Theorizing about temperatures…The effect of Farenheit vs. Celsius
Asked by: Aviatrix 6936 views General Aviation
If I have two thermometers (one is scaled to Farenheit and the other is scaled to Celsius) and I stick them both in the oven and increase the heat. (Notice, I'm not saying HOW many degrees I incresase the heat b/c that is relative to the thermometer)
So, I increase the heat. The Farenheit thermometer shows a 10 degree increase and the Celsius therometer shows a 5.5 degree increase. The same AMOUNT of heat is acting on both thermometer, but they're each showing a different degree of increase.
This brings me to my point...
If I'm looking at a takeoff distance chart and it says increase your distance by 10% for every 10 degree above standard Farenheit.
I'm at sea level. Therefore, if the temperature is currently 69 degrees F...I would increase the distance by 10%.
However, 69 F is basically equal to 20.5 degrees C. And 20.5 is only 5.5 degrees above the Celsius standard of 15 degrees. However, I suppose it's safe to say the plane would behave the same way at 20.5C as it would at 69F. If the takeoff chart was based on Celsius...I guess it would be "adjusted differently." It may state something to the effect of increase 10% for every 5.5 degree above standard.
If I'm in Canada (metric system) and it is 20C today...and 30C tomorrow...that is an increase of 10 degrees. However on the Farenheit scale, 20C = 68 degrees...and 30C = 86 degrees...That's a whole heck of a lot hotter than a "10 degree" increase.
I guess an increase of 10 degrees in Canada doesn't feel nearly as hot as it does in the U.S. Wait, I guess that's not accurate to say either...I guess the point is that you have to know your units and scale!
Am I way off base?
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