How high can you fly?

On Sep 19, 12:12*am, wrote:
Mark wrote:
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?"

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

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- Show quoted text -

Thanks Jim.

---
Mark

On Sep 19, 12:12*am, wrote:

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

Who ever said that a sealed brushless motor is magic
and won't need cooling? I certainly didn't. This is just another
example of your revisionistic debating style.

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.

Most people are unable to see beyond today. I don't
envision heavy low-density batteries. No ICE dragster
can beat an electric one. That's real now. Yes, it's
short run. Yes gravity isn't a factor. But people are flying
electric planes today. That's real. Billions are being spent
on a better power technology...and I believe they're going
to make it and when they do...I will retrofit a plane
such as one that currently is an LSA.

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.

And if they didn't need oxygen for combustion...

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.

That's because it's too specialized. An electric plane can fly
at any elevation it want's to under the stratosphere until air
density prevents lift, or cooling is impossible. Therefore a cheap
retrofitted small plane would simply fly over inclement weather,
changing the paradigm of general aviation. And, the fun level
would be off the chart.

snip your snip

---

Mark

--
Jim Pennino

Mark wrote:
On Sep 19, 12:12Â*am, wrote:

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

Who ever said that a sealed brushless motor is magic
and won't need cooling? I certainly didn't. This is just another
example of your revisionistic debating style.

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.

Most people are unable to see beyond today. I don't
envision heavy low-density batteries. No ICE dragster
can beat an electric one. That's real now. Yes, it's
short run. Yes gravity isn't a factor. But people are flying
electric planes today. That's real. Billions are being spent
on a better power technology...and I believe they're going
to make it and when they do...I will retrofit a plane
such as one that currently is an LSA.

Yeah, sure, and it is going to happen any day now along with controlled
fusion, a cure for the common cold, and artificial intelligence.

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.

And if they didn't need oxygen for combustion...

No one would care.

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.

That's because it's too specialized. An electric plane can fly
at any elevation it want's to under the stratosphere until air
density prevents lift, or cooling is impossible.

Nope, doable today with either a turbocharger on a piston engine or a
turbine. A turbine would get you higher, but there is no market for even
a turbocharged C172 size airplane.

And it doesn't require magic batteries that don't exist.

Therefore a cheap
retrofitted small plane would simply fly over inclement weather,
changing the paradigm of general aviation. And, the fun level
would be off the chart.

Wet dream babble.


--
Jim Pennino

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Jim Logajan wrote:
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.

The only aviation market I can see for electric airplanes, if batteries
ever get good enough and cheap enough, is for self launched gliders.


--
Jim Pennino

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On Sun, 19 Sep 2010 14:44:28 -0000, wrote:

Jim Logajan wrote:
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.

The only aviation market I can see for electric airplanes, if batteries
ever get good enough and cheap enough, is for self launched gliders.

Doesn't surprise me, you have no vision. Most
people don't which is why I am wealthy beyond
your imagination.

Get on board. I can make you loads of money.
You could afford to buy a hat for your pinhead.

Mark Of The Financial World

Mark wrote:
On Sun, 19 Sep 2010 14:44:28 -0000, wrote:

Jim Logajan wrote:
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.

The only aviation market I can see for electric airplanes, if batteries
ever get good enough and cheap enough, is for self launched gliders.

Doesn't surprise me, you have no vision. Most
people don't which is why I am wealthy beyond
your imagination.

Get on board. I can make you loads of money.
You could afford to buy a hat for your pinhead.

Mark Of The Financial World

More like Mark the babbling child-man.


--
Jim Pennino

Remove .spam.sux to reply.

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

While I think Mark is starry eyed (at best,) you are technically mistaken
in the above assertion because in fact electric airplanes (actually solar-
electric airplanes) hold some world records:

When the solar-electric "Pathfinder" reached 80,000 ft in 1999 it set the
altitude record for highest altitude flown by prop-driven aircraft.

When the solar-electric "Helios" reached 96,863 ft in 2001 it set the
altitude record for highest altitude flown by non-rocket powered aircraft.

When the solar-electric "Zepher" stayed aloft for for over 2 weeks in 2010,
it set the endurance record for unmanned aircraft.

The common element of these is "solar-electric". None of them would have
been possible with batteries. They could not have gotten off the ground had
they used batteries. None of them would have been plausibly accomplished
with internal (or external) combustion engines. The latter gasp for breath
at high altitudes.

So electric (specifically solar-electric) is indeed superior for certain
applications. Just not general aviation.

On Sun, 19 Sep 2010 17:31:59 -0500, Jim Logajan wrote:

While I think Mark is starry eyed (at best,)

If starry eyed means delusional fukknutzoind, yeah, you got it.
--

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

While I think Mark is starry eyed (at best,) you are technically mistaken
in the above assertion because in fact electric airplanes (actually solar-
electric airplanes) hold some world records:

When the solar-electric "Pathfinder" reached 80,000 ft in 1999 it set the
altitude record for highest altitude flown by prop-driven aircraft.

When the solar-electric "Helios" reached 96,863 ft in 2001 it set the
altitude record for highest altitude flown by non-rocket powered aircraft.

When the solar-electric "Zepher" stayed aloft for for over 2 weeks in 2010,
it set the endurance record for unmanned aircraft.

The common element of these is "solar-electric". None of them would have
been possible with batteries. They could not have gotten off the ground had
they used batteries. None of them would have been plausibly accomplished
with internal (or external) combustion engines. The latter gasp for breath
at high altitudes.

So electric (specifically solar-electric) is indeed superior for certain
applications. Just not general aviation.

They hold records for R/C airplanes.

None of them had a human, or anything alive, on board.

One off research prototypes can be interesting, but that's about it.



--
Jim Pennino

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Mark opined

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?

This will soon be a real consideration.

I don't have the figures available at the moment, but I can tell you what to
look for and what to do.

Find the Vs for a C152.

Find the Mmo, likely about M.75.

Your max altitude is where the true Vs == Mmo.


-ash
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Vote the greater evil.