3 replies to this topic

[JamesW]

Hello everyone
Ive made a program in Delphi which reads in descriptions of made-up tracks (in simple text files) and draws them on screen. I then have calculated (a simplified version of) the racing line for the track, and overlayed this on top of the track.
The next part of my Uni project consists of working out how fast a car can travel around this track..But this is where I need some help.

1) How much lateral acceleration can an F1 car produce at varying speeds? Is the relationship between downforce and speed a simple linear one, or something more complex? (drag squares as speed doubles...is this the same as downforce?)

2) How much downforce does a F1 car produce with different set-ups? I know that at Monaco for example, a lot more downforce is created at a certain speed than at Monza. At Monaco, the top speed may only be 170Mph, but is the car generating the same amount of downforce at that speed as a car at Monza would be, when travelling at 220Mph? How much does the car effectively weigh at this speed? Is 2500kg a good guess?


I really would appreciate any input people have.

Thanks

James

[MrAerodynamicist]

Force = 0.5 * Ro * S * V^2 * Coefficient of Lift|Drag

Hence, both lift and drag square with respect to velocity. The question is knowing what sort of values for Cd and Cl you can expect.

[Paolo]

For a rough estimate of the downforce generated, you can take 800 Kg at 320 Km/h for a really fast track, such as Hockeneim, and 1800 Kg at the same speed for a Monaco setting (only, at Monaco nobody goes 320... )
You must add to that the weight of the car (say 600 Kg).
So your estimated total of 2500 is fully acceptable, but remember it is referred to a maximum downforce setting at high speed, and it will not be seen in reality.

To check your calculations, look at the centripetal forces in bends : they should be around 2 g in slow bends (<100 Km/h) in any downforce setting, and around 4 g in fast bends (> 280 Km/h) in low downforce settings.

About question 2), no, there is no direct and simple relationship beetween the maximum downforce and the top speed.

You'll need also the tire's friction coefficient ; 1.8 is a good starting value.

[JamesW]

Thank you very much both of you for your help It certainly cleared up a couple of things.

I had estimated the co-efficient of grip as about 1.5 before...I was almost right

James