Quote:
Originally Posted by PerryB
I think nitrogen came into use in aircraft that experience large temperature swings in their operating environments. Think of a commercial airliner that leaves Texas and lands in Michigan. How much more temperature stable is it? I don't know. I don't see it having any real advantages in most daily applications though.
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In aircraft there are two reasons...
The temperature swings you mentioned, and they're way bigger than just going city to city... Think about what temperature a wheel well is at 38,000 feet above sea level...
And moisture content. Most of the N fills on aircraft are also very sure the N is very very dry. An ice chunk that has adhered to the inside wall of a tire that goes from 0 to over 100 mph in the blink of an eye, is a heck of a balance problem.
Many aircraft also have special tires with "chines" or extensions that stick out and help deflect foreign objects that get thrown up off of a runway, away from the aircraft. The most commonly seen aircraft most people have seen with them, would probably be the LearJet.
Tossing trash from the runway into those low mounted twin engines on the fuselage near the tail during a takeoff from a slightly fouled runway (water, ice chunks, rocks, whatever) could make for a "bad day" at departure time.
Having a tire expand to the point where it gets "stuck" in a wheel well could also be a "bad day" when it comes time to drop the gear to land. Usually that's handled by strict pressure limits when filling them. (Very rare to see the equivalent of TPM on aircraft.) And careful engineering design to allow for expansion at very high altitudes -- where you probably wouldn't be dropping the gear anyway.
(But you might. Read up on what actually must happen after a decompression at high altitude. All that nice talk about calmy putting the yellow mask over your mouth and nose doesn't really describe the screaming descent at barber pole that needs to occur... some aircraft call for tossing the gear out to add to the drag on the way down. All depends on the airplane but it isn't going to be a calm ride down... Gotta get the airplane below 12,000 or so, and usually to 10,000 so everyone can breathe again... The folks in the cockpit get a nice pressure mask to accomplish that dive...)
So anyway... I don't think N is really worth it in stuff that's just tooling down the highway -- and is not hanging out at lower pressures and lower temperatures similar to say, what one would find on the way up Mt Everest ...
But I won't argue too hard with someone h***-bent on putting N into road tires. It's their money. I've spent money on much dumber things.
It just isn't for the same reasons, is all.
