Air getting into airplanes!?!? help!?
help! i hate getting on airplanes cause i feel costraphobic but i think it would make me feel better if i knew how air got into airplanes and allowed you to breath and stuff. so please help! thanks.
- SkechersLv 71 decade agoFavorite Answer
Airplanes are at their best up high, where the air is thin and smooth. And therein lies the rub: We invented a machine that thrives where we don’t. This became obvious as soon as engine power increased to a point at which aviators could reach altitudes where they lost consciousness.
Air is pressurized by the engines. Turbofan engines compress intake air with a series of vaned rotors right behind the fan. At each stage of compression, the air gets hotter, and at the point where the heat and pressure are highest, some air is diverted. Some of the hot, high-pressure air, called bleed air, is sent to de-ice wings and other surfaces, some goes to systems operated by air pressure, and some starts its journey to the cabin.
The cabin-bound air has to be cooled first in an intercooler, a device like a car radiator that sheds the heat to the ambient air scooped aboard for that purpose. From there the air travels into the airplane’s belly, where air packs cool it further using air cycle refrigeration. An air cycle cooler is perhaps the simplest air conditioner ever invented, because it doesn’t need a refrigerant as an intermediate fluid to dump heat. The air packs compress the incoming air to heat it before sending it to another intercooler to dump the heat to the outside. The air then expands through an expansion turbine, which cools it the way blowing with your lips pursed results in a cool flow of air. (Test the principle by blowing with your mouth wide open to see how warm the air would be if it weren’t compressed and then allowed to expand.)
Now the air is ready to mix with air from the cabin in a mixer, or manifold, that adds the new air to the recirculating cabin air, which is moved by fans. To maintain a comfortable temperature for the passengers, automatic systems regulate the mixture of heat from the engines and cold from the air packs. To maintain the pressure in the cabin equal to that at low altitude, even while the airplane is at 30,000 feet, the incoming air is held within the cabin by opening and closing an outflow valve, which releases the incoming air at a rate regulated by pressure sensors. Think of a pressurized cabin as a balloon that has a leak but is being inflated continuously.
On the ground, the airplane is unpressurized and the outflow valve is wide open. During preflight, the pilot sets the cruise altitude on a cabin pressure controller. As soon as the weight is off the main wheels at takeoff, the outflow valve begins to close and the cabin starts to pressurize. The airplane may be climbing at thousands of feet per minute, but inside the cabin, the rate of “climb” is approximately what you might experience driving up a hill. It might take an average airliner about 20 minutes to reach a cruise altitude of, say, 35,000 feet, at which point the pressurization system might maintain the cabin at the pressure you’d experience at 7,000 feet: about 11 pounds per square inch. Your ears may pop, but the effect is mild because the climb rate is only 350 feet per minute. When the airplane descends, the pilot sets the system controller to the altitude of the destination airport, and the process works in reverse.
The structural strength of the airplane determines how much differential pressure the cabin can tolerate—a typical figure is eight pounds per square inch—and the fuselages of new airplane designs are pressurized and depressurized many thousands of times during testing to ensure their integrity. The higher the maximum differential pressure, the closer to sea level the system can maintain the cabin. Federal Aviation Regulations say that without pressurization, pilots begin to need oxygen when they fly above 12,500 feet for more than 30 minutes, and passengers have to use it continuously above 15,000. On airliners that operate at altitudes well above that, regulations require that everyone aboard be supplied with 10 minutes of oxygen in the event the cabin pressure can’t be maintained, which brings us to the dramatic scenario known as explosive decompression.
If the door blew off a jet at altitude, all the air in the cabin would depart very quickly and a momentary thick fog would envelope the cabin as the water vapor in the air condensed instantly. Loose articles would fly around and foam rubber would burst as the tiny air bubbles within it expanded. Within a couple of seconds, oxygen masks would drop down from the overhead panels, and you would have to pull yours toward you and place it over your mouth and nose. The act of donning the mask tugs on a lanyard that starts the flow of life-sustaining oxygen.
- Anonymous1 decade ago
Not only does air get into airplanes, it typically is FORCED through commercial airplanes with powerful air pumps. It is NOT the same recirculated air, and it is NOT from a tank. It is from outside, forced through the cabin, and exits out a vent in the back.
And obviously it is enough to allow you to breathe, for people on airplanes do not suffocate.
- billrussell42Lv 71 decade ago
you have some false answers. What happens is some air from outside the plane is piped inside via a pump that pressurizes it to the equivalent of 10,000 feet altitude. Most of the air is recirculated around, but some is fresh air.
Since it costs money to bring in outside air and pressurize it, and also to heat or cool it to get it to the proper temperature, the airlines want to recirculate as much air as possible and bring in outside air as little as possible. This is an ongoing battle between the airlines and consumer groups, as too much recirculation increases the risk of catching diseases.
Air is NOT from tanks, nor is it totally from outside.
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- 1 decade ago
If I'm not mistaken, they have stored tanks of oxygen, otherwise they have vents in the back, into the tanks, that then goes out through the air conditioning vents, don't worry, if a substantial altitude is reached, the emergency head masks (which are fed from the oxygen tanks) will automatically fold down from the ceiling, don't worry, you'll be able to breath =o) Remember, air travel is by FAR the safest means of transportation known to man. More people die a year from ground travel (even trains) a year than the air. The worst part is taking off, you lose your stomach for 5 seconds but otherwise flying is a fun experience. Don't worry. Stay cool. It'll be fine!
EDIT: Some planes recirculate
- 6 years ago
takes air from outside, and puts in airplanes.
- Anonymous1 decade ago
The same air is always in the airplane no new air comes in but that same air is recirculated and that is how you don't suffocate you can breath just fine in an airplane just like on the ground.
- 6 years ago
air is outside the plane, air is pushed into the plane by a pump.
What else is there to it?