19 replies to this topic

[Wuzak]

I posted this question elsewhere a while back.

I am interested to see what the more technically aware F1 fans think....

[Wuzak]

Any thoughts?

[Chevy II Nova]

Because it is a good way to destroy tyres, and TC makes it difficult/impossible.

[Ben]

As much now relative to when?

The sideslip angle of the body is related to the slip angle where the tyres generate peak lateral force. For a crossply this is around 12-13 degrees, for a radial around 6, and for a grooved F1 dry tyre maybe as low as 3-4 degrees.

The sideslip angle of the body means that the rear of the car is inboard or outboard of the front even in nuetral steer, otherwise the rear tyres wouldn't generate any grip. Therefore modern race cars look less tail out due to the tyres they run. The reason they run tyres with lower peak slip angles is that the power consumption in a turn is proportional to the sin of the slip angle, smaller slip angle = less power consumption = faster.

What I suspect you actually mean is the tail out due to oversteer where the rate of change of rear slip angle with respect to lateral acceleration is greater than at the front. The answer as to why you see less of this is that it is a very slow way to get around a racetrack.

Having said that TC systems generally use slip ratio as an output and this may allow a degree of power oversteer to optimise traction on the exit of a turn. However in longer faster corners, tail out is just plain slow, like it or not.

Ben

[Wuzak]

Yes, what I mean is the big power oversteer moments that you used to see in the past.

I have often read people's opinions that the drivers of today have it easy because they don't have to fight oversteer like they did in the past, and that the cars corner like they are on rails. That traction control does it all for the driver, etc, etc.

[Peter Perfect]

I thought I'd read somewhere that some of it was due to the grooved tyres. Apparently they're a bit of a knife edge in terms of the amount of grip they give close to the limit of a slide.

[alexbiker]

Traction control allows big powerslides in the right circumstances - more than one article has detailed that TC is calibrated to allow a large amount of slip for feel and sliding reasons. Brundle himself pointed out that "in the wet, TC won't save you. It will still spin".

Three things spring to mind.

1. Fly by wire throttles on normally aspirated engines allow greater linearity in throttle control, meaning that a large dump of unplanned-for power does not suddenly appear, causing the slide.

2. Gravel traps - putting a wheel on the gravel = end of race in most circumstances, so the exit oversteer is a lot more of a risk.

3. Aerodynamics - yaw knackers the efficiency of modern undertrays, diffusers and wings, as does off-axis wind, so a significant slide would lower grip, and therefore becoming an even bigger slide, and so on to a spin.

Alex

[Scoots]

Originally posted by Peter Perfect
I thought I'd read somewhere that some of it was due to the grooved tyres. Apparently they're a bit of a knife edge in terms of the amount of grip they give close to the limit of a slide.

The drivers have said that the grooved tyres actually give more warning and are more forgiving than the slicks were.

Oversteer is tuned into TC systems to help rotate the car in slow corners, assuming tire wear isn't a big problem.

[wegmann]

Originally posted by Scoots


The drivers have said that the grooved tyres actually give more warning and are more forgiving than the slicks were.

Oversteer is tuned into TC systems to help rotate the car in slow corners, assuming tire wear isn't a big problem.

I've heard both sides, so I'm not sure which is true.

In any case, Ben's analysis of the situation is right on - the slip angles for peak cornering force are pretty low nowadays. According to the Formula 1 2001 Technical Analysis book by Piola, page 41, the peaks are somewhere between 5-7 degrees, maybe manufacturer-dependent.

I should also point out that the slip angle where the peak force occurs depends on both load and speed. Theoretically, at least, bigger slip angles should be more advantageous at larger loads and higher speeds. The heat and wear generated in these situations can be outrageous, though, so TC might be tuned to avoid it. Besides that possibility, I'm not sure why theory doesn't meet practice here.

[MrSlow]

You forgot the aero in the poll. That is IMO the most important factor.
Going sideways with an "old" F1 did not punish the laptimes so much since the tyres provided most of the grip. Look at rally, if there is little grip, on snow, or mud for instance, the cars will go very sideways compared to when they drive on dry tarmac. Same cars, same drivers, different styles depending on grip.

