## Brakes idea

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
manchild
22
Joined: Fri Jun 03, 2005 9:54 am

### Brakes idea

An old idea of mine which I've never presented. I was thinking of a lock that would connect disc instantly when pedal is touched and unlock it when foot is raised so that disc spin freely without actually adding the weight to the wheel during acceleration, and have much less intertia before braking. It would improve both the braking effectiveness and acceleration.

When driver touches the pedal, the disc would actually begin the braking process due to its weight that needs to be accelerated, even before the pads engage, and slightly cool themselves just before the heating up under braking.

I reckon that it could also be used when driver needs to additionally cool discs on the straight, with just touching the peddal.

It would also enable the disc to maintain its speed during slowdowns without braking, thus maintain its cooling.

And possibly, if accordingly designed, the air pressure from the brake inlet could do the spinning of the disc and level up in a way, likely reducing the drag.

4 discs x approximately 1kg = 4kg less to accelerate, with ditched inertia under braking.
Last edited by manchild on Fri Aug 10, 2018 11:02 am, edited 5 times in total.

bucker
3
Joined: Thu Aug 02, 2012 8:33 pm

### Re: Brakes idea

Pictures, sketches,....

manchild
22
Joined: Fri Jun 03, 2005 9:54 am

### Re: Brakes idea

bucker wrote:
Fri Aug 10, 2018 10:10 am
Pictures, sketches,....
Well, it would be far fetched for me to design the actual device. I reckon that would require an f1 engineer
Last edited by manchild on Fri Aug 10, 2018 10:21 am, edited 1 time in total.

Just_a_fan
409
Joined: Sun Jan 31, 2010 7:37 pm

### Re: Brakes idea

Would the system's benefit offset the issue of adding the weight of the locking mechanism to the unsprung weight?
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools."

zac510
39
Joined: Tue Jan 24, 2006 11:58 am

### Re: Brakes idea

Like the freewheel hub of a bicycle, but fitted in reverse?

manchild
22
Joined: Fri Jun 03, 2005 9:54 am

### Re: Brakes idea

Indeed. And to reply to Just_a_fan, definitely, but having in mind how tiny it would have to be, guess that benefits would greatly surpass the small weight added to upright.

Dr. Acula
18
Joined: Sat Jul 28, 2018 12:23 pm

### Re: Brakes idea

Not in F1 my friend, not in F1.
11.3.1 No more than one brake disc is permitted on each wheel which must have the same rotational velocity as the wheel it is connected to.
manchild wrote:
Fri Aug 10, 2018 9:59 am
And possibly, if accordingly designed, the air pressure from the brake inlet could do the spinning of the disc and level up in a way, likely reducing the drag.
Actually this would increase drag. You can design the brake disc like an radial impeller, that's not a problem at all and is already done in some brake discs to improve the airflow a bit. But the energy to turn the disc has to come from somewhere if not from the wheel.

rscsr
63
Joined: Sun Feb 19, 2012 12:02 pm
Location: Austria

### Re: Brakes idea

manchild wrote:
Fri Aug 10, 2018 9:59 am
An old idea of mine which I've never presented. I was thinking of a lock that would connect disc instantly when pedal is touched and unlock it when foot is raised so that disc spin freely without actually adding the weight to the wheel during acceleration, and have no intertia before braking. It would improve both the braking effectiveness and acceleration.

It would also enable the disc to maintain its speed during slowdowns without braking, thus maintain its cooling.

And possibly, if accordingly designed, the air pressure from the brake inlet could do the spinning of the disc and level up in a way, likely reducing the drag.

4 discs x approximately 1kg = 4kg less to accelerate, with ditched inertia under braking.
There are some problems with that idea.
The wheel assembly has about 10kg. If we assume the mass distribution can be approximated as a disc we get an inertia of about $I_{wheel}=0.5 \cdot m r_{tyre}^2 = 0.56 kgm^2$. With the same approximation for the disc (1kg, r=139mm) we get about $I_{disc}=0.5 \cdot m r_{disc}^2 = 0.014 kgm^2$. That means the brake disc contributes to the total inertia of the wheel assembly only 2.5%.
When we assume the only relevant inertia for our purposes comes from the 4 tyres we can calculate the effective mass during acceleration as $m_{eff}=m_{car}+4\cdot \frac{I_{wheel}}_{r_{wheel}^2}}=733kg+4\cdot \frac{0.56kgm^2}_{(335mm)^2}}=753kg=1.027\cdot m_{car}$

Or in other words the total rotating mass of the wheels reduce the acceleration by 2.7% and the inertia of the brake discs only 0.0675%.
So in short even if it would work as intended it had barely any effect on the performance.

