[VMaxMuffin]

So I’m studying for a physics exam and I was thinking about cornering in a race car and how camber affects it, from a physics point of view.

Firstly, the big issue with overtaking in F1 is – and has been for a while – is the difficulty of following another car due to the affect of the turbulent air coming off a car on the aerodynamics of the car behind. So, a general principle to improve overtaking is to decrease the dependence on aerodynamic grip and increase the dependence on mechanical grip from the tyres and overall chassis and suspension geometry – which of course is unaffected by turbulent air. We have seen the FIA try to enforce this through regulation since the major rules overhaul of 2009, but as always progress keeps marching forward and I believe the cars are are probably still producing as much downforce now as they did in 2008. If not they can’t be far off.

Now, on to off camber corners. Tilke’s new circuits are full of them. The most recent example is in Mexico – look at the esses before the overhaul:

And now afterwards:

It is clear to see that several of the corners in the esses are now off camber, whereas before they all had a decent amount of camber.

Sochi and Abu Dhabi also have lots of off-camber corners – those are the ones that particularly come to mind.

Now, on to my point.

I believe the logic behind the off-camber corners is that they are more difficult (so a driver is more likely to make a mistake) and they are also slower (reducing aero dependence). This, supposedly, should promote overtaking. But, I think there is a problem with this.

If a car is driving through an off camber corner, it is similar to driving over a crest where the car goes “light” – in physics terms, the normal force between the car and the road decreases. As normal force is proportional to the maximum static friction force between the tyres and the road, this results in a decrease in mechanical grip. Aero, on the other hand, is not directly affected by the banking. Meanwhile, if the car is travelling through a corner with positive camber, the normal force increases and friction increases whilst, again, aero is not directly affected.

Obviously the question at hand is whether the increase in speed through a positively cambered corner is great significant enough to create a greater dependence on aero compared to the increase in mechanical grip provided. I suspect this is not the case. What do you guys think?

I’m trying to think about how the racing plays out at slightly older tracks with positively cambered corners. Obvious examples in my mind:

– Blanchimont at Spa: This corner is very fast and you’re right on the edge of being able to go through it flat out in an F1 car. Despite this high speed, cars seem to be able to follow reasonably closely – allowing overtaking into the (not) Bus Stop chicane.

– The Lesmos and Parabolica at Monza: Probably not the best example due to the low downforce levels run at Monza, but still, cars don’t seem to have too much trouble following through these corners.

– Bit-Kurve, Nurburgring: This is the corner that leads onto the last straight (with the kink in it) before the chicane. It has decent banking and is quite fast, yet cars can follow closely and the chicane is a good passing opportunity.

[Iestyn Davies]

Wow – I think you might be on to something. There are parallels with the unintended consequences brought in with a lot of FIA rule changes – the best example I can think of is the 1998 rule set, originally meant to encourage overtaking, actually making it a lot harder to accomplish.

I wonder if there is a comparison with ovals? It seems to me that the more banking there is in ovals, the more chance there is of it being easier to overtake at/having multiple lines. Also in F1, some positive camber helps open up multiple lines – Hockenheim stadium hairpin is a nice example, Nurburgring’s original stadium section as well.

Off-camber corners – harder to take a ‘non-shortest’ line – it’s more like having lots of marbles off-line.

[Atticus]

You are perfectly right right there – I’m building tracks for GP4 as a hobby and I’ve encountered the most varied circuit designs used during the years and yes, on-camber corners definitely help overtaking just by giving you more mechanical grip in a corner. (Thus making a car easier to follow – as that mechanical side is not ‘taken away’ from you in the wake of another vehicle as downforce is.)

Pretty neatly worded post though, so kudos for that one. :)

Not that Tilke, the most important people who should read it, will ever read it of course…

(Obviously this will make it to the From the forum section of tomorrow’s round-up, and mightily rightly so, but still.)

[DavidS]

Excellent post.

I agree with all the points made in the thread.

I think that positive camber corners do not punish drivers for using a non-optimal line. With off-camber corners, unless you hit the apex and use all the track on the exit, you’ll lose time.

