Electrically Powered Ultralight Aircraft

Please keep in mind that there are many lithium ion and lithium polymer
chemstries. It isn't too informative to just say "Lithium Polymer" or
Lithium Ion" without stating the precise chemistry. Further, chemistries
are changing almost daily. Many are proprietary. There's no such thing as
a "standard" lithium battery chemistry.

Valence, Saft and A123 Systems use chemistries that are far safer than the
relatively inexpensive Korean made model airplane batteries - safer than the
typical laptop or cell phone battery which are spec'd mainly on price.

Interestingly, the safest chemistries in the latest cells also offer faster
charging, greater energy density and will endure a FAR greater number of
charge cycles. They're also potentially cheaper.

I've already made a cell holder for A123 Systems "A1" cells. That's the
lithium phosphate nano cathode one used in 36V DeWalt power tools. You can
buy a couple of new DeWalt 36V power packs for $50 or so on Ebay. Then,
dismantle the pack to retrieve the individual cells. My pack will be 13.8
volts and 11AH weighing 3 pounds. It will be the same size as a 7AH 12V SLA
but weigh less than half as much.

Bill Daniels

Some Lithium cells can suffer thermal runaway and fire. Others are
extremely
wrote in message
oups.com...
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 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
--
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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.

It's sort of like a neighbor of mine who was complaining
about the price
of
gas - his SUV only gets 12MPG. I suggested he think
about pushing his
6000
pound truck 12 miles by hand. That would give him
the proper respect
for
the energy in a gallon of gasoline - and its value.

Liquid petroleum fuels are extremely energy dense.
It's going to be
really
hard to replace that with electricity. But maybe not
impossible.

Bill Daniels
For many applications a better 'alternative energy'
might be to squeeze
the maximum available power out of existing technology.
Below is an
engine which uses the heat from combustion to add another
power stroke
to an engine. Its not electrically powered but in
the future it may
compete with electric engines.
http://www.popsci.com/popsci/technology/
c1609351d9092110vgnvcm1000004eecbccdrcrd.html

Name: Steam-o-Lene Engine
Inventor: Bruce Crower
Cost to Develop: $1,000
Time: 1.5 years
Prototype | | | | | Product


Bruce Crower's Southern California auto-racing parts
shop is a temple for
racecar mechanics. Here's the flat eight-cylinder Indycar
engine that won
him the 1977 Louis Schwitzer Award for racecar design.
There's the
Mercedes five-cylinder engine he converted into a squealing

supercharged two-stroke, just 'to see what it would
sound like,' says the
now half-deaf 77-year-old self-taught engineer.

Crower has spent a lifetime eking more power out of
every drop of fuel
to make cars go faster. Now he's using the same approach
to make them
go farther, with a radical six-stroke engine that tops
off the familiar
four-stroke internal-combustion process with two extra
strokes of old-
fashioned steam power.

A typical engine wastes three quarters of its energy
as heat. Crower's
prototype, the single-cylinder diesel eight-horsepower
Steam-o-Lene
engine, uses that heat to make steam and recapture
some of the lost
energy. It runs like a conventional four-stroke combustion
engine
through each of the typical up-and-down movements of
the piston
(intake, compression, power or combustion, exhaust).
But just as the
engine finishes its fourth stroke, water squirts into
the cylinder, hitting
surfaces as hot as 1,500°F. The water immediately evaporates
into
steam, generating a 1,600-fold expansion in volume
and driving the
piston down to create an additional power stroke. The
upward sixth
stroke exhausts the steam to a condenser, where it
is recycled into
injection water.

Crower calculates that the Steam-o-Lene boosts the
work it gets from a
gallon of gas by 40 percent over conventional engines.
Diesels, which are
already more efficient, might get another 5 percent.
And his engine does
it with hardware that already exists, so there's no
waiting for
technologies to mature, as with electric cars or fuel
cells.

'Crower is an innovator who tries new ideas based on
his experience and
gut instincts,' says John Coletti, the retired head
of Ford's SVT high-
performance group. 'Most people won't try something
new for fear of
failure, but he is driven by a need to succeed.' And
he just might.
Crower has been keeping the details of his system quiet,
waiting for a
response to his patent application. When he gets it,
he'll pass off the
development process to a larger company that can run
with it, full-
steam.

Warning: A boring essay on obsolete internal combustion technology follows.

A merging of steam and internal combustion is probably the first "hybrid"
with the first efforts dating from the beginning of the last century. The
pinacle of its development was the monster water-injected turbo-compound
radial engines developed late in WWII.

Water injection acts is several favorable ways. First, somewhat as
described below, it flashes into steam to increase the cylinder pressure and
then escapes through the exhaust valves to a pressure recovery turbine which
transmits its power back to the crankshaft through a fluid coupling - the
"turbo compound" part.

Water also cools the cylinder allowing more fuel/air mixtue to be forced
into it. Finally, and this not widely known, water is even more effective
than tetraethyl lead in decreasing the tendency of the fuel/air mixture to
detonate or pre-ignite thus allowing far higher boost pressures. The only
compound more effective than water is nitros oxide.

