| Author | Topic |
|---|
Location:
Brisbane
Registered:
May 2002
|
|
Brake limitations....
|
Sun, 22 August 2004 13:33
|
 |
Just a bit of a random tech question to try and improve my knowledge on the subject.....
In current braking systems, what is the limiting factor? I can think of a number of things that effect braking performance (Disk thickness (fade resistance), disk surface area, pad area, pad/disk coefficient of friction, piston area (generally more pistons are better (due to better force distribution) but when does limited returns set in?), suspension set up, and also tyres.
I'm just curious as to what the bottle neck in current braking systems actually is.....it seems that having the thickest, biggest disks with massive pads and as many pistons per caliper as possible would ideal, but if that is the case how come someone hasn't invented a 'full disk face' friction material (i.e. a similar setup to a clutch!)?. I guess the bigger the pads and disks the quicker the energy can be dissipated from the system (a case of bigger is better  ) .........
Anyway, was something that came across my mind, and thought that you knowledgeable people here would have some interesting knowledge to share 
Cheers
Wilbo
|
|
|
Location:
Brisbane
Registered:
May 2002
|
|
Re: Brake limitations....
|
Sun, 22 August 2004 13:59
|
|
I think you'll find that cost is the biggest limiting factor. Sure you could probably design a "caliper" that covers the entire surface of the disc, but it would end up costing more than, say, the carbon-fibre brakes used by F1 (which are more effective anyway).
Weight is another factor to consider in high-performance applications as well. Big brakes made from conventional materials are HEAVY, and that does bad things to handling since it's all unsprung mass.
|
|
|
Banned user
Location:
ADELAIDE - The Drift City
Registered:
July 2002
|
|
Re: Brake limitations....
|
Sun, 22 August 2004 14:03
|
|
also, in further discussion to the entire rotor caliper. heat would be a major factor as you would have no exposed caliper getting cooling air..
if F1 isnt doing it, then it doesnt work. thats my theory!
|
|
|
Registered:
June 2004
|
|
Re: Brake limitations....
|
Mon, 23 August 2004 02:00
|
|
|
they do, i've seen them. they need it coz they've got piss all room inside those little wheels for big disks.
|
|
|
Location:
Adelaide
Registered:
September 2003
|
|
Re: Brake limitations....
|
Tue, 24 August 2004 06:03
|
|
Basically cost and weight, but mainly cost.
One new development is a multi disc setup by Delphi. The discs are non-vented and typically have 3 discs per wheel. Works a treat, but is still very expensive.
|
|
|
I supported Toymods
Location:
Perth
Registered:
May 2002
|
|
Re: Brake limitations....
|
Tue, 24 August 2004 06:30
|
|
| bbaacchhyy wrote on Tue, 24 August 2004 14:03 |
Basically cost and weight, but mainly cost.
One new development is a multi disc setup by Delphi. The discs are non-vented and typically have 3 discs per wheel. Works a treat, but is still very expensive.
|
But well cool Was reading about it the other day. If it wasn't so expensive it'd make a lot of sense.
|
|
|
Location:
Adelaide
Registered:
September 2003
|
|
Re: Brake limitations....
|
Tue, 24 August 2004 06:39
|
|
| wilbo666 wrote on Sun, 22 August 2004 23:33 |
but if that is the case how come someone hasn't invented a 'full disk face' friction material (i.e. a similar setup to a clutch!)?.Cheers
Wilbo
|
Just remembered, many aircraft have the system that you were thinking of. Personally, the only one that I have had ACTUAL experience with was in my days with the RAAF and the P3 Orion. The main wheels had a brake setup on each wheel that consisted of 4 rotors and 5 stators, and the "caliper" had about 12 pistons. Each strut had two such setups (one per wheel) and they wer farkin heavy. They would typically last about 50 landings from memory and then need to be changed.
The rotors were driven off the inside face of the wheel, and the stators were part of the "caliper". Took about 2 hours per unit to change, test check and do the paperwork. Great fun !!!!
|
|
|
Location:
Brisbane
Registered:
May 2002
|
|
Re: Brake limitations....
|
Sun, 29 August 2004 00:58
|
|
woot, good to see that in this day and age its impossible to reinvent the wheel 
Cheers
Wilbo
|
|
|
Location:
Brisbane
Registered:
February 2003
|
|
Re: Brake limitations....
|
Sun, 29 August 2004 11:11
|
|
and this is how they do it to a 747:
designed to stop a fucking heavy and goddam big airplane...
thanks to Bill Sherwoods site:
http://www.billzilla.org/aviationpage3.html
|
|
|
Location:
Brisbane
Registered:
May 2002
|
|
Re: Brake limitations....
|
Mon, 30 August 2004 06:37
|
|
Hmmmmm multiple calipers, its something I've thought about before 
Tho I must say I am also pretty keen on the multiple disk idea as well Heck multiple disk and say quad calipers ought to have it covered?
Cheers
Wilbo
|
|
|
Location:
Brisbane
Registered:
May 2002
|
|
Re: Brake limitations....
|
Mon, 30 August 2004 06:49
|
|
Multiple discs would work OK if you don't mind using wheels with a -100mm offset!
|
|
|
Location:
Finland
Registered:
November 2002
|
|
Re: Brake limitations....
|
Mon, 30 August 2004 10:36
|
|
|
Quite many older cars like big mercedes from 60' and 70' used twin calipers in front. I remember to seen pic of Toyota with twin calipers, Crown Eight maybe?
|
|
|
I supported Toymods
Location:
Perth
Registered:
May 2002
|
|
Re: Brake limitations....
|
Tue, 31 August 2004 01:09
|
|
| Norbie wrote on Mon, 30 August 2004 14:49 |
Multiple discs would work OK if you don't mind using wheels with a -100mm offset!
|
Actually, if you saw the Delphi setup, it wasn't a whole heap wider than a conventional setup.
|
|
|
Location:
Albany WA
Registered:
October 2003
|
|
Re: Brake limitations....
|
Thu, 02 September 2004 12:30
|
|
I figured the way to do the handbrake on my 86 was to have twin calipers on the back with a trailer master cylinder hooked up to the handbrake mechanism... but then someone told me it's illegal to have a hydralic handbrake setup. 
|
|
|
