Nitrogen in tires?

[PeterR]

As an A&P, I can tell you that nitrogen is used widely and almost exclusively (most aircraft manufacturers will let you top off with dry compressed air (if N is not available).........

And of course there are those military aircraft where hydrogen has been  used.

[Bruce Dorsi]

Thanks, Steve!

I have no problem accepting the points which you made in your last post, but the following statement has me scratching my head.  

 

.....brake fires are frequent on aircraft and N is a safer and more stable gas should the tire fail (see para above).

There is enough oxygen in the surrounding air to support combustion of flammable materials, without relying on the gas inside the tire to support combustion.

If the tire should fail, doesn't the contents of the tire become moot if compressed air were to be discharged fom the tire?

[entodad]

Thanks, Steve!

I have no problem accepting the points which you made in your last post, but the following statement has me scratching my head.  

 

.....brake fires are frequent on aircraft and N is a safer and more stable gas should the tire fail (see para above).

There is enough oxygen in the surrounding air to support combustion of flammable materials, without relying on the gas inside the tire to support combustion.

If the tire should fail, doesn't the contents of the tire become moot if compressed air were to be discharged fom the tire?

As an addendum,

Oxygen inside the tire at high pressures would also increase the rate of degradation of the tire.  Reactions with oxygen is what causes our beloved antique tires to crack and fail.

Atmospheric oxygen is only about 22 psi at sea level (I forget what the partial pressure is, I think about 5 psi) and is not a correctable factor, but inside the tire it is.

Yes Oxygen is an accellerant, not a fuel, but historically when atmospheric oxygen raises above 27-28 percent as it has in the distant past, fires burn with a ferocity that is not seen today.  In fact those fires were very wide spread and were one possible cause for the ice ages that occurred (due to the tremendous amount of smoke).
Doug

[PeterR]

Oxygen inside the tire at high pressures would also increase the rate of degradation of the tire.  Reactions with oxygen is what causes our beloved antique tires to crack and fail.

Degradation of rubber is aggravated by ozone and ultraviolet radiation.   This is the reason old tires which are severely cracked on the outside rarely show any indication of the problem on the inside of the case.

Inflation with nitrogen would not avoid long term deterioration.

[terrarodder]

They use helium to put ballons up, if you use in your tires would it make your car lighter?

[junkyardjeff]

I have good old air in the goodyear wranglers on my 92 F150 and they have 140,000 miles on them with enough tread that might get me through the winter if I dont buy something else.  Jeff