Both Allied and Axis ari forces used water injection but only Germany used
nitros oxide. Either could double an engines power for as long as the
supply of H2O or NO lasted. But, on a power to weight basis, avgas easily
wins so water injection was only used for takeoff or when maximum military
power was needed to escape an enemy.

The citation for the above is a very old engineering textbook titled "High
Speed Internal Combustion Engines" by Sir Harry Recardo. I highly recomend
it if you are at all interested in IC engines. Sir Harry's work on sleeve
valve engines is particularly interesting.

I could be wrong but I would guess that water injection gets 90% of the
benifits possible without the major modification to the engine required by
Bruce Crower's "6-stroke".

Bill Daniels


"Steve Davis" wrote in message
...
It's sort of like a neighbor of mine who was complaining
about the price
of
gas - his SUV only gets 12MPG. I suggested he think
about pushing his
6000
pound truck 12 miles by hand. That would give him
the proper respect
for
the energy in a gallon of gasoline - and its value.

Liquid petroleum fuels are extremely energy dense.
It's going to be
really
hard to replace that with electricity. But maybe not
impossible.

Bill Daniels
For many applications a better 'alternative energy'
might be to squeeze
the maximum available power out of existing technology.
Below is an
engine which uses the heat from combustion to add another
power stroke
to an engine. Its not electrically powered but in
the future it may
compete with electric engines.
http://www.popsci.com/popsci/technology/
c1609351d9092110vgnvcm1000004eecbccdrcrd.html

Name: Steam-o-Lene Engine
Inventor: Bruce Crower
Cost to Develop: $1,000
Time: 1.5 years
Prototype | | | | | Product


Bruce Crower's Southern California auto-racing parts
shop is a temple for
racecar mechanics. Here's the flat eight-cylinder Indycar
engine that won
him the 1977 Louis Schwitzer Award for racecar design.
There's the
Mercedes five-cylinder engine he converted into a squealing

supercharged two-stroke, just 'to see what it would
sound like,' says the
now half-deaf 77-year-old self-taught engineer.

Crower has spent a lifetime eking more power out of
every drop of fuel
to make cars go faster. Now he's using the same approach
to make them
go farther, with a radical six-stroke engine that tops
off the familiar
four-stroke internal-combustion process with two extra
strokes of old-
fashioned steam power.

A typical engine wastes three quarters of its energy
as heat. Crower's
prototype, the single-cylinder diesel eight-horsepower
Steam-o-Lene
engine, uses that heat to make steam and recapture
some of the lost
energy. It runs like a conventional four-stroke combustion
engine
through each of the typical up-and-down movements of
the piston
(intake, compression, power or combustion, exhaust).
But just as the
engine finishes its fourth stroke, water squirts into
the cylinder, hitting
surfaces as hot as 1,500°F. The water immediately evaporates
into
steam, generating a 1,600-fold expansion in volume
and driving the
piston down to create an additional power stroke. The
upward sixth
stroke exhausts the steam to a condenser, where it
is recycled into
injection water.

Crower calculates that the Steam-o-Lene boosts the
work it gets from a
gallon of gas by 40 percent over conventional engines.
Diesels, which are
already more efficient, might get another 5 percent.
And his engine does
it with hardware that already exists, so there's no
waiting for
technologies to mature, as with electric cars or fuel
cells.

'Crower is an innovator who tries new ideas based on
his experience and
gut instincts,' says John Coletti, the retired head
of Ford's SVT high-
performance group. 'Most people won't try something
new for fear of
failure, but he is driven by a need to succeed.' And
he just might.
Crower has been keeping the details of his system quiet,
waiting for a
response to his patent application. When he gets it,
he'll pass off the
development process to a larger company that can run
with it, full-
steam.

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.

On Tue, 14 Aug 2007 08:40:29 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

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.


You have a point. While a source of ignition (sparking wires, hot
muffler?) is required to ignite post-crash gasoline fumes, it would
take an un-fused short circuit or significant deformation of a battery
to potentially ignite a lithium battery. Granted, if the crash occurs
as a result of fuel exhaustion, there is little fire hazard, while the
lithium would always be aboard.

On Aug 13, 8:10 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
Warning: A boring essay on obsolete internal combustion technology follows.

A merging of steam and internal combustion is probably the first "hybrid"
with the first efforts dating from the beginning of the last century. The
pinacle of its development was the monster water-injected turbo-compound
radial engines developed late in WWII.

Water injection acts is several favorable ways. First, somewhat as
described below, it flashes into steam to increase the cylinder pressure and
then escapes through the exhaust valves to a pressure recovery turbine which
transmits its power back to the crankshaft through a fluid coupling - the
"turbo compound" part.

Water also cools the cylinder allowing more fuel/air mixtue to be forced
into it. Finally, and this not widely known, water is even more effective
than tetraethyl lead in decreasing the tendency of the fuel/air mixture to
detonate or pre-ignite thus allowing far higher boost pressures. The only
compound more effective than water is nitros oxide.