Positive camber gives an overtaking driver options. If they have more grip than the guy in front, they can take a different line and get out from behind the leading driver. They can get on the power earlier (or stay on the power) which allows them to get side by side into the next braking zone. Blanchimont is the best example of this, most overtakes are set up in Blanchimont for execution into the chicane.

[David Not Coulthard]

Brilliant.

@vmaxmuffin Anyway “physics exam” shouts “school-aged student” to me and as a school-aged kid who scores pretty OK in physics myself, I suddenly feel so dumb.

So, f=N(that thing used by a torrent client, won’t bother looking for a special character)

N decreases due to the inertia a car experiences at an off-chamber turn (on a turn banked the other way inertia would increase mechanical grip)

f decreases along with it

(mechanical) grip decreases as the action-reaction thingie described in Newton’s 3rd law decreases due to a decrease in f

More of the grip left now is aero, leaving cars more aero-dependant.

Brilliant. (of course all that along with the lack of line options one gets from off-chamber turns)

Anyway I’m reminded of the comment of a user a few years back (comeout where and whoever you are!) saying that (an event of which I don’t remember) proved her/his “theory” of the availability of multiple lines that can be taken in corners helping overtaking – and that comment was referring to Interlagos as a good example of it!

And now we know how to make a turn with many line choices.

[David Not Coulthard]

Brilliant.

Anyway “physics exam” shouts “school-aged student” to me and as a school-aged kid who scores pretty OK in physics myself, I suddenly feel so dumb.

So….f=N(that thing used by a torrent client, won’t bother looking for a special character)

N decreases due to the inertia a car experiences at an off-chamber turn (on a turn banked the other way inertia would increase mechanical grip)

f decreases along with it

(mechanical) grip decreases as the action-reaction thingie described in Newton’s 3rd law decreases due to a decrease in f

More of the grip left now is aero, leaving cars more aero-dependant.

Brilliant. (of course all that along with the lack of line options one gets from off-chamber turns…)

Anyway I’m reminded of the comment of a user a few years back (comeout where and whoever you are!) saying that (an event of which I don’t remember) proved her/his “theory” of the availability of multiple lines that can be taken in corners helping overtaking – and that comment was referring to Interlagos as a good example of it!

[VMaxMuffin]

Glad to hear people are agreeing with my theory and it didn’t get shot down at first sight with something I completely missed, haha.

@davidnotcoulthard Well, first year university student if that makes you feel better haha.

It just wasn’t something that I’d really thought of before, but more and more I keep thinking about why I find the races at old tracks so much more satisfying – was it just “sentimental” value or something more? I figured the banking aspect is a fairly obvious difference and it just kinda went from there.

Another thing that I’ve been thinking about is the tarmac runoffs. Track limits issues aside – it’s so refreshing when we have a weekend where the word doesn’t have to appear – I was thinking about their affect on overtaking too. I remember when they were first introduced, it was said that by providing little penalty for running off, drivers would be encouraged to take bigger risks in the braking zone – so there would be more overtaking.

I actually think it works the other way.

If I’m ahead of a faster car, I know that I can just keep pushing as deep as I can into every single braking zone. Best case scenario, I make the corner and I stayed in front because I pushed the braking zone. Worst case scenario, I run wide, and I may end up keeping the position I was going to lose anyway.

Now, on a track without tarmac runoffs, the risk of me continuing to push the braking zones is much higher – too deep and I lose lots of positions. I may end up getting stuck and being out of the race. So, I keep a bit in reserve each time until, eventually, Ricciardo – master of the lunge – sticks it up the inside and with his superior skill and grip, is able to make it work. With tarmac runoffs this couldn’t happen because I was not braking early enough for him to even consider taking the risk.

Thoughts?

[Iestyn Davies]

That’s another good one, I think you’ve nailed it! 2/2. Especially in junior series, it gets more prevalent due to the increased battling – just use the extra tarmac to hold on to the place.

The other side of the coin is shown at Interlagos qualifying however – Grosjean spun, but didn’t contact the wall (same for Hamilton at Mergulho in practice). If he did, that would have been a hefty repair bill for Lotus, and he was out of qualifying anyway with his tyres severely flat-spotted.

