The new Electric Cessna 172

There was a contest recently where one had to demonstrate more than 200 passenger miles per gallon equivalent, and an engineering team from Penn State won it with a battery powered airplane.

See

http://live.psu.edu/story/55543

for details.




On Friday, December 21, 2012 9:02:15 PM UTC-5, wrote:
Ideal for flight schools. The amazing

brushless electric ring motors which

I mentioned before, produce 600 lbs.

static thrust.



http://www.flyingmag.com/news/two-pl...na-172-skyhawk



--

Mark

On Tuesday, January 1, 2013 10:10:37 AM UTC-5, a wrote:
There was a contest recently where one had to demonstrate more than 200 passenger miles per gallon equivalent, and an engineering team from Penn State won it with a battery powered airplane.



See



http://live.psu.edu/story/55543



for details.


http://nextbigfuture.com/2009/12/sup...-electric.html

--
Mark

wrote:


http://nextbigfuture.com/2009/12/sup...-electric.html

--
Mark

Practical, manufacturable high temperature superconductors would enable
a whole bunch of neat things and would be as spectacular as a cure for the
common cold, lasting peace in the Middle East, and controlled fusion, and
is just as likely to happen in the near future.

On Jan 1, 1:24*pm, wrote:
wrote:

http://nextbigfuture.com/2009/12/sup...enable-electri...

--
Mark

Practical, manufacturable high temperature superconductors would enable
a whole bunch of neat things and would be as spectacular as a cure for the
common cold, lasting peace in the Middle East, and controlled fusion, and
is just as likely to happen in the near future.

I recently read up on some work being done with graphene
supercapacitors. I IRC, it was at Caltech. What was interesting is how
they performed at lower temperatures (e.g. room temp.). Also, charging
times were impressive. Still in the realm of research, so it wasn't
clear to me how well it would scale beyond smaller applications
(consumer electronics, for example.

wrote:
On Jan 1, 1:24Â*pm, wrote:
wrote:

http://nextbigfuture.com/2009/12/sup...enable-electri...

--
Mark

Practical, manufacturable high temperature superconductors would enable
a whole bunch of neat things and would be as spectacular as a cure for the
common cold, lasting peace in the Middle East, and controlled fusion, and
is just as likely to happen in the near future.

I recently read up on some work being done with graphene
supercapacitors. I IRC, it was at Caltech. What was interesting is how
they performed at lower temperatures (e.g. room temp.). Also, charging
times were impressive. Still in the realm of research, so it wasn't
clear to me how well it would scale beyond smaller applications
(consumer electronics, for example.


Supercapacitors are great for things like keeping your clock from flashing
on every minor power failure, but not that great for real power application.

The basic physics of capacitors says the energy density can never be as
good as existing batteries. Graphene makes them better but it will take
yet to be invented materials to match batteries.

Capacitors are also a poor choice for running something like a motor because
of their discharge curve.

While a battery's discharge curve is basically flat until it gets close to
full discharge, then takes a big dive, a capacitor discharge curve is a
straight line between fully charged and zero.

Motors operate over a narrow voltage range. Electric motor speed control
is done by pulsing the motor voltage on and off, not by varying a constant
voltage.

Now it is possible to build a thing that will take in a lower voltage and
output some constant higher voltage to keep a motor happy.

The problem with that is it is more complexity subject to failure, not
good with airplanes, and it would require big, heavy, high current
transformers, which ups the weight a good bit.

My wild assed guess is that if electric airplanes ever become practical
without Star Trek technology, it will likely be through a fuel cell that
is yet to be invented.

On Feb 1, 12:25*pm, wrote:
wrote:
On Jan 1, 1:24*pm, wrote:
wrote:

http://nextbigfuture.com/2009/12/sup...enable-electri....

--
Mark

Practical, manufacturable high temperature superconductors would enable
a whole bunch of neat things and would be as spectacular as a cure for the
common cold, lasting peace in the Middle East, and controlled fusion, and
is just as likely to happen in the near future.

I recently read up on some work being done with graphene
supercapacitors. I IRC, it was at Caltech. What was interesting is how
they performed at lower temperatures (e.g. room temp.). Also, charging
times were impressive. Still in the realm of research, so it wasn't
clear to me how well it would scale beyond smaller applications
(consumer electronics, for example.

Supercapacitors are great for things like keeping your clock from flashing
on every minor power failure, but not that great for real power application.

The basic physics of capacitors says the energy density can never be as
good as existing batteries. Graphene makes them better but it will take
yet to be invented materials to match batteries.

Capacitors are also a poor choice for running something like a motor because
of their discharge curve.

While a battery's discharge curve is basically flat until it gets close to
full discharge, then takes a big dive, a capacitor discharge curve is a
straight line between fully charged and zero.

Motors operate over a narrow voltage range. Electric motor speed control
is done by pulsing the motor voltage on and off, not by varying a constant
voltage.

Now it is possible to build a thing that will take in a lower voltage and
output some constant higher voltage to keep a motor happy.

The problem with that is it is more complexity subject to failure, not
good with airplanes, and it would require big, heavy, high current
transformers, which ups the weight a good bit.

My wild assed guess is that if electric airplanes ever become practical
without Star Trek technology, it will likely be through a fuel cell that
is yet to be invented.

Most of what I was reading didn't seem to indicate that the goal is to
replace, but rather to compliment existing technologies, e.g. charging
applications.

http://phys.org/news/2012-10-sponge-...ectrodes..html
- Graphene

http://phys.org/news/2011-08-energy-...-electric.html
- SMC

I'm not saying it will (ever) power an airplane. Just looked
interesting and sometimes there are great discoveries that come out of
research, often in applications that were never part of the planned
research itself.

Peace.

wrote:

snip old stuff


Most of what I was reading didn't seem to indicate that the goal is to
replace, but rather to compliment existing technologies, e.g. charging
applications.

http://phys.org/news/2012-10-sponge-...lectrodes.html
- Graphene

http://phys.org/news/2011-08-energy-...-electric.html
- SMC

Lot's of little techical problems in both of those articles.

The biggest is talking about recharging in minutes.

It is a rather simple calculation to calculate the current requirments
to recharge a device (doesn't matter battery or capacitor) to the full
energy level in a few minutes.

When you do that you discover that the size of the cable required so that
it will not vaporize due to the current density is as big around as your
leg with matching connectors.

Energy sources are rated in KWh and is equivalent to 1000 x V x A x h.

A typical electric car battery is around 30 KWh and 100 volts and 6 minutes
is 0.1 hours so:

30,000 / (100 x .1) = 3,000 Amps

To put the wire required in perspective, those big heavy cables on an
arc welder are good for a current of around 100 Amps so your charging
cable would have to be about 30 times bigger than arc welder cables.

I'm not saying it will (ever) power an airplane. Just looked
interesting and sometimes there are great discoveries that come out of
research, often in applications that were never part of the planned
research itself.

Yeah, that is usually the case.


Peace.

a wrote:
There was a contest recently where one had to demonstrate more than
200 passenger miles per gallon equivalent, and an engineering team from
Penn State won it with a battery powered airplane.

See

http://live.psu.edu/story/55543

for details.


It is just a big motor glider.