Both Allied and Axis ari forces used water injection but only Germany used
nitros oxide. Either could double an engines power for as long as the
supply of H2O or NO lasted. But, on a power to weight basis, avgas easily
wins so water injection was only used for takeoff or when maximum military
power was needed to escape an enemy.

The citation for the above is a very old engineering textbook titled "High
Speed Internal Combustion Engines" by Sir Harry Recardo. I highly recomend
it if you are at all interested in IC engines. Sir Harry's work on sleeve
valve engines is particularly interesting.

I could be wrong but I would guess that water injection gets 90% of the
benifits possible without the major modification to the engine required by
Bruce Crower's "6-stroke".

Bill Daniels

"Steve Davis" wrote in message

...



It's sort of like a neighbor of mine who was complaining
about the price
of
gas - his SUV only gets 12MPG. I suggested he think
about pushing his
6000
pound truck 12 miles by hand. That would give him
the proper respect
for
the energy in a gallon of gasoline - and its value.

Liquid petroleum fuels are extremely energy dense.
It's going to be
really
hard to replace that with electricity. But maybe not
impossible.

Bill Daniels
For many applications a better 'alternative energy'
might be to squeeze
the maximum available power out of existing technology.
Below is an
engine which uses the heat from combustion to add another
power stroke
to an engine. Its not electrically powered but in
the future it may
compete with electric engines.
http://www.popsci.com/popsci/technology/
c1609351d9092110vgnvcm1000004eecbccdrcrd.html

Name: Steam-o-Lene Engine
Inventor: Bruce Crower
Cost to Develop: $1,000
Time: 1.5 years
Prototype | | | | | Product

Bruce Crower's Southern California auto-racing parts
shop is a temple for
racecar mechanics. Here's the flat eight-cylinder Indycar
engine that won
him the 1977 Louis Schwitzer Award for racecar design.
There's the
Mercedes five-cylinder engine he converted into a squealing

supercharged two-stroke, just 'to see what it would
sound like,' says the
now half-deaf 77-year-old self-taught engineer.

Crower has spent a lifetime eking more power out of
every drop of fuel
to make cars go faster. Now he's using the same approach
to make them
go farther, with a radical six-stroke engine that tops
off the familiar
four-stroke internal-combustion process with two extra
strokes of old-
fashioned steam power.

A typical engine wastes three quarters of its energy
as heat. Crower's
prototype, the single-cylinder diesel eight-horsepower
Steam-o-Lene
engine, uses that heat to make steam and recapture
some of the lost
energy. It runs like a conventional four-stroke combustion
engine
through each of the typical up-and-down movements of
the piston
(intake, compression, power or combustion, exhaust).
But just as the
engine finishes its fourth stroke, water squirts into
the cylinder, hitting
surfaces as hot as 1,500°F. The water immediately evaporates
into
steam, generating a 1,600-fold expansion in volume
and driving the
piston down to create an additional power stroke. The
upward sixth
stroke exhausts the steam to a condenser, where it
is recycled into
injection water.

Crower calculates that the Steam-o-Lene boosts the
work it gets from a
gallon of gas by 40 percent over conventional engines.
Diesels, which are
already more efficient, might get another 5 percent.
And his engine does
it with hardware that already exists, so there's no
waiting for
technologies to mature, as with electric cars or fuel
cells.

'Crower is an innovator who tries new ideas based on
his experience and
gut instincts,' says John Coletti, the retired head
of Ford's SVT high-
performance group. 'Most people won't try something
new for fear of
failure, but he is driven by a need to succeed.' And
he just might.
Crower has been keeping the details of his system quiet,
waiting for a
response to his patent application. When he gets it,
he'll pass off the
development process to a larger company that can run
with it, full-
steam.- Hide quoted text -

- Show quoted text -

The reference in Sir Harry Recardo's book to doubling HP with water
injection and Nitrous Oxide could lead someone to believe that those
two ingredients were all that was needed.

There is no advantage to injecting water into a conventional normally
aspirated 4-stroke IC engine although an endless array of systems to
do so has been sold to the unwary. Water or water/alcohol injection
however has long been known to do an excellent job of reducing
combustion temperatures thereby preventing detonation. While this is
of little importance in a normally aspirated engine it is a big help
in forced induction engines. I have used both water and water/alcohol
in two turbocharged motorcycle engines over a 15-year period with very
good results. Dyno results have not shown any measurable added HP from
the water alone (possibly because the water displaces some air/fuel
mixture) but it allows a significant increase in boost pressure, which
can add a bunch. Any engine dependent on this scheme for detonation
protection will however self-destruct in short order should the water
flow stop.

Nitrous Oxide injection provides more oxygen, which in turn allows
more fuel to be added which is the source of the extra HP.

Crower's Steam-o-Lene is another matter. Think I'll wait until they go
into mass production. It must have an interesting exhaust sound.