Electrically Powered Ultralight Aircraft

wrote:

If you go to http://xtronics.com/reference/energy_density.htm you find
the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.


Thanks Jim, that is exactly the kind of data I was looking for. It does kind
of show that all this talk of electric airplanes while a nice thought is
something that at best is way in the future.

On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
:

If you go to http://xtronics.com/reference/energy_density.htm you find
the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.

When you compare the efficiency of internal combustion Otto Cycle
engines (30% - 40%) against electric motors (80% - 95%), it appears
that a factor of five might be a more realistic comparison of their
relative merits. Then there is the issue of power plant weight...

Electric motors don't lose power in thin air either. With regard to
reliability, electric motors have only one moving part compared to
scores of moving parts for IC engines, their failure rate should be
substantially greater than IC engines.

In rec.aviation.piloting Gig 601XL Builder wrDOTgiaconaATsuddenlink.net wrote:
wrote:

If you go to http://xtronics.com/reference/energy_density.htm you find
the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.


Thanks Jim, that is exactly the kind of data I was looking for. It does kind
of show that all this talk of electric airplanes while a nice thought is
something that at best is way in the future.

Well, to be fair, there is solar cell research that if it becomes
practical and cheap enough would work on sail planes with lithium
batteries.

But there is no technology on the horizon for a practical electric 172.

--
Jim Pennino

Remove .spam.sux to reply.

I e-mailed a copy of the article below to Eric Raymond. Here is his
reply:

Larry,

Thanks for the info on Specrolab's progress. I used to be in
contact with them, but gave up because their prices were too high.
A much more interesting company is SunPower. They are making
cheap, one sun cells that are 22% efficient. I plan to use them
on my next plane, a two seater.

Eric Raymond


A two-place photovoltaic powered aircraft will be interesting. Here's
some information on SunPower:


http://www.sunpowercorp.com
http://www.sunpower.com
http://www.sunpowercorp.com/commercial/solar_cells.html
The SunPower A-300 solar cell is a 125mm, 20% (minimum) efficiency,
high-performance, single crystal silicon solar cell. The A-300 cell
offers up to 50% more power per unit area than conventional solar
cells. It is particularly unique because the metal contacts needed to
collect and conduct electricity are located on the back surface – away
from the sunlight. This design eliminates the need for reflective
metal contacts to be placed on the front of the solar cell, improving
our solar cell performance and creating a uniformly smooth, black
appearance.



================================================== =======
On Mon, 06 Aug 2007 16:01:03 GMT, Larry Dighera
wrote in :

On Mon, 06 Aug 2007 06:33:20 -0700, Airjunkie
wrote in .com:

Eric Raymond has been at it for a long time. Check it out at
www.solar-flight.com

http://www.solar-flight.com/sslink.html

Thank you for the information. His achievement is remarkable for the
time. Imagine what he could do 17 years later with today's ~40%
efficient photovoltaic cells and light weight lithium-ion polymer
batteries:



The Boeing Company http://www.boeing.com/news/releases/index.html
Boeing Spectrolab Terrestrial Solar Cell Surpasses 40 Percent
Efficiency

ST. LOUIS, Dec. 06, 2006 -- Boeing [NYSE: BA] today announced that
Spectrolab, Inc., a wholly-owned subsidiary, has achieved a new world
record in terrestrial concentrator solar cell efficiency. Using
concentrated sunlight, Spectrolab demonstrated the ability of a
photovoltaic cell to convert 40.7 percent of the sun's energy into
electricity. The U.S. Department of Energy's National Renewable Energy
Laboratory (NREL) in Golden, Colo., verified the milestone.

"This solar cell performance is the highest efficiency level any
photovoltaic device has ever achieved," said Dr. David Lillington,
president of Spectrolab. "The terrestrial cell we have developed uses
the same technology base as our space-based cells. So, once qualified,
they can be manufactured in very high volumes with minimal impact to
production flow."

High efficiency multijunction cells have a significant advantage over
conventional silicon cells in concentrator systems because fewer solar
cells are required to achieve the same power output. This technology
will continue to dramatically reduce the cost of generating
electricity from solar energy as well as the cost of materials used in
high-power space satellites and terrestrial applications.

"These results are particularly encouraging since they were achieved
using a new class of metamorphic semiconductor materials, allowing
much greater freedom in multijunction cell design for optimal
conversion of the solar spectrum," said Dr. Richard R. King, principal
investigator of the high efficiency solar cell research and
development effort. "The excellent performance of these materials
hints at still higher efficiency in future solar cells."

Spectrolab is reducing the cost of solar cell production through
research investments and is working with several domestic and
international solar concentrator manufacturers on clean, renewable
solar energy solutions. Currently, Spectrolab's terrestrial
concentrator cells are generating power in a 33-kilowatt full-scale
concentrator system in the Australian desert. The company recently
signed multi-million dollar contracts for its high efficiency
concentrator cells and is anticipating several new contracts in the
next few months.

Development of the high-efficiency concentrator cell technology was
funded by the NREL's High Performance Photovoltaics program and
Spectrolab.

A unit of The Boeing Company, Boeing Integrated Defense Systems
http://www.boeing.com/ids/index.html is one of the world's largest
space and defense businesses. Headquartered in St. Louis, Boeing
Integrated Defense Systems is a $30.8 billion business. It provides
network-centric system solutions to its global military, government,
and commercial customers. It is a leading provider of intelligence,
surveillance and reconnaissance systems; the world's largest military
aircraft manufacturer; the world's largest satellite manufacturer; a
foremost developer of advanced concepts and technologies; a leading
provider of space-based communications; the primary systems integrator
for U.S. missile defense; NASA's largest contractor; and a global
leader in sustainment solutions and launch services.
###

On Tue, 7 Aug 2007 14:51:55 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

all this talk of electric airplanes while a nice thought is
something that at best is way in the future.

