Parabollica

[Ciro Pabón]

I need some help here: I'm pre-designing a track. I intend to give the shape of the Parabollica to a couple of curves, that is, with a variable banking, higher in the outer part of the curve (red line shows the parabola). I will keep it under 15% (yellow line shows how small is the visual effect of a 15% slope) and this will be spread over a wider track than the small yellow line.



I've been told aerodynamics of F1 cars is sensitive to this kind of banking. Is this true? Any references? Any critics? Thanks in advance for your time.

[Carlos]

Ciro - This gives me an excuse to post 10 minutes of the movie Grand Prix which includes the footage from Monza .. on the banking

http://youtube.com/watch?v=FwppPI0tQiU

This is a little bit of Monza from the 1967 GP...I didn't watch it though...cause I haven't learned to speak Spanish or Rapidshare yet

http://rapidshare.com/files/61901660/fo ... 4.avi.html

This is very much OT-Belatti ...you may want to watch these Fangio videos
http://youtube.com/watch?v=QeQ_jVjBvg4
http://youtube.com/watch?v=xoimATBQXfA

For the aero effect you might take a look at the IRL , the banking at The Texas Motor Speedway is the most extreme ...24degrees.

[checkered]

Waaay back in

1999, when everybody was enthusiastic about going back to the US with F1 - once again - Patrick Head and Mike Coughlan (... one could say Arrows' downfall has cost F1 dearly) thought that Indy's nine degree bank wouldn't be much of a challenge. Of course this was before Ralf made a habit of crashing in the oval part and tyre companies, the FIA and the teams could hardly agree on anything much on one fateful weekend at the Brickyard. Curiously, Joe Saward seems to contradict the engineers' opinions later on in the article ("F1 at Indianapolis - link, grandprix.com, 1999") but doesn't attribute this directly to aerodynamics, but general design tolerances. Worth a read, perhaps, because its full of references to F1 tracks, current and past, with banking turns and other references that may prove useful when researching the subject further.

Of course there are racetrack designers who are bound to have accumulated a lot of knowledge on the subject. I've seen you post links to some, but I can't remember whether those links included companies like Apex Circuit Design or Paxton Waters Architecture. How inclined they'd be to consult and with what terms is another matter. I'm always interested in race track design, so if this is a project you can showcase later on, please consider doing so.

[flynfrog]

I have no idea but i would guess it keeps the diffuser farther off the ground

but i love banking

[tomislavp4]

Yes, it keeps the whole underbody further of the ground
more air under the car=less downforce

[Ciro Pabón]

Thanks, flyn, tomislav, you're totally right. Any idea of the influence?

I mean, has anybody seen a graph or relationship between ride height and downforce?

Or do you know any (hopefully free) simulator able to simulate that kind of effect (ride height vs downforce)?

As I write this, it occurs to me that the only rational shape for superelevation is a circle, not a parabola. Ride height is the same at any point of the track, the outer car gains an advantage because of banking.

Here is the pic of the fundamentals (yes, I know, the circle can have a larger radius to avoid such radical banking:



Well, it could work. You'd need special paving finisher equipment for that one...

Notice that if you put this kind of curve after a regular one, where the inner trajectory is faster, it could, in theory, give you two lanes that can be traveled in the same time with equal cars.

If your car is faster, or you drive it better through the curve, you will overtake, no matter what lane you're in. Or so I think, until you point out what's wrong...

[flynfrog]

[IMG:800:600]http://www.lazyforums.net/uploadfiles/df001.jpg[/img]
[IMG:800:600]http://www.lazyforums.net/uploadfiles/df004.jpg[/img]

[flynfrog]

sorry for the blury pictures

they are taken form McBeaths Competition car aerodynamics

[Ciro Pabón]

I don't understand, flyn.

The first graph: which curve goes with reality, Viscous CFD or Bernoulli?

The second one: the numbers are not clear, but it seems like the downforce at 100 mm is more or less the same that at 20 mm... as in the Viscous CFD curve. Is this true?

And what do you think of a banking in the shape of a circle? Ride height is the same, no matter how much banking you take.

[flynfrog]

the graph is comparing Bernoulli's predicted results with that don't take into account viscous effects with viscous cfd results

ignore the blue line in other words

the reason for the 100 and 20 mm being about the same is the diffuser starts to choke off

but yes i agree with your theory that a circle would maintain the same ground clearance negating the suspension travel form the increased centrifugal force by running higher/faster on the banking


its a great book if i highly recommended it

[jddh1]

yep, great book.
I also love Competition Car composites. Same series essentially.