Electrically Powered Ultralight Aircraft

"Snowbird" wrote:

"kontiki" wrote

Yeah sure, but its not practical for anything but an hour or two of
playing around on a Saturday afternoon.

Flight training in the pattern is an obvious first application.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Well, well.
Looks who is still alive.

Hi there.


- Barnyard BOb -

Ken Finney wrote:
I'm willing to
drive a car with Li-Ion batteries, I can run away from the fire.

Are you going to park it in your garage while you sleep at night?

"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Ken Finney wrote:
I'm willing to
drive a car with Li-Ion batteries, I can run away from the fire.

Are you going to park it in your garage while you sleep at night?


Well, people park Fords in their garages!

;^)

"Morgans" wrote in message
...

"Ken Finney" wrote

Yes. GM is also working with another company, A123, on their
"nano-phosphate" technology, but it is just a different flavor of Li-Ion.

Close, but not quite accurate.

The common lithium ion battery outgases oxygen in the process of burning,
which then feeds conventional fires and helps consume the other cells.

The 123 batteries are a different chemistry that do not outgas oxygen,
thus do not catastrophically fail.


Thanks for the info!

Ken Finney wrote:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Ken Finney wrote:
I'm willing to
drive a car with Li-Ion batteries, I can run away from the fire.

Are you going to park it in your garage while you sleep at night?


Well, people park Fords in their garages!

;^)

And they're screwed if someone runs into the back of their garaged Pinto.

On Fri, 10 Aug 2007 17:12:09 GMT, Larry Dighera
wrote:

It sounds like you have quite a bit of experience in this area. Are
you able to provide links to any forums or web sites related to this
topic?

Try http://electricppg.com

I've been flying PPG for about 6 years now; got into it when I
realized I couldn't afford to restore my Taylorcraft. Finally managed
to get another plane (Kolb this time), but PPG is so much fun I don't
intend to give it up.

Never flew an electric PPG, though... they're still pretty rare birds.

-Dana
--
--
If replying by email, please make the obvious changes.
-------------------------------------------------------------------------------
Abandon all hope, ye who PRESS ENTER here.

On Sat, 11 Aug 2007 15:35:25 GMT, Larry Dighera
wrote:

I would assume that the source of these Li-ion Polymer battery fires
is excessive electrical current flowing through the battery either
from too high a charging rate, too high a discharge rate, or a short
internal (as in the case of the Sony laptop cells) or external, or
being over charged. Perhaps it would be prudent to install a circuit
breaker of fuse to prevent too high a current and a timer to
disconnect a forgotten charger.

I imagine the root of the problem is very low internal resistance
which, while making them very efficient, also allows the current to
"run away". Good circuit design can alleviate many of the issues, but
safety if the batteries are damaged in a crash is still an issue.

-Dana
--
--
If replying by email, please make the obvious changes.
-------------------------------------------------------------------------------
Abandon all hope, ye who PRESS ENTER here.

"Dana M. Hague" d(dash)m(dash)hague(at)comcast(dot)net wrote in message
...
On Sat, 11 Aug 2007 15:35:25 GMT, Larry Dighera
wrote:

I would assume that the source of these Li-ion Polymer battery fires
is excessive electrical current flowing through the battery either
from too high a charging rate, too high a discharge rate, or a short
internal (as in the case of the Sony laptop cells) or external, or
being over charged. Perhaps it would be prudent to install a circuit
breaker of fuse to prevent too high a current and a timer to
disconnect a forgotten charger.

I imagine the root of the problem is very low internal resistance
which, while making them very efficient, also allows the current to
"run away". Good circuit design can alleviate many of the issues, but
safety if the batteries are damaged in a crash is still an issue.

-Dana
--

Any battery chemistry, including lead-acid, can overheat with excess
charging current - usually to the detriment of the battery and whatever it
is in at the time. All can do damage if they are shorted. The problem with
the first generation lithium cells was the chemistry released oxygen when
overheated which combined with the flammable lithium made an incendiary
bomb.

The newest lithium-nanophosphate cells do not release oxygen and thus do not
burn or explode although they can be damaged by overcharging. Cells made by
A123 Systems, Saft, Valence and others are more than safe enough for use in
aircraft or cars. They have a little less energy capacity than the old
chemistry but they make up for it with fast charging and long life. They
can typically manage a 20C discharge rate without harm - that's 200 amps for
a 10 AH battery. Admittedly, you don't want to short that.

Bill Daniels

On Mon, 13 Aug 2007 17:39:44 -0400, Dana M. Hague
d(dash)m(dash)hague(at)comcast(dot)net wrote in
:

safety if the batteries are damaged in a crash is still an issue.

I would think the hazard somewhat less than gasoline.

Larry Dighera wrote:
On Mon, 13 Aug 2007 17:39:44 -0400, Dana M. Hague
d(dash)m(dash)hague(at)comcast(dot)net wrote in
:

safety if the batteries are damaged in a crash is still an issue.

I would think the hazard somewhat less than gasoline.

The battery can produce it's own ignition source.