The Mother of All F1 Brake Threads

[avatar]

- New regulations to ensure that the brake discs rotate at the same speed as the wheels

Does this imply someone has implemented a system of differing rotation speeds? What benefit could be gained from this?

[:!: Warning: armchair engineering ahead ]

Depending on how you controlled it (if you could find a loophole to allow active control, or just a "useful" passive slip):
1> ABS and/or active brake torque control - would require a loophole for active control - e.g. (& I don't know of a loophole that would allow this, just an extreme example) a clutch that releases the disc from the wheel to effectively remove the brake without the pads being controlled.
2> Harvesting control on rear axle - allowing slip of the disk on the axle to balance the engine braking within the BBW system - could be a passive setup choice - harvest always at maximum in the MGU-k, modify disk slip to change engine to disk balance in BBW.
- no idea whether that would be better/worse than either controlling resistance at MGU-K for balance, or a differential splitting MGU-K braking from standard engine braking (not even sure this diff would be legal!)
3> Some degree of left/right brake torque control, e.g. inside wheel is unloaded, so de-clutches the disk from the axle slightly, reducing inside wheel locking.
- More advanced 4 wheel skid steer (brakes de-clutch on one side = skid steer on other side) might be possible, but I can't think of a legal way.
- A differential between this disks could have a locked disk counter rotating, but I'm not sure that's legal.

I'd say passive declutching of disk/axle on inside wheel sounds plausible, the rest might be a bit fanciful!

[langwadt]

- New regulations to ensure that the brake discs rotate at the same speed as the wheels

Does this imply someone has implemented a system of differing rotation speeds? What benefit could be gained from this?

[:!: Warning: armchair engineering ahead ]

Depending on how you controlled it (if you could find a loophole to allow active control, or just a "useful" passive slip):
1> ABS and/or active brake torque control - would require a loophole for active control - e.g. (& I don't know of a loophole that would allow this, just an extreme example) a clutch that releases the disc from the wheel to effectively remove the brake without the pads being controlled.
2> Harvesting control on rear axle - allowing slip of the disk on the axle to balance the engine braking within the BBW system - could be a passive setup choice - harvest always at maximum in the MGU-k, modify disk slip to change engine to disk balance in BBW.
- no idea whether that would be better/worse than either controlling resistance at MGU-K for balance, or a differential splitting MGU-K braking from standard engine braking (not even sure this diff would be legal!)
3> Some degree of left/right brake torque control, e.g. inside wheel is unloaded, so de-clutches the disk from the axle slightly, reducing inside wheel locking.
- More advanced 4 wheel skid steer (brakes de-clutch on one side = skid steer on other side) might be possible, but I can't think of a legal way.
- A differential between this disks could have a locked disk counter rotating, but I'm not sure that's legal.

I'd say passive declutching of disk/axle on inside wheel sounds plausible, the rest might be a bit fanciful!

The brake by wire is already there to provide balance between mechanical brakes and MGU-K
McLaren already did the left-right braking with the "magic pedal", it was ruled illegal as a form of 4 wheel steering

[avatar]

- New regulations to ensure that the brake discs rotate at the same speed as the wheels

Does this imply someone has implemented a system of differing rotation speeds? What benefit could be gained from this?

[:!: Warning: armchair engineering ahead ]

Depending on how you controlled it (if you could find a loophole to allow active control, or just a "useful" passive slip):
1> ABS and/or active brake torque control - would require a loophole for active control
2> Harvesting control on rear axle - allowing slip of the disk on the axle to balance the engine braking within the BBW system
3> Some degree of left/right brake torque control, e.g. inside wheel is unloaded, so de-clutches the disk from the axle slightly, reducing inside wheel locking.
- More advanced 4 wheel skid steer (brakes de-clutch on one side = skid steer on other side) might be possible, but I can't think of a legal way.
- A differential between this disks could have a locked disk counter rotating, but I'm not sure that's legal.

I'd say passive declutching of disk/axle on inside wheel sounds plausible, the rest might be a bit fanciful!

Option 1 may banned under the old powered devices affecting braking system (though presumably that had to be relaxed for the BBW systems?)

