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Posted: Tue Jan 03, 2006 8:46 pm
by crzyone
MNFatz wrote: I mean, come on--if I remember right Schumacher rarely hits 2.0 in the Ferrari F1 car.

3+ g? I don't think so.
http://www.formula1.com/insight/technic ... 1/468.html
A modern Formula One car is capable of developing 3.5 g lateral cornering force (three and a half times its own weight) thanks to aerodynamic downforce.

You were saying?

Image

Posted: Tue Jan 03, 2006 8:49 pm
by Series8217
You could just draw a circle with cones or something, drive around it many many times, and go as fast as possible while maintaining a constant speed. Have someone start the timer when you get to the start of the circle, and stop it after a few laps at constant speed. Since its pretty damn close to uniform circular motion you can calculate the lateral G force using the time/laps (which gives your period) and the radius of the "skidpad" circle. This will actually be quite accurate!

Posted: Tue Jan 03, 2006 9:03 pm
by MNFatz
crzyone wrote:
MNFatz wrote: I mean, come on--if I remember right Schumacher rarely hits 2.0 in the Ferrari F1 car.

3+ g? I don't think so.
http://www.formula1.com/insight/technic ... 1/468.html
A modern Formula One car is capable of developing 3.5 g lateral cornering force (three and a half times its own weight) thanks to aerodynamic downforce.

You were saying?

Image
Yeah, you got me.

Here's a link to nurburring complete with the g-forces experienced in each turn.

http://www.f1express.com/nurburgring.shtml

Posted: Tue Jan 03, 2006 9:06 pm
by Series8217
Guess I should provide the formula, huh?

Code: Select all

                         4 * (pi)^2 * R
lateral acceleration =  ---------------
                            T^2
Where R is the radius of the circle, T is the period (time to go around it once), and pi=3.1416.

Use T in seconds, and R in meters.
The result will be in ms^-2
1G = 9.8 ms^-2

Remember to maintain a constant speed! Don't start the timer until you've got it pretty darn steady... oh and stay on the circle :-P

Will will correct me if I'm wrong.

Posted: Tue Jan 03, 2006 9:06 pm
by crzyone
Thats ok, you learn something new every day.

Posted: Tue Jan 03, 2006 10:54 pm
by Aaron
crzyone wrote:
MNFatz wrote: I mean, come on--if I remember right Schumacher rarely hits 2.0 in the Ferrari F1 car.

3+ g? I don't think so.
http://www.formula1.com/insight/technic ... 1/468.html
A modern Formula One car is capable of developing 3.5 g lateral cornering force (three and a half times its own weight) thanks to aerodynamic downforce.

You were saying?

Image
I never doubted them hitting that on a race course.

I doubted them hitting that in the type of course and situation outlined by my post, a 200ft diameter cirlce. I HIGHLY doubt it could generate 3.5g or anywhere close to it. Same situation at that course, the rate of speed is much higher, thus more downforce created.

Posted: Thu Jan 05, 2006 3:17 pm
by Chase Race
aaron wrote:I'm going to respectfully disagree Doug.
Also respectfully, I think you're underestimating the importance and capabilities of real race rubber. Like those Hoosier slicks in Howard's picture.
eHoward wrote:The number I hear from solo 2 guys is 1.5 peak.
I know a couple autocrossers who recently purchased data acquisition systems. I'll ask what sort of lateral Gs they're seeing this season and I'll keep you all posted if they don't mind.

Diverging a little bit, this is the data acqusition system they purchased: http://www.maxqdata.com. I know the guy who started this company and he's really sharp. I saw a demo of the first version a few years ago and it's slick.

Does anybody remember several years ago when GM came out with the shifting algorithm for automatics that used accelerometer and yaw sensor data to determine if you were in a corner so it would not upshift when you lifted from the throttle? I think it was in the Northstar and I remember it made the Car & Driver 10 best list that year. Anyway, the guy that developed that is Ed, the guy that started Max Q Data. I highly recommend him and his products.

Posted: Thu Jan 05, 2006 3:26 pm
by Aaron
I probably am, having not really been in a car before and after a tire upgrade.

Posted: Thu Jan 05, 2006 3:43 pm
by crzyone
The street tire record is 1.08Gs in a corner, and there is a huge difference between a street tire and a hot race tire.

Posted: Thu Jan 05, 2006 4:31 pm
by Aaron
There is also a huge difference in a corner and a 200ft circle.

Posted: Thu Jan 05, 2006 4:53 pm
by donk_316
Aaron,
As stated in another thread, that 1.08g is the 200ft skidpad record for a dry street radial tire.

Posted: Thu Jan 05, 2006 6:30 pm
by Aaron
Gotcha, Kohburn said in a corner, which allows for much different G's than the test provisions provide for.

I don't doubt 1.08 at all.

Posted: Thu Jan 05, 2006 6:31 pm
by crzyone
Aaron, come on. Man up and admit you were wrong.



aaron wrote:A 1.17g is not possible by a Fiero. Period. Stock, modified, tube chassis, roll bar, whatever. Not possible. In fact, a 1.17g is not possible by any production car. I shouldn't say not possible, but not by a factory stock car. Not a Vette, not a Porsche, not a fucking Lotus. I would venture to say there are some cars that could do it, but these are the 600lb race cars built solely for the purpose of racing. ie the custom built race cars with laser welded tube chassis out of magnesium. I would like to see a Formula 1 car's g-rating though, I'd say it is up around 1.1-1.3.

VERY VERY few cars can even break a 1.00. The actual testing procedure is done around a 200ft circle. The car takes a number of laps, and is timed and from there they use mathematics to figure out its G-rating with respect to the individual lap time.
You are speaking here like its all hard fact. 1.17 might not be possible on street tires, but to say that it can't be done at all end of story is wrong.

Posted: Thu Jan 05, 2006 6:44 pm
by Aaron
Until I see it I don't believe it. I just don't think it is possible. The only car I know of that'd have a chance at breaking 1.0 is that yellow SBC IMSA car over at OE.