Caterham Wind Tunnel Testing

[xcarguy]

This was loaded onto the Storker (Stalker :jester:) forum as a doc file. It's an older article, but worth a look at/revisit. I couldn't figure out a way to load this as a doc, so here it is photos. Hopefully the resolution is good enough to enlarge and read.

 

:cheers:

[scannon]

I have that article in higher res jpegs if anyone is interested in reading them. They run around 2.2mb each so I can't post them but will email them if someone is interested.

[Manshoon11]

This got me thinking.... before seeing this i thought Cd was The number. i.e. our cars are worse than Hummer h2's.

 

soooo the verdict is in.... since I tend to be paranoid and look for imaginary problems with my car.

 

The # I should care about is CdA. and it is probably around .8 or .9m(^2) CdA

 

we get a sort of mention here

 

http://people.bath.ac.uk/ob225/design-aero.htm

 

and that H2 is considerably draggier at 2.46m(^2)

 

 

this page has frontal area at 1.26m^2 for a seven s3

 

http://carspector.com/car/lotus/039397/

 

 

thanks X.C.G.

[Klasik-69]

Actually our 7's have a Cd somewhere near a school bus. Coefficient of Drag (Cd) is the ratio of effective surface area to real area. If you're holding a square meter plate perpendicular to the wind, the Cd is the effective drag that your shape is even though you actually have one square meter exposed to that wind. Our cars are NOT aerodynamic, but they are quick. We zip thru the twisties but lag on the straights, hence the need for more power....and here comes the Stalkers to solve that problem. Long live HP !!!!

[BobbeySR27]

I have that article in higher res jpegs if anyone is interested in reading them. They run around 2.2mb each so I can't post them but will email them if someone is interested.

 

 

i would love to read this.. if you can shoot them at oleduc@industrieshd.com it would be awesome!!

[Croc]

I did manage to put my CSR in a wind tunnel in the New York State area soon after it was built. The research was confidential as it was supporting a doctoral thesis but that did not worry me as I was very interested in the informal results. I do have pages of notes from that session somewhere in one of the boxes currently migrating from my home garage to my new garage but the simple summary is on a blatchat post I made here (half way down the page under my usual sign in ID Croc):

 

http://www.blatchat.com/t.asp?id=243097&pn=2&ps=15

[ecarte56]

Actually our 7's have a Cd somewhere near a school bus. Coefficient of Drag (Cd) is the ratio of effective surface area to real area. If you're holding a square meter plate perpendicular to the wind, the Cd is the effective drag that your shape is even though you actually have one square meter exposed to that wind. Our cars are NOT aerodynamic, but they are quick. We zip thru the twisties but lag on the straights, hence the need for more power....and here comes the Stalkers to solve that problem. Long live HP !!!!

 

Are you sure about Cd being an area ratio? For cars we would normally be talking about projected frontal area. Real or planform area would not come into it. I can't see anyway to derive a single Cd in terms of multiple areas and have not run across anything about it. Hey I am not an aerodynamics engineer.. am I missing something?

 

I agree with Manshoon11 about CdA being more relevant than Cd. Gives us an excuse for having pitiful Cd's!