The brake by wire is already there to provide balance between mechanical brakes and MGU-K

Good point - BBW's allowed to control the harvest/break balance electronically already! So that's option 2 out.

McLaren already did the left-right braking with the "magic pedal", it was ruled illegal as a form of 4 wheel steering

I did say I can't think of a legal way (does amaze me the amount of diff control they're allowed under that rule!)

Option 3 (front brakes only) though still looking good though & has previous:
I managed to dig out a previous device I was trying to remember that had the same intent. There were a couple of incarnations to try to find a legal way of using an axle to balance front brake torque left to right. The team in question were BAR (Brackley).
http://www.f1network.net/main/s169/st58369.php

Although maybe not as effective without interlinking as per the BAR-Honda torque transfer system (unless another loophole has allowed that), passive (partial) declutching of the disk from unloaded wheel (effectively a bias transfer to the loaded wheel that would increase with lateral load on the vehicle) could reduce front locking and allow greater braking to the loaded wheel without locking the unloaded inside wheel.

[CBeck113]

How about a simpler idea, for instance something like a 2:1 ratio to increase the speed of the brake discs, which would help getting them up to temperature? I don't think that it would be difficult to get the brakes to withstand higher temperatures - they could finally use the brake ducts for cooling (would be novel idea, actually ).

[langwadt]

How about a simpler idea, for instance something like a 2:1 ratio to increase the speed of the brake discs, which would help getting them up to temperature? I don't think that it would be difficult to get the brakes to withstand higher temperatures - they could finally use the brake ducts for cooling (would be novel idea, actually ).

They run them at the temperature they have to run at, too hot and they turn to dust, too cold and they don't work.

And why should running them faster make any more heat?, you still have to dump the same amount of energy

[CBeck113]

How about a simpler idea, for instance something like a 2:1 ratio to increase the speed of the brake discs, which would help getting them up to temperature? I don't think that it would be difficult to get the brakes to withstand higher temperatures - they could finally use the brake ducts for cooling (would be novel idea, actually ).

They run them at the temperature they have to run at, too hot and they turn to dust, too cold and they don't work.

Yes, and the too cold part is an issue during starts (1st lap), restarts, 1st lap out of the pit & rain. This operational window can be adjusted for the higher temperatures, so the discs don't turn to dust. They would also have to insure that the surface doesn't glaze over.

And why should running them faster make any more heat?, you still have to dump the same amount of energy

And that's the novelty on the setup - the increased rpms would only increase the heat between the pads and the discs, without changing the system dimensions, since there is no more weight to stop. Or do you believe that the higher velocity won't cause move friction (=>heat) when the brakes are initially activated? The teams are already using the heat from the brakes to warm up (and regulate) the tire temperatures, with more available this task would also be easier.
How about a practical test: flip over a bicycle and crank the pedals, and then stop the rear tire with your hand...then try the same with twice the speed of the tire.

I'm speculating about possible uses for this negated technology, so you (and everyone else for that matter) are more than welcome to shoot down my ideas, but please use facts in the process - thanks!

[langwadt]

How about a simpler idea, for instance something like a 2:1 ratio to increase the speed of the brake discs, which would help getting them up to temperature? I don't think that it would be difficult to get the brakes to withstand higher temperatures - they could finally use the brake ducts for cooling (would be novel idea, actually ).

They run them at the temperature they have to run at, too hot and they turn to dust, too cold and they don't work.

Yes, and the too cold part is an issue during starts (1st lap), restarts, 1st lap out of the pit & rain. This operational window can be adjusted for the higher temperatures, so the discs don't turn to dust. They would also have to insure that the surface doesn't glaze over.

And why should running them faster make any more heat?, you still have to dump the same amount of energy

And that's the novelty on the setup - the increased rpms would only increase the heat between the pads and the discs, without changing the system dimensions, since there is no more weight to stop. Or do you believe that the higher velocity won't cause move friction (=>heat) when the brakes are initially activated? The teams are already using the heat from the brakes to warm up (and regulate) the tire temperatures, with more available this task would also be easier.
How about a practical test: flip over a bicycle and crank the pedals, and then stop the rear tire with your hand...then try the same with twice the speed of the tire.

the bike wheel at twice the speed hold four times the energy, but in a car it is not the brake disc that hold the energy it is the weight and speed of the car

[avatar]

On the spinning up the disks for heat (all hypothetical obv's):

Have the BBW rules entirely removed the "no powered device can affect the brake system" rule?

