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Cars & Coffee Killer
Join Date: Sep 2004
Location: State of Failure
Posts: 32,246
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Full-Circle Disc Brakes?
I was watching "How It's Made" the other night, and they featured a segment on full-circle disc brakes. Part of the segment even has a 911 running in the Motorola Cup with them. I'd never heard of these before.
While I can understand why they are not used on most production cars (I'd imagine they are expensive and hard to work on), I don't get why they wouldn't be used in racing and on expensive, high performance vehicles. More info here: http://www.brakingtechnologies.com/PDF/SAEPaper.pdf
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Some Porsches long ago...then a wankle... 5 liters of VVT fury now -Chris "There is freedom in risk, just as there is oppression in security." |
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12-19-2007, 06:41 AM
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Evolved
Join Date: Jan 2007
Posts: 3,338
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I'm no mechanical engineer, but it seems like 'overkill' for a car, even a race car.
Heat dissipation would be one consideration. Ever see night photos of brake discs at 24 hr races ...glowing red hot? Once you got heat built up in those baby's (they look like twin clutch-packs) ...that might be a problem. Now for stopping a landing aircraft, or other applications...?
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12-19-2007, 06:51 AM
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My 3 year old and I watch this show every day.
At first I thought that this was a really good idea, but then I wondered if there really was an advantage... If the current brake caliper technology can lock up the tires even on the stickiest of rubber in race conditions, what would MORE pad surface do? I suppose it would allow for more heat dissapation in the caliper itself (similar to increasing rotor mass, you increase caliper mass), but is this really an issue? Would the problem of unsprung weight increase offset the advantage?
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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12-19-2007, 06:57 AM
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Cars & Coffee Killer
Join Date: Sep 2004
Location: State of Failure
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Because of the increased surface area (and increased friction), couldn't you stop a car by applying less brake pressure than in a conventional system? Could you possibly eliminate the brake booster?
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Some Porsches long ago...then a wankle... 5 liters of VVT fury now -Chris "There is freedom in risk, just as there is oppression in security." |
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12-19-2007, 07:03 AM
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Join Date: Jan 2002
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What serves as the primary heat sink in brakes, the rotor or the caliper? If it's the rotor, thicker, vented rotors make sense. If it's the caliper, full circle calipers make sense.
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12-19-2007, 07:11 AM
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Quote:
F = mu*N where F equals the friction force, N is the normal force applied (how hard you're pushing the brake pedal for instance) and mu is the coefficient of friction. Area doesn't matter. I would imagine that a disc brake set-up approximates the classical application pretty well, so pad area doesn't make a difference in friction force. What pad area does give you is longer lasting pads and supposedly better feel. I'm sure Bill V can add more to that.
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Mike 1976 Euro 911 3.2 w/10.3 compression & SSIs 22/29 torsions, 22/22 adjustable sways, Carrera brakes |
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12-19-2007, 07:20 AM
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Quote:
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12-19-2007, 07:34 AM
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Quote:
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Mike 1976 Euro 911 3.2 w/10.3 compression & SSIs 22/29 torsions, 22/22 adjustable sways, Carrera brakes |
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12-19-2007, 07:47 AM
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unsprung weight ????
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12-19-2007, 08:12 AM
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Join Date: Dec 2003
Location: WI
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Braking, the company producing the full circle brakes has been around for a while. I remember seeing their booth 8 or 10 years ago at the SAE Congress in Detroit. Their product has not caught on for the reasons listed, it is heavier, more expensive, more difficult to service, has cooling issues and does not out perform lighter, cheaper, simpler solutions.
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12-19-2007, 04:24 PM
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Join Date: Dec 2004
Location: Suwanee, GA
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Heck.. this might be a good application for semi-trucks and trailers. 5 Axles to provide stopping for 80,000lbs, but at what cost?
I've seen some semi's with disc brakes now, appears they are making a comeback.
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1982 Porsche 911SC Coupe - Factory Short Shift |7:31 R&P in AL case | Toyo RA1 Tires | Corbeau TRS seats | M&K 2 in 2 out muffler |
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12-19-2007, 06:14 PM
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Slackerous Maximus
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Quote:
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2022 Royal Enfield Interceptor. 2012 Harley Davidson Road King 2014 Triumph Bonneville T100. 2014 Cayman S, PDK. Mercedes E350 family truckster. Last edited by HardDrive; 12-19-2007 at 09:33 PM.. |
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12-19-2007, 09:24 PM
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1970 Porsche 911 S 
1976 Porsche 911
