Electrically Powered Ultralight Aircraft

Morgans wrote:
"Dana wrote
The major problem is the weight of the batteries, still far heavier
than gasoline. Also the lithium polymer batteries used are still
quite expensive (over $10,000 for enough for a half hour flight) and
somewhat dangerous (sort them out and they can explode!)

Damn straight! No way am I going to strap a bunch of lithium polymer
batteries to my butt.

Some of the newer Lithium iron cells, maybe, but they also cost a LOT
more.
Still, electric flight, like many have said, still have a way to go.

And as if we need more proof of this.

TOKYO: Japan's Toyota Motor Corp. will delay by one or two years the rollout
of new high-mileage hybrids with lithium-ion batteries because of safety
concerns, reported a newspaper.

Toyota's decision was prompted by worries that the batteries could overheat,
catch fire or even explode, the Wall Street Journal on Thursday reported in
its online edition, quoting unnamed Toyota executives.

Gig

Just saw where GM bought a battery company here in US that has
developed batteries that do not catch fire or expload like current
Lithium Polymer's.

GM expects to have a plug in auto on market at least two years before
Toyota can get their batteries sorted out and their auto on the
market.

Big John
*************************************************


On Fri, 10 Aug 2007 11:37:39 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote:

Morgans wrote:
"Dana wrote
The major problem is the weight of the batteries, still far heavier
than gasoline. Also the lithium polymer batteries used are still
quite expensive (over $10,000 for enough for a half hour flight) and
somewhat dangerous (sort them out and they can explode!)

Damn straight! No way am I going to strap a bunch of lithium polymer
batteries to my butt.

Some of the newer Lithium iron cells, maybe, but they also cost a LOT
more.
Still, electric flight, like many have said, still have a way to go.

And as if we need more proof of this.

TOKYO: Japan's Toyota Motor Corp. will delay by one or two years the rollout
of new high-mileage hybrids with lithium-ion batteries because of safety
concerns, reported a newspaper.

Toyota's decision was prompted by worries that the batteries could overheat,
catch fire or even explode, the Wall Street Journal on Thursday reported in
its online edition, quoting unnamed Toyota executives.

GM on the cutting edge of anything is a little funny. And I'm sure Sony
didn't think their batteries would do this...
http://www.youtube.com/watch?v=WeWq6rWzChw



Is this the story you are talking about John? If so what is an "LG Chem
cell?"
http://www.autobloggreen.com/2007/06...cts-for-chevy/


Big John wrote:
Gig

Just saw where GM bought a battery company here in US that has
developed batteries that do not catch fire or expload like current
Lithium Polymer's.

GM expects to have a plug in auto on market at least two years before
Toyota can get their batteries sorted out and their auto on the
market.

Big John
*************************************************

Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT TO:
GM on the cutting edge of anything is a little funny. And I'm sure
Sony didn't think their batteries would do this...
http://www.youtube.com/watch?v=WeWq6rWzChw



Is this the story you are talking about John? If so what is an "LG
Chem cell?"
http://www.autobloggreen.com/2007/06...gm-awards-two-
battery-development-contracts-for-chevy/


GM doing this also kind of proves my point that the new battery technology
is coming from somewhere with a lot more money in play than the ultralight
and LSA market.

On Thu, 09 Aug 2007 23:13:55 -0400, Dana M. Hague
d(dash)m(dash)hague(at)comcast(dot)net wrote in
:

On Tue, 07 Aug 2007 14:58:07 GMT, Larry Dighera
wrote:

If a 14 HP electric propulsion system weighing 46 lbs could be
constructed, apparently it would permit the use of PPGs by pilots up
to 180 lbs.

A PPG is a LOT more efficient than a powered parachute (PPC), but
still far less efficient than a rigid wing. Still, several electric
PPG's have been flown. The primary goal here is noise and vibration
reduction, a worthy goal when the engine is strapped to the pilot's
back.

The major problem is the weight of the batteries, still far heavier
than gasoline. Also the lithium polymer batteries used are still
quite expensive (over $10,000 for enough for a half hour flight) and
somewhat dangerous (sort them out and they can explode!)

-Dana

That's interesting information. Thank you.


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?

Are
you able to provide links to any forums or web sites related to this


Check this out: http://www.calcars.org/news-archive.html

David Johnson

On Aug 10, 5:12 pm, Dave wrote:
Are

you able to provide links to any forums or web sites related to this

Check this out:http://www.calcars.org/news-archive.html

David Johnson

Lithium Polymer batteries are widely used in RC planes, cars, etc and
are known to be potentially dangerous. Most runaway fires occur during
charging but it has also occurred to a lessor degree during discharge
and even storage. Vented charging safety bags are recommended for this
reason. There is a video on this link that shows the explosive power
of small LiPo's. Consider the size differance of these batteries to
the one hung under the trike in one of the first posts or those that
could be installed in the wings of a sailplane.
http://www.liposack.com/video.html

On Sat, 11 Aug 2007 06:59:02 -0700, wrote in
.com:


Lithium Polymer batteries are widely used in RC planes, cars, etc and
are known to be potentially dangerous. Most runaway fires occur during
charging but it has also occurred to a lessor degree during discharge
and even storage.

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.

Vented charging safety bags are recommended for this
reason. There is a video on this link that shows the explosive power
of small LiPo's. Consider the size differance of these batteries to
the one hung under the trike in one of the first posts or those that
could be installed in the wings of a sailplane.
http://www.liposack.com/video.html

Thank you for the link. It is spectacular.


Here are some links relevant to the Sony Lithium laptop battery
recall:

Story: http://www.theinquirer.net/default.aspx?article=32550
http://news.com.com/Dell+takes+heat+...3-6105828.html

Video:
http://www.youtube.com/watch?v=WeWq6...lated&search=#

Explanation of cause:
http://reviews.cnet.com/4660-10165_7-6625980.html
http://www.prnewstoday.com/release.h...H05424082006-1
The recall arises because, on rare occasions, microscopic metal
particles in the recalled battery cells may come into contact with
other parts of the battery cell, leading to a short circuit within the
cell. Typically, a battery pack will simply power off when a cell
short circuit occurs. However, under certain rare conditions, an
internal short circuit may lead to cell overheating and potentially
flames. The potential for this to occur can be affected by variations
in the system configurations found in different notebook computers.

The thing that strikes me most in this thread is that so many people
just don't seem to understand...

1) weight

2) power

3) scale

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
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