Re: [Phys-L] Aeroplanes and air temperature

[brian whatcott <betwys1@sbcglobal.net>]

I find this explanation is what I would call a physicist-style approach. 
Talking about air molecules....    Better to say that the ground 
elevation / altitude that an airplane cares about at takeoff is the 
density altitude - which increases with air temperature.
Increased density altitude requires higher ground speed in order to have 
lift balance weight at takeoff, which in turn demands longer runways or 
higher power to weight. Civil airliners are operated so as to have 
enough 'balanced' runway length left to brake to a halt from takeoff 
speed, which further constrains hot and high operations.

Brian W


On 6/21/2017 11:50 AM, antti.j.savinainen via Phys-l wrote:
> Hi,
> there has been recent news on aeroplanes which cannot fly because the air temperature is too high. Here is one explanation why this is so:
> https://www.wired.com/story/phoenix-flights-canceled-heat/
> How do you find the explanation?
> Regards,
> Antti Savinainen, Finland
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