Additionally the freewheeling part would need to withstand all of the breaking forces (ergo heavier than the bolts used now), would need to be able to accelerate a standing brake disc within a fraction of a second and fit into an already cramped space.

manchild
22
Joined: Fri Jun 03, 2005 9:54 am

### Re: Brakes idea

Thanks for the bad news Dr. Aacula

Perhaps it could find its use in other series or automobile industry.
Any idea why that rule was ever defined?

Thanks for the math rscsr

roon
350
Joined: Sat Dec 17, 2016 6:04 pm

### Re: Brakes idea

zac510 wrote:
Fri Aug 10, 2018 10:16 am
Like the freewheel hub of a bicycle, but fitted in reverse?
That would not transmit braking torque from the rotor to the hub.

Dr. Acula
18
Joined: Sat Jul 28, 2018 12:23 pm

### Re: Brakes idea

manchild wrote:
Fri Aug 10, 2018 10:52 am
Thanks for the bad news Dr. Aacula

Perhaps it could find its use in other series or automobile industry.
Any idea why that rule was ever defined?
Well it's a guess, but probably to prevent a geared setup. The relative small brake discs used in F1 create some problems with brake application. Small discs mean you have to apply more force on the brake discs to achieve the same brake torque because of the shorter lever. (distance between the axle and the center line of the brake pad...more or less) This often results in a less sensitive brake pedal which can cause more lockups.
The rules prevent indirectly discs with a larger diameter, but what you could do in theory is to let the brake discs run on the outside of a small planetary gearbox which would have the same effect as a larger diameter brake disc, by increasing torque for the brake disc but let it turn slower so it's harder to lock it up.

Tommy Cookers
488
Joined: Fri Feb 17, 2012 3:55 pm

### Re: Brakes idea

there was a race motorcycle that had its front brake discs gear-driven (at higher than wheel speed iirc)

but this gearing was the reverse of the wheel rotation
so the disc rotation largely cancelled the gyroscopic effects due to the wheel rotation

at one time some cars had a transmission brake

Just_a_fan
409
Joined: Sun Jan 31, 2010 7:37 pm

### Re: Brakes idea

manchild wrote:
Fri Aug 10, 2018 10:25 am
Indeed. And to reply to Just_a_fan, definitely, but having in mind how tiny it would have to be, guess that benefits would greatly surpass the small weight added to upright.
Would it be small/light? Whatever device is used, it must not break. Having that device fail at the point of braking at 300km/h and causing the car to rotate around the still working front wheel and in to the barriers would be a bad thing. The barriers are often lightly protected in the braking zone - usually without the multiple layers of tyres seen elsewhere.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools."

hollus
Moderator
Joined: Sun Mar 29, 2009 12:21 am
Location: Copenhagen, Denmark

### Re: Brakes idea

Any idea why that rule was ever defined?
I can't believe I am suggesting that the rule makes did anything right, but... safety first?
Maybe they added the rule to prevent systems like this, that, while adding performance, increase the chances of brake failure? Brakes simply M-U-S-T work at all times. Also, imagine if in a freak accident, your fastly rotating brake disk works itself free from the rest of the wheel and the car?

That said, maybe the rule was added just because whoever makes them is paid by word? /off-topic.
...not because they are easy, but because they are hard!

roon
350
Joined: Sat Dec 17, 2016 6:04 pm

### Re: Brakes idea

Tommy Cookers wrote:
Fri Aug 10, 2018 12:58 pm
there was a race motorcycle that had its front brake discs gear-driven (at higher than wheel speed iirc)

but this gearing was the reverse of the wheel rotation
so the disc rotation largely cancelled the gyroscopic effects due to the wheel rotation

at one time some cars had a transmission brake
I remember reading about that as well. Would this not reduce the bike's tendency to upright itself?