That's only true if you overlook Randall Fishman's electrically
powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
Sonex proof-of-concept Waiex aircraft
(http://www.sonexaircraft.com/press/r...r_072407.html).

But, I know, you were referring to electrically powered aircraft with
the same utility as today's GA aircraft, right?

In rec.aviation.piloting Larry Dighera wrote:
On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
:

If you go to http://xtronics.com/reference/energy_density.htm you find
the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.

When you compare the efficiency of internal combustion Otto Cycle
engines (30% - 40%) against electric motors (80% - 95%), it appears
that a factor of five might be a more realistic comparison of their
relative merits. Then there is the issue of power plant weight...

Well, you have to look at total system weight.

A 100 HP electric motor is not going to be particularly light and
the power cables are going to weigh a whole lot more than fuel lines
for example.

When you look at the total installed system, assuming you have batteries
5 times better than you have now, I doubt the total weight difference
will be all that much.

Electric motors don't lose power in thin air either. With regard to
reliability, electric motors have only one moving part compared to
scores of moving parts for IC engines, their failure rate should be
substantially greater than IC engines.

AC motors have only one moving part but would require a beefy inverter
to generate (and induce more system loss) the AC.

DC motors have brushes but motor control is simpler.

If the DC motor was designed for easy inspection and replacement of
the brushes, then the failure rate should be much lower than a gas
engine.


--
Jim Pennino

Remove .spam.sux to reply.

Larry Dighera wrote:
On Tue, 7 Aug 2007 14:51:55 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

all this talk of electric airplanes while a nice thought is
something that at best is way in the future.

That's only true if you overlook Randall Fishman's electrically
powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
Sonex proof-of-concept Waiex aircraft
(http://www.sonexaircraft.com/press/r...r_072407.html).

But, I know, you were referring to electrically powered aircraft with
the same utility as today's GA aircraft, right?

Right. When the electric Sonex can do the same thing the VW powered Sonex
can do then it will become something more than an interesting idea.

Larry Dighera wrote:
On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
:

If you go to http://xtronics.com/reference/energy_density.htm you
find the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.

When you compare the efficiency of internal combustion Otto Cycle
engines (30% - 40%) against electric motors (80% - 95%), it appears
that a factor of five might be a more realistic comparison of their
relative merits. Then there is the issue of power plant weight...

Electric motors don't lose power in thin air either. With regard to
reliability, electric motors have only one moving part compared to
scores of moving parts for IC engines, their failure rate should be
substantially greater than IC engines.

Here is a 100hp electric motor. I don't know if it is typical for an
electric motor but damn the thing weighs over half a ton. I might make the
601XL a little nose heavy. But it's priced right up there with a Lyc of
equal power.

http://www.baldor.com/products/detai...neralPur pose

Catalog Number: D50100P
Description: STOCK MOTOR,368AT,100HP,1750/2000RPM,DPFG
Ship Weight: 1,118 lbs.
List Price: $21,195
Multiplier Symbol: N2

Gig 601XL Builder wrote:
Larry Dighera wrote:
On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
:

If you go to http://xtronics.com/reference/energy_density.htm you
find the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.
When you compare the efficiency of internal combustion Otto Cycle
engines (30% - 40%) against electric motors (80% - 95%), it appears
that a factor of five might be a more realistic comparison of their
relative merits. Then there is the issue of power plant weight...

Electric motors don't lose power in thin air either. With regard to
reliability, electric motors have only one moving part compared to
scores of moving parts for IC engines, their failure rate should be
substantially greater than IC engines.

Here is a 100hp electric motor. I don't know if it is typical for an
electric motor but damn the thing weighs over half a ton. I might make the
601XL a little nose heavy. But it's priced right up there with a Lyc of
equal power.

http://www.baldor.com/products/detai...neralPur pose

Catalog Number: D50100P
Description: STOCK MOTOR,368AT,100HP,1750/2000RPM,DPFG
Ship Weight: 1,118 lbs.
List Price: $21,195
Multiplier Symbol: N2



Just a wild guess, but wouldn't this make for a very, very safe airplane??

George

On Aug 7, 3:04 pm, "Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net
wrote:
Larry Dighera wrote:
On Tue, 7 Aug 2007 14:51:55 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

all this talk of electric airplanes while a nice thought is
something that at best is way in the future.

That's only true if you overlook Randall Fishman's electrically
powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
Sonex proof-of-concept Waiex aircraft
(http://www.sonexaircraft.com/press/r...r_072407.html).

But, I know, you were referring to electrically powered aircraft with
the same utility as today's GA aircraft, right?

Right. When the electric Sonex can do the same thing the VW powered Sonex
can do then it will become something more than an interesting idea.


I have not seen any significant flight duration claim on the Sonex,
which speaks well for the design team. The 2 hours flight duration on
the trike is IMO a gross exaggeration extrapolated from a much shorter
actual time in thermal conditions. If the ability to get off the
ground were the sole criteria we are there already but practical
flight characteristics for mass consumption are way down the road. To
be safe an aircraft needs a lot more power than the amount required to
rise from the ground. My first home built ultralite was a 32 ft rigid
wing using an IC engine of about 18hp and while it would fly the lack
of climb ability was a big disadvantage. In marginal conditions it
wouldn't lift beyond ground effect which resulted in interesting
obstacle flights around trees and under power lines. It didn't take
long for me to decide that my life was worth more than the 18hp engine
and a new 30hp engine ultimately made for a much safer aircraft.