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Spectators Balcony (Spotters Corner) If you're not a professional pilot but want to discuss issues about the job, this is the best place to loiter. You won't be moved on by 'security' and there'll be plenty of experts to answer any questions.


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Old 31st July 2008, 15:16   #1 (permalink)
diddy1234
 
Join Date: May 2007
Location: hertfordshire
Age: 34
Posts: 80
How does temperature effect Take off performance ?

I was wondering how temperature effects take off performance on a modern day aircraft.

for example, would an aircraft take off better on a cold day compared to a hot day (if it had the same weights and passengers onboard) ?

I can understand that if an aircraft lands at a high elevation airport it would need a longer runway to take off again.

So thinner air will make the engines develop less power (am I correct ?).

This also started me thinking, what other factors would make the engines develop less power ?

Its probably a really stupid question but I had to ask.

Thanks

RD

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Old 31st July 2008, 16:18   #2 (permalink)
 
Join Date: Jul 2004
Location: UK sometimes
Posts: 25
Hi there.
Air Temperature has a great effect on aircraft performance. Basically,the warmer the air the less dense it is, and consequently the less thrust a jet engine is able to produce. By way of illustration, the aircraft I fly can "lift" 40750kgs from London City at 12C but only 38615kgs on a day like today with 28C.

However, armed with that knowledge and figures we use that to our advantage. On a cool day we trick the engines that it is much warmer and provided we can still lift what the aircraft weighs (obviously!) we can take off using reduced power settings, saving fuel and increasing engine life.

Rgds

Rb311
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Old 5th August 2008, 10:49   #3 (permalink)
 
Join Date: May 2008
Location: Altrincham
Age: 43
Posts: 20
Temperatures at take-off

Hi

If you wanted to study how airliners performance is affected by temperature or how they fly in general, you might find this book useful. It tells you everything about how planes fly from clearnce for take off to landing and performance in the air. It uses language most of us desk pilots understand but explains everything as well.




It isnt too expensive and I got my copy from Waterstone's.

Enjoy!


Donnlass
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Old 5th August 2008, 13:16   #4 (permalink)
grizzled
 
Join Date: Dec 2007
Location: Itinerant
Posts: 46
Effect of temperature on A/C performance

Hi Diddy,

The previous posts in reply to your question are all good and accurate. And I would endorse the mentioned book if you have a general interest. One general comment I will add is that many questions that took a lot of time and research to find answers to only a few years ago can now be answered quickly and accurately thanks to Wikipedia. With respect to your question in particular, this Wiki page is quite helpful:
Density altitude - Wikipedia, the free encyclopedia

Grizzled

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