[QuadList] Toluene

[Joe Owens]

>
> 	I think you must be kidding (based on your other droll  
> statements!).  Though Freon (a registered trademark, I think DuPont  
> owns it) is an excellent refrigerant, the gas itself is not simply  
> 'cold', so tires could not be kept from over-heating by being  
> inflated with it.  The act of inflating a tire actually INCREASES  
> the temperature of the gas inside (it is this property that  
> partially explains how refrigeration systems work).

Inflating a tyre does heat it up (PV=nRT),  but not to the operating  
temperatures required by Formula One.  Quote:

"A dry-weather racing tyre in Formula One generally operates at an  
optimal temperature of around 100° C.

  In contrast, intermediate spec tyres operate at between 40°C to 100° 
C, depending on the wetness of the track, while full wets approximate  
30°C to 50°C. "


"The lead article in the December 2007 issue of Racecar Engineering  
is titled Secrets of the F2007.

Mentioned in this article are 4 items that were exposed in the  
spygate matter.

The first item discussed is about the gas that Ferrari uses to  
inflate their race tires.

Ferrari uses a 50% mixture of R404a and CO2. They found that this mix  
transfers heat effectively from the tire to the wheel. Ferrari did  
not blister tires as much as their competitors.

Ferrari also found that the performance of the tire did not drop off  
as dramatically compared to using pure nitrogen."

The gas mixture also did not need to be de-humidified (its the water  
vapour content of regular air that raises the real havoc with pressures)

One drawback, however,  is that CO2 apparently starts bonding with  
the rubber compounds and will eventually compromise the overall  
structure, so this will be okay for the normal (about 20-25 laps)  
life of an F1 tyre, but not for a club car or a street vehicle.

So the refrigerant is not used in its normal manner (as an adiabatic  
heat cycle), but as an inert, dry, heat conductor.


Joe Owens
Presto!Digital Colourgrade
302-9664 106 Avenue
Edmonton, Alberta T5H0N4
+1 780 421-9980
jpo at prestodigital.ca



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