Air plane pressure

topsquark

Forum Staff
Apr 2008
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648
On the dance floor, baby!
So I'm flying on a jet and I have to swallow to reduce the pressure in my ears and a thought occurred to me.

The jet is essentially a flying tube, sealed to maintain normal air pressure. But if it is sealed then how can the air pressure in the plane rise and fall?

Thanks!

-Dan
 
Jun 2010
422
33
NC
My Guess!

At altitude (~30,000ft) the ambient outside aircraft pressure is about 6psi.
An air bleed from an engine compressor section to the craft interior
pressurizes the in-flight cabin to about 10psi... About typical flight
pressure.

There is no "pressure of the ear." There is a pressure outside acting on
the ear membrane (drum) via passage through the outer ear. Also a pressure
acts interior to the ear membrane. This pressure path passes through the nose, mouth then sinus passages interior to the head.

Upon a headache, when pressure one side of the drum differs from the other - blow your nose!

Just my thoughts ....
 
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Apr 2017
538
140
Aircraft are not fully pressurised (to 15Psi) they want to keep the weight of the aircraft down ... just enough pressure to keep the passengers alive (12 to 11 psi ) with normal air , then the fuselage can be thin ...
If they had pure oxygen the fuselage could be even thinner .... astronauts live in 5psi pure oxygen.

At altitude (~30,000ft) the ambient outside aircraft pressure is about 6psi.

There is no "pressure of the ear." There is a pressure outside acting on
the ear membrane (drum) ....
30,000ft =4.36 psi ....

I think it's true to say there is (over) pressure in the (inner) ear ...outside pressure is reduce , ear drum is pushed outwards when aircraft ascends ... pushed inwards when aircraft descends .
 
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Pmb

PHF Hall of Fame
Apr 2009
1,579
335
Boston's North Shore
So I'm flying on a jet and I have to swallow to reduce the pressure in my ears and a thought occurred to me.

The jet is essentially a flying tube, sealed to maintain normal air pressure. But if it is sealed then how can the air pressure in the plane rise and fall?

Thanks!

-Dan
There are other ways to normalize ear pressure. Just yawn with your mouth closed.
 
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Mar 2018
118
5
Xinhui Guangdong Province China
gravity

Just imagine what's the reaction of the atmosphere if gravity of the earth vibrates...
 
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