Electrically Powered Ultralight Aircraft

[Larry Dighera]

Electrically Powered Ultralight Aircraft

Below is a report of an electrically powered ultralight aircraft.
Further down is information about Sonex's electrically powered
home-built aircraft, and below that is information about Royal
Aeronautical Society's 2007-8 design competition (submissions close
May 2, 2008).

Personally, I'd like to see an electrically powered parachute
(http://skyhighflying.com/homepage.html) design attempted. Surly the
lighter weight would require less power. It would seem that
lithium-ion polymer batteries are a potential enabling technology.


AVGAS? WHO NEEDS IT? TRIKE RUNS ON BATTERIES
(http://www.avweb.com/eletter/archives/avflash/925-full.html#195816)
While concerns over price, availability and environmental impact
have aviators worried about the future of fuel, one ultralight
flyer in New Jersey has already solved that problem. Randall
Fishman has been testing lithium-ion polymer battery packs to
drive the prop on his ultralight trike, and he says they work
great. They are powerful, smooth, sturdy, safe and quiet, Fishman
claims. "The closest thing to a magic carpet ride ever," he says
on his Web site (http://www.electraflyer.com/). The quiet is not
only enjoyable for the pilot, it improves relations with
neighbors, he notes. The batteries will run for up to two hours
and cost about 60 cents to charge via a standard electric outlet.
However, the batteries are expensive -- $3,800 to $7,500,
depending on size.
http://www.avweb.com/eletter/archives/avflash/925-full.html#195816

First attempted takeoff video:

Brochure:
http://www.electraflyer.com/brochure.pdf
Technical Specifications:
Motor - 18 H.P. High Torque - 90% Efficient at Cruise
Controller - Electronic, Pulse Width Modulation, For High
Efficiency and Smooth Control
Battery Packs - Custom Built, Lithium Ion Polymer, Super High
Capacity Choose the Size You Want
Voltmeter - To Monitor How Much Power Is Available
Ammeter - To Monitor How Much Power You Are Using
Thrust - With Folding Prop - 140 Pounds
With Big, Ultra Quiet Prop - 155 Pounds
Duration - Up to Two Hours Depending on Battery Pack Chosen, Total
Weight and Efficiency of the Wing - 1 to 1.5 Hour Flights Most
Common
Total Weight - 210 to 250 Pounds Complete With Wing and Battery
Packs The ElectraFlyer is a True Legal Part 103 Ultralight

Electric Aircraft Corporation
Randall Fishman, President
phone: [phone]
website: www.ElectraFlyer.com
email: ***@electraflyer.com


http://www.electraflyer.com/52_53_womf.pdf
An EAA MEMbEr First...
The ElectraFlyer, an Electric-Powered Trike!


http://www.electraflyer.com/lightsport.pdf
Light Sport and Ultralight Flying July 2007






===================================================
Sonex web site: http://www.sonexaircraft.com/

Photo of Sonex e-flight electric aircraft:
Loading Image...

Photo of electric powerplant:
Loading Image...

Diagram of e-Flight powerplant:
Loading Image...

Pricing: http://www.sonexaircraft.com/kits/pricing.html


Article:
http://www.greencarcongress.com/2007/07/sonex-aircraft-.html#more

http://www.sonexaircraft.com/press/releases/pr_072407.html
Sonex Aircraft, LLC and AeroConversions Unveil E-Flight Initiative for
Sport Aircraft Alternative Energy Research & Development

Electric Power; a new mission: The contemporary E-Flight electric
project will benefit greatly by the maturation of technology since our
initial studies. Using a purpose-built AeroConversions brushless DC
cobalt motor, controller, and highly efficient battery and charging
system, the E-Flight electric systems will be able to power a larger
aircraft to higher top speeds with greatly increased endurance.
E-Flight’s proof-of-concept prototype will use the flight proven Waiex
airframe, flown single pilot only, so that the emphasis can be placed
solely on powerplant research and development. Initial top speeds will
reach approximately 130 mph, and endurance is expected to range
between 25-45 minutes or longer, depending upon power usage on each
individual flight.

The initial emphasis for the E-Flight proof-of concept aircraft has
been shifted away from immediate pursuit of FAI speed records,
although the possibility remains that those records could be obtained
in short-order after successful first flight. With the advanced state
of the technologies concerned, the goal of the project is to develop
and prove the application of the technology and pave the way for
near-term electric powerplant Sonex and AeroConversions products for
sale to the sport aviation marketplace and beyond.

The current state and growing popularity of electric powered model RC
aircraft leads the layman to assume that an electric powered aircraft
of this type is simply a matter of hooking a bigger battery to a
bigger motor, charging it up in an hour or two and taking-off. While
that is essentially true in raw principle, the reality of this project
is that scaling-up these technologies in a viable manner presents
significant challenges.

• Electric Power; AeroConversions Electric Motor: Brushless DC cobalt
motor technology has advanced significantly since 1994’s Flash Flight
study, allowing the design team to now consider their use, however,
just like before, a suitable brushless DC cobalt motor of this level
of power output with an acceptable size and weight does not exist and
can not be built and provided by a third party vendor without
incurring unacceptable costs. As a result, the design team, in
collaboration with Bob Boucher of Astro Flight, Inc., has designed and
built a completely new AeroConversions motor.

This motor is the most powerful, lightest-weight, and efficient unit
of this type ever produced. It is a 3 phase, 270 volt, 200 amp motor
that will be over 90 percent efficient. It uses elegantly designed CNC
machined anodized aluminum and nickel-plated steel parts in
combination with “off the shelf” bearings, races, snap rings, magnets,
etc.

The prototype AeroConversions motor is slightly larger than a 35 ounce
coffee can and weighs approximately 50 pounds. The motor is a
modular, scalable unit. The motor core’s design has modular sections
that can be reduced to a lower-output, smaller motor (shortened in
length), or added upon to make a larger motor with a higher power
output.

• Electric Power; AeroConversions Electronic Motor Controller:
Electronic motor controllers for brushless electric motors are quite
commonplace today, mostly used in the electric RC market. A suitable
controller for a 270 volt, 200 amp motor does not exist. Running such
high current requires much larger components. Although there are a
handful of third party vendors who could design and build the
appropriate controller for this project, it would take 6-7 months lead
time and cost 20-50 Thousand Dollars. The time and cost associated
with acquiring such a controller was deemed unacceptable and the
research and development team, in cooperation with a key electronics
expert, began designing a proprietary AeroConversions electronic motor
controller.

The controller can commutate the motor in two different ways: using
Hall effect sensors to determine the magnet core’s position in
relation to the coils, or using the motor’s back-EMF to sense rotor
position, eliminating the need for Hall sensors. The AeroConversions
controller will initially employ a Hall effect sensor-equipped motor,
but back-EMF controlling will also be explored to potentially further
simplify the AeroConversions motor design. The AeroConversions
controller will also provide in-cockpit monitoring of battery power
levels to the pilot.

• Electric Power; AeroConversions Battery System: Most contemporary
electric powerplants for gas-electric and pure electric cars and
previous generations of RC electric vehicles utilize Lithium Ion
battery technology. While much improved in power density and discharge
rate over lead-acid and NiCad batteries, Li-Ion batteries still do not
offer enough power discharge-to-weight ratio to support an electric
powerplant for an aircraft that is based on battery power alone and
has a market-viable endurance. Newer RC electric vehicles, cell phone,
laptop computers and other mobile devices have been moving toward
Lithium Polymer cells. Li-Poly battery cells can safely discharge at a
rate of 25 times their capacity, or “25c.”

With all the extra energy of a Li-Poly cell, however, comes extra
volatility. The E-Flight design team has engineered and constructed 10
battery “safe boxes” intended to contain 8 Li-Poly battery packs per
box and consolidate their charge/discharge and balancing wiring into
two sets of multi-pin connectors. The Boxes will accommodate natural
cell expansion and contraction while safely securing each cell pack
and facilitating cell cooling with “cooling foam” padding. Cooling
will further be aided by heat sink surfaces on each box that will have
cooling inlet air directed over them. Additionally, the boxes are
designed to contain and safely direct fire or explosion within the box
through a “blow hole” in the box that will be connected to a small
exhaust manifold.

For the proof-of-concept aircraft, the battery boxes will be removed
from the aircraft and charged individually. The charging units need to
be configured to safely keep all cells balanced during charging.
Lessons learned from the proof-of-concept systems will lead to the
design of more advanced charging and balancing systems allowing safer
battery handling by consumers, including a single-plug charging system
that may remain in the aircraft at all times, featuring easy exchange
of battery boxes to enable consecutive back-to-back flights in a short
period of time by pilots who wish to invest in spare batteries.

Future generations of safer, more powerful Li-Poly batteries show the
near-term possibility of further extended flight duration while
personal electronics and transportation will undoubtedly continue to
push improvement of the technology in years to come.

“By developing a viable electric motor and controller system for this
proof-of-concept aircraft, we will open a door to future flight that
we have only been able to dream of,” comments Monnett. “Self-launching
electric powered gliders already exist. The potential of electric
power goes beyond that single use and relates directly to sport
flying, aerobatics and high altitude flight in purpose-built
airframes. It is essential that our proof-of-concept vehicle is a
conventional aircraft that the majority of aviation enthusiasts can
relate to.”

One remarkable reality about the E-Flight electric aircraft project is
that, by necessity, the entire R&D project for the proof-of-concept
stage of the project will cost less than the price of the average
ready-to-fly LSA aircraft available today. This project undeniably
highlights the spirit of EAA in that it is truly a grass-roots effort
to push technology for advancement of our sport and improvement of our
planet’s ecosystem and it has been accomplished, not by a large
aerospace firm or government agency, but by EAA members on an
extraordinarily cost-effective budget.


http://www.aeroconversions.com/

--------------------------------------------------------------------------------
The official daily newspaper of EAA AirVenture Oshkosh

Volume 8, Number 4 July 25, 2007

--------------------------------------------------------------------------------

Sonex rolls out electric plane
By Randy Dufault

Jeremy Monnett shows off the electric motor and mount employed in a
proof-of-concept Waiex airframe to demonstrate the potential of
compact electric power and advanced-technology batteries. Photo by
Dave Higdon

With the price of oil rising faster than an F-15 in an unrestricted
climb and the potential for $6 per gallon self-serve avgas a real
possibility, alternate ways of powering aircraft, ways that require
much less fossil fuel, are going to be important to the future of
sport aviation.

On Tuesday, Sonex Aircraft LLC took the wraps off its previously
secret e-Flight initiative.

"This is an exciting announcement and one that you are really going to
appreciate," EAA President Tom Poberezny said at the beginning of the
press conference. He added, "It addresses the grass-roots research
that is important to the integrity of EAA and the homebuilt movement.
More importantly, it is growing aviation by making it more
economical."

The most visible aspect of e-Flight right now is a Sonex Waiex
airframe equipped with a proof-of-concept prototype electric
powerplant. The aircraft, which is expected to fly later this year,
will be used to further develop the motor, along with the requisite
control systems, charging systems, and of course, battery systems.

"It was [apparent] that once we started down this path to developing
an alternative power source for the airplane, that we had to do it in
very specific steps," John Monnett, Sonex founder and president, said
when he introduced the electric plane. "The whole object of [the
proof-of-concept] is to come up with a powerplant that is equivalent
in weight and in power to our AeroVee-powered Sonex and Waiex
[models]."

