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24 Oct 2000, 14:10 (Ref:44495) | #1 | ||
Racer
Join Date: Sep 1999
Posts: 250
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Do carbon brakes, such as those found on F1, sports cars, etc., have any use outside of racing? Could they ever be adapted to road car use? Thanks.
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24 Oct 2000, 14:44 (Ref:44500) | #2 | ||
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Join Date: Jun 2000
Posts: 1,275
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They do have uses outside motersport, al large number of commercial airliners use them, as do most western military jets (I believe up to and including the Mig 29, the Russioan still used cast iron).
The reason that they aren't used on road cars is you need to use a lot of pressure to get them to work properly, and more importantly they have to opperate at a temperature of at least 500-600C to be effective. Road cars don't generate that kind of energy requirement. I did read that the next SL Mercedes will feature ceramic rotor's (a la F1 safety car) and Lotus Elise's use Metal Matrix Composite (Silicon Carbide particles in Aluminium). I assume both of these are in the pusuit of reduced unsprung weight, as modern pads and cast iron do form a pretty effective friction surface. |
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4 Nov 2000, 13:18 (Ref:46664) | #3 | ||
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Join Date: Feb 1999
Posts: 12,451
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Do Rally Cars use carbon brakes or the road car kind of brakes? Since rally cars encounter so many different kinds of terrain in the same race, and they don't have the sudden braking needs (usually) of a paved closed track, would the carbon brakes be an advantage or not?
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4 Nov 2000, 17:47 (Ref:46691) | #4 | ||
Racer
Join Date: Jan 2000
Posts: 235
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The new Porsche 911 Turbo roadcar has carbon brakes. They look like carbon reproductions of the steel version, with involute cooling vents and cross drillings instead of the F1 carbon cooling holes and no cross-drillings. A 50% weight reduction is claimed.
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4 Nov 2000, 17:54 (Ref:46692) | #5 | ||
Racer
Join Date: Jan 2000
Posts: 235
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Liz, Rally cars use steel brakes. They get a fair pasting over a rally stage, particularly tarmac stages. In the recent San Remo rally, the brakes on the Subaru's and the Peugeot 206's were glowing red hot. Just like an F1 car. The brake disks are 12" x 1"
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4 Nov 2000, 20:37 (Ref:46708) | #6 | ||
Veteran
Join Date: Jun 2000
Posts: 963
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Ah yes....that red glow. It looks soooooooo nice.
I was also wondering if rally cars used carbon fiber discs because the guy that was broadcasting the WRC said that they were carbon but when they showed the garage area....they looked like steel brakes. |
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5 Nov 2000, 02:34 (Ref:46757) | #7 | ||
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Join Date: Feb 1999
Posts: 12,451
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I was surprised this weekend to see that Champ Cars use steel brakes too - the announcers showed them glowing after a particularly difficult maneuver. I always thought they used the same carbon fibre ones that F1 cars use.
Do you think that made it ahrder for Zanardi, using different brakes to what he was used to? |
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5 Nov 2000, 03:16 (Ref:46761) | #8 | ||
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Join Date: Jun 2000
Posts: 963
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Well Liz, champ cars are allowed to use carbon fiber discs in super ovals (not so sure about regular ovals though) as carbon fiber descs are much lighter....and if you think about....it's knd of a "funny" rule because, like Marshal said, carbon fiber discs need a very high temperature to start working properly. Now....everyone knows that in a super oval you never use the brakes...except when you're pitting and therefore the discs stay very cool during the race. So....if a driver had an emergency and had to brake...he would find himself with a very low braking power as the discs are cold....so.....in that situation he would have been better off with steel brakes.
As for Zanardi. remember that when he raced at hockenheim, if I'm not mistaken, the williams team installed steel brakes on his car to see if that would solve his performance problem. However....it didn't work. |
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5 Nov 2000, 17:32 (Ref:46855) | #9 | ||
Racer
Join Date: Jan 2000
Posts: 235
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On most courses Champ Cars use carbon-metallic pads/steel discs which offer similar stopping power to carbon discs & pads. The tricky bit is how the braking power is developed. Apparently, carbon discs/pads are very 'grabby' and need a lot of confidence from the driver.
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6 Nov 2000, 09:42 (Ref:46938) | #10 | |||
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Join Date: Jun 2000
Posts: 1,275
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Quote:
I thought they were ceramic not carbon. |
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6 Nov 2000, 20:29 (Ref:47044) | #11 | ||
Racer
Join Date: Jan 2000
Posts: 235
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Extracted & Edited from the October 2000 issue of Automotive Engineering International..." The Porsche Ceramic Composite Brake is based on a three phase system with specially treated Carbon Fibers silicated in a high vacuum process at 1700 deg C (3100 deg F).
There's also a picture of a disc and it has the familiar grey & white marbled effect. |
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7 Nov 2000, 10:11 (Ref:47136) | #12 | ||
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Join Date: Jun 2000
Posts: 1,275
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Ah, so they are ceramic matrix composites (CMC) not the same as the carbon discs used on F1 cars. That makes sense.
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10 Nov 2000, 11:54 (Ref:47793) | #14 | ||
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Join Date: Nov 1999
Posts: 1,101
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The need for high temperatures for the carbon discs to work properly is an interesting one. The ones used in F1 are covered with a kind of very little airbox to provide cooling, as one can spot at every wheel. Because the operating temperature is quite sensitive, they change the size of the intake opening for every race to find the optimal temeprature range.
The same happens in GP bike racing, although there they really don't want the brakes to be cooled that much coz they're already out in the open. So carbon discs are wholly covered in a carbon casing to keep temperatures up. The ceramic brakes on 911 Turbo, S, S Coupe and SL are optional btw and very expensive. |
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12 Nov 2000, 20:50 (Ref:48100) | #15 | |
Rookie
Join Date: Jul 2000
Posts: 67
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An interesting sidebar to this is that Mika often will run a smaller set of scoops to cool his brakes than DC, due to his "smoother" braking style heating his rotors less! This can give him a measurable aero advantage as it allows more air by to use for downforce.
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16 Nov 2000, 13:58 (Ref:48594) | #16 | ||
Veteran
Join Date: Nov 1999
Posts: 1,101
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Are you sure about that desmo? Interesting, I didn't know there was an driver to driver variation in those ducts as well.
I recall Jordan not using them at all at Monza in qualify for reducing drag. There are some other aspects too; the thickness of the brakes varies per track and per session as well. Most teams use qualifying brakes which are about 4\5 mm thinner than race brakes thus saving weight. |
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16 Nov 2000, 22:27 (Ref:48676) | #17 | |
Rookie
Join Date: Jul 2000
Posts: 67
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Dino,
Yes, please refer to pages 82-83 of Giorgio Piola's must-read '99 Technical Analysis. |
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18 Nov 2000, 16:45 (Ref:48874) | #18 | ||
Veteran
Join Date: Nov 1999
Posts: 1,101
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I'll try to buy that one desmo; Piola is indeed the no.1 spotter in F1 I've heard.
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20 Nov 2000, 11:13 (Ref:49130) | #19 | |
Rookie
Join Date: Oct 1999
Posts: 5
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Brembo have also announced that one of their major customers cars will next year feature their carbon brakes. The problems for the road user have always been the levels of heat required to generate good braking adhesion. The manufacturing process for Carbon brakes takes around 150 days according to their press release.
Their new patent applied for process allows 50 a day to be produced and uses a polymer based system to expand the brake discs thus removing the initial heat threshold of many thousands of degrees. If you have any more queries just take a look at the news section of Motorsport Online which will have an article in the next week. Chris Billington |
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