Brake disc rotation speed

[andyps]

I was intrigued to see in the revised technical regulations for 2015 this - "- New regulations to ensure that the brake discs rotate at the same speed as the wheels." It made me wonder if any team is currently doing this and if so how and why? Purely out of interest I would love to know more. I saw this here - http://www.formula1.com/news/headlines/2014/6/1600... near the very end of the list.

[marcgti6]

Yeah, I saw this too and wondered the same.

Never heard of discs not rotating at the same speed of the wheels.

[Tc24]

andyps said:

I was intrigued to see in the revised technical regulations for 2015 this - "- New regulations to ensure that the brake discs rotate at the same speed as the wheels." It made me wonder if any team is currently doing this and if so how and why? Purely out of interest I would love to know more. I saw this here - http://www.formula1.com/news/headlines/2014/6/1600... near the very end of the list.

I also spotted that - all the focus has been on the standing starts malarky so no real mention of it anywhere.

Can't see how it could rotate at any different speed if it then has to stop the wheel. Gearing the brake disc/wheel seems pointless (and would put a lot of strain on these components), but I'm sure there's a reason for the new rule. The brains in F1 have probably been exploiting it somehow

[PhillipM]

There has been some experimentation with running an epicyclic gearset to gear up the brake disc speed compared to the wheel, resulting in more air flow through the disc and through the wheel housings, but I haven't seen any of the systems on a live car yet. Maybe just a revision to head them off.

[andyps]

PhillipM said:

There has been some experimentation with running an epicyclic gearset to gear up the brake disc speed compared to the wheel, resulting in more air flow through the disc and through the wheel housings, but I haven't seen any of the systems on a live car yet. Maybe just a revision to head them off.

Thanks for that, I still can't quite get my head round how that would actually work although I thought it would have to be something like an epicyclic gear. The cooling makes sense although presumably a faster rotating disc would also add further to the disturbance of airflow - but then again maybe that could be used to positive effect like the exhaust blown diffuser was.

[Tc24]

andyps said:

PhillipM said:

There has been some experimentation with running an epicyclic gearset to gear up the brake disc speed compared to the wheel, resulting in more air flow through the disc and through the wheel housings, but I haven't seen any of the systems on a live car yet. Maybe just a revision to head them off.

Thanks for that, I still can't quite get my head round how that would actually work although I thought it would have to be something like an epicyclic gear. The cooling makes sense although presumably a faster rotating disc would also add further to the disturbance of airflow - but then again maybe that could be used to positive effect like the exhaust blown diffuser was.

Your mention of the blown diffuser made me wonder if Ferrari had somehow tied a fast rotating brake disc to the blown wheel nuts that I seem to remember they're using this year...

[TheRealFingers99]

marcgti6 said:

Yeah, I saw this too and wondered the same.

Never heard of discs not rotating at the same speed of the wheels.

Pretty sure it has been done, historically. Maybe in the olde days, disk on driveshaft? Hard to think of it giving an advantage (except, maybe, unsprung weight/mass).

[andyps]

TheRealFingers99 said:

Pretty sure it has been done, historically. Maybe in the olde days, disk on driveshaft? Hard to think of it giving an advantage (except, maybe, unsprung weight/mass).

No idea about the brake speed but the Lotus 72 certainly had inboard discs.

[Some Gump]

Aye, but driveshafts turn at the same speed as the wheels. The only way to have a different speed would be on the propshaft, but not only do f1 engines not have one, but you'd be mad to put the breaking force through the gearbox.
I was trying to figure if it was to do with wheel mounted kers / hub motors - but mgu-k has to be 1 unit, so that's not it.
This only leaves the stermy archer option, but for the life of my my tiny mind can't fathom how it's be a good idea?

[rdjohn]

But if you could get it to work, you would effectively suck air from the diffuser at the rear. So not a blown diffuser, but having a similar effect.

So, perhaps it makes sense to cut it off before every team blows a fortune trying to make it work.

[TheRealFingers99]

Some Gump said:

Aye, but driveshafts turn at the same speed as the wheels. The only way to have a different speed would be on the propshaft, but not only do f1 engines not have one, but you'd be mad to put the breaking force through the gearbox.

Sure, modern, mid engined, F1 cars. But a propshaft is a driveshaft.

I've a sneaking suspicion Ferguson P99, but........

[stevesingo]

I see two possibilities both using epicyclic gear trains,

1, using curved vanes within the disc, speed up the disc speed and use it as an air pump for aero benefit, driving the air outside of the wheel to reduce drag.

2, speed up the disc may (correct me if I'm wrong) allow lower brake pedal pressure as a disc with 2x the speed would only need 1/2 the pressure to dissipate the same energy.

The former is more likely.

Some opinions here...

http://www.f1technical.net/forum/viewtopic.php?f=4...

Edited by stevesingo on Saturday 28th June 10:20

[nickboazracing]

Perhaps teams have been looking at using part of the ERS system as a full time braking system further back up the drive train?? It could eliminate the need for traditional rear calipers, discs and pads. They are already using BBW to control brake bias due the the retardation effect the ERS has, so maybe this is the next step?

[Adrian W]

Maybe if the disc spins faster it can be smaller, so less unsprung weight

[BritishRacinGrin]

I'd be surprised, Epicyclic gearboxes are heavy.

[TheConverted]

Forgive my ignorance but could this be todo with the ERS/KER harvesting side of the braking? maybe moving the Braking systems further into the drive system has some advantage?

Andy

edit beaten to it!

Edited by TheConverted on Wednesday 16th July 11:10

[Scuffers]

Other upside of running geared hubs is to reduce the torque on the gearbox, you can run thinner driveshafts, the driveshafts can be run lower to the ground, etc etc..

[CanAm]

TheRealFingers99 said:

Some Gump said:

Aye, but driveshafts turn at the same speed as the wheels. The only way to have a different speed would be on the propshaft, but not only do f1 engines not have one, but you'd be mad to put the breaking force through the gearbox.

Sure, modern, mid engined, F1 cars. But a propshaft is a driveshaft.

I've a sneaking suspicion Ferguson P99, but........

The 1960 BRM P48 used a single rear disc mounted on the rear of the gearbox.

[Some Gump]

CanAm said:

The 1960 BRM P48 used a single rear disc mounted on the rear of the gearbox.

Didn't work too well though - they switched to a 2 disk layout for the more competitive mk ii part way through the season...

[CanAm]

The bacon slicer was never going to be a good idea.