Monnett went on to add the sole mission of the airplane displayed here
is to develop the technologies that will ultimately result in
production systems. The test-bed airplane is also expected to test
other, as yet unspecified, electric power sources.

The prototype powerplant uses brushless, cobalt motor technology and,
according to AeroConversions, is the most powerful, lightest weight,
and efficient motor of the type ever produced. It was developed with
the help of Bob Boucher of Astro Flight Inc. Astro Flight is a major
producer of electric radio-controlled model motors.

The 200-amp motor is 90 percent efficient and operates on 270 volts of
direct current electricity, as advertised by the Waiex’s tail number,
N270DC.

According to Pete Buck, Sonex’s chief engineer, the motor was
manufactured in-house. He added that Sonex expects to construct
virtually all of the components of the future production systems
themselves. Production systems, unlike the current AeroVee engine,
likely will not be offered as kits, due to the critical tolerances and
potential dangers with some of the electrical components.

Monnett pointed out that a couple of technologies are key to making
electric flight a reality. Of course, powerful and light batteries are
a must, but a motor controller capable of managing the high power
involved also is required. A charging system, capable of replenishing
the batteries in a reasonable amount of time, is another must. Sonex
is developing both technologies.

Target flight duration for the proof-of-concept airplane is 25 minutes
to 45 minutes. Production systems are expected to allow for one-hour
flights. Buck says an hour’s endurance is difficult right now but
ultimately is very possible as both the system and the available
technologies are further developed.

In addition to the electric Waiex, Sonex’s e-Flight initiative also
involves two other aspects: the practical use of ethanol fuels in the
AeroConversions AeroVee 2.0 engine and developing other enhancements
to the AeroVee, improving its already-impressive efficiency.

Sonex partnered with Wisconsin-based Renew Fuel Stations, a
distributor of E85, a blend of up to 85 percent ethanol and 15 percent
gasoline, to develop an AeroVee engine configuration that can use the
fuel. Renew’s interest in the project is expansion of the market for
ethanol fuels. Testing is under way right now.

The idea of electric flight is not new to Sonex. It dates back to 1994
when Monnett and Buck looked into the possibility of building an
electric plane specifically for the purpose of establishing speed
records for a new class of aircraft. Although the project was deemed
to be practical, Sonex put the project aside to further develop its
current set of kit airplanes and to support their customers. The
company is committed to completing the effort this time, though
Monnett stated firmly that the e-Flight program will never detract
from Sonex’s commitment to its customers.

Sonex is financing the entire effort itself.

Once production systems are available, Sonex plans to make them
available to the experimental market for installation on other
airframes.

Sonex will present a forum on the e-Flight project Wednesday at 11:00
a.m. in Forum Building 11. More information about the project is
available on the web at www.AeroConversions.com/E-Flight.


==========================================================



The RAeS General Aviation Group aims to encourage the development of
light aviation through the promotion of technologies, in particular
those that minimise its impact upon the environment.

The 2007-8 design competition therefore offers awards for technical
developments that can include:

• whole aircraft design
• propulsion
• operational methods
• specific technologies within the aircraft.

The competition is open to any individual or group; entries are
particularly encouraged from teams from educational institutions or
RAeS corporate members.

Entries should be received by Friday 2 May 2008 and consist firstly
of a 10 page report , showing how it works, its benefits both to
light aviation and to the environment, and who is responsible for the
entry.

A shortlist of entrants will then be selected, who will be invited to
give a 20 minute presentation at a special event at RAeS Headquarters
in London during mid June 2008. At that event, a judging panel will
select the final winning entries; prizes and final award categories
will be announced nearer to the entry deadline.

Judging criteria will be based upon feasibility, originality,
reduction of impact upon the environment and the potential benefits
to light aviation overall. Final presentations will also be judged
on presentation quality and response to questioning.

The judging panel will consist of highly qualified light aviation
professionals – including representatives from industry, regulatory
authorities and academia.

Further Details:
General Aviation Group
Royal Aeronautical Society
No.4 Hamilton Place
London, W1J 7BQ, UK

[Phil]

