Saftey of exposed wheel at 41,000 feet

[stephen]

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?

[EDR]

In article >, 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?

What difference does it make how high the airplane flies?
The Cessna Citation has had exposed wheels since it was developed in
the late 60's/early 70's.

[Don Tuite]

On Sat, 06 Dec 2003 02:31:24 GMT, EDR > wrote:

>In article >, 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?
>
>What difference does it make how high the airplane flies?
>The Cessna Citation has had exposed wheels since it was developed in
>the late 60's/early 70's.

I think he's asking about either excess tire pressure bursting the
tire or the tire expanding and getting stuck in the wheel well.

Some sort of variation on the question comes up a couple to times a
year here. The answer is usually that no, the maximum pressure
differential is about 15 psi, which is trivial for a tire.

Don

[Tom]

"stephen" > wrote in message
m...
> 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?

Cessna Citation's have half open wheel bays. They cruise FL410 and up.

[Tom]

"Don Tuite" > wrote in message
...
> On Sat, 06 Dec 2003 02:31:24 GMT, EDR > wrote:
>
> >In article >, 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?
> >
> >What difference does it make how high the airplane flies?
> >The Cessna Citation has had exposed wheels since it was developed in
> >the late 60's/early 70's.
>
> I think he's asking about either excess tire pressure bursting the
> tire or the tire expanding and getting stuck in the wheel well.
>
> Some sort of variation on the question comes up a couple to times a
> year here. The answer is usually that no, the maximum pressure
> differential is about 15 psi, which is trivial for a tire.
>
Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the nose
wheel and 98 PSI on the mains. They are filled with dry nitrogen.

[Paul Tomblin]

In a previous article, "Tom" > said:
>> Some sort of variation on the question comes up a couple to times a
>> year here. The answer is usually that no, the maximum pressure
>> differential is about 15 psi, which is trivial for a tire.
>>
>Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the nose
>wheel and 98 PSI on the mains. They are filled with dry nitrogen.

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.


--
Paul Tomblin > http://xcski.com/blogs/pt/
"We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard...." - John F Kennedy

[Tom]

"Paul Tomblin" > wrote in message
...
> In a previous article, "Tom" > said:
> >> Some sort of variation on the question comes up a couple to times a
> >> year here. The answer is usually that no, the maximum pressure
> >> differential is about 15 psi, which is trivial for a tire.
> >>
> >Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the
nose
> >wheel and 98 PSI on the mains. They are filled with dry nitrogen.
>
> 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' )

[Tom]

"Paul Tomblin" > wrote in message
...
> In a previous article, "Tom" > said:
> >> Some sort of variation on the question comes up a couple to times a
> >> year here. The answer is usually that no, the maximum pressure
> >> differential is about 15 psi, which is trivial for a tire.
> >>
> >Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the
nose
> >wheel and 98 PSI on the mains. They are filled with dry nitrogen.
>
> 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.
>
I believe he's talking about the differential between the air in the tires
and the outside air.

[DaveSproul]

>> differential is about 15 psi, which is trivial for a tire.
>>
>Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the nose
>wheel and 98 PSI on the mains.

Apparently, another "sorry" would be in order. What he's saying is that the
difference between sea level and outer space is only around 15psi, which is
PROBABLY an almost insignificant fraction of the pressure usually existing
inside a properly inflated tire. Besides, it doesn't make any difference if the
wheel is behind a wheel well door if it is still not in the pressure vessel of
the fuselage.

An extrapolation of this discussion: the tires on the Space Shuttles. To the
best of my knowledge, they stay inflated the whole time, even in near zero
pressure on orbit.

David Sproul, Bethesda, MD

[Steven P. McNicoll]

"stephen" > wrote in message
m...
>
> How safe is Eclipse Aviaion's decision to expose the wheel on jet that
> cruises at 41,000 feet?
>

Perfectly safe. What is your concern?

[Steven P. McNicoll]

"Don Tuite" > wrote in message
...
>
> I think he's asking about either excess tire pressure bursting the
> tire or the tire expanding and getting stuck in the wheel well.
>

If that's his concern leaving the wheel exposed would make no difference as
wheel wells are not pressurized anyway.

[Steven P. McNicoll]

"Tom" > wrote in message
...
>
> Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the nose
> wheel and 98 PSI on the mains. They are filled with dry nitrogen.
>

Not maximum pressure, maximum pressure differential. Normal sea level
pressure is about 14.7 psi.

