Is there an optimum brake disc temperature or is it: the cooler the better? And is this the same for carbon brakes and steel brakes?
Does anyone have some figures on this?
And same for brake pads? Do they need to be as cool as possible or is there an optimum temperature range?
Thanks in advance!
Brake Temperature?
Started by
Froilan_G
, Jan 13 2002 14:27
7 replies to this topic
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#2
dragonas-teo
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Posted 13 January 2002 - 14:37
I would say that the cooler is not the better for brake temparatures.
For each brake disk material there is an optimum range of temparatures in which the brakes orerates best.
For sure the range for carbon disks is much higher than the range of steel disks.
For each brake disk material there is an optimum range of temparatures in which the brakes orerates best.
For sure the range for carbon disks is much higher than the range of steel disks.
#3
ehagar
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Posted 13 January 2002 - 19:00
Going from memory here, but...
C-C has a temperature dependent coefficient of friction. At low temperatures, it is about 0.1 while at operating temperature of somewhere around 0.6.
I believe they have to be kept above 350 degrees C, and the operating wind is around 400-600... any much more than 600 degrees and you run the risk of oxidizing the brakes.
Two types of material used... CVD brakes (made by CI) and a resin pyrolysis material...
C-C has a temperature dependent coefficient of friction. At low temperatures, it is about 0.1 while at operating temperature of somewhere around 0.6.
I believe they have to be kept above 350 degrees C, and the operating wind is around 400-600... any much more than 600 degrees and you run the risk of oxidizing the brakes.
Two types of material used... CVD brakes (made by CI) and a resin pyrolysis material...
#4
desmo
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Posted 13 January 2002 - 20:57
According to a data traces published in Piola's latest book of the braking telemetry of an undisclosed car at Montreal the following conclusions can be drawn:
Normal operational temperature for an F1 C-C disc will be ~450C upon initiation of braking. In a hard stop the disc temp will peak at about 1000C about one second after initial application and 5 seconds subsequent to peak temp, the disc will have returned to ~700C. This data is from braking from 186mph to 37mph in about 4 seconds with a caliper pressure of ~60 bar.
Normal operational temperature for an F1 C-C disc will be ~450C upon initiation of braking. In a hard stop the disc temp will peak at about 1000C about one second after initial application and 5 seconds subsequent to peak temp, the disc will have returned to ~700C. This data is from braking from 186mph to 37mph in about 4 seconds with a caliper pressure of ~60 bar.
#5
imaginesix
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Posted 14 January 2002 - 04:47
4 sec? That hardly seems representative. That gives the driver enough time for a spot of tea and scone before turning in for the corner.
That works out to 1.7g. Deceleration is commonly thought to be around 5g in F1. Even if we assume that a large portion of the time was spent trail-braking, we're still a long way off from 5g.
Is it possible that those figures are for a wet race (2 years ago)?
That works out to 1.7g. Deceleration is commonly thought to be around 5g in F1. Even if we assume that a large portion of the time was spent trail-braking, we're still a long way off from 5g.
Is it possible that those figures are for a wet race (2 years ago)?
#6
desmo
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Posted 14 January 2002 - 18:56
I don't believe the traces are from a wet track as no mention is made of that. The trace for longitudinal acceleration shows a peak of about -30[M/S2] about 1/2 second into the braking, with the accompanying text as follows: "The deceleration values to which the driver is subjected are also impressive. In the space of not much more than a second, they swing from 0.8g positive to 3g negative."
#7
Ben
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Posted 14 January 2002 - 20:29
Some of the decelleration will be aero drag. This can be at least 1g at speeds around 250km/h.
Ben
Ben
#8
BRIAN GLOVER
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Posted 15 January 2002 - 01:24
In the Airforce , we refered to positive or negative g's as mass acceleration on the vertical axis of the aircraft only. This comes with a rotation around the lateral axis or pitch. In other words, an outside loop, one would experience negitave g's and an inside loop, positive g's. I think that in linear acceleration as found in a F1 car, the g's are all positive.
For instance, travelling thru Euo Rouge at spa at 190mph, the driver will experience a combination of one negative g acceleration vertically and 3 g laterally in the left hander whilst the car stays positive. Then, thru the dip and into the right hander, the driver will experience 6 g lateral and 3g positive acceleration on the vertical axis. As acceleration on all axis tends toward zero, the driver experiences 1g positive, which is his normal weight. Under max braking, initially with aerodynamic drag, the driver may reach 5 g de acceleration.
In a positive or negative acceleration, the pilot in an aircraft, can experience a black out or a red out, depending which way the blood travels. Positive gs require a G suit, that forces blood to the brain by squeezing the legs. The unit of one G is one atmosphere or 32'/sec/Sq
At texas Motor Speedway, they stopped the IRL race, because drivers were experiencing a type of vitigo, due to blood being forced to the right side of the brain, which actually drained blood from their left eye. True virtigo is the interaction of the inner ear function and visual reference or lack there of.
If that were an aircraft turning at that speed at the appropriate bank, the mass would be accelerated and the pilot would experience positive g. If the plane was inverted, the pilot would experience negative gs.
So what is the IRL driver experiencing. Just a thought.
QUOTE]Originally posted by desmo
I don't believe the traces are from a wet track as no mention is made of that. The trace for longitudinal acceleration shows a peak of about -30[M/S2] about 1/2 second into the braking, with the accompanying text as follows: "The deceleration values to which the driver is subjected are also impressive. In the space of not much more than a second, they swing from 0.8g positive to 3g negative." [/QUOTE]
For instance, travelling thru Euo Rouge at spa at 190mph, the driver will experience a combination of one negative g acceleration vertically and 3 g laterally in the left hander whilst the car stays positive. Then, thru the dip and into the right hander, the driver will experience 6 g lateral and 3g positive acceleration on the vertical axis. As acceleration on all axis tends toward zero, the driver experiences 1g positive, which is his normal weight. Under max braking, initially with aerodynamic drag, the driver may reach 5 g de acceleration.
In a positive or negative acceleration, the pilot in an aircraft, can experience a black out or a red out, depending which way the blood travels. Positive gs require a G suit, that forces blood to the brain by squeezing the legs. The unit of one G is one atmosphere or 32'/sec/Sq
At texas Motor Speedway, they stopped the IRL race, because drivers were experiencing a type of vitigo, due to blood being forced to the right side of the brain, which actually drained blood from their left eye. True virtigo is the interaction of the inner ear function and visual reference or lack there of.
If that were an aircraft turning at that speed at the appropriate bank, the mass would be accelerated and the pilot would experience positive g. If the plane was inverted, the pilot would experience negative gs.
So what is the IRL driver experiencing. Just a thought.
QUOTE]Originally posted by desmo
I don't believe the traces are from a wet track as no mention is made of that. The trace for longitudinal acceleration shows a peak of about -30[M/S2] about 1/2 second into the braking, with the accompanying text as follows: "The deceleration values to which the driver is subjected are also impressive. In the space of not much more than a second, they swing from 0.8g positive to 3g negative." [/QUOTE]