Post by Larry Dighera
Electrically Powered Ultralight Aircraft
Below is a report of an electrically powered ultralight aircraft.
Further down is information about Sonex's electrically powered
home-built aircraft, and below that is information about Royal
Aeronautical Society's 2007-8 design competition (submissions close
May 2, 2008).
Personally, I'd like to see an electrically powered parachute
(http://skyhighflying.com/homepage.html) design attempted. Surly the
lighter weight would require less power. It would seem that
lithium-ion polymer batteries are a potential enabling technology.
AVGAS? WHO NEEDS IT? TRIKE RUNS ON BATTERIES
(http://www.avweb.com/eletter/archives/avflash/925-full.html#195816)
While concerns over price, availability and environmental impact
have aviators worried about the future of fuel, one ultralight
flyer in New Jersey has already solved that problem. Randall
Fishman has been testing lithium-ion polymer battery packs to
drive the prop on his ultralight trike, and he says they work
great. They are powerful, smooth, sturdy, safe and quiet, Fishman
claims. "The closest thing to a magic carpet ride ever," he says
on his Web site (http://www.electraflyer.com/). The quiet is not
only enjoyable for the pilot, it improves relations with
neighbors, he notes. The batteries will run for up to two hours
and cost about 60 cents to charge via a standard electric outlet.
However, the batteries are expensive -- $3,800 to $7,500,
depending on size.
http://www.avweb.com/eletter/archives/avflash/925-full.html#195816
First attempted takeoff http://youtu.be/Wksx-jmhY7c
http://www.electraflyer.com/brochure.pdf
Motor - 18 H.P. High Torque - 90% Efficient at Cruise
Controller - Electronic, Pulse Width Modulation, For High
Efficiency and Smooth Control
Battery Packs - Custom Built, Lithium Ion Polymer, Super High
Capacity Choose the Size You Want
Voltmeter - To Monitor How Much Power Is Available
Ammeter - To Monitor How Much Power You Are Using
Thrust - With Folding Prop - 140 Pounds
With Big, Ultra Quiet Prop - 155 Pounds
Duration - Up to Two Hours Depending on Battery Pack Chosen, Total
Weight and Efficiency of the Wing - 1 to 1.5 Hour Flights Most
Common
Total Weight - 210 to 250 Pounds Complete With Wing and Battery
Packs The ElectraFlyer is a True Legal Part 103 Ultralight
Electric Aircraft Corporation
Randall Fishman, President
phone: [phone]
website:www.ElectraFlyer.com
http://www.electraflyer.com/52_53_womf.pdf
An EAA MEMbEr First...
The ElectraFlyer, an Electric-Powered Trike!
http://www.electraflyer.com/lightsport.pdf
Light Sport and Ultralight Flying July 2007
===================================================
Sonex web site:http://www.sonexaircraft.com/
Photo of Sonex e-flight electric aircraft:http://www.sonexaircraft.com/news/images/airventure07/e-flight_058.jpg
Photo of electric powerplant:http://www.sonexaircraft.com/news/images/airventure07/e-flight_5947.jpg
Diagram of e-Flight powerplant:http://bioage.typepad.com/.shared/image.html?/photos/uncategorized/20...
Pricing:http://www.sonexaircraft.com/kits/pricing.html
Article:http://www.greencarcongress.com/2007/07/sonex-aircraft-.html#more
http://www.sonexaircraft.com/press/releases/pr_072407.html
Sonex Aircraft, LLC and AeroConversions Unveil E-Flight Initiative for
Sport Aircraft Alternative Energy Research & Development
Electric Power; a new mission: The contemporary E-Flight electric
project will benefit greatly by the maturation of technology since our
initial studies. Using a purpose-built AeroConversions brushless DC
cobalt motor, controller, and highly efficient battery and charging
system, the E-Flight electric systems will be able to power a larger
aircraft to higher top speeds with greatly increased endurance.
E-Flight's proof-of-concept prototype will use the flight proven Waiex
airframe, flown single pilot only, so that the emphasis can be placed
solely on powerplant research and development. Initial top speeds will
reach approximately 130 mph, and endurance is expected to range
between 25-45 minutes or longer, depending upon power usage on each
individual flight.
The initial emphasis for the E-Flight proof-of concept aircraft has
been shifted away from immediate pursuit of FAI speed records,
although the possibility remains that those records could be obtained
in short-order after successful first flight. With the advanced state
of the technologies concerned, the goal of the project is to develop
and prove the application of the technology and pave the way for
near-term electric powerplant Sonex and AeroConversions products for
sale to the sport aviation marketplace and beyond.
The current state and growing popularity of electric powered model RC
aircraft leads the layman to assume that an electric powered aircraft
of this type is simply a matter of hooking a bigger battery to a
bigger motor, charging it up in an hour or two and taking-off. While
that is essentially true in raw principle, the reality of this project
is that scaling-up these technologies in a viable manner presents
significant challenges.
· Electric Power; AeroConversions Electric Motor: Brushless DC cobalt
motor technology has advanced significantly since 1994's Flash Flight
study, allowing the design team to now consider their use, however,
just like before, a suitable brushless DC cobalt motor of this level
of power output with an acceptable size and weight does not exist and
can not be built and provided by a third party vendor without
incurring unacceptable costs. As a result, the design team, in
collaboration with Bob Boucher of Astro Flight, Inc., has designed and
built a completely new AeroConversions motor.
This motor is the most powerful, lightest-weight, and efficient unit
of this type ever produced. It is a 3 phase, 270 volt, 200 amp motor
that will be over 90 percent efficient. It uses elegantly designed CNC
machined anodized aluminum and nickel-plated steel parts in
combination with "off the shelf" bearings, races, snap rings, magnets,
etc.
The prototype AeroConversions motor is slightly larger than a 35 ounce
coffee can and weighs approximately 50 pounds. The motor is a
modular, scalable unit. The motor core's design has modular sections
that can be reduced to a lower-output, smaller motor (shortened in
length), or added upon to make a larger motor with a higher power
output.
Electronic motor controllers for brushless electric motors are quite
commonplace today, mostly used in the electric RC market. A suitable
controller for a 270 volt, 200 amp motor does not exist. Running such
high current requires much larger components. Although there are a
handful of third party vendors who could design and build the
appropriate controller for this project, it would take 6-7 months lead
time and cost 20-50 Thousand Dollars. The time and cost associated
with acquiring such a controller was deemed unacceptable and the
research and development team, in cooperation with a key electronics
expert, began designing a proprietary AeroConversions electronic motor
controller.
The controller can commutate the motor in two different ways: using
Hall effect sensors to determine the magnet core's position in
relation to the coils, or using the motor's back-EMF to sense rotor
position, eliminating the need for Hall sensors. The AeroConversions
controller will initially employ a Hall effect sensor-equipped motor,
but back-EMF controlling will also be explored to potentially further
simplify the AeroConversions motor design. The AeroConversions
controller will also provide in-cockpit monitoring of battery power
levels to the pilot.
· Electric Power; AeroConversions Battery System: Most contemporary
electric powerplants for gas-electric and pure electric cars and
previous generations of RC electric vehicles utilize Lithium Ion
battery technology. While much improved in power density and discharge
rate over lead-acid and NiCad batteries, Li-Ion batteries still do not
offer enough power discharge-to-weight ratio to support an electric
powerplant for an aircraft that is based on battery power alone and
has a market-viable endurance. Newer RC electric vehicles, cell phone,
laptop computers and other mobile devices have been moving toward
Lithium Polymer cells. Li-Poly battery cells can safely discharge at a
rate of 25 times their capacity, or "25c."
With all the extra energy of a Li-Poly cell, however, comes extra
volatility. The E-Flight design team has engineered and constructed 10
battery "safe boxes" intended to contain 8 Li-Poly battery packs per
box and consolidate their charge/discharge and balancing wiring into
two sets of multi-pin connectors. The Boxes will accommodate natural
cell expansion and contraction while safely securing each cell pack
and facilitating cell cooling with "cooling foam" padding. Cooling
will further be aided by heat sink surfaces on each box that will have
cooling inlet air directed over them. Additionally, the boxes are
designed to contain and safely direct fire or explosion within the box
through a "blow hole" in the box that will be connected to a small
exhaust manifold.
For the proof-of-concept aircraft, the battery boxes will be removed
from the aircraft and charged individually. The charging units need to
be configured to safely keep all cells balanced during charging.
Lessons learned from the proof-of-concept systems will lead to the
design of more advanced charging and balancing systems allowing safer
battery handling by consumers, including a single-plug charging system
that may remain in the aircraft at all times, featuring easy exchange
of battery boxes to enable consecutive back-to-back flights in a short
period of time by pilots who wish to invest in spare batteries.
Future generations of safer, more powerful Li-Poly batteries show the
near-term possibility of further extended flight duration while
personal electronics and transportation will undoubtedly continue to
push improvement of the technology in years to come.
"By developing a viable electric motor and controller system for this
proof-of-concept aircraft, we will open a door to future flight that
we have only been able to dream of," comments Monnett. "Self-launching
electric powered gliders already exist. The potential of electric
power goes beyond that single use and relates directly to sport
flying, aerobatics and high altitude flight in purpose-built
airframes. It is essential that our proof-of-concept vehicle is a
conventional aircraft that the majority of aviation enthusiasts can
relate to."
One remarkable reality about the E-Flight electric aircraft project is
that, by necessity, the entire R&D project for the proof-of-concept
stage of the project will cost less than the price of the average
ready-to-fly LSA aircraft available today. This project undeniably
highlights the spirit of EAA in that it is truly a grass-roots effort
to push technology for advancement of our sport and improvement of our
planet's ecosystem and it has been accomplished, not by a large
aerospace firm or government agency, but by EAA members on an
extraordinarily cost-effective budget.
http://www.aeroconversions.com/
---------------------------------------------------------------------------­-----
The official daily newspaper of EAA AirVenture Oshkosh
Volume 8, Number 4 July 25, 2007
---------------------------------------------------------------------------­-----
Sonex rolls out electric plane
By Randy Dufault
Jeremy Monnett shows off the electric motor and mount employed in a
proof-of-concept Waiex airframe to demonstrate the potential of
compact electric power and advanced-technology batteries. Photo by
Dave Higdon
With the price of oil rising faster than an F-15 in an unrestricted
climb and the potential for $6 per gallon self-serve avgas a real
possibility, alternate ways of powering aircraft, ways that require
much less fossil fuel, are going to be important to the future of
sport aviation.
On Tuesday, Sonex Aircraft LLC took the wraps off its previously
secret e-Flight initiative.
"This is an exciting announcement and one that you are really going to
appreciate," EAA President Tom Poberezny said at the beginning of the
press conference. He added, "It addresses the grass-roots research
that is important to the integrity of EAA and the homebuilt movement.
More importantly, it is growing aviation by making it more
economical."
The most visible aspect of e-Flight right now is a Sonex Waiex
airframe equipped with a proof-of-concept prototype electric
powerplant. The aircraft, which is expected to fly later this year,
will be used to further develop the motor, along with the requisite
control systems, charging systems, and of course, battery systems.
"It was [apparent] that once we started down this path to developing
an alternative power source for the airplane, that we had to do it in
very specific steps," John Monnett, Sonex founder and president, said
when he introduced the electric plane. "The whole object of [the
proof-of-concept] is to come up with a powerplant that is equivalent
in weight and in power to our AeroVee-powered Sonex and Waiex
[models]."
Monnett went on to add the sole mission of the airplane displayed here
is to develop the technologies that will ultimately result in
production systems. The test-bed airplane is also expected to test
other, as yet unspecified, electric power sources.
The prototype powerplant uses brushless, cobalt motor technology and,
according to AeroConversions, is the most powerful, lightest weight,
and efficient motor of the type ever produced. It was developed with
the help of Bob Boucher of Astro Flight Inc. Astro Flight is a major
producer of electric radio-controlled model motors.
The 200-amp motor is 90 percent efficient and operates on 270 volts of
direct current electricity, as advertised by the Waiex's tail number,
N270DC.
According to Pete Buck, Sonex's chief engineer, the motor was
manufactured in-house. He added that Sonex expects to construct
virtually all of the components of the future production systems
themselves. Production systems, unlike the current AeroVee engine,
likely will not be offered as kits, due to the critical tolerances and
potential dangers with some of the electrical components.
Monnett pointed out that a couple of technologies are key to making
electric flight a reality. Of course, powerful and light batteries are
a must, but a motor controller capable of managing the high power
involved also is required. A charging system, capable of replenishing
the batteries in a reasonable amount of time, is another must. Sonex
is developing both technologies.
Target flight duration for the proof-of-concept airplane is 25 minutes
to 45 minutes. Production systems are expected to allow for one-hour
flights. Buck says an hour's endurance is difficult right now but
ultimately is very possible as both the system and the available
technologies are further developed.
In addition to the electric Waiex, Sonex's e-Flight initiative also
involves two other aspects: the practical use of ethanol fuels in the
AeroConversions AeroVee 2.0 engine and developing other enhancements
to the AeroVee, improving its already-impressive efficiency.
Sonex partnered with Wisconsin-based Renew Fuel Stations, a
distributor of E85, a blend of up to 85 percent ethanol and 15 percent
gasoline, to develop an AeroVee engine configuration that can use the
fuel. Renew's interest in the project is expansion of the market for
ethanol fuels. Testing is under way right now.
The idea of electric flight is not new to Sonex. It dates back to 1994
when Monnett and Buck looked into the possibility of building an
electric plane specifically for the purpose of establishing speed
records for a new class of aircraft. Although the project was deemed
to be practical, Sonex put the project aside to further develop its
current set of kit airplanes and to support their customers. The
company is committed to completing the effort this time, though
Monnett stated firmly that the e-Flight program will never detract
from Sonex's commitment to its customers.
Sonex is financing the entire effort itself.
Once production systems are available, Sonex plans to make them
available to the experimental market for installation on other
airframes.
Sonex will present a forum on the e-Flight project Wednesday at 11:00
a.m. in Forum Building 11. More information about the project is
available on the web atwww.AeroConversions.com/E-Flight.
==========================================================
The RAeS General Aviation Group aims to encourage the development of
light aviation through the promotion of technologies, in particular
those that minimise its impact upon the environment.
The 2007-8 design competition therefore offers awards for technical
· whole aircraft design
· propulsion
· operational methods
· specific technologies within the aircraft.
The competition is open to any individual or group; entries are
particularly encouraged from teams from educational institutions or
RAeS corporate members.
Entries should be received by Friday 2 May 2008 and consist firstly
of a 10 page report , showing how it works, its benefits both to
light aviation and to the environment, and who is responsible for the
entry.
A shortlist of entrants will then be selected, who will be invited to
give a 20 minute presentation at a special event at RAeS Headquarters
in London during mid June 2008. At that event, a judging panel will
select the final winning entries; prizes and final award categories
will be announced nearer to the entry deadline.
Judging criteria will be based upon feasibility, originality,
reduction of impact upon the environment and the potential benefits
to light aviation overall. Final presentations will also be judged
on presentation quality and response to questioning.
The judging panel will consist of highly qualified light aviation
professionals - including representatives from industry, regulatory
authorities and academia.
General Aviation Group
Royal Aeronautical Society
No.4 Hamilton Place
London, W1J 7BQ, UK

Very interesting. It doesn't mention how long it takes to charge the
batteries. It strikes me that if they could get the duration up to
about 2 hours or so, you could use an electric plane for basic flight
training. But you would need to be able to swap out the battery pack.

An electic motor should be more reliable than a piston engine. But I
wonder what the life span of the batteries would be. If they need to
be replaced periodically at the costs mentioned, it's possible that
electric propulsion would be as expensive if not more so than gas.

[Larry Dighera]

Post by Phil
Very interesting. It doesn't mention how long it takes to charge the
batteries.

There's a pod-cast here in which Sonex's owner John Monnett and
engineer Pete Buck discuss that topic:
http://www.aviationweek.com/media/audio/sonex.mp3

[Phil]

Post by Larry Dighera

Post by Phil
Very interesting. It doesn't mention how long it takes to charge the
batteries.

There's a pod-cast here in which Sonex's owner John Monnett and
engineer Pete Buck discuss that topic:http://www.aviationweek.com/media/audio/sonex.mp3

I wonder if anyone has done any experiments with a hybrid drive system
for an aircraft. I am thinking of something like a 3-cylinder diesel
engine providing enough power for cruise, supplemented with a battery
pack and motor for takeoff and climb.

[j***@specsol.spam.sux.com]

Post by Phil

Post by Larry Dighera

Post by Phil
Very interesting. It doesn't mention how long it takes to charge the
batteries.

There's a pod-cast here in which Sonex's owner John Monnett and
engineer Pete Buck discuss that topic:http://www.aviationweek.com/media/audio/sonex.mp3

I wonder if anyone has done any experiments with a hybrid drive system
for an aircraft. I am thinking of something like a 3-cylinder diesel
engine providing enough power for cruise, supplemented with a battery
pack and motor for takeoff and climb.

The advantage for hybrids comes from stop and go driving where the
battery is charged by regenerative braking.

There isn't much stop and go flying.

[Michael Ash]

Post by j***@specsol.spam.sux.com

Post by Phil
I wonder if anyone has done any experiments with a hybrid drive system
for an aircraft. I am thinking of something like a 3-cylinder diesel
engine providing enough power for cruise, supplemented with a battery
pack and motor for takeoff and climb.

The advantage for hybrids comes from stop and go driving where the
battery is charged by regenerative braking.
There isn't much stop and go flying.

There is also an advantage which comes from only needing to size the
engine for cruise, not for acceleration, since you can suppliment the
smaller engine with the batteries during acceleration. Smaller engines are
generally more efficient than larger ones when putting out the same amount
of power.

The other advantage is that the engine can stay in the engine's efficiency
band even when the RPM demanded of it is higher (acceleration) or lower
(initial start).

However, these also don't help nearly as much on aircraft as on cars. The
difference between acceleration and cruise power on an aircraft is much
less than in a car, and aircraft engines tend to spend most of their time
in the efficiency band anyway, especially if there's a constant-speed prop
affixed. The extra drag caused by the extra weight of the batteries and
the rest of the hybrid system would probably outweigh any efficiency gain.

[Bill Daniels]

Post by Michael Ash

Post by j***@specsol.spam.sux.com

Post by Phil
I wonder if anyone has done any experiments with a hybrid drive system
for an aircraft. I am thinking of something like a 3-cylinder diesel
engine providing enough power for cruise, supplemented with a battery
pack and motor for takeoff and climb.

