# How many degrees into a turn does a car go before getting to its maximum g-force?

1. Dec 28, 2011

### JimEd

I am interested in a car's transition from zero cornering force (just before entering a corner) to maximum cornering force (somewhere in the corner). In particular, I would like to know how far into the corner it takes (in degrees) for this transition to happen.

Assume a car is capable of making a 180 degree turn at a certain constant velocity and radius at 1g. The car is going down a long straight at this same constant velocity (not accelerating or braking) and then enters said turn. How many degrees into the turn will the car go before it gets to it's 1g cornering maximum?

Thanks.

2. Dec 29, 2011

### elegysix

If the max cornering force is 1g, then it can handle a cent. accel of 9.8m/s^2. (assuming its a flat track)

a=v^2/R , so 9.8=v^2/R which are both constant, and have to be since you said a constant R and V.

If R or V were not constant, I could give you a force as a function of angle in the turn. But driving in a circle at a constant speed gives a constant centripetal acceleration, and so unless V or R are variables of the angle, there is no solution.

If you're thinking of nascar or something, they try to corner in such a way that it minimizes time - a balance of speed and path length.
I believe they are at the maximum force when their speed is lowest in the turn.

3. Dec 29, 2011

### rcgldr

Assuming the goal is to acheive maximum cornering acceleration as soon as possible (versus best racing line through a turn), the transition time mostly depends on how stiff the suspension and tires are. It's probably less than 1 second for a race car, but if you need a more accurate time, you'd probably need to watch a slow motion video of a race car that includes telemetry data, at least elapsed time and lateral acceleration.

4. Dec 29, 2011

### JimEd

Thanks.

Last edited: Dec 29, 2011
5. Dec 29, 2011

### JimEd

Thanks.

Last edited: Dec 29, 2011