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Old September 19th 10, 05:12 AM posted to rec.aviation.piloting
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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

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