,circa 2004 came in around Cd 0.165.
They started with the EV-1 in the windtunnel,and did two development teams in parallel to develop a body in white.
Their "solution" addressed many issues Mr. Voll cites as barriers to lower drag in production cars.
There's a good chance I've missed some things,as after Clinton left the White House it's been really difficult to look out the window.

[aerohead]

The October 1999 issue of MECHANICAL ENGINEERING has an article about the development of GM's 80-MPG Precept concept car.
During wind tunnel studies one of the 1/3-scale clay models came in at Cd 0.146.
In full-scale,and adding wipers,wheel covers,mirrors(cameras),door handles,and cut lines,the drag coefficient rose to Cd 0.163.
My guess,is that this is the Cd 0.14 model referred to.
Underfloor heat issues are solved by the rear engine layout ( yeah Preston Tucker,you're vindicated!) and the rear cooling solves the issue of the open nose.
I'll post a photo of the Precept when Al gets un-busy.
Also I have a pic of the Cd 0.18 Mercedes-Benz F300 research vehicle of 1997,which attained 100-MPG.

[aerohead]

here are pics

[Piwoslaw]

Originally Posted by aerohead

here are pics

Aerohead, you found it!! The 0.14 Cd GM is just what I was looking for in Chrysler diesel-electric hybrid.
Do know where I can find more info on it? Does it have a (code)name?

[aerohead]

Piwoslaw,my photo comes from the June 2000 issue of POPULAR MECHANICS,on pages 88,89,and 90.On page 90 is a phantom view with cutaways.
You might be able to get a reprint of the article from the POP MECH.This article also touches on Ford's "Prodigy" and the Dodge ESX3.
These were to be the 80-mpg cars although there were never commitments made to production.
Let me know if you have trouble with the articles,we'll work somethin' out.

[NeilBlanchard]

Hi,

I found some additional pictures of the GM Precept:

GM Unveils Concept Car That Gets 80 Miles A Gallon






That web page quotes the Cd as 0.163. It has video mirrors. An electric motor drives the front wheels and a small diesel drives the rear (hence the cooling vents in the rear sides).

[cfg83]

NeilBlanchard -

I get so depressed when I see these cars. Maybe not ready for prime-time, but still birds in the hand.

CarloSW2

[smokeyj]

Alfa Romeo BAT 5 in 1954 claimed cD of .19.

So I suppose it is pretty safe to go out on a limb and predict that in 10 years from now we will be able to achieve what we did 50 years ago.

[Piwoslaw]

So this is where the "Bigger, Better, Faster, More" philosophy got us: as time went by cars had bigger Cd, bigger frontal area, bigger fuel consumption, etc...
Only was it really better?

[aerohead]

Originally Posted by cfg83

NeilBlanchard -

I get so depressed when I see these cars. Maybe not ready for prime-time, but still birds in the hand.

CarloSW2

The upshot for me,is that whenever these cars emerge,they basically confirm assertions going back to at least 1922,when the Jaray/Klemperer work was published,which infers what WILL happen,should truly low drag vehicles make it onto the roads.
With fiberglass cloth and polyester resin I can mimic the successes of the Masters and taste the sweet fruit of their endeavors.
Cogito,ergo imodifi !