[Steven P. McNicoll]

"Tom" > wrote in message
...
>
> Your math doesn't add up (how cliche' )
>

How so?

[aptim]

B-737 don't have main gear doors either. But I don't know if a 737 can
cruise at FL410.

aptim A&P

"Tom" > wrote in message
...
>
> "stephen" > wrote in message
> m...
> > 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?
>
> Cessna Citation's have half open wheel bays. They cruise FL410 and up.
>

[Tom]

"DaveSproul" > wrote in message
...
> >> differential is about 15 psi, which is trivial for a tire.
> >>
> >Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the
nose
> >wheel and 98 PSI on the mains.
>
> Apparently, another "sorry" would be in order. What he's saying is that
the
> difference between sea level and outer space is only around 15psi, which
is
> PROBABLY an almost insignificant fraction of the pressure usually existing
> inside a properly inflated tire.

I suppose that he could be saying THAT! I figured he was addressing the
outside/inside air pressure.

This group is not known for high literacy content :~)

[[email protected]]

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.

--
Jim Pennino

Remove -spam-sux to reply.

[EDR]

In article >, Tom >
wrote:

> I suppose that he could be saying THAT! I figured he was addressing the
> outside/inside air pressure.

Nowhere does the original poster make any inferences to anything. It is
a straight question.

"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?"

[G.R. Patterson III]

Tom wrote:
>
> Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the nose
> wheel and 98 PSI on the mains. They are filled with dry nitrogen.

Which means that, if you took one into outer space, the nose tire would be
essentially at 135 PSI and the mains at 113.

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".

[Tom]

"G.R. Patterson III" > wrote in message
...
>
>
> Tom wrote:
> >
> > Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the
nose
> > wheel and 98 PSI on the mains. They are filled with dry nitrogen.
>
> Which means that, if you took one into outer space, the nose tire would be
> essentially at 135 PSI and the mains at 113.
>
Still the 'ol PITA, eh George?

[unrepentent]

On Fri, 5 Dec 2003 23:04:51 -0700, "Tom" > wrote:

>
> "DaveSproul" > wrote in message
> ...
> > >> differential is about 15 psi, which is trivial for a tire.
> > >>
> > >Sorry, but the tires on a Citation are inflated to 120 +/- PSI on the
> nose
> > >wheel and 98 PSI on the mains.
> >
> > Apparently, another "sorry" would be in order. What he's saying is that
> the
> > difference between sea level and outer space is only around 15psi, which
> is
> > PROBABLY an almost insignificant fraction of the pressure usually existing
> > inside a properly inflated tire.
>
> I suppose that he could be saying THAT! I figured he was addressing the
> outside/inside air pressure.
>
> This group is not known for high literacy content :~)

Nor are its readers. :-))

[Mike Beede]

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

[Roger Hamlett]

"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

[G.R. Patterson III]

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".

[stephen]

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.

[Dashi]

"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

[Tom]

"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.

[Thomas Borchert]

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)

[David Lesher]

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

[Ron Natalie]

"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.

[stephen]

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?

[Thomas Borchert]

David,

> Do the tires warm at all during decent?
>

Have you followed the Columbia accident analysis at all? The short
answer is: Yes.

--
Thomas Borchert (EDDH)

[Ron Natalie]

"Thomas Borchert" > wrote in message ...
> David,
>
> > Do the tires warm at all during decent?
> >
>
> Have you followed the Columbia accident analysis at all? The short
> answer is: Yes.

Well, what if you don't have a hole in the wing?

By the way, I notice that the inboard leading edge panel is missing off the Enterprise
when I was at the Udvar-Hazy center on Saturday. I suspect NASA has it for testing.

[Margy Natalie]

Ron Natalie wrote:

> "Thomas Borchert" > wrote in message ...
> > David,
> >
> > > Do the tires warm at all during decent?
> > >
> >
> > Have you followed the Columbia accident analysis at all? The short
> > answer is: Yes.
>
> Well, what if you don't have a hole in the wing?
>
> By the way, I notice that the inboard leading edge panel is missing off the Enterprise
> when I was at the Udvar-Hazy center on Saturday. I suspect NASA has it for testing.

Yup, that's where it is.

Margy