Welcome Guest. Sign in or Signup

4 Answers

Theorizing about temperatures…The effect of Farenheit vs. Celsius

Asked by: 6711 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?

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

4 Answers



  1. Brian on Nov 12, 2010

    “Am I way off base?
     
    Will let you know soon as I figure out what base you’re looking to be on. 🙂
     
    In all seriousness, just pay attention to the units of measure. As long as your units are uniform you will be alright, be them Celsius or Fahrenheit.
     

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  2. Gary Moore on Nov 12, 2010

    I think you just might be over analyizing it a bit.  A lot of things could affect your ‘test’ ovens don’t always heat evenly across their volume, the thermometers proabably are super accurate etc…Brian’s correct – keep track of yoru units and don’t worry about it….

    -1 Votes Thumb up 0 Votes Thumb down 1 Votes



  3. Aviatrix on Nov 12, 2010

    Lol!  I didn’t actually have a “test oven.”  I was just saying that I think if you had two thermometers in the oven and applied the same amount of heat evenly…one thermometer would display a higher reading that the other…due to scale.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  4. Jason Schappert on Nov 12, 2010

    This might be overthinking something that is really basic.
    As long as your units of measurement are the same across the board it shouldn’t be a problem.
    I like your test oven though hhehe! teasing
     
    Jason

    -2 Votes Thumb up 2 Votes Thumb down 4 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.