The advantage for hybrids comes from stop and go driving where the
battery is charged by regenerative braking.
There isn't much stop and go flying.

There is also an advantage which comes from only needing to size the
engine for cruise, not for acceleration, since you can suppliment the
smaller engine with the batteries during acceleration. Smaller engines are
generally more efficient than larger ones when putting out the same amount
of power.
The other advantage is that the engine can stay in the engine's efficiency
band even when the RPM demanded of it is higher (acceleration) or lower
(initial start).
However, these also don't help nearly as much on aircraft as on cars. The
difference between acceleration and cruise power on an aircraft is much
less than in a car, and aircraft engines tend to spend most of their time
in the efficiency band anyway, especially if there's a constant-speed prop
affixed. The extra drag caused by the extra weight of the batteries and
the rest of the hybrid system would probably outweigh any efficiency gain.
--
Michael Ash

There is, I believe, a UAV using hybrid power. The idea is to switch off
the gas engine and run on electric power for a stealthy approach to a
"location of interest".

Bill Daniels

Post by Michael Ash
Rogue Amoeba Software

[Morgans]

Post by Michael Ash
The extra drag caused by the extra weight of the batteries and
the rest of the hybrid system would probably outweigh any efficiency gain.

Probably? You are being far too kind. A redundant power system, only
helping at takeoff is GOING to waste efficiency. There is no way to avoid
that fact unless then cruise speed is going to be painfully slow.

[Michael Ash]

Post by Morgans

Post by Michael Ash
The extra drag caused by the extra weight of the batteries and
the rest of the hybrid system would probably outweigh any efficiency gain.

Probably? You are being far too kind. A redundant power system, only
helping at takeoff is GOING to waste efficiency. There is no way to avoid
that fact unless then cruise speed is going to be painfully slow.

I don't doubt you in any way, and in fact my general feeling is in
complete agreement with you. But I'm not speaking from a position of great
knowledge so I used a weasel word to indicate that. :)

[j***@specsol.spam.sux.com]

Post by Michael Ash

Post by j***@specsol.spam.sux.com

Post by Phil
I wonder if anyone has done any experiments with a hybrid drive system
for an aircraft. I am thinking of something like a 3-cylinder diesel
engine providing enough power for cruise, supplemented with a battery
pack and motor for takeoff and climb.

The advantage for hybrids comes from stop and go driving where the
battery is charged by regenerative braking.
There isn't much stop and go flying.

There is also an advantage which comes from only needing to size the
engine for cruise, not for acceleration, since you can suppliment the
smaller engine with the batteries during acceleration. Smaller engines are
generally more efficient than larger ones when putting out the same amount
of power.

If you are trying to say it takes less power to maintain speed than to
accelerate, yes that is true.

The advantage from the electric engine at cruise is that it uses zero
energy.

There were attempts to increase mileage of gas engines by turning off
uneeded cylinders at cruise. They didn't work that well and you still
had to move the pistons, the big crank, and all the rest of the stuff.

Post by Michael Ash
The other advantage is that the engine can stay in the engine's efficiency
band even when the RPM demanded of it is higher (acceleration) or lower
(initial start).

The transmission keeps the engine RPM within a limited range.

Hybrids have no effect on that.

Post by Michael Ash
However, these also don't help nearly as much on aircraft as on cars. The
difference between acceleration and cruise power on an aircraft is much
less than in a car, and aircraft engines tend to spend most of their time
in the efficiency band anyway, especially if there's a constant-speed prop
affixed. The extra drag caused by the extra weight of the batteries and
the rest of the hybrid system would probably outweigh any efficiency gain.

It doesn't help at all on airplanes.

The advantage to hybrids is they get better gas mileage.

They do that by using the deceleration to charge batteries which recovers
some of the kinetic energy instead of using it all to heat the brake linings.

[Tim Ward]

Post by j***@specsol.spam.sux.com
The advantage from the electric engine at cruise is that it uses zero
energy.

<Snippage>

Post by j***@specsol.spam.sux.com
--
Jim Pennino
Remove .spam.sux to reply.

You want to support this, somehow?

Tim Ward

[j***@specsol.spam.sux.com]

Post by Tim Ward

Post by j***@specsol.spam.sux.com
The advantage from the electric engine at cruise is that it uses zero
energy.

<Snippage>

Post by j***@specsol.spam.sux.com
--
Jim Pennino
Remove .spam.sux to reply.

You want to support this, somehow?
Tim Ward

At cruise the electric motor is turned off.

The only energy used is some slight bearing friction.

The electric motor is only turned on when more power than the gas
engine can provide is needed.

[Michael Ash]

Post by j***@specsol.spam.sux.com

Post by Michael Ash
There is also an advantage which comes from only needing to size the
engine for cruise, not for acceleration, since you can suppliment the
smaller engine with the batteries during acceleration. Smaller engines are
generally more efficient than larger ones when putting out the same amount
of power.

If you are trying to say it takes less power to maintain speed than to
accelerate, yes that is true.
The advantage from the electric engine at cruise is that it uses zero
energy.
There were attempts to increase mileage of gas engines by turning off
uneeded cylinders at cruise. They didn't work that well and you still
had to move the pistons, the big crank, and all the rest of the stuff.

Right, so a hybrid is like that system, except that the undeeded cylinders
are replaced with an electric motor. Instead of, say, having six cylinders
and only running four during cruise, you only *have* four cylinders, and
then you suppliment them with the electric system during acceleration.
That way you aren't moving them around and you get better efficiency from
the smaller engine.

Post by j***@specsol.spam.sux.com

Post by Michael Ash
The other advantage is that the engine can stay in the engine's efficiency
band even when the RPM demanded of it is higher (acceleration) or lower
(initial start).

The transmission keeps the engine RPM within a limited range.
Hybrids have no effect on that.

The transmission *tries to* keep the engine RPM within a limited range,
but it doesn't always work.

My car's efficiency band appears to be around 1500-2000RPM since that's
where it stays most of the time. But if I floor it on the highway it'll
easily hit 6000RPM at a great loss of efficiency. On a hybrid that extra
power is going to come from the electrical system.

Post by j***@specsol.spam.sux.com

Post by Michael Ash
However, these also don't help nearly as much on aircraft as on cars. The
difference between acceleration and cruise power on an aircraft is much
less than in a car, and aircraft engines tend to spend most of their time
in the efficiency band anyway, especially if there's a constant-speed prop
affixed. The extra drag caused by the extra weight of the batteries and
the rest of the hybrid system would probably outweigh any efficiency gain.

It doesn't help at all on airplanes.
The advantage to hybrids is they get better gas mileage.
They do that by using the deceleration to charge batteries which recovers
some of the kinetic energy instead of using it all to heat the brake linings.

This is true but incomplete. Regenerative braking is *one of the ways*
hybrids get better mileage. They also get better mileage by using smaller
engines and running those engines in a more efficient than would be
possible with a direct-drive system. But the conclusion is the same in the
end: although the last two would help in an aircraft they would not help
nearly enough to make such a system worthwhile.

[Gattman]

Post by Phil
Very interesting. It doesn't mention how long it takes to charge the
batteries.

It looks like they're using an Etek motor which was increasingly common in
the superheavyweight Battlebots and Robot Wars. Real monsters. (Got
thumped by 'em a few times.) For perspective, I used four smaller
power-chair motors to propel a 250-pound machine that could pull my jeep,
but heating became a real problem. If the motor and batteries are cooled
properly they'll operate a lot longer on a charge. I don't think you'd get
two hours out of a charge, though. I used a total of 120 C-cell nicads
bundled in 6 clusters of 20 wired serial, with the clusters in parallel, and
got about 30 minutes with no additional load on the frame. That's the
equivalent of two 20-pound sealed lead acid lawnmower batteries. Also, the
runtime could drop to 5 minutes if the motors operated at full stall.

Depending on the battery types they can charge pretty fast. I can't
remember the figure but it was hours or less. What you'd need to do for a
day of flying is have one or two sets charging while you're flying.

The other factor is the discharge characteristics of the batteries; some
such as the $70 Hawker 12v SLAs will carry full charge and then crap out all
at once, whereas start at 100% and gradually decrease. Lithium Ion and
later change the metric quite a bit, but you still have to be able to
predict when and how your power will drop.

The weight for these batteries and hardware was about 40 pounds total, IIRC.

Post by Phil
An electic motor should be more reliable than a piston engine. But I
wonder what the life span of the batteries would be.

If they're treated well and conditioned properly they should last quite
awhile, but they certainly won't last as long as a Rotax. It would be a joy
not to have an internal combustion engine roaring behind your head,
though....

Weird. Except for the ultralight itself, which I sold many years ago, I
have all of the components necessary to build a couple of these.

-c

[James Sleeman]

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).

That said though, I recently saw an article somewhere about an
electric car with a stirling engine tucked away in the back (Deam
Kamen was in on it somewhere - he's the Segway and fancy wheelchair
guy).

On the face of it, that seems like not a bad idea for how an electric
aircraft could be realistic - take your stirling engine, hook it
through a smaller, cheaper, lighter battery system to your electric
motor. The battery would act as a buffer (capacitor) to allow for
stored energy to do rapid changes in power to the drive motor, the
stirling engine would tick away at a constant rate feeding it's
generated electricy into the battery.

But then, I'm no engineer, I'm sure it's already been discounted as
impractical by the real engineers :) Maybe the stirling engine ends
up so big and heavy to produce the power required that it's useless.

[g***@cox.net]

Post by James Sleeman

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).
That said though, I recently saw an article somewhere about an
electric car with a stirling engine tucked away in the back (Deam
Kamen was in on it somewhere - he's the Segway and fancy wheelchair
guy).
On the face of it, that seems like not a bad idea for how an electric
aircraft could be realistic - take your stirling engine, hook it
through a smaller, cheaper, lighter battery system to your electric
motor. The battery would act as a buffer (capacitor) to allow for
stored energy to do rapid changes in power to the drive motor, the
stirling engine would tick away at a constant rate feeding it's
generated electricy into the battery.
But then, I'm no engineer, I'm sure it's already been discounted as
impractical by the real engineers :) Maybe the stirling engine ends
up so big and heavy to produce the power required that it's useless.

For a battery-powered car todays practical approach is to have a
second engine for backup or as you suggest to generate electricity.
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business. For aircraft the best use for
batteries today is to start the engine. Lange has demonstrated what is
possible with today's batteries/motors and while it provides an
attractive self-launch the cost and range tradeoffs bring it back into
perspective.

[Airjunkie]

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

[Larry Dighera]

Post by Airjunkie
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.
###

[Larry Dighera]

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.



=========================================================

Post by Larry Dighera

Post by Airjunkie
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
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.
###

[Bill Daniels]

Post by g***@cox.net
For a battery-powered car todays practical approach is to have a
second engine for backup or as you suggest to generate electricity.
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business. For aircraft the best use for
batteries today is to start the engine. Lange has demonstrated what is
possible with today's batteries/motors and while it provides an
attractive self-launch the cost and range tradeoffs bring it back into
perspective.

I think this is a little pessimistic. Critics of the pure electric seem to
focus on the "one-car does everything" strategy where it's easier to find
faults. The "electrics don't equal engine powered cars" isn't the whole
story.

Americans, at least, seem to have developed a another strategy for dealing
with fuel prices that spike every summer. They own an old, cheap econobox
they dust off when gas prices exceed $3. They drive their SUV's only when
they need the capacity.