If not, the spin would have to be passive mechanical (meaning hard to separate behaviour when you need heat and when you don't). The setup I'm thinking that could spin the disk for heating would be (not saying/sure whether this is viable/desirable, just playing with CBeck's idea):
- the suspension upright as static point
- axle into differential gear upon which the disk is mounted
- second axle to wheel
- 2:1 ratio inside diff

= disk rotates twice speed (rev's) of wheel = geared braking, more breaking force, more heat
= maybe opens up different brake materials?
= possible disk speed control mechanism by allowing & controlling spin at the the inboard axle to control speed of the disks (I can't think of a useful, passive way to do that)

But also
= adds resistance to spin up wheels
= adds friction loss in diff gears
= Probably also means those diffs explode as soon as you hit the brakes!

[langwadt]

On the spinning up the disks for heat (all hypothetical obv's):

Have the BBW rules entirely removed the "no powered device can affect the brake system" rule?

If not, the spin would have to be passive mechanical (meaning hard to separate behaviour when you need heat and when you don't). The setup I'm thinking that could spin the disk for heating would be (not saying/sure whether this is viable/desirable, just playing with CBeck's idea):
- the suspension upright as static point
- axle into differential gear upon which the disk is mounted
- second axle to wheel
- 2:1 ratio inside diff

= disk rotates twice speed (rev's) of wheel = geared braking, more breaking force, more heat
= maybe opens up different brake materials?
= possible disk speed control mechanism by allowing & controlling spin at the the inboard axle to control speed of the disks (I can't think of a useful, passive way to do that)

But also
= adds resistance to spin up wheels
= adds friction loss in diff gears
= Probably also means those diffs explode as soon as you hit the brakes!

the energy you have to get rid of to stop the car down is 1/2*m*v^2
The speed of the brake rotors doesn't change that, you put the same number of joules into the rotor/pads to stop the car

[flyboy2160]

By request, I'm going to start a thread for all the F1 brake discussions. I'll be merging posts and older threads into this one.

[CBeck113]

langwadt, you put energy into the discs by increasing their speed, so there is more energy in this system. There's certainly a loss, but the gain could outweigh it.

[rscsr]

As langwandt already noted, the energy you dump is just m*v^2/2+I*w^2/2.

With that transmission for the brakediscs you would increase the effective inertia of the discs, but let's assume this is negligible. Also assume that the friction coefficient and brake pressure is the same. So this means that your breaking torque doubles while doubling the speed of the disc.
This same effect would be achievable by doubling the diameter of the disc. Or using 2 brakediscs (with 4 pads). But this is all only unnecessary since the braking performance is anyway more than enough to lock the tires at every speed.

[Jersey Tom]

If this is a for real rules change, that's probably the most curious / interesting thing I've seen on F1T since I've been here.

Having actively controlled braking or whatever would have zero impact on rotors spinning at same speed as the wheels, same with regenerative braking. I think every brake configuration I've seen or heard of - be it inboard or outboard - would have the brake rotor spinning at the same rate as the wheel.

I'll admit I'm at a loss on this one.

[PhillipM]

This same effect would be achievable by doubling the diameter of the disc. Or using 2 brakediscs (with 4 pads). But this is all only unnecessary since the braking performance is anyway more than enough to lock the tires at every speed.

However, you're also now pumping more air through the vanes in the discs, so they'll run cooler. And as your gearing gives you a leverage advantage, you could reduce both the size of the disc and the weight/stiffness of the caliper.
Whether that offsets the weight of the gearing is another matter, I suspect not, but I believe the ruling came from that as if you start gearing the discs up you give yourself the potential for some powerful air pumps in the wheels. A bit of trick work to start extracting air from the rear corner of the floor would get interesting...

[RickRick]

what about a brake balance controler for the front axle linked to steering rack / linkage that decreased the inside wheel brakes by a small amount, therfore it would be driver controled?