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How high can you fly?



 
 
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  #11  
Old September 18th 10, 11:30 PM posted to rec.aviation.piloting
Mark
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Posts: 815
Default How high can you fly?

On Sep 18, 6:08*pm, wrote:
Mark wrote:
On Sep 18, 5:19*pm, wrote:
Mark wrote:
On Sep 18, 1:37*pm, wrote:
Mark wrote:
Ok, it's the year 2016. You are in a little Cessna 150.
You're plane isn't pressurized because it will implode,
so you're wearing a pressurized body suit. You have
an oxygen mask. You plane is powered by a very
powerful brushless electric motor supplied by a 20lb
carbon nanotube source that is basically limitless.
Your powerplant is equivalent to 700hp in an LSA.
The electric motor and cabin are heated.


How high can you fly? 95,000ft?


Gibberish.


Eludication: my sentence ends in a question mark. The figure
was discriminate and taken from reference to U-2 heights.
Airfoils stop working in thin density. I asked when.


I wan't talking about the last sentence; your entire post is gibberish..


Little airplanes aren't presurized because the seals to keep things like
doors and windows from leaking are heavy. A soda can can hold 100 psi.


Little planes aren't pressurized because the ones I'm proposing
aren't currently able to reach anywhere near these elevations. Given
the heights I'm proposing, the airframe will buckle if the cabin is
pressurized. Fact.


If the airplane went into space and the interior were pressurized to sea
level, the pressure diffential would be about 14 psi.


The extremely thin aluminum in a soda can holds a pressure differential
of 100 psi.


The Apollo craft were pressurized and the skin on them is so thin the
average person could punch a hole through it bare handed.


You are full of crap.


And you bet the electric motor is heated, you will play hell keeping it
cool, even at altitude.


Brushless DC motors are different from conventional ones.


All motors have loss and the loss shows up as heat.


Cooling things at altitude is a problem because even though the air is cold,
it is very thin and you have to move a lot of it.


--
Jim Pennino


Remove .spam.sux to reply.- Hide quoted text -


- Show quoted text -


I studied the topic of service ceilings as well as ramifications
of what can occur at this elevation. Do the same and find
out about airframe distortion, pressure loss and break-ups.
It's aviation 101, not Coke can 101. You can stand on an
upright egg collection. You can stand on a coke can. Your
anologys are laughable. Spacecraft are made different
than Cessnas.


Babbling nonsense.

Read for content. Air density and cooling aren't relevant
to a sealed unit.


Cooling is especially relevant for heat producing sealed units.

Are you sure you aren't around 12 years old?

--
Jim Pennino


Er, I'm trying to go do something else and rushing
answers.

Clarification: With regard to the cooling of a sealed brushless
motor, your concerns and comments about air density are
basically irrelevant. They cool differently than open typical
electric motors that rely on air circulation.

Better?

Allrighty then.

---
Mark

ps. If you think I'm 12 then why are you debating
with a child. And why is this child kicking your...
forget it. Think about these conversations next
May when you look at the car lot.

  #12  
Old September 18th 10, 11:55 PM posted to rec.aviation.piloting
[email protected]
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Posts: 2,892
Default How high can you fly?

Mark wrote:

Clarification: With regard to the cooling of a sealed brushless
motor, your concerns and comments about air density are
basically irrelevant. They cool differently than open typical
electric motors that rely on air circulation.


Yeah, how is that, magic?

There are only two ways to cool any motor, and it doesn't matter whether
it is an ICE or electric.

You either put a bunch of pipes in the motor, run a fluid through them,
and dump the heat with a radiator that has air flowing through it or you
put cooling fins on the motor and that have air flowing over them.

And air at altitude may be cold, but it is also thin which means you have
to move a lot more air at altitude than sea level to get the same cooling.


--
Jim Pennino

Remove .spam.sux to reply.
  #13  
Old September 19th 10, 02:28 AM posted to rec.aviation.piloting
Mark
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Posts: 815
Default How high can you fly?

On Sep 18, 6:55*pm, wrote:
Mark wrote:
Clarification: With regard to the cooling of a sealed brushless
motor, your concerns and comments about air density are
basically irrelevant. They cool differently than open typical
electric motors that rely on air circulation.


Yeah, how is that, magic?

There are only two ways to cool any motor, and it doesn't matter whether
it is an ICE or electric.

You either put a bunch of pipes in the motor, run a fluid through them,
and dump the heat with a radiator that has air flowing through it or you
put cooling fins on the motor and that have air flowing over them.

And air at altitude may be cold, but it is also thin which means you have
to move a lot more air at altitude than sea level to get the same cooling..

--
Jim Pennino


Correct. The higher you go, the harder it is to displace the heat.
I believe the topic of this post is..."How high *can* you go?"

This doesn't mean you cannot have electric airplanes, or that
at 20,000 ft. they aren't superior to internal combustion.

You say, "You'll play hell keeping it cool". Well, yes and no.
At 95,000ft...it very well may be impossible. IMHO, the motor at any
elevation needs to be cooled with circulating glycol through a
patented design that runs through the center. At what elevation
your radiator ceases to displace heat...I don't know.