This 2-car strategy works for pure electrics (EV's) too. Survey after
survey notes that a huge majority of drivers do less than 40 miles a day
which is easilly met with EV's. The current best range of 100 miles
provides better than a 2:1 safety margin.

Economically, the 2- car strategy can be implemented without owning two
cars. Just RENT the SUV when you need it. Considering total ownership
costs, this is a good deal. Looking at all the rental discounts available
to me, I don't plan to replace my SUV.

Interestingly, range alone isn't, in itself, a killer. If the battery pack
can be recharged in less than 10 minutes, the limited range is less of a
factor. The newest Lithium Phospate cells can reach 80% charge in one
minute and full charge in 5 minutes. So, if you invest in a tow truck, get
one with a diesel generator set.

Most likely, popular parking areas will be equipped with charging outlets.
I can imagine shopping centers with signs saying, "Shop here while you
recharge, FREE!" I can also imagine employers getting tax incentives to
provide their workers with access to a recharging station.

My bets are on the pure electric vehicle.

Bill Daniels

[Ken Finney]

Post by Bill Daniels

Post by g***@cox.net
For a battery-powered car todays practical approach is to have a
second engine for backup or as you suggest to generate electricity.
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business. For aircraft the best use for
batteries today is to start the engine. Lange has demonstrated what is
possible with today's batteries/motors and while it provides an
attractive self-launch the cost and range tradeoffs bring it back into
perspective.

I think this is a little pessimistic. Critics of the pure electric seem
to focus on the "one-car does everything" strategy where it's easier to
find faults. The "electrics don't equal engine powered cars" isn't the
whole story.
Americans, at least, seem to have developed a another strategy for dealing
with fuel prices that spike every summer. They own an old, cheap econobox
they dust off when gas prices exceed $3. They drive their SUV's only when
they need the capacity.
This 2-car strategy works for pure electrics (EV's) too. Survey after
survey notes that a huge majority of drivers do less than 40 miles a day
which is easilly met with EV's. The current best range of 100 miles
provides better than a 2:1 safety margin.
Economically, the 2- car strategy can be implemented without owning two
cars. Just RENT the SUV when you need it. Considering total ownership
costs, this is a good deal. Looking at all the rental discounts available
to me, I don't plan to replace my SUV.
Interestingly, range alone isn't, in itself, a killer. If the battery
pack can be recharged in less than 10 minutes, the limited range is less
of a factor. The newest Lithium Phospate cells can reach 80% charge in
one minute and full charge in 5 minutes. So, if you invest in a tow
truck, get one with a diesel generator set.
Most likely, popular parking areas will be equipped with charging outlets.
I can imagine shopping centers with signs saying, "Shop here while you
recharge, FREE!" I can also imagine employers getting tax incentives to
provide their workers with access to a recharging station.
My bets are on the pure electric vehicle.

In the early 1980's, Mother Earth News made a hybrid car that got 75 miles
per gallon. It was a Opel GT (heavy) powered by a jet engine starter motor
(inefficient) and a relatively inefficient small gas motor. The gas motor
powered the alternator which charged the batteries which ran the electric
motor. At the time, they noted that this wasn't new technology, but was the
way diesel train engines worked. In 2010, GM will introduce the Chevy Volt,
which is pretty much the same concept, which I'm convinced is the way to go.
I think this does have promise for airplanes as well. The IC engine and
batteries can be place for optimum weight distribution, and the IC engine
can be heavilly vibration isolated.

[Ricky]

Post by Bill Daniels
This 2-car strategy works for pure electrics (EV's) too. Survey after
survey notes that a huge majority of drivers do less than 40 miles a day
which is easilly met with EV's. The current best range of 100 miles
provides better than a 2:1 safety margin.
Bill Daniels

The Tesla Roadster gets 200 miles per charge and takes 3.5 hours to re-
charge. It goes 0-60 in something like 3 seconds.
You ought to check out Tesla Motors website.
It's an incredible, beautiful car though overpriced. Tesla is coming
out with a more reasonably priced family-type sedan for their #2 entry
to the electric car market.

Ricky

[Larry Dighera]

Post by g***@cox.net
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business.

The time has arrived:
http://www.teslamotors.com/index.php

[Gig 601XL Builder]

Post by Larry Dighera

Post by g***@cox.net
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business.

http://www.teslamotors.com/index.php

And a good place to base the new tow truck business is about half way
between SF and LA, because that's about how far this $100,000 car will take
you.

Scroll to the bottom of the page.

http://www.teslamotors.com/performance/charging_and_batteries.php

[j***@specsol.spam.sux.com]

Post by Gig 601XL Builder

Post by Larry Dighera

Post by g***@cox.net
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business.

http://www.teslamotors.com/index.php

And a good place to base the new tow truck business is about half way
between SF and LA, because that's about how far this $100,000 car will take
you.
Scroll to the bottom of the page.
http://www.teslamotors.com/performance/charging_and_batteries.php

Or half way between LA and Vegas.

The page leads to some "interesting" information.

If you cruise around you find claims that the energy usage is 110 Wh/km,
and recharge time of about 3.5 hours.

110 Wh/km is about 11.7 kWh for a 100 mile trip.

If the charging process is 100% efficient (not in this universe), to
recharge in 3.5 hours requires 11.7/3.5, or about 3.3 kW.

At 120 V, that's 27.5 A, which is a bit beyond the standard 15 A outlet.

At 220 V, that's about 15 A, so you better have a 220 outlet nearby.

Elsewhere they talk about recharging in 2 hours with some 70 A system.

Anyone out there got a 70 A plus safety factor outlet in their house?

They talk about "With your electrical company's incentive pricing
factored in, it will cost you roughly 1 cent per mile to drive the
Tesla Roadster".

Keep in mind they are targeting California.

In California, the "incentive pricing" is the more you use, the more
you pay per kWh.

There is the quote "Single-occupancy access to all carpool lanes".

Yeah, true for a while, but all the permits that are ever going to
be issued were issued long ago.

Just too much hype and inconsistancy for me.

[g***@cox.net]

Post by j***@specsol.spam.sux.com

Post by Gig 601XL Builder

Post by Larry Dighera

Post by g***@cox.net
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business.

http://www.teslamotors.com/index.php

And a good place to base the new tow truck business is about half way
between SF and LA, because that's about how far this $100,000 car will take
you.
Scroll to the bottom of the page.
http://www.teslamotors.com/performance/charging_and_batteries.php

Or half way between LA and Vegas.
The page leads to some "interesting" information.
If you cruise around you find claims that the energy usage is 110 Wh/km,
and recharge time of about 3.5 hours.
110 Wh/km is about 11.7 kWh for a 100 mile trip.
If the charging process is 100% efficient (not in this universe), to
recharge in 3.5 hours requires 11.7/3.5, or about 3.3 kW.
At 120 V, that's 27.5 A, which is a bit beyond the standard 15 A outlet.
At 220 V, that's about 15 A, so you better have a 220 outlet nearby.
Elsewhere they talk about recharging in 2 hours with some 70 A system.
Anyone out there got a 70 A plus safety factor outlet in their house?
They talk about "With your electrical company's incentive pricing
factored in, it will cost you roughly 1 cent per mile to drive the
Tesla Roadster".
Keep in mind they are targeting California.
In California, the "incentive pricing" is the more you use, the more
you pay per kWh.
There is the quote "Single-occupancy access to all carpool lanes".
Yeah, true for a while, but all the permits that are ever going to
be issued were issued long ago.
Just too much hype and inconsistancy for me.
--
Jim Pennino
Remove .spam.sux to reply.

I was aware of this project based upon the Lotus Elise which is a
pretty amaxing performance car with only a small gas engine. Its
pretty much hand built with composites and looks even better in person
than in pictures. With enough battery power the power potentail is
impressive. I think I'll hold off on the tow truck business until they
sell enough $100,000 (assuming they will give away the charging
station) cars to justify my investment.

[Ken Finney]

Post by j***@specsol.spam.sux.com

Post by Gig 601XL Builder

Post by Larry Dighera

Post by g***@cox.net
When they start selling cars only powered by batteries I'm going to
invest in a tow truck business.

http://www.teslamotors.com/index.php

And a good place to base the new tow truck business is about half way
between SF and LA, because that's about how far this $100,000 car will take
you.
Scroll to the bottom of the page.
http://www.teslamotors.com/performance/charging_and_batteries.php

Or half way between LA and Vegas.
The page leads to some "interesting" information.
If you cruise around you find claims that the energy usage is 110 Wh/km,
and recharge time of about 3.5 hours.
110 Wh/km is about 11.7 kWh for a 100 mile trip.
If the charging process is 100% efficient (not in this universe), to
recharge in 3.5 hours requires 11.7/3.5, or about 3.3 kW.
At 120 V, that's 27.5 A, which is a bit beyond the standard 15 A outlet.
At 220 V, that's about 15 A, so you better have a 220 outlet nearby.
Elsewhere they talk about recharging in 2 hours with some 70 A system.
Anyone out there got a 70 A plus safety factor outlet in their house?

Well, I just put in a dedicated 50 A receptable for charging electric cars.
Now, I just need the electric car.

[kontiki]

Post by j***@specsol.spam.sux.com
Just too much hype and inconsistancy for me.

Has anyone done an analysis on the amount of energy required to
produce a vehicle like this vs what it will actually "save" during
its supposed lifetime? Some of these exotic battery materials and
manufacturing techiques take a lot of energy on the front end to
produce, and dispose of and/or recycle on the back end. You have
to factor that into the net energy gain or loss of actual use of
these vehicles.

[Snowbird]

Post by kontiki
Has anyone done an analysis on the amount of energy required to
produce a vehicle like this vs what it will actually "save" during
its supposed lifetime? Some of these exotic battery materials and
manufacturing techiques take a lot of energy on the front end to
produce, and dispose of and/or recycle on the back end. You have
to factor that into the net energy gain or loss of actual use of
these vehicles.

Since the ethanol discussion started, it seems we're starting to see more
and more "total industry ecosystem cost" analyses of this type. Anyway the
oil supply infrastructure does not come for free either. Even though initial
investments are already written off the infrastructure has to be maintained.
You might even want to count in the cost of the military power needed to
secure access to oil supplies, especially in the future.

[Larry Dighera]

On Mon, 06 Aug 2007 00:14:14 -0700, James Sleeman

Post by James Sleeman

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).

There is a fundamental problem with attempting to power an aircraft
with batteries: The propulsion system must not only move the vehicle
forward as it would with an automobile, but it must also
simultaneously maintain the aircraft's altitude; unlike an automobile
that only requires a small amount of energy to overcome rolling and
wind resistance once in motion, an aircraft can't coast without losing
altitude, so energy demands for powering an aircraft are considerably
more demanding than those for an automobile.

Post by James Sleeman
That said though, I recently saw an article somewhere about an
electric car with a stirling engine tucked away in the back (Deam
Kamen was in on it somewhere - he's the Segway and fancy wheelchair
guy).

Are external combustion engines as efficient as internal combustion
engines? Stirling engines are great for converting waste heat to
mechanical energy, but I'm not sure how appropriate they would be for
aircraft propulsion.

