Why do aircraft tires use nitrogen instead of regular air?

Answer 1

since you already have several correct answers to this question i wont reiterate what people like eferrell ricardo, and drew said. ill just say that nitrogen reacts differently to pressure and temperature than air does. it being an inert gas has nothing to do with it. and its just as easy to get dry air in a pressurized cylinder as it is to get nitrogen. also the vast majority of small aircraft do not have tubes in there tires. just reread what eferrel, ricardo, and drew said and you'll have a good grasp on it.

Answer 2

Most of these answers are simply wrong, and even the best has inaccuracies. Here is what Boeing has to say http://www.boeing.com/commercial/aeromagazine/aero_05/m/m03/index.html

Facts: 1. Over the pressure and temperature ranges involved, Nitrogen reacts to pressure and temperature almost exactly the same as dry air. The differences are miniscule. This would be true even for pure oxygen, or for pure carbon dioxide or any mixture of the three over the pressure and temperature ranges involved.
2. The rate of pressure loss, by gas migrating through the rubber is slightly higher for oxygen. The difference between pure nitrogen and air that is 78% nitrogen and only 20% oxygen is minute. Other pressure loss mechanisms (leaky valves for one) are often higher in practice.
3. Moisture in compressed air is a concern for some applications. I'm not sure whether anybody worries about it in aircraft tires. The technology for producing dry air is not terribly different from that used to produce shop grade nitrogen. If you have to have nitrogen for one job, you might as well use it for the others, too.
4. As explained in the Being document referenced above, the main concern is that, especially given the high pressure in aircraft tires, under unusual conditions of very high temperature resulting from severe braking or malfunction, enough flammable vapors can be produced inside a tire to catch fire in an air atmosphere. Fire inside a tire will cause a rapid pressure rise and probably an explosion of the tire.

Answer 3

Nitrogen is chemically more inert and will not support combustion. It is also typically dry (because of the way it is produced), whereas atmospheric air always contains some water vapor. It's not a bad idea for all types of tires, not just aircraft tires, but it's much more expensive than ordinary compressed air from a service station. Nitrogen expands and contracts with temperature just like any other gas.

Answer 4

Used Aircraft Tires

Answer 5

To build on Drew's answer, I should point out a couple of things.

Many aircraft, (primarily low altitude aircraft,) do use regular air from a shop air compressor. These are typically tube type tires that require an air pressure lower than what you'd get from a Sears air compressor.

Aircraft that will fly at higher altitudes, such as light turboprops, typically (prefer,) nitrogen but can use regular compressed air.

Nitrogen won't entrain moisture, so the vast majority of jets require either nitrogen or dried air for the tires. While some compressors and storage tanks may exceed the industry standard, for compressors, of 125 psi, and may get to the ranges required for jets, dryers for regular air and the expense of maintenance makes it far less expensive to have nitrogen delivered virtually on demand by the AirGas, coming in cylinders with 4700psi crammed into them and allowing a mechanic to quickly, efficiently and easily service the tires of a jet up to the 225 or better psi that's required as determined by the manufacturer of the aircraft and the tire.

It's faster to wheel out a bottle of inert gas, open the valve and set regulator pressure than it is to untangle the air hose that the last knucklehead to use it left in a bird's nest, string it out, go back and make sure the air dryer is working, and you have sufficient pressure, then run back to the aircraft, (remember that you forgot a tire guage, and make a trip back to the tool room,) when you forgot that there's a calibrated guage already on the nitrogen cart you should have used in the first place.

You also have the added safety of nitrogen being, as I mentioned before, an inert gas. Air contains, as well as nitrogen, oxygen, which is not an inert gas. Not only is it corrosive, in the form of a pure gas, it will spontaneously combust in the presence of petrochemicals, which are typically found in airplanes, in the wings, to which the landing gear is attached, and which most aircraft leak.

That doesn't sound like something I really want to try, and I'm reasonably sure I wouldn't want to be on hand if any of the variables went amiss. Give me a bottle and a cart any day.

DGI

Answer 6

Used Airplane Tires

Answer 7

Nitrogen does not contain moisture. Air does and can cause problems (freezing up and potential for corrosion) since aircraft fly at altitudes that have sub zero temperatures. The hydraulic accumulators, shock struts and other systems are also serviced with nitrogen for the same reason

Answer 8

Nitrogen does not contain moisture. Nitrogen pressure does not increase with altitude or temperature.
Tires inflated with compressed air increase pressure with heat and altitude.
The only thing that uses compressed air o na jet is the engine.

Answer 9

I believe it is because nitrogen is less subject to volume-changes due to temperature. Sin airplanes experience -60°F temps at cruise altitudes. I also remember once hearing that nitrogen does not leak as much as regular air would, but I am not sure of that.

Answer 10

because the nitrogen gas is lighter than regular air,higher flashing point and not expanded when temperature rising