So yes, the elevation is relevant to cooling as you said, but
I am asserting that for GA purposes between AGL and
20,000 ft., you won't "play hell keeping it cool". On the
other hand, try leaving the troposphere and you might
better pack dry ice.

---
Mark

  #14  
Old September 19th 10, 03:28 AM posted to rec.aviation.piloting
Mark
external usenet poster
 
Posts: 815
Default How high can you fly?

On Sep 18, 2:40*pm, Jim Logajan wrote:
Mark wrote:
Ok, it's the year 2016. You are in a little Cessna 150.
You're plane isn't pressurized because it will implode,


Explode, not implode. Unless it is an underwater submersible?

so you're wearing a pressurized body suit. You have
an oxygen mask. You plane is powered by a very
powerful brushless electric motor supplied by a 20lb
carbon nanotube source that is basically limitless.


Your claims are absurd.


Ok, yes I'm just conceptualizing to paint my hypothetical
picture, and indiscriminately pulled out a number of 20lbs.,
and posters such as "a" have already explained the
parameters that must be analyzed to do the math. But
I keep running across new technologies and it takes time
to come up with hard data and numbers that would allow
me or anyone else to tell you what the new batteries
weigh or what their energy density and durations are.

I have however had them described to me in general
terms and you know what? 1) it's exciting 2) few people
have a clue what is on the horizon 3) the impetus has
already swung in this direction and lastly 4) we really
have no choice afa worldwide auto application goes.
5) I think most pilots would rather fly without vibration.

---
Mark
  #15  
Old September 19th 10, 05:06 AM posted to rec.aviation.piloting
Jim Logajan
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Posts: 1,958
Default How high can you fly?

Mark wrote:
I keep running across new technologies and it takes time
to come up with hard data and numbers that would allow
me or anyone else to tell you what the new batteries
weigh or what their energy density and durations are.


I'm trying to point out that some of us have some of idea of what is
possible within the next 10 years and what the ultimate physical limits are
of energy density.

Wikipedia has a table of energy densities for several battery technologies
compared with traditional energy storage:

http://en.wikipedia.org/wiki/Energy_density

So far as I can tell it appears roughly correct.

Avgas has an energy density of ~44MJ/kg.
The best _emerging_ battery technology has an energy density of ~3.6MJ/kg.

Ground vehicles can still be useful with low energy densities, but aircraft
rapidly decline in utility. Put another way, airlines will be flying jets
burning jet fuel for the forseeable future.
  #16  
Old September 19th 10, 05:12 AM posted to rec.aviation.piloting
[email protected]
external usenet poster
 
Posts: 2,892
Default How high can you fly?

Mark wrote:
On Sep 18, 6:55Â*pm, wrote:
Mark wrote:
Clarification: With regard to the cooling of a sealed brushless
motor, your concerns and comments about air density are
basically irrelevant. They cool differently than open typical
electric motors that rely on air circulation.


Yeah, how is that, magic?

There are only two ways to cool any motor, and it doesn't matter whether
it is an ICE or electric.

You either put a bunch of pipes in the motor, run a fluid through them,
and dump the heat with a radiator that has air flowing through it or you
put cooling fins on the motor and that have air flowing over them.

And air at altitude may be cold, but it is also thin which means you have
to move a lot more air at altitude than sea level to get the same cooling.

--
Jim Pennino


Correct. The higher you go, the harder it is to displace the heat.
I believe the topic of this post is..."How high *can* you go?"


So you are finally giving up on your assertion that a sealed brushless
motor is magic and won't need cooling?

This doesn't mean you cannot have electric airplanes, or that
at 20,000 ft. they aren't superior to internal combustion.


Electric airplanes are not and will not be superior to ICE airplanes
at any altitude any time in the foreseeable future.

There are already GA aircraft that regularly fly at flight levels, though
most of them that go much over 20,000 feet don't use pistons in the engine.

There is no market for small, as in C172 size, airplanes that can get to the
flight levels or someone would already be making them powered by small
turbines.


snip babble


--
Jim Pennino

Remove .spam.sux to reply.
  #18  
Old September 19th 10, 07:20 AM posted to rec.aviation.piloting
Ted Sherman
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Posts: 24
Default How high can you fly?

On Sat, 18 Sep 2010 18:28:59 -0700 (PDT), Mark wrote:

Correct. The higher you go, the harder it is to displace the heat.
I believe the topic of this post is..."How high *can* you go?"


Me? When I take a triple does of my Xanax and follow it with a few
Tequilas, I can maintain an altitde of 95.000 AGL.


ooooooooooooooK
  #20  
Old September 19th 10, 07:27 AM posted to rec.aviation.piloting
Ted Sherman
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Posts: 24
Default How high can you fly?

On Sat, 18 Sep 2010 19:28:08 -0700 (PDT), Mark wrote:

Ok, yes I'm just conceptualizing to paint my hypothetical picture
and you know what? 1) it's exciting 2) few people have a clue what
is on the horizon so I should be called the Messiah Of Bull****
3) I think most pilots would rather fly without vibration. 4) Most
women rave about vibration 5) I never get laid so I hate vibration
6) Go **** yourselves.


oooooooooooooooK
 




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