Post by James Sleeman
On the face of it, that seems like not a bad idea for how an electric
aircraft could be realistic - take your stirling engine, hook it
through a smaller, cheaper, lighter battery system to your electric
motor. The battery would act as a buffer (capacitor) to allow for
stored energy to do rapid changes in power to the drive motor, the
stirling engine would tick away at a constant rate feeding it's
generated electricy into the battery.
But then, I'm no engineer, I'm sure it's already been discounted as
impractical by the real engineers :) Maybe the stirling engine ends
up so big and heavy to produce the power required that it's useless.

The comparative light weight and high energy density of lithium-ion
polymer batteries makes them a potential enabling technology for
electrically powered aircraft as well as automobiles. All-electric
automobiles are entering the marketplace finally:

Our customers are a diverse group. All value the sports car
performance of zero to 60 mph in about 4 seconds and a top speed
of more than 130 mph, but many of our customers are also concerned
about the environment. Some, such as customer Stephen Casner, have
owned (and still own) older electric vehicles like Toyota's Rav 4.
(Read his Tesla Motors blog at:
http://cts.vresp.com/c/?TeslaMotors/c0366b684a/0106cc84be/9291be675f

Early customers include Google Co-Founders Sergey Brin and Larry
Page, actor George Clooney, comedian Jay Leno, and California
Governor Arnold Schwarzenegger. Tesla Motors continues to take
reservations for the 2008 model year Tesla Roadster at our website
at:
http://cts.vresp.com/c/?TeslaMotors/c0366b684a/0106cc84be/d99894a034

Tesla Motors is closing out July with another significant
milestone reached: We have now accepted more than 560 reservations
for the Tesla Roadster toward an anticipated first year production
total of 800 cars.
http://cts.vresp.com/c/?TeslaMotors/c0366b684a/0106cc84be/4ed5aad61f

And if this prototype is an indication, all-electric automobiles will
no longer suffer from an image of being slow and impractical:

http://www.gizmag.com/go/6104/1/
The 640 bhp MINI QED plug-in EV
(link to this article)

Page: 1 2

September 4, 2006 Q.E.D. is an abbreviation of the Latin phrase
"quod erat demonstrandum" which means, "which was to be
demonstrated". In simple terms, it indicates that something has
been definitively proven. Accordingly, the MINI QED electric
hybrid is aptly named as it dispels any doubts about the validity
of in-hub electric motors playing their part in the future of the
automobile. PML FlightLink designs and manufacture electric
motors, EV drive systems, joystick controls and controllers and
bespoke motors for specialist applications and the MINI QED was
built to showcase their expertise in wheelmotors, with a view to
supplying what we expect will be a booming market in electric
vehicle applications over coming decades.

The result is a MINI with four times the horsepower of a Cooper S,
supercar performance and the prospects of some very serious EVs in
the near future. The QED is a ripper, using four 120kW (160bhp)
wheel motors complete with invertors to convert momentum back into
stored energy under brakes. With one on each corner you have
Ferrari-like power and very controllable independent drive on all
four wheels.

In the MINI QED, this package offers a 0-60mph time of 3.7 seconds
and a 150mph top speed – supercar territory. An on-board petrol
engined generator offers enough electrons to run continuously at
motorway speeds without depleting the battery, and you can plug it
in at night and commute in full electric mode if you wish.

As the invertor can exert more retardation than brakes, the
conventional disc brakes have been discarded altogether.

The inwheel motors and magnesium alloy wheels, and tyres, have a
total mass of 24kg. The original assembly mass on the MINI One was
22.5kg. With so little difference in unsprung mass (the brake
hubs and discs have been removed), and full regenerative braking,
the ride is claimed to be no different.

More importantly, it means dynamic management of up to 750Nm
torque at each wheel, (3000Nm total) in either direction, to
ensure optimum use of available power. The system can also use
steering (driver intent and wheel alignment) and vehicle attitude
(gyroscopic sensors read pitch, roll and yaw) as inputs to the
traction control and vehicle stability systems. Put simply, the
vehicle stability system will be the key, and it will ultimately
be the software that determines what the optimum tractive
distribution will be at each instant - how the energy stored in
the 300V 70Amp Hour (700Amp peak) Lithium Polymer battery is most
effectively distributed.

...continued: http://www.pmlflightlink.com/archive/news_mini.html

So it would appear that high-performance all-electric automobiles are
viable and in fact being produced commercially now. And while there
have been some successful electrically powered, unmanned aircraft
demonstrated, such as those of Dr. Paul MacCready's AeroVironment:

http://www.avinc.com/uav_lab_project_detail.php?id=40
Pathfinder flew to 50,567 feet at Edwards September 12, 1995, its
first trip to the stratosphere. From there, it was improved and
taken to the Pacific Missile Range Facility (PMRF), Kauai, Hawaii
for test flights in 1997, where it flew to 71,504 feet on July 7,
before performing a series of science missions over the Hawaiian
Islands.

http://www.avinc.com/uas_dev_project_detail.php?id=115
Global Observer is the latest development in High Altitude Long
Endurance (HALE) UAS, being the first operational configuration
able to provide long-dwell stratospheric capability with global
range and no latitude restrictions. Global Observer's unique
combination of both extreme flight duration and stratospheric
operating altitude is designed to deliver advantages in cost,
capacity, coverage, flexibility, and reliability that make it a
compelling complement to existing satellite, aerial and
terrestrial assets.

Missions Communications Relay & Remote Sensing
Features High-Altitude, Long-Endurance platform (all latitude
capability)
Endurance/Range Over 1 week/global
Payload Up to 400 lbs. for GO-1 & 1,000 lbs for GO-2
Operating Altitude 65,000 feet
Expected Availability Within 2 years for U.S. government, with
funding

There are also manned, commercially produced, electrically powered
sailplanes available in the marketplace:


http://www.lange-flugzeugbau.de/htm/english/products/antares_20e/antares_20E.html
Antares 20E

http://lange-flugzeugbau.com/pdf/news/EASA/TCDS_%20A_092_E1_Antares_%20issue01.pdf
Today Lange Flugzeugbau received the EASA type certification for
the Antares 20E. (EASA TCDS No. A.092). This is the first time in
the world that an aircraft with an electrical propulsion system
receives a type certificate.
http://www.nadler.com/public/Antares.html


http://www.dg-flugzeugbau.de/elektroflieger-e.html
DG-800E the uncompromised Motor glider with Electro-Power?


Here's a little history:

http://www.solarimpulse.com/the-history-of-solar-aviation-en20.html
Solar aviation began with reduced models in the 1970s, when
affordable solar cells appeared on the market. But it was not
until 1980 that the first human flights were realised. In the
United States, Paul MacCready's team developed the Gossamer
Penguin, which opened up the way for the Solar Challenger. This
aircraft, with a maximum power of 2.5 kW, succeeded in crossing
the Channel in 1981 and in quick succession covered distances of
several hundred kilometres with an endurance of several hours. In
Europe, during this time, Günter Rochelt was making his first
flights with the Solair 1 fitted with 2500 photovoltaic cells,
allowing the generation of a maximum power of 2.2kW.

In 1990, the American Eric Raymond crossed the United States with
Sunseeker in 21 stages over almost two months. The longest lap was
400 kilometres. The Sunseeker was a solar motor bike-sail plane
with a smoothness of 30 for a tare weight of 89 kg and was
equipped with solar cells of amorphous silicon.

In the middle of the 1990s, several airplanes were built to
participate in the "Berblinger" competition. The aim was to be
able to go up to an altitude of 450m with the aid of batteries and
to maintain a horizontal flight with the power of at least 500W/m2
of solar energy, which corresponds to about half of the power
emitted by the sun at midday on the equator. The prize was won in
1996 by Professeur Voit-Nitschmann's team of Stuttgart University,
with Icare 2 (25 meters wingspan with a surface of 26 m2 of solar
cells.)
http://www.solarimpulse.com/the-solar-impulse-en5.html


And here's a glimpse at the future:

http://www.boeing.com/news/releases/2007/q1/070327e_pr.html
MADRID, March 27, 2007 -- In an effort to develop environmentally
progressive technologies for aerospace applications, Boeing
researchers and industry partners throughout Europe plan to
conduct experimental flight tests in 2007 of a manned airplane
powered only by a fuel cell and lightweight batteries.

The Boeing Fuel Cell Demonstrator Airplane uses a Proton Exchange
Membrane (PEM) fuel cell/lithium-ion battery hybrid system to
power an electric motor, which is coupled to a conventional
propeller. The fuel cell provides all power for the cruise phase
of flight.

During takeoff and climb, the flight segment that requires the
most power, the system draws on lightweight lithium-ion batteries.
(Boeing graphic)



Photo of Sonex e-flight electric aircraft's electric power plant:

http://www.sonexaircraft.com/news/images/airventure07/e-flight_5947.jpg


More info:
http://en.wikipedia.org/wiki/Electric_airplane

[D***@yahoo.com]

Post by Larry Dighera
As the invertor can exert more retardation than brakes, the
conventional disc brakes have been discarded altogether.

Oh, boy. Knowing first-hand the reliability of
electrical stuff...

Dan

[Larry Dighera]

Post by D***@yahoo.com

Post by Larry Dighera
As the invertor can exert more retardation than brakes, the
conventional disc brakes have been discarded altogether.

Oh, boy. Knowing first-hand the reliability of
electrical stuff...

It's a prototype. The choice not to equip the automobile with brakes
demonstrates how effective the regenerative braking is, but apparently
you have to carry chocks when you park it. :-)

[brtlmj]

Post by Larry Dighera
There is a fundamental problem with attempting to power an aircraft
with batteries: The propulsion system must not only move the vehicle
forward as it would with an automobile, but it must also
simultaneously maintain the aircraft's altitude;

This is significant at low airspeeds. At higher airspeeds overcoming
wind resistance takes much more power than maintaining altitude.

Post by Larry Dighera
unlike an automobile
that only requires a small amount of energy to overcome rolling and
wind resistance once in motion, an aircraft can't coast without losing
altitude,

It sure can, until it loses speed and stalls.

Bartek

[James Sleeman]

Post by Larry Dighera
Are external combustion engines as efficient as internal combustion
engines? Stirling engines are great for converting waste heat to
mechanical energy, but I'm not sure how appropriate they would be for
aircraft propulsion.

In theory, I think that stirling engines are quite well suited to
aircraft, all it needs is a source of "hot" and a source of "cold",
the cold is in abundance (stick a heatsink in the wind, higher you go,
colder it gets, more power the engine can deliver, directly the
opposite of IC), the hot could be provided with any number of
combustables (and some oxygen delivery system).

I found yesterday after writing my initial post an article about
exactly this - http://www.qrmc.com/fourpartstirling.html "Why Aviation
Needs the Stirling Engine by Darryl Phillips" from 1993/1994.

Given what was said in the article, I'm kind of surprised that nobody
has come up with a working protoype actually.

[Adhominem]

Post by James Sleeman
stick a heatsink in the wind, higher you go,
colder it gets, more power the engine can deliver, directly the
opposite of IC

What I didn't get from the article: Where does the "hot" come from? A fuel
burner, probably, which would have the same problems with altitude as an IC
engine, wouldn't it?

Ad-

[Larry Dighera]

On Mon, 06 Aug 2007 18:22:41 -0700, James Sleeman

Post by James Sleeman

Post by Larry Dighera
Are external combustion engines as efficient as internal combustion
engines? Stirling engines are great for converting waste heat to
mechanical energy, but I'm not sure how appropriate they would be for
aircraft propulsion.

