CdA list

[SteveP]

Re the .85, .81 etc.

I have noticed that many car makers seem to be going in two directions: to give cars the "macho" look they tend to make them squarer (when seen from front)--think Hummmer and other SUVs. On other cars (and I suspect they'd be the wider and more luxury oriented cars), they seem to increase the amount of tumblehome.

I noticed that the Prius and Insight did not have much tumblehome, though they weren't perfectly square, either. I did the "reverse calcs" on both and found that .85/.85 calculated out as about right.

--Steve

[Big Dave]

The Cd of a Scion xB is 0.32? Pardon me if I don't believe that the brick of bricks has a Cd under 0.45.

The only good thing I can say is that it is a small brick.

[toomuch]

Originally Posted by Daox

Well, I thought it might be nice to get a good aerodynamic comparison going between different cars and CdA is really the only way to get that. So, this morning I threw some data together on an excel spreadsheet and totaled up some of Toyota's smaller cars on it. I'd like to expand it to other brands (I'm most familiar with Toyota) and I would like you guy's help for that. Here is what I have so far.

You can see I sorted it by CdA. The height and width are in inches and frontal are is in square feet (W * H * .84). The formula used for CdA is Frontal Area * Cd.

CdA List

CdA List.xls

Thanks, I could not find my Frontal Area anywhere. But I guess I could have just figured it out, but I wanted a number from the Manufacturer.

[Daox]

Originally Posted by Big Dave

The Cd of a Scion xB is 0.32? Pardon me if I don't believe that the brick of bricks has a Cd under 0.45.

The only good thing I can say is that it is a small brick.

That would be the new xB has the Cd of .32. The older (smaller more boxy) xB is .35. Radiused edges on the front and sides do wonders for aerodynamics.

[orange4boy]

Toyota Previa 1990
Cd.35
frontal area 34.45 sq.ft. / 3.2 m2
Cx 1.12
width 70.8 in
height 68.7 in
Source: Carfolio.com

That's the Egg.
I think the later ones have a cd of .33 but I can't remember where I read that.

[alohaspirit]

How accurate is this list?


Id read through a lot of it and it seems a little up for contention.

[NachtRitter]

Since the Civic data has not been updated, I thought I'd throw that info out.

Honda Civic HB 1992 - 1995
Cd: 0.36 (according to basjoos's posting)
Frontal Area: 20.76 sq ft (using drawing in Honda Service Manual)

Honda Civic Coupe 1992 - 1995
Cd: 0.31 (according to basjoos's posting)
Frontal Area: 20.76 sq ft (using drawing in Honda Service Manual)

Not sure about the Honda Civic Sedan numbers

[NeilBlanchard]

Hi,

I have an amateur measurement of the Aptera 2e (the current prototype):

The area is taken from a long lens photo, and measured with a polyline tracing the outline in DataCAD: 19.881 sq. ft. The factory Cd is 0.15, so the CdA is 2.98.

[Daox]

Originally Posted by alohaspirit

How accurate is this list?
Id read through a lot of it and it seems a little up for contention.

your answer:

Originally Posted by Daox

Well, its definitly no Bible. But, its a heck of a lot better than nothing. Most of my info that I wasn't sure about I double checked against multipule sites. That being said I have used info from tons of different sites since I pulled most of the info from google. Frontal area is definitly estimated, so this really is a 'best guess'. No offense, I'm not going to go through and source every piece of info. The numbers will vary, but not by that much. You can see generally where your car sits against the pool of cars on the list. So, when someone comes on the site and says they have a frontal area of 19ft^2 you can know that is pretty small.

So, basically its as good as its probably going to get.


Thanks for the added info NachtRitter and Neil. It will be added.

[alohaspirit]

Is it possible to make this a sticky or give it its own page

Honestly this was the first thing I searched for and I found it way back on page 17.

Its really usefull methinks.