air density and stall
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Join Date: May 2007
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air density and stall
I was wondering if an aircraft had more chance of stalling at cruise speed if flying over the north pole at 39k feet ?
I am thinking in terms of air density, the atmosphere is thinner at the north and south pole compared to the equator.
So for example, an aircraft flying at the equator at 39k feet would have little chance of stalling at cruise speed but if it were at the same height over the north pole could it stall ?
Or another example, Concorde is flying at 60k feet and say it flew over the north pole, would it have to descend to a lower altitude to keep the same speed ?
How do pilot's compensate, fly at a lower altitude ?
I am thinking in terms of air density, the atmosphere is thinner at the north and south pole compared to the equator.
So for example, an aircraft flying at the equator at 39k feet would have little chance of stalling at cruise speed but if it were at the same height over the north pole could it stall ?
Or another example, Concorde is flying at 60k feet and say it flew over the north pole, would it have to descend to a lower altitude to keep the same speed ?
How do pilot's compensate, fly at a lower altitude ?
You are indeed starting to think along the right lines. Have a read of this :
http://en.wikipedia.org/wiki/Coffin_corner_(aviation)
http://en.wikipedia.org/wiki/Coffin_corner_(aviation)
Join Date: Mar 2005
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Way up high stall speeds and such are related to the density (and therefore temperature) of the air. The atmosphere at the poles isn't exactly thinner, it's just more compact and thus the tropopause is lower as the air is much colder.
Roughly speaking, for the same indicated altitude the density altitude will be higher near the equator as the air is warmer and therefore less dense meaning your operational aerodynamic ceiling will be actually lower.
S.
Roughly speaking, for the same indicated altitude the density altitude will be higher near the equator as the air is warmer and therefore less dense meaning your operational aerodynamic ceiling will be actually lower.
S.
