MKIII aerodynamics question
- Thread starter CRE
- Start date
Cd is only the coefficient of drag, it needs to be multiplied by the car's frontal area to get the drag force acting on the car. The actual force is also a function of the air density and of course the square of the car's speed.
Cd's for cars are usually in the .25 to .45 range, so a .31 is a pretty good number.
Cd's for cars are usually in the .25 to .45 range, so a .31 is a pretty good number.
OK, here it is...
Notice the upper lip thing is raised up? Also notice that they folded the mirrors back...wish I could read Japanese...LOL.
256km/h is about 160MPH.
Notice the upper lip thing is raised up? Also notice that they folded the mirrors back...wish I could read Japanese...LOL.
256km/h is about 160MPH.
Fatty cruises at 250 kph going by the GPS 
Any faster and I'd be concerned with the plastic inner guards and a few other bits falling off, Tape over the Hood gaps would help.
Interesting conversation guys.
Any faster and I'd be concerned with the plastic inner guards and a few other bits falling off, Tape over the Hood gaps would help.
Interesting conversation guys.
ive hit 240kph on my nearly stock car (only intake and catback). doubt a modified car would have too much trouble gearing out (IIRC stock gearing and stock rev limit makes the gear limited speed ~174mph)
Nick M said:
The dynamics of the two situations are quite different (ground vehicle versus aircraft). Despite that, I'd welcome their speculation from a perspective which is still probably more accurate.
EDIT: That or they're just sitting back laughing at us. :naughty:
Last edited:
For those of you thinking a lower Cd is better are wrong. As speed increases, you want more drag. Look at the Ferraris and high speed cars, they range from about .40 -.50 Cd.
More drag does not necessarily mean more downforce/stability... If you have two cars with the same downforce but one has a lower Cd then the lower Cd one is better.
Well, i have been reading the thread since it started. I could not really fully understand about down force and CD and all the other stuff, but then I was on you tube and i saw this. I hope you guys watch it from top video to second video there kinda long but it made me understand a lot.
http://www.youtube.com/watch?v=g2oawVvwGjM
http://www.youtube.com/watch?v=PhbmBQwGSqI
http://www.youtube.com/watch?v=L9JQETXTA8s
http://www.youtube.com/watch?v=g2oawVvwGjM
http://www.youtube.com/watch?v=PhbmBQwGSqI
http://www.youtube.com/watch?v=L9JQETXTA8s
"like a Norse god of thunder gargling a hammer!"
I love those three clips. Although in this discussion they don't really explain much of anything. I do have to say the bit with the tree is my favorite.
I love those three clips. Although in this discussion they don't really explain much of anything. I do have to say the bit with the tree is my favorite.
yes, but it does prove downforce vs drag
I'll take mine with the wing....never knew they beat the Zonda's time, damn...
I'll take mine with the wing....never knew they beat the Zonda's time, damn...
CRE: The books show high pressure at both points. Makes sense. Unfortunately they show the pressures to be equal there. Whether that's true or not would require measuring them with a manometer, preferably a differential one using a static port at right angles to the flow and further back along the car. The pitot would go at the area of interest.
slidebabyslide said:
that guys has WAY to much fun. I wanna drive that
edit: lol take a look at this(off topic)
http://www.youtube.com/watch?v=uExWe1lm0BM&mode=related&search=
Last edited:
ViR2 said:
Your IS might have a lower cD, but its frontal area is very large. The older vipers have a cD of something like .42, but are fantastic because their frontal area is very small. We've all seen proof of vipers going 220+. The drag coefficient isn't the only thing to consider when you're trying to make an aerodynamic car.
Jon
edit: bah, already been discussed! oh well.
Thanks for the info JetJock. If they're both reported to be equal they're probably close enough for my needs. One more question, is the any difference between the center area and the sides of the openings?
Really awesome thread!
Please continue!
I'm replacing my 88 wing hatch with a non-wing and was curious about this info.
Please continue!
I'm replacing my 88 wing hatch with a non-wing and was curious about this info.