In theory, I think that stirling engines are quite well suited to
aircraft, all it needs is a source of "hot" and a source of "cold",
the cold is in abundance (stick a heatsink in the wind, higher you go,
colder it gets, more power the engine can deliver, directly the
opposite of IC), the hot could be provided with any number of
combustables (and some oxygen delivery system).

I see what you mean. Unfortunately, the highest power requirements of
aircraft engines are during the takeoff and climb phases of flight.
Power requirements are even greater when the ambient temperature rises
resulting in less air density or a higher density altitude. That is
when the most power is required for takeoff, but that would be a
situation where the Stirling engine would have its minimum power
production.

I would also like to see a comparison of the efficiencies of IC and EC
engines and their relative weight and size per horsepower compared.

Unlike electrical motors, that must be constructed with heavy iron, IC
and EC engines can be constructed of lighter materials like aluminum,
but electrical motors are usually 80% to 95% efficient. With the
Stirling aircraft engine there is a requirement for what I would
imagine would be a large heat sink or heat exchanger located in the
slip stream. The weight of this heat exchanger and its drag penalty
must also be considered.

Post by James Sleeman
I found yesterday after writing my initial post an article about
exactly this - http://www.qrmc.com/fourpartstirling.html "Why Aviation
Needs the Stirling Engine by Darryl Phillips" from 1993/1994.
Given what was said in the article, I'm kind of surprised that nobody
has come up with a working protoype actually.

The article is interesting; thank you for mentioning it. I am
e-mailing a copy of this followup article to the author Darryl
Phillips.

There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if the
weight of the lead shielding were not too great. Imagine an aircraft
that effectively never runs out of fuel! There'd be no more fuel
exhaustion mishaps.

[Neil Gould]

Post by Larry Dighera
On Mon, 06 Aug 2007 18:22:41 -0700, James Sleeman

Post by James Sleeman

Post by Larry Dighera
Are external combustion engines as efficient as internal combustion
engines? Stirling engines are great for converting waste heat to
mechanical energy, but I'm not sure how appropriate they would be
for aircraft propulsion.

In theory, I think that stirling engines are quite well suited to
aircraft, all it needs is a source of "hot" and a source of "cold",
the cold is in abundance (stick a heatsink in the wind, higher you
go, colder it gets, more power the engine can deliver, directly the
opposite of IC), the hot could be provided with any number of
combustables (and some oxygen delivery system).

I see what you mean. Unfortunately, the highest power requirements of
aircraft engines are during the takeoff and climb phases of flight.
Power requirements are even greater when the ambient temperature rises
resulting in less air density or a higher density altitude. That is
when the most power is required for takeoff, but that would be a
situation where the Stirling engine would have its minimum power
production.

If an engine's minimum power production is greater than the power required
for takeoff, would it matter? It would seem that if this could be
achieved, the operating conditions of the Stirling engine would be mostly
understressed.

Post by Larry Dighera
I would also like to see a comparison of the efficiencies of IC and EC
engines and their relative weight and size per horsepower compared.
Unlike electrical motors, that must be constructed with heavy iron, IC
and EC engines can be constructed of lighter materials like aluminum,
but electrical motors are usually 80% to 95% efficient. With the
Stirling aircraft engine there is a requirement for what I would
imagine would be a large heat sink or heat exchanger located in the
slip stream. The weight of this heat exchanger and its drag penalty
must also be considered.

Why couldn't the heat exchanger be an integral part of the airframe? Wings
come to mind... ;-)

Post by Larry Dighera
There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if the
weight of the lead shielding were not too great. Imagine an aircraft
that effectively never runs out of fuel! There'd be no more fuel
exhaustion mishaps.

One downside would be the hazardous materials that could be dispersed in a
crash. I'd like to see a prototype Stirling using conventional fuels
before exploring more exotic options.

Neil

[Larry Dighera]

On Tue, 7 Aug 2007 11:48:50 -0500, "Neil Gould"
[snip]

Post by Neil Gould

Post by Larry Dighera
I see what you mean. Unfortunately, the highest power requirements of
aircraft engines are during the takeoff and climb phases of flight.
Power requirements are even greater when the ambient temperature rises
resulting in less air density or a higher density altitude. That is
when the most power is required for takeoff, but that would be a
situation where the Stirling engine would have its minimum power
production.

If an engine's minimum power production is greater than the power required
for takeoff, would it matter?

Probably not, but it would mean you'd have significantly more power
available at altitude if the Sterling engine were sized to provide
takeoff power at high density altitudes.

What I was getting at was the author of the articles emphasis on
overcoming the reduced power output of IC engines at lower atmospheric
pressure overlooks its possibly anemic performance (due to minimal air
movement through the heat exchanger and higher ambient temperatures on
the ground) when it is needed most, at takeoff. I find it revealing
that the author failed to mention that point, and it reduces my
confidence in the assertions he made in that article.

Post by Neil Gould
It would seem that if this could be achieved, the operating conditions
of the Stirling engine would be mostly understressed.

I am unable to infer your meaning by that statement. Do you mean
under emphasized or less mechanical stress on the engine, or what?

Post by Neil Gould

Post by Larry Dighera
I would also like to see a comparison of the efficiencies of IC and EC
engines and their relative weight and size per horsepower compared.
Unlike electrical motors, that must be constructed with heavy iron, IC
and EC engines can be constructed of lighter materials like aluminum,
but electrical motors are usually 80% to 95% efficient. With the
Stirling aircraft engine there is a requirement for what I would
imagine would be a large heat sink or heat exchanger located in the
slip stream. The weight of this heat exchanger and its drag penalty
must also be considered.

Why couldn't the heat exchanger be an integral part of the airframe? Wings
come to mind... ;-)

I'm thinking there would be necessity for some means of conducting the
heat from the engine to a remote heat exchanger, and the resulting
complexity and weight increase would negatively impact the potential
advantages of a Stirling aviation engine. In any event, in addition
to the Stirling engine and its fuel, a heat exchanger of some type
needs to factored into the weight, cost, performance, and efficiency
equations.

Post by Neil Gould

Post by Larry Dighera
There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if the
weight of the lead shielding were not too great. Imagine an aircraft
that effectively never runs out of fuel! There'd be no more fuel
exhaustion mishaps.

One downside would be the hazardous materials that could be dispersed in a
crash.

There are a lot of down sides to atomic power, but NASA uses it to
power Stirling engines in space.


Here's some information about what NASA successfully has accomplished
with nuclear power:


http://www.grc.nasa.gov/WWW/tmsb/index.html
The Thermo-Mechanical Systems Branch (5490) is responsible for
planning, conducting and directing research and technology
development to advance the state-of-the-art in a variety of
thermal systems for space, aerospace, as well as non-aerospace
applications. The systems of interest include thermal energy
conversion for power systems and solar thermal propulsion systems.
The effort involves working at the component level to develop the
technology, the subsystem level to verify the performance of the
technology, and the system level to ensure that the appropriate
system level impact is achieved with the integrated technology.
System analysis is used to identify high-impact technology areas,
define the critical aspects of the technology that need to be
developed, and characterize the system level impact of the
technology. Specific technology areas of interest include:


Dynamic Power Systems: Brayton, Rankine and Stirling Convertors,
Solar Receivers and Thermal Energy Storage
Primary Solar Concentrators: Thin film, SRP and Rigid
Secondary Solar Concentrators: Refractive and Reflective
Thermal Management: Radiators, Electronics Packaging, and Heat
Pipe Technology


http://www.grc.nasa.gov/WWW/tmsb/stirling.html
Animation of a 55 We Stirling TDC
(click on image to view)


http://www.grc.nasa.gov/WWW/tmsb/stirling/doc/stirl_radisotope.html
AVAILABLE TODAY FOR TOMORROW'S NEEDS
NASA Glenn Research Center and the Department of Energy (DOE) are
developing a Stirling convertor for an advanced radioisotope power
system to provide spacecraft on-board electric power for NASA deep
space missions. Stirling is being evaluated as an alternative to
replace Radioisotope Thermoelectric Generators (RTGs) with a
high-efficiency power source. The efficiency of the Stirling
system, in excess of 20%, will reduce the necessary isotope
inventory by a factor of at least 3 compared to RTGs. Stirling is
the most developed convertor option of the advanced power concepts
under consideration [1,2].


http://www.grc.nasa.gov/WWW/tmsb/stirling/doc/stirling_bckgrd.html
However, about this time NASA became interested in development of
free-piston Stirling engines for space power applications. These
engines use helium as the working fluid, drive linear alternators
to produce electricity and are hermetically sealed. These 12.5 kWe
per cylinder engines were intended for use with a nuclear reactor
power system; the Space Demonstrator Engine (or SPDE) was the
earliest 12.5 kWe per cylinder engine that was designed, built and
tested by MTI. A later engine of this size, the Component Test
Power Convertor (or CTPC), used a "Starfish" heat-pipe heater
head, instead of the pumped-loop used by the SPDE. Recently, in
the 1992-93 time period, this work was terminated due to the
termination of the related SP-100 nuclear power system work and
NASA's new emphasis on "better, faster, cheaper" systems and
missions.


http://www.spacedaily.com/news/outerplanets-00a2.html
Europa Orbiter was replanned to use a new "Sterling" nuclear
generator design which would use less plutonium



http://www.cndyorks.gn.apc.org/yspace/articles/boeing_lockheed_offer.htm
Boeing, Lockheed Offer NASA Two Choices for Nuclear Power

[Neil Gould]

Post by Larry Dighera
On Tue, 7 Aug 2007 11:48:50 -0500, "Neil Gould"
[snip]

Post by Neil Gould

Post by Larry Dighera
I see what you mean. Unfortunately, the highest power requirements
of aircraft engines are during the takeoff and climb phases of
flight. Power requirements are even greater when the ambient
temperature rises resulting in less air density or a higher density
altitude. That is when the most power is required for takeoff, but
that would be a situation where the Stirling engine would have its
minimum power production.

If an engine's minimum power production is greater than the power
required for takeoff, would it matter?

Probably not, but it would mean you'd have significantly more power
available at altitude if the Sterling engine were sized to provide
takeoff power at high density altitudes.

Exactly, but I don't see that as a negative... ;-)

Post by Larry Dighera
What I was getting at was the author of the articles emphasis on
overcoming the reduced power output of IC engines at lower atmospheric
pressure overlooks its possibly anemic performance (due to minimal air
movement through the heat exchanger and higher ambient temperatures on
the ground) when it is needed most, at takeoff. I find it revealing
that the author failed to mention that point, and it reduces my
confidence in the assertions he made in that article.

I understand your perspective, which is what prompted my reply. If there
is sufficient power to take off, then the issue should be moot, unless I'm
overlooking something. It should be reasonable to presume that any
practical aircraft engine would have sufficient power to take off, right?
;-)

Post by Larry Dighera

Post by Neil Gould
It would seem that if this could be achieved, the operating
conditions of the Stirling engine would be mostly understressed.

I am unable to infer your meaning by that statement. Do you mean
under emphasized or less mechanical stress on the engine, or what?

Less mechanical stress due to operating well below maximum power settings
under normal cruise. That should provide plenty of reserve power at
altitude and increase the fuel efficiency as well.