But add aero, consider the fact that when the car goes sideways the aero loses it effeciency (sp?) faster than the tyres, and you will have a car that does not like big "slide angles".
But Jenson Button proved last year (notably at the qual in Hungary) that it is possible to go very sideways, but he also showed that sideways is definetly not fast with a modern F1 car.

[04Wolverine]

I agree with the aero bit. The cars are designed to go into the wind, not slide sideways through it.

I also agree with the tires. The Radials produce more grip at smaller slip angles. However F1 tires are not pure radials. So I would like to pose a new question, how much would it be possible for a team (read Ferrari, because IMO they would be in the best position for something like this considering their relationship with bridgstone) to ask a tire company to build a tire that would have maximum grip within a certain window of slip angles. To me it seems pretty possible, since the tires and car are designed in tandom nowadays. But if this is the case, theorhetically (sp?) Ferrari could request a tire that likes larger slip angles if that would be desireable. Just some food for thought.

To me, I still feel the biggest reason is the aero concerns, then the tires. Both contribute to the current situation.

[Greg Locock]

Surely if you agree with the aero argument (and it makes sense to me) then you would want tyres with maximum grip at very low slip angles?

It would be very interesting to see how well the drivers maintain the current tyres within (say) 10% of their optimum grip - and to imagine how reducing the margn for error would affect lap times.

[Powersteer]

Aerodynamics and fat tyres.

[Ben]

Originally posted by 04Wolverine
But if this is the case, theorhetically (sp?) Ferrari could request a tire that likes larger slip angles if that would be desireable. Just some food for thought.

Why would you want to increase your power requirement in a corner. Your fuel consumption will go up.

As for F1 tyres not being pure radials. Again correct, but they still have very low slip angles at peak Fy.

Ben

[JwS]

Was fastest way then, not fastest way now, what else matters??
I think if MS drove a Bugatti T35 to its limits you would see it drifting,
(btw, pet peeve, why do they call that new sport 'drifting' when what they are doing is hanging the tail out?? I equate drifting with a 4 wheel drift, all four at a slip angle, not just the rears)
JwS

[canon1753]

I put that it is the slow way to drive. But... The cars are also designed to be driven smoothly or else the airflow gets messy= less downforce=suspension doesn't work well and the tires get fried earlier= thus it slows you down.

I also think the design of cars today being aero-optimized and with maximum rigidity in mind does force the car into being driven a certain way to be fastest. GV once said (In Ask Nigel this week) that the '81 126C was a tremendously forgiving car to drive, so he could take risks and the car would not bite him. I would think that today's cars would be both slow and an ironclad sob to drive the way GV drove his Ferrari at Jarama.

my 2 cents worth

[Powersteer]

Another reason why not too much oversteer is being used, wheelbase. I would pay to see Petre Solberg drive a limousine around an oval dirt track sideways.

[Wuzak]

Ok, the reason I started this thread is that I have found that many, if not most, people seem to consider it the fault of the mordern car's electronics - ie the traction control system.

You have shown me that there are many things that contribute to why the cars aren't sideways (oversteering) in the corner.

My opinion was that the main reason that the drivers don't throw their cars sideways is that it really is the slowest way to drive an F1 car around a circuit. There are many contributing factors as to why it is the slow way, but in essence that is why they don't have huge slides.

They didn't before all the electronics were re-introduced in 2001, and they haven't since.

[derstatic]

TC could help preventing powerslides as it compensates should a driver push his accelerator to much. But i dont think it prevents oversteering in corners.
And another aspect could be that the tracks of today arent constructed like tracks used to be. You dont slide around 2nd 3rd gear 90 degree corners.

[mart]

It looks flashy (especially in bike raciing) but you probably don't see (big) slides much these days because it isn't the quickest way around a corner & as that's what they're after, drivers will eliminate anything from their driving style that's slowing them down.