I'm currently having this discussion with someone, and I'm sure there's some physics involved somewhere, but I'll be fucked if I can explain it properly.

We're talking mechanical grip/slip angles/tractive effort etc, and he is claiming that if you take two identical cars one with more power, with the the same weight, tyres, suspension etc - that the more powerful car will be able to corner faster thanks to being able to apply more power post-apex.

I'm trying to limit his argument by suggesting that power aside, the cornering speed is always goverened by the slip angle of the tyre......

What are the physics involved and why?

 

Peak corner speed will be the same

Steve.

 

That's what I'm saying, but I can't explain why! I don't have the techincal knowledge or the language.......

 

It's Saturday afternoon and Pon wants to discuss physics

I would have thought it would make no difference and both would corner the same as they are governed by the amount of grip the tyres, suspension etc will allow. As this won't change I don't see how power has any relevence to cornering speed

 

i not sure rich ..

most people with more power tend to enter the apex faster.. realise they cant corner and fall off

i think tho you would be able to leave the corner faster but dont know how much faster it would be .. suppose its all about how much extra power you have and if the driver is any good..

 

Surely all the power in the world is no use if it dissapears in smoke? Surely the major governing factor is the amount of grip you have as soon as you go beyond the grip you slide and lose speed. When I've done gokarts if you drive smooth you go fast start to slide and it looks good but the times suffer

 

However, what I'm saying is that reagradless of power, the grip available is surely limited by the adhesion of the contact patch.

The more power, the greater tractive effort applied, therefore you can overcome the slip angle of the tyre, and you lose grip.

 

if the two cars are limitied by the same levels of grip, downforce etc then the maximum corner speed will still be exactly the same. The same laws of friction still apply if you have a bigger engine. only difference will be when it comes to accelerating out of the bend onto the straight when the faster car starts to be able to use its power again.

 

a 250cc gp bike corners faster than a 900cc 4 stroke with three times the power yet a 250 being lighter also has smaller tyres.strange but true,and even stranger on many corners the 125 is even quicker on tiny tyres.

bikes are different i know but thought it would add more to your discussion.

 

I was told how to work out maximum corner speed by a Police Accident investigator once but I can't for the life of me remember how to do it.

 

if its anything to do with the police it will be a load of complette bollocks.

 

and there was me thinking the laws of physics applied to everyone!

 

With bikes it is also to do with the gyroscpoic effect of the engine on the chassis, Gyroscopic effect of the front and rear wheels and so on.......

 

You'd be surprised how they fudge things to give the answer that an accident was caused by speed. My brothers accident went down as a speed related RTC despite it actually being caused by the twat pulling out of the junction

 

watch police traffic cops getting trained,where they get them ideas from of how to drive fast is beyond me,its just as well they have radios.

 

Thing is advances with tyres/suspension/geometry and so on corner speed will increase so a policeman cant work out the max speed on any given corner untill he knows the vehicle, tyres, set-up and so on.........

 

I have watched them. And I know EXACTLY how police drivers are trained in high speed driving.

 

Eddited as gone off topic

 

Take my saff (please ) it's running stg 1, and goes round corners OK ish for what it is, if I decide to stg 3 it, it won't get round the corners any faster at all, but it will exit them quicker, probably a lot more sideways than it does now.

 

To add further fuel to the fire, if its purely dowm to contact patch and grip of tyres, why do people say 4wd cars corner better than 2wd?

 

surely you are supposed to brake before the corner.. there for your accelarating as you actually enter the corner.therefor the car with more power will actually go round the corner quicker and will have greater corner speed or greater cornering speed if you get hat im saying

 

But the power is irrelevant if the grip isn't there to allow it to be utilised

 

Okay, but if it's exiting sideways, in theory, that's slower.

If you were to radar trap the exit point of a corner, would the more powerful car be travelling faster at that point, assuming everything else bar engine power is equal?

 

Far to complicated for this time day and week

 

No, because you brake down to your corner speed as you enter the corner. hold your speed around the corner and then accelerate as the corner starts to open out.

 

I would say yes, as long as the driver is able to start accelerating without sliding.

 

I think from your example Rich, the peak corner speed would be the same for both cars, BUT if you radar trapped the exit of the corner the more powerful car would be travelling faster..........it can accelerate out of the apex better can it not?

 

I would say if the ballance or weight distribution of the 1st car is better then the second then this would certainly efect the out come,
I also think that maybe the shape of the car might have some efect if its going quick enough form down force.

 

Becuase generally you can just boot it into the corner and around the apex, when it starts to slide on the apex put your foot down give it a bit of opposite lock and away you go.

With a 2wd if you take that approach when it starts to slide and give it full throttle youre just gonna make matters worse and end up facing the wrong way unless your a good track driver.

Bascily a 4x4 is easier to correct when it starts to go pair shaped so you'll get around the corner at a higher speed than a 2wd that would probably spin off if entering the corner at the same speed!

i think anyways, correct me if i am wrong?

 

Instead of a corner imagine it as a large roundabout, power will be irrelevent. Max speed will be determined by grip so long as both cars are able to reach a speed great enough to overcome adhesion.

 

Because unless you drive REALLY strangely, you dont go round every corner totally off throttle!

 

I beleive you are focusing too much on 1 aspect of cornering. Yes, at the point where Lateral Forces vs Mechanical Grip are at their highest, speed will be the same for both cars. (See "A" on my crappy pic )



But, as you know, a corner is not about 1 tiny moment, its about the entire process Entry-Apex-Exit .

Ignore the first parts (Braking and trailing throttle up to just before the apex) Its all about the exit. Thats because both cars in our scenario have the same driver, braking ability, and same mass that needs to change direction. Thus the first part of the corner will be the same for both cars. (Yes I realise the more powerful car will arrive faster but for simplicity, lets assume he can only carry X amount of speed on turn in. So his speed at B1 wil be identical)

Anyway As turning angle decreases, (straighten up) and the driver starts to pick up the throttle, (hopefully those 2 things are inversely proportional to each other. Sadly not always ) the amount of power the tyres can transmit obviously increases, so as one car can accelerate quicker its the point from the the start of aceleration to B2 that will be a shorter time and thus the crucial factor in getting through the whole corner (B1 to B2) the fastest.



make sense?

 

I dont actually subscribe to that theory in full,two cars will never be the same, as two drivers will never be the same,one will always take a slightly different angle of entry to another,thus making the exit different to the other.
One will always be on the brakes at a different time to the other as will the gas.

I actually think there are too many varible for the out come to equal the same.

steve.

 

you talking about me?