Post by Larry Dighera

Post by Neil Gould

Post by Larry Dighera
I would also like to see a comparison of the efficiencies of IC and
EC engines and their relative weight and size per horsepower
compared.
Unlike electrical motors, that must be constructed with heavy iron,
IC and EC engines can be constructed of lighter materials like
aluminum, but electrical motors are usually 80% to 95% efficient.
With the Stirling aircraft engine there is a requirement for what I
would imagine would be a large heat sink or heat exchanger located
in the slip stream. The weight of this heat exchanger and its drag
penalty must also be considered.

Why couldn't the heat exchanger be an integral part of the airframe?
Wings come to mind... ;-)

I'm thinking there would be necessity for some means of conducting the
heat from the engine to a remote heat exchanger, and the resulting
complexity and weight increase would negatively impact the potential
advantages of a Stirling aviation engine. In any event, in addition
to the Stirling engine and its fuel, a heat exchanger of some type
needs to factored into the weight, cost, performance, and efficiency
equations.

Of course, but I don't see a lot of reason why that couldn't be
incorporated into the overall design. My point is that heat exchangers
need not be heavy, and could probably double as structural and/or
aerodynamic components, further reducing (and possibly enhancing) their
impact.

Post by Larry Dighera

Post by Neil Gould

Post by Larry Dighera
There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if
the weight of the lead shielding were not too great. Imagine an
aircraft that effectively never runs out of fuel! There'd be no
more fuel exhaustion mishaps.

One downside would be the hazardous materials that could be
dispersed in a crash.

There are a lot of down sides to atomic power, but NASA uses it to
power Stirling engines in space.

Understandable, but their expectation is that catastrophic destruction
would disperse the nuclear material harmlessly. That can't be presumed for
light aircraft.


Neil

[Larry Dighera]

On Tue, 07 Aug 2007 17:51:27 GMT, "Neil Gould"
[...]

Post by Neil Gould

Post by Larry Dighera
I'm thinking there would be necessity for some means of conducting the
heat from the engine to a remote heat exchanger, and the resulting
complexity and weight increase would negatively impact the potential
advantages of a Stirling aviation engine. In any event, in addition
to the Stirling engine and its fuel, a heat exchanger of some type
needs to factored into the weight, cost, performance, and efficiency
equations.

Of course, but I don't see a lot of reason why that couldn't be
incorporated into the overall design. My point is that heat exchangers
need not be heavy, and could probably double as structural and/or
aerodynamic components, further reducing (and possibly enhancing) their
impact.

How would you get the heat from the Stirling engine to the heat sink?
If you use liquid coolant, it would be heavy and prone to leaks.

Post by Neil Gould

Post by Larry Dighera

Post by Neil Gould

Post by Larry Dighera
There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if
the weight of the lead shielding were not too great. Imagine an
aircraft that effectively never runs out of fuel! There'd be no
more fuel exhaustion mishaps.

One downside would be the hazardous materials that could be
dispersed in a crash.

There are a lot of down sides to atomic power, but NASA uses it to
power Stirling engines in space.

Understandable, but their expectation is that catastrophic destruction
would disperse the nuclear material harmlessly. That can't be presumed for
light aircraft.

If the rocket detonated in the atmosphere, it might not be so
harmless. I would guess the reactor is jacketed with sufficient
strength to preclude its destruction. Presumably, that could be done
for a Stirling aircraft engine also.

[Neil Gould]

Post by Larry Dighera
On Tue, 07 Aug 2007 17:51:27 GMT, "Neil Gould"
[...]

Post by Neil Gould

Post by Larry Dighera
I'm thinking there would be necessity for some means of conducting
the heat from the engine to a remote heat exchanger, and the
resulting complexity and weight increase would negatively impact
the potential advantages of a Stirling aviation engine. In any
event, in addition to the Stirling engine and its fuel, a heat
exchanger of some type needs to factored into the weight, cost,
performance, and efficiency equations.

Of course, but I don't see a lot of reason why that couldn't be
incorporated into the overall design. My point is that heat
exchangers need not be heavy, and could probably double as
structural and/or aerodynamic components, further reducing (and
possibly enhancing) their impact.

How would you get the heat from the Stirling engine to the heat sink?
If you use liquid coolant, it would be heavy and prone to leaks.

I'm not a Stirling engine designer, so I can't answer that factually. I
have been reading up on it a bit since the article was referenced in this
thread, but I haven't seen such things as the required rate of dissipation
for the engine to work efficiently. If the heat sink needs to be large and
close to the engine, perhaps a design where the engine is mounted on or
even incorporated into the wing is a way to go.

Post by Larry Dighera

Post by Neil Gould

Post by Larry Dighera

Post by Neil Gould

Post by Larry Dighera
There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if
the weight of the lead shielding were not too great. Imagine an
aircraft that effectively never runs out of fuel! There'd be no
more fuel exhaustion mishaps.

One downside would be the hazardous materials that could be
dispersed in a crash.

There are a lot of down sides to atomic power, but NASA uses it to
power Stirling engines in space.

Understandable, but their expectation is that catastrophic
destruction would disperse the nuclear material harmlessly. That
can't be presumed for light aircraft.

If the rocket detonated in the atmosphere, it might not be so
harmless.

I don't see why it would be nearly as bad as a "dirty bomb" would be, as
the material would be dispersed over a pretty large area.

Post by Larry Dighera
I would guess the reactor is jacketed with sufficient
strength to preclude its destruction.

My guess is that NASA et al are just hoping for good fortune. Having a
reactor land from orbit intact in the middle of a city wouldn't be all
that desirable. ;-) So, my bet is on there being no good plan for
dealing with such a catastrophe *other* than wide dispersal of the nuclear
material or the luck of landing in the ocean. Not that *that* outcome is
desirable either...

Neil

[James Sleeman]

Post by Larry Dighera
I see what you mean. Unfortunately, the highest power requirements of
aircraft engines are during the takeoff and climb phases of flight.

Hence why i was thinking more along the lines of a electric motor +
reasonable battery coupled to a stirling. The battery provides the
oompfh for takeoff (and other moments of urgency) from stored energy.
The stirling charges the battery, or passes current through to the
motor when the battery is at peak charge (hand waving the bajillion
technical details which I don't know), it doesn't matter that the
stirling doesn't run at peak efficiency at all times, in cruise mode
you'd want it to be at peak and providing more than enough current to
the motor with some spare to charge the battery.

The article I linked to was more along the lines of a direct-drive,
but I think hooking the output shaft from a stirling straight to a
gearbox/prop would not be a good idea, you are stuck with too many
disadvantages and it makes the engine design more complicated than
necessary.

The main advantage of the stirling+battery versus just battery, is
that you remove the requirement for major infrastructure change
(abundant charging points at airports), the stirling just needs some
fuel (which could be anything from mogas to radiant solar heat) and
that's it, no infrastructure change is necessary in the interim, and
minimal in the long term. As an added benefit, you get much better
cruise endurance than battery alone.

[Ash Wyllie]

James Sleeman opined

Post by James Sleeman

Post by Larry Dighera
Are external combustion engines as efficient as internal combustion
engines? Stirling engines are great for converting waste heat to
mechanical energy, but I'm not sure how appropriate they would be for
aircraft propulsion.

In theory, I think that stirling engines are quite well suited to
aircraft, all it needs is a source of "hot" and a source of "cold",
the cold is in abundance (stick a heatsink in the wind, higher you go,
colder it gets, more power the engine can deliver, directly the
opposite of IC), the hot could be provided with any number of
combustables (and some oxygen delivery system).
I found yesterday after writing my initial post an article about
exactly this - http://www.qrmc.com/fourpartstirling.html "Why Aviation
Needs the Stirling Engine by Darryl Phillips" from 1993/1994.
Given what was said in the article, I'm kind of surprised that nobody
has come up with a working protoype actually.

I see 2 problems. First is that although the temperature at 30,000' is low, so
is the air density, so the size of the heat sink is smaller than one might
think. Second is heat generated by compression of airby the high true airspeeds
at altitude.


-ash
Cthulhu in 2007!
Why wait for nature?

[Orval Fairbairn]

Post by James Sleeman

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).

Look at the problem this way: In an all-electric machine, you carry ALL
of your energy supply with you: fuel and oxidizer -- to make electricity.

With any IC engine, you carry the fuel only -- the air is free (20%
oxygen), so, at 15:1 air/fuel ratio, you would need 90 lb of air for
each gallon of fuel.

Therefore, for a nominal 50 gallon fuel capacity (300 lb), you would
have to carry an additional 7500 lb of air.

That is a lot of weight for a 3000 lb aircraft!

[Orval Fairbairn]

Post by Orval Fairbairn

Post by James Sleeman

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).

Look at the problem this way: In an all-electric machine, you carry ALL
of your energy supply with you: fuel and oxidizer -- to make electricity.
With any IC engine, you carry the fuel only -- the air is free (20%
oxygen), so, at 15:1 air/fuel ratio, you would need 90 lb of air for
each gallon of fuel.
Therefore, for a nominal 50 gallon fuel capacity (300 lb), you would
have to carry an additional 7500 lb of air.
That is a lot of weight for a 3000 lb aircraft!

DUH! I meant 4500 lb of air! That is still a lot of weight penalty.

[Larry Dighera]

On Mon, 06 Aug 2007 17:57:47 GMT, Orval Fairbairn

Post by Orval Fairbairn

Post by Orval Fairbairn
Look at the problem this way: In an all-electric machine, you carry ALL
of your energy supply with you: fuel and oxidizer -- to make electricity.
With any IC engine, you carry the fuel only -- the air is free (20%
oxygen), so, at 15:1 air/fuel ratio, you would need 90 lb of air for
each gallon of fuel.
Therefore, for a nominal 50 gallon fuel capacity (300 lb), you would
have to carry an additional 7500 lb of air.
That is a lot of weight for a 3000 lb aircraft!

DUH! I meant 4500 lb of air! That is still a lot of weight penalty.

I hadn't thought of that. I wonder if a zinc-air batter might be
lighter than a lithium-ion polymer battery. Lithium, being number
three in the periodic table of elements, is pretty light; zinc is
number 30, so it's ten times heaver. But there are other concerns
like packaging requirements that come into play.

Here's some information about zinc-air batteries:

http://en.wikipedia.org/wiki/Zinc-air_battery
Zinc-air battery

Zinc-air batteries, also called “zinc-air fuel cells,“ are
non-rechargeable electro-chemical batteries powered by the
oxidation of zinc with oxygen from the air. These batteries have
very high energy densities and are relatively inexpensive to
produce. They are used in hearing aids and in experimental
electric vehicles. They may be an important part of a future zinc
economy.

Particles of zinc are mixed with an electrolyte (usually potassium
hydroxide solution); water and oxygen from the air react at the
cathode and form hydroxyls which migrate into the zinc paste and
form zincate (Zn(OH)42-), at which point electrons are released
and travel to the cathode. The zincate decays into zinc oxide and
water is released back into the system. The water and hydroxyls
from the anode are recycled at the cathode, so the water serves
only as a catalyst. The reactions produce a maximum voltage level
of 1.65 volts, but this is reduced to 1.4–1.35 V by reducing air
flow into the cell; this is usually done for hearing aid batteries
to reduce the rate of water drying out.

The term zinc-air fuel cell usually refers to a zinc-air battery
in which zinc fuel is replenished and zinc oxide waste is removed
continuously. This is accomplished by pushing zinc electrolyte