Acceleration of F1 car

[xpensive]

Ciro, I think the basic flaw in your thinking comes from the way you behold the concept of "Work". As a hard labouring criollo you should perhaps know better than most that this can be appreciated in may forms, where comparing kinetic energy "before and after", being one of the most reliable such.

Regarding the mass of the vehicle, I merely wanted to point out that I don't think the Renault is running on anti-matter.

[Tim.Wright]

Brembo itself says otherwise
http://www.brembo.com/ENG/Formula1/2009 ... _eng13.pdf
Here's Monza data - 5g deceleration routinely, lap after lap. Try to do the same with chute

About 1G of that 5 could be due to aero drag. So the brakes are probably only producing 4G of force.

Tim

[FW17]

However, I will give you some leeway: any comments about the beauty of Ashley Force will be considered to be a homage to acceleration of a race car (... and of my heart, when I see her ).

Other than the machine that churns out some 8000 HP the other thing that amazing about the series is that the entire thing is down to reaction time at the lights. A race that lasts 4.5 seconds the race is decided purely by the drivers getaway from the lights and less to do with the 2 cars performance.

[timbo]

So the brakes are probably only producing 4G of force.

Tim

I quite like "only" in that sentence

[FW17]

So the brakes are probably only producing 4G of force.

Tim

I quite like "only" in that sentence

And braking during downshift, this is quiet significant.

[F1_eng]

I think people are missing the most important factor, the fact that the tyres have to transmit these forces in to the road.

It's almost irrelevant what the brakes can do, all they need to be able to do is lock the wheels, which they certainly can do. I can tell you that theoreticaly it's impossible to achive a deceleration in Gs due to braking higher than the friction co-efficient on the tyre.

And the spreadsheet thing a while ago is a very bad attempt in my oppinion. There's no requirement to bring energy in to the equations.

[Tim.Wright]

I think people are missing the most important factor, the fact that the tyres have to transmit these forces in to the road.

It's almost irrelevant what the brakes can do, all they need to be able to do is lock the wheels, which they certainly can do. I can tell you that theoreticaly it's impossible to achive a deceleration in Gs due to braking higher than the friction co-efficient on the tyre.

And the spreadsheet thing a while ago is a very bad attempt in my oppinion. There's no requirement to bring energy in to the equations.

I recall Claude Rouelle saying in a seminar a few years ago that at top speed, there is sufficient downforce and therefore grip available on the tyres that the drivers can't actually push hard enough on the brake pedal to lock the brakes. I've never actually had this confirmed by anyone since so I'm still dubious at this claim. But... if its true then 'more powerful' brakes would help the driver produce more of a braking torque during high speed braking.

Tim

[F1_eng]

Derrive the formula for maximum braking effort due to load transfer, you will see it's not possible to deccelerate quicker. Ofcourse massive drag loads COULD cause an exception to the law.
I'm sure there will be a nice derrivation in Milliken.

It's also good to remember that the effective Mu of the tyre decreases as downforce increases.

[ringo]

I think people are missing the most important factor, the fact that the tyres have to transmit these forces in to the road.

It's almost irrelevant what the brakes can do, all they need to be able to do is lock the wheels, which they certainly can do. I can tell you that theoreticaly it's impossible to achive a deceleration in Gs due to braking higher than the friction co-efficient on the tyre.

And the spreadsheet thing a while ago is a very bad attempt in my oppinion. There's no requirement to bring energy in to the equations.

I recall Claude Rouelle saying in a seminar a few years ago that at top speed, there is sufficient downforce and therefore grip available on the tyres that the drivers can't actually push hard enough on the brake pedal to lock the brakes. I've never actually had this confirmed by anyone since so I'm still dubious at this claim. But... if its true then 'more powerful' brakes would help the driver produce more of a braking torque during high speed braking.

Tim

The braking capacity would be reduced non linearly as the speed drops too.

[xpensive]

I think people are missing the most important factor, the fact that the tyres have to transmit these forces in to the road.
...
And the spreadsheet thing a while ago is a very bad attempt in my oppinion. There's no requirement to bring energy in to the equations.

Ciro's spreadsheet was indeed flawed, but that was because his failure to properly appreciate the energy needed
to speed up the car from 130 to 250 km/h, but tyre-to-road friction is not a limitation between those speeds.

Energy has everything to do with it, because energy over time is a direct and reliable measurement of power.

[F1_eng]

"The braking capacity would be reduced non linearly as the speed drops too."

I'm not sure what you mean by this? Plus I don't see how simply making a statement like this on its own has any bearing on the topic?

Xpensive, I was referring to the tyres in relation to decceleration. Thank you for the lesson in units, clears everything up for me now. There is simply no need to consider energy and power. It can be done much more straight-forward using torque, speed, rolling radius and tractive effort.

No matter anyway, people can do it their own way, but it would be nice for them to find a way that works for them, which didn't happen in this case.

[xpensive]

There is simply no need to consider energy and power. It can be done much more straight-forward using torque, speed, rolling radius and tractive effort.

No matter anyway, people can do it their own way, but it would be nice for them to find a way that works for them, which didn't happen in this case.

I'm afraid this is where you got things wrong, what engineering is all about is to try to identify a "control-volume" as simple as possible, in this case the accelleration of an object from one speed to another.

Using the change in kinetic-energy as your "control-volume" comprises everything inside said volume as torque, rpm, wheel-radius and what not, by going the other way you are only complicating things for yourself. I think.

[F1_eng]

Clearly that approach didn't work in this instance, for sure it could work.

Engineering is not always about control volumes, in a lot of instances constraining yourself to control volumes can complicate things immensly.

Doesn't matter, it's going a little off topic. The figure quoted by Brembo is pretty close to what is seen on our cars anyway.

[xpensive]

Au contraire, Brembo-case is an xcellent xample of the Control-volume, just remember every Force acting on said volume;

Tyre-to-road friction and air-resistance, Force equals Mass times Accelleration.

[F1_eng]

What are you going on about? Who said that Brembo does/doesn't use a control volume approach?

Control volume methods are brilliant, in the right application, which would not be my first choice in this example.

What are you trying to achieve stating the obvious?
"Force equals mass time acceleration"

Anyway, the approach shown was simply finding the average acceleration.