Arguably, in a race situation it would be better to see that being a retirement, but necessitating a tyre change is pretty much that for most race prospects.

[Matthijs]

I wasn’t aware that Tilke’s corners are off camber, but if so then you might be on to something.

To add to this discussion: off camber makes the corner slower. And it’s more difficult to follow a car exiting a slow corner than a fast corner, making it more difficult to pass. The theory behind this: you spend more time in a slow corner than in a fast corner. When the difference in meters behind the leading and the following car is constant, the difference in time is bigger in a slow corner than in a fast corner. So the leading car will always accelerate away from you earlier in a slow corner, not in meters but in time. Take corner 7 in Abu Dhabi (the hairpin leading to the straight), at one point you can’t get any close, yet the leading car is able to pull away.

[David Not Coulthard]

@vmaxmuffin Personally I think the safety reasons for tarmac are valid enough (if not for F1 then for other series’ which of course need to be run to save the owners’ pocket, no?), as long as they’re painted so they look like run-offs (I haven’t watched any footage of Brazil 2015 but previous years featured green-painted tarmac run-offs so those are OK examples) which on too many tracks (Hungaroring, Monza, Silverstone, etc) are left in the same colour as the track which look terrible.

The relation between corner banking and mechanical grip (and overtaking) is a topic I find more interesting than whether tarmac run-offs should be as they have been made to be, personally :)

[Atticus]

@matthijs Yes, I used to say that a lot.

It’s for very long since I’m saying hairpins do not set up good overtaking opportunities, near flat-out or flat-out corners do. I didn’t know why – although I had a vague idea about what you explained here – but I had a reasonable amount of empirical evidence on it.

Take Spa, for example, watch famous overtakes after Eau Rouge (2008, 2009) and you can see how drivers gain massively in the flat-out or near flat-out kinks of the corner combination. They are side by side on the entry to Kemmel quite often; they don’t even need the whole straight – we often say DRS is too powerful there anyway.

Take Silverstone – There’s that near flat-out kink past the hairpin of the Arena section and there’s a legitimate opportunity into Brooklands despite the audaciously short length of the Wellington straight.

The curves before the main straight in Interlagos and Curva Grande also seem to suck cars right up onto each other for some reason – both are preceded by low speed, hairpin-like corners and still there are lot better overtaking opportunities after those turns than after the hairpin in Abu Dhabi for instance.

Now, one good thing is that Tilke seems to have somehow gotten to grips with this notion (I dare not say he read my previous rambling on this issue) and the Baku main straight should actually be preceded by two flicks that look to be very high-speed.

[Matthijs]

@atticus-2

I think your Silverstone example is very good. After Monaco, Silverstone has the shortest straights on the calendar, yet there is ‘always’ plenty of overtaking. Even/especially before DRS and Pirelli.

Overtaking possibilities are created by corners, not by straights. Long straights are only needed for overtaking when the preceding corners are designed poorly. Take that Tilke ;)

I must admit though that nowadays the ‘usual’ boring circuits provide the best action and the traditional monumental GPs are rather boring. But I think that is down to Pirelli and DRS.

[glacierre]

I think you are right, the on-camber should give a significant increase of mechanical grip, minimizing the downsides of losing aero performance.

Moreover, if it is really a sweeping cambered turn you can have many lines through that turn that are nearly optimal (whereas for an off-camber anything slightly away from the optimal line is a laptme disaster). I have in mind the first few turns of Zandvoort, or a couple in Watkins Glen, where you can basically enter side by side and still exit side by side.

[Iestyn Davies]

I get the feeling that if Tilke was designing Abu Dhabi now, that the section before the back straight would look more like the corners going into the straights at New Delhi, or a tighter version of the faster ones afterwards, i.e. more like a reverse of Malaysia, which does lead to passing into the hairpin.

Plus, there would be more positive camber and less negative camber, which really makes that track a lot more bland than it should be. Not to mention that the blank run-offs on the calendar could be painted in country flag colours etc. like at COTA (anything to help justify the race fees!).

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