# I have a question.

Discussion in '2007 SSC Ultimate Aero TT' started by saleen88, Jan 29, 2007.

1. #1
About the 0.367 drag figure, can someone explain what this means. There was a 5,000 plus pound SUV that had 0.36.

2. #2
It's actually point .357

It's a (mostly meaningless) representation of aero drag for a given object. Remember, downforce creates drag. For example, racecars have relatively high (.40) cDs, but make shitloads of downforce. However, since this is supposed to be a top speed queen, they really want as little drag as possible.

3. #3
actually F1 have closer to .5cD.

this has about the same cD as the veyron

4. #4
I was going along the lines of a C6R/DB9R.

5. #5
So is it the drag created by downforce.

6. #6
See, the more downforce a car has, the more drag there is. Some vehicles, like the Koenigsegg CCX, have a cd of about .29, meaning there is relatively little drag, but none of that drag also produces downforce. The Saleen S7 probably has a cD in the neighborhood of .38, but a great deal of its drag also produces downforce.

7. #7
Last edited by a moderator: Apr 25, 2016
8. #8
The drag of F1 cars depend on settings. On low-speed tracks like Monaco the cd can be almost 1. With these settings the downforce of the car is larger than the car's own weight from 140 km/h and faster.
In SSC the drag is used to create downforce= grip= handling, but big American SUV's waste energy just to push the air away because of their square front ends.

9. #9
1. The Cd is NOT meaningless, it's a critical component in caluclating vehicle performance. What the Cd indicates is the EFFICIENCY of a partiular shape and is one of TWO components of calculating the overall drag of a vehcile, the other being the FRONTAL AREA. The actual number that determines overall vehicle drag is the CdA, or the product of Cd x frontal area. While an efficent SUV might (pending manufacturer exagerations) have a Cd of .36, it is likely to have nearly 3.0 meters of frontal area or a Cd of 1.08... where low slung cars like the SSC may have only 1.6 - 1.8 square meters of frontal area, or a CdA of, say, .576. Motorcyles are a good example of vehicles with (typically) horrible Cd's, but still decent top speeds / high-speed acelleration times thanks to a very small frontal area.

2. As for race/circuit cars, drag coefficients are typically much higher as downforce is the route to the lowest lap times most places. The goal is generally to reduce the frontal area as much as possible (look at a typical Le Mans car for example) in lieu of making a thicker shape (i.e. more frontal area) and countouring the upper surfaces. Logic being that the CdA will likely be the same, but the car with the most streamlined upper surfaces will generate the most lift, thus negating precious (thanks to a myrid of aero rules) downforce. As another poster metnioned, open wheel cars like F1 cars generate a massive amount of drag. A .7 - .8 Cd would be best-case somewhere like Monza, and a Monaco setup typically yields 1.1+. (Race Tech Magazine, December/January, 2002/03, P.22) The number that most racecar designers are actually looking for is the lift-to-drag ratio or L ratio. That varies from one racecar type to another. F1 cars have been quoted in the vacinity of -3.5:1 or, in other words, 3.5 lbs of downforce for every 1 lb of drag. Closed wheel racecars yield much better L's, often exceeding 5.0:1, even 6.0:1. Recall though, that downforce works against weight, so 1000 lbs of downforce on a 1322 lb. F1 car is much more effective in raising cornering speeds (and reducing brakng distances) to that of 1000 lbs. of downforce on, say, a 2900 lb. GT car.

3. Also, drag is NOT the result of downforce. Positive and negitive lift are dictated by the shape of the vehicle and it's aerodynamic elements. MOST street cars create some lift, many performace cars and "supercars" crate mild (compared to race cars) downforce, and some make ~zero lift... or neither lift or downforce. But all objects moving (unless they are in a vacuum) make drag.

10. #10
The drag coefficient is meaningless unless you know thr frontal area of the thing as well.
I worked it out and the SCC has a higher amount of drag than a lot of its competitors.

11. #11
Variant - everything you posted is correct, except that to generate downforce you have to add to the drag of the car. As you pointed out, there is a lift/drag ratio, and as you add lift (turned upside down to create downforce), you also create ADDITIONAL (I put that in all caps so as not to confuse Variant's original point) drag. But Variant is correct in stating that even a car that has zero downforce will still generate aero drag.

Theunwantedbeing - where did you come up with a reliable number for this car's frontal area? I can think of a couple of ways that you could have done that, but I'm curious.

12. #12
The SSC website?

13. #13
competitors such as the Honda Fit???
wait no the Honda is more reliable.

14. #14
AHHH....thank you for preaching the truth, man.

15. #15
OH....HAHA!!! Very funny I almost forgot to laugh, dude. Duh, its oblivious that the Fit is a little more reliable than this especially since this has oh, i don't know 1183bhp @ 15 psi. Its been rumored to have for city mpg of around 10-20 and highway of around 14-26 mpg, I believe.

16. #16
i dont know what Caparo T1 owns alls problem is but the retard has no idea what a real car is or horsepower for that matter but i know that a honda fit could not beat down on my buddies GT-R or my Camaro no matter how much tuning you do to it that little I4 cant get enough room for all the gear but there is a S2000 running around my town with a little more than 2000 horses and i still whomp on him on the quarter mile.

17. #17
Nice......way to show us all on this thread how...OFF you are on the topic at hand, MFC!! OH...and what's the fuel economy on the Fit...isn't it somewhere around 25-35mpg highway, right??? So...DUH the Ultimate Aero isn't reliable enough for you, so...that's the reason to deny yourself one...if EVER you...(especially you) and the rest of us can afford one??? OH...yeah the Bugatti Veyron has WORSE fuel economy, as well as the Dauer 962 GTLM...hell almost EVERY supercar has horrific fuel economy. That's the hole idea, jacka*s!! So that means then...you would deny yourself anyone of them???

Oh, behind the hole idea about supercars is this, take one vehicle that's beautiful and give everything it needs to be fast...(at all performance phases), and give it a high price tag and...persto, changeo...now you have a fast car and a rich owner, (who doesn't EVEN NEED to worry about the price of gas, or its fuel mileage)! WOW...imagine that the "miracle" of \$\$\$...HOLYSH*T its new to me, too!!!