Why nitrogen?

"Viperdoc" wrote in
:

It all sounds like BS to me- if it's the tire we're discussing,
there's no contact with the nitrogen, just the inner tube. The outer
surface of the tire is in air of course, along with exposure to UV
light, salts, etc. The tire is going to lose its rubber well before it
starts to oxidize and crack.

Yeah, I kinda thought that myself which gave me the notion that the fire
thing wiht heavies might be more relevant we run anything up to 300PSI as
well, which might be a factor. I must ask around again.



Bertie

I don't know whether nitrogen alone versus plain old air would make that
much difference in supporting a fire. As I recall, the heavies have blow out
plugs in case of a hot brake, so the plug melts and lets the air (nitrogen)
out before the tire blows.

On our base they fill the KC-135 tires in a big steel mesh cage- kind of a
reminder of what could happen if it let go.

Reminds me of the time a line guy in a local airport filled the air bottle
for a Vendenyev engine (they use an air start and not an electrical starter)
with oxygen rather than compressed air. The resulting fire burned up the
whole plane. The initial start-up must have been something to watch-
ignition on, engage starter, two blades, .... then kaboom!

At least it was in a Wilga, and not an aerobatic plane. It was the aviation
equivalent of Darwinism- ridding the world of ugly airplanes.

"Viperdoc" wrote in
:

I don't know whether nitrogen alone versus plain old air would make
that much difference in supporting a fire. As I recall, the heavies
have blow out plugs in case of a hot brake, so the plug melts and lets
the air (nitrogen) out before the tire blows.

That's right. they do, but they can and do catch fire as well.

On our base they fill the KC-135 tires in a big steel mesh cage- kind
of a reminder of what could happen if it let go.

Reminds me of the time a line guy in a local airport filled the air
bottle for a Vendenyev engine (they use an air start and not an
electrical starter) with oxygen rather than compressed air. The
resulting fire burned up the whole plane. The initial start-up must
have been something to watch- ignition on, engage starter, two blades,
.... then kaboom!


wow!


At least it was in a Wilga, and not an aerobatic plane. It was the
aviation equivalent of Darwinism- ridding the world of ugly airplanes.


So, the O2 fueled an already existing fire or caused it?


Bertie

So, the O2 fueled an already existing fire or caused it?


I suspect that pumping the oxygen into the system somehow started the fi
it probably is a new definition for the term "hot start"

"Viperdoc" wrote
I suspect that pumping the oxygen into the system somehow started the
fi it probably is a new definition for the term "hot start"

In that engine, the compressed air is injected into the top of the
cylinders by an air distributor at about the same time as the spark
is fired. (it also has a "shower of sparks" system)
This sometimes results in the engine firing (and starting) before it
seems like it even turns.

In the YAK-52, the compressed air also operates the retractable gear,
the flaps and the brakes.

Bob Moore