Notes on Track Design

[Purist]

Please read my earlier posts in this thread, titled "A Crucial Misconception" and "A Further Consequence", which deal with the accordion effect, that is, the relationship between the time gap and physical gap as the cars go up and down throughout the speed range around a circuit.

No, it doesn't make it worse. Like I said, you can see it on display. Perhaps I was a bit crude in my initial explanation. The gravitational constant, is, well, a constant. When exiting a corner, if you get a better launch, you are, in theory, going faster at the same point on the track. When exiting a corner downhill, gravity is working with you, but because you have resistance from rolling friction and aerodynamic drag, you're actually getting relatively less help from gravity than if you had a poorer launch.

I'm sorry, but I do suspect that. What gets ignored with slower corners is the accordion effect, and its impact is seen because two objects cannot occupy the same space at the same time. That means, the leading car necessarily reaches the acceleration point sooner chronologically than the trailing car, and the physical gap opens between them as a result.

Downforce-producing aerodynamics get unduly blamed for the perceived difficulty in following another car, but you're missing something essential here. In a high-speed corner, the apparent accordion effect will be smaller; so the amount that it looks like the second car is closing in on the leader mid-corner is reduced. Remember, if you have a slow corner where the cars are immediately nose to tail, and you have a corner with triple the apex speed where the nose of the pursuer is two lengths behind the leader's tail, the time gap in those two scenarios is the same. That means that the cars are actually running closer together than you think when negotiating a high-speed corner.

As for the problem you get with what Tilke does, well, have you ever noticed how far apart the cars get on the first half of the first back straight at Abu Dhabi? There are multiple slow corners right before that straight. You have a situation where if you can't make the pass into the chicane, you may be forced to relinquish time in order not to hit the back of the leader at the hairpin, but then the physical gap blows out heading onto the straight, and you need a lot of space for the slipstream to tow you back up to the car you're trying to pass.

A couple of other things can/do help a trailing through high-speed corners. The first is the simple fact that generally a driver isn't going 100-110% allo-out all the time, unless you're Ayrton Senna, so you usually have margin to simply push harder than the guy in front. The second is that, no matter how much downforce the car makes, there is a finite limit to how much grip the tires can actually give. So even if you're losing downforce in the leader's wake, if you're still making enough that the tires are giving you all that they can, it doesn't matter.