What would happen to a plane if it continued to gain altitude?

Question

You need to reach a certain speed to break the earth's gravity, But what happens to a plane that keeps gaining altitude? Does it eventually become physically unable to go any higher? Does it get forced to level off?

Answer 1

Even if we are not talking about the engine, which will only work to certain altitudes depending on it's design, the aircraft has limitations.
Say we are using some sort of rocket that has the equivalent thrust of a regular engine. Since rockets don't need oxygen to run (they bring it with them as part of the fuel load) it isn't limited by altitude.
As the aircraft gets higher and higher the air becomes less dense so the wing produces less and less lift. At some point the maximum lift the wing is capable of generating will equal the weight of the plane and it will quit climbing higher.

Answer 2

The density of the air, enabling the plane to lift, gradually goes down, as the plane goes up. You can look up what the record height is for a plane, probably around 25 miles, if that.
The reason a plane lifts, is air molecules passing by on the upper side of the wing faster, then on the lower side, such creating a vacuum, or lift, pulling the plane up. A modern sailboat uses the same physics to sail against the wind.
If there aren't enough air molecules (nitrogen, oxygen, carbon dioxide and in the USA sulfur and carbon monoxide), the lift just ceases to lift

Answer 3

two things...

first

jet engines require oxygen to operate. eventually you will reach an altitude where the oxygen concentration is insufficient for combustion and the engines will stall.

second,

jets climb because of the "bernoulli effect" air rushing over the top of the wing has to travel faster than air below the wing because of the shape of the wing. that increased speed results in a pressure drop above the wing and gives the plane lift . as the jet climbs, eventually the air will thin out enough that the lift will be less than the weight of the plane and it will reach a maximum height.

not sure which effect happens first. may depend on the plane.

regardless, the plane cannot just travel off into space......

******update******

interesting that one of you gave me a thumbs down. was it the oxygen issue that mig-31 firefox brought up or the lift?

as to oxygen...

there are a variety of aircraft fuels available. The standard used in commercial jets, A, and A1 (kerosine based fuels) have a range of fuel to air that support combustion. That limit is .6 to 4.7 volumes of fuel to air. see here....
http://www.chevron.com/products/prodserv/fuels/bulletin/aviationfuel/2_at_fuel_perf.shtm
in the absence of air, the ratio of fuel to air is too high to support combustion. Other aircraft, military for example, may use different fuels with different oxygen contents but as far as I know, there are no fuels available that support combustion without external oxygen. here's a list of available fuels
http://www.csgnetwork.com/jetfuel.html

as to lift. bernouillis equation goes like this.

v^2 = k P/d
v = velocity, k = constant, P = pressure, d = density
as density of air decreases, so does P for constant v.

ie, as air thins, for the same velocity, lift decreases. there comes a point when lift = weight of the plane and the plane can no longer rise.

as to an aircrafts "ceiling" that is it's recommend safe maximum operating height and depends on the airplane and the fuel..

Answer 4

I not an aviation specialist. A plane and not a jet will have two things happen I guess. One as it gain altitude it would eventually lose lift and fall to a point it regain lift. The other I guess happen is the Engine stop from lack of air and would not restart until the plane fall to a point there be sufficient air for the engine.

Answer 5

It is called the ceiling of the aircraft, it cannot go any higher. The gaining of altitude is primarily because of the lift produced by the wings. Lift is a function of speed and density and density decreases with altitude. Speed is dependent on the engine's thrust which is in turn dependent on density. So as the air becomes rarer, lift and thrust decreases to a point where it cannot sustain flight.

It is not oxygen deficiency that limits altitude gain, we can provide oxygen rich fuel that can sustain itself. Its density that makes the limitations.

Answer 6

As the air becomes less dense with altitude, it will reach it's top ceiling and will not climb any more.

Answer 7

The engines will shut off because there isn't enough oxygen. After a stall, the plane will nosedive, probably in an uncontrollable spin. Then you can probably guess how it ends.

Answer 8

it depends on the plane, if it is using turbofan, or troboprop. it would have no oxygen to power it and it would crash ,if it is a rochet plane it would go into space.

Answer 9

hi it generates raise yet reason for its angel of attack that's the attitude between relative wind and rope line of the wing the produced raise is perpendicular to the relative wind and the the relative wind is almost to vertical(diveing physique of concepts ) so the raise may be horizontally .