Saftey of exposed wheel at 41,000 feet

In article , Tom wrote:

Yes, and at sea level it's pushing against 15 psi, and in vacuum they're
pushing against nothing, which means the maximum pressure differential
between ground and cruise is 15 psi.

Your math doesn't add up (how cliche' )

It doesn't? If you have X psi in your tire at sea level and then you
take it to . . . say . . . 300,000,000 feet, you'll have X+15 psi.
So, what he's saying is

X + 15 - X = 15

which seems to "add up" just fine.

Mike Beede

"Mike Beede" wrote in message
...
In article , Tom
wrote:

Yes, and at sea level it's pushing against 15 psi, and in vacuum
they're
pushing against nothing, which means the maximum pressure differential
between ground and cruise is 15 psi.

Your math doesn't add up (how cliche' )

It doesn't? If you have X psi in your tire at sea level and then you
take it to . . . say . . . 300,000,000 feet, you'll have X+15 psi.
So, what he's saying is

X + 15 - X = 15

which seems to "add up" just fine.

Mike Beede
Also, to answer the original question, having the wheel 'exposed', makes no
difference at all, since wheel wells on aircraft are not normally
pressurised. Folding the wheel away, is done to improve the aerodynamics,
not to protect the tyre from the reduction in pressure...

Best Wishes

Tom wrote:

Still the 'ol PITA, eh George?

You certainly are.

George Patterson
Some people think they hear a call to the priesthood when what they really
hear is a tiny voice whispering "It's indoor work with no heavy lifting".

Hi,

Very interesting replys. I have no expeience in airplane engineering,
I'm just a curious layman looking at jets; so my question implied
nothing, no need to read deeper into it.

I literally wanted to know if exposing wheels at 41,000 was safe. If
it is, great! Tell me why. I was curious because the only exposed
wheels I've seen were on rickety Cessnas, and never Boeings or
Airbuses.

I was worried that the things would freeze up and mess up the landing,
but aptim pointed out that 737s have exposed wheels too (I've never
noticed that!) so most of my concerns (and those raised on the board)
were taken care of with aptim's that post. Hey, if Boeing does it,
Eclipse can too... It just isn't very reassuring - although sitting in
a 2 ton tube of metal at 41,000...

Thanks.

Link: http://www.airliners.net/open.file/341467/L/


wrote in message ...
stephen wrote:
Hello,

How safe is Eclipse Aviaion's decision to expose the wheel on jet that
cruises at 41,000 feet?

Has this been done before? On what airplane?

Safe from what?

If the aircraft isn't supersonic and the wheel wells aren't
heated and pressurized, they are going to see the same environment
whether they are hanging in the breeze or totally enclosed.

"Roger Hamlett" wrote in message
...
Also, to answer the original question, having the wheel 'exposed', makes
no
difference at all, since wheel wells on aircraft are not normally
pressurised. Folding the wheel away, is done to improve the aerodynamics,
not to protect the tyre from the reduction in pressure...

Best reply yet!

Dashi

"Mike Beede" wrote in message
...
In article , Tom
wrote:

Yes, and at sea level it's pushing against 15 psi, and in vacuum
they're
pushing against nothing, which means the maximum pressure differential
between ground and cruise is 15 psi.

Your math doesn't add up (how cliche' )

It doesn't? If you have X psi in your tire at sea level and then you
take it to . . . say . . . 300,000,000 feet, you'll have X+15 psi.
So, what he's saying is

X + 15 - X = 15

which seems to "add up" just fine.

Yes...I read the original (badly worded) post too quickly and was thinking ,
first inches of mercury, not atmospheric pressure. Then, was not seeing the
point he was making (again from the broken wording).

My apologies.

Stephen,

Tell me why.


Tell us why not! We fail to see the problem that you see - so what is
it?

Again, the wheel well, if covered, is not heated at all. Any freezing
that happens to an "exposed" wheel happens to a covered wheel as well.
So what's the difference you see? And what kind of danger do you see
from a wheel with subzero temperature?


--
Thomas Borchert (EDDH)

My question is not pressure but temperature. A tire (especially on
the Shuttle) is going to be pretty damn cold after a long flight.
In rubber, cold is the opposite of flexible.

Do the tires warm at all during decent? Or do they hit the runway
just as cold?

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"David Lesher" wrote in message ...


My question is not pressure but temperature. A tire (especially on
the Shuttle) is going to be pretty damn cold after a long flight.
In rubber, cold is the opposite of flexible.

Do the tires warm at all during decent? Or do they hit the runway
just as cold?

I suspect they heat up pretty durn fast once they touch the ground.
Most of the references I can find about airliner (and even Space Shuttle)
tire temperatures involve the issue of pressure changing with tire
more than the material properties of the rubber.

Hi Thomas,

I wasn't implying that it was unsafe to expose the wheel. I was just
wondering how safe it was. If it's perfectly safe, as the group has
told me, great! I am just a layman on these matters so I would love to
learn more about these things; on a very informal basis obviously...
My first post was vague because I had no idea what
direction/parameters I should set.

Tell us why not! We fail to see the problem that you see - so what is
it?

Seeing the things exposed concerned me; it merely "felt unsafe" - this
is what you get from people who aren't knowledgeable about these
things. I think you can't to see the problem I see because you find an
exposed wheel perfectly natural, whereas I do not.

Best Regards,
Stephen

Thomas Borchert wrote in message ...
Stephen,

Tell me why.


Tell us why not! We fail to see the problem that you see - so what is
it?

Again, the wheel well, if covered, is not heated at all. Any freezing
that happens to an "exposed" wheel happens to a covered wheel as well.
So what's the difference you see? And what kind of danger do you see
from a wheel with subzero temperature?