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Old November 15th 15, 03:24 AM posted to rec.aviation.piloting
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Default Siemens' 110 lb world-record electric aircraft motor produce 348hp at 2,500 RPM

On Saturday, November 14, 2015 at 10:02:07 PM UTC-5, wrote:
On Saturday, November 14, 2015 at 6:51:57 PM UTC-5, Vaughn Simon wrote:
On 11/14/2015 5:14 PM, wrote:
As researchers continue to work on creating better
batteries, the logical solution all along was always
the Auxiliary Power Unit for charging.

Well yes that will work (assuming an electric drive train with a
battery) , long as that APU produces significantly MORE power than
the average that you will need at the prop hub. The reason why you
would need MORE power is to make up for the losses inherent in the
generator, motor, battery, and controller.

In an ideal world, there would be a RTG such as NASA
and Russian lighthouses have used for decades. The
Radioisotope Thermoelectric Generators can put out
whopping power from a container the size of a coffee
thermos. Fairly benign from a gamma ray exposure
standpoint, you could keep an electric airplane up
for weeks at a time.

Sorry, that is just complete nonsense! Forgetting for a moment the
problems with carrying highly radioactive materials in an aircraft,

Yes, I said "in a perfect world" (not the current one). While
it's legal to obtain a permit to work with radioactive material,
few can do it, and the FAA wouldn't even consider such. But
then, who says you have to do it in a modern country.

forgetting that those materials are so rare and expensive

They can be obtained for a few planes, but no, you couldn't
mass produce this system. I think you may be surprised at
how easy it is to obtain an isotope on the world market.

that even few
spacecraft use them these days,

They are still used in every deep space mission.

RTGs are very inefficient devices.

They are highly efficient. It's just a thermocouple system.

produce, at most, a few hundred watts of electrical power, a tiny
fraction of what a full-sized aircraft would need.

Well yes. I wasn't suggesting attaching the motor itself to
the RTG. I'm saying- if you have a battery bank that may last
say 2 hours stand alone, then having the storage system
permanently connected to this battery charger, depending on
your draw, would be a tremendous extender. It's like having
your battery bank plugged into a wall socket at all times
to an electrical source much stronger than a trickle charger.
Your watt/amp gauge would tell you when to conserve.

And yes, 400 watts would be about max. Really the question is,
"how much electricity can I replace with the charger, as
opposed to what the motor is pulling out of the battery bank".
If you are soaring, you're using no power but it's still


I believe an automobile, due to weight and tire friction, requires more power
than a plane. This is just a guess.

"According to the company, their technology would allow you to charge the battery of a Nissan Leaf in 12 minutes instead of four hours. Because that battery has a capacity of 24 kWh, a back-of-the-envelope extrapolation would give us a charging time of 42 minutes for the 85 kWh battery of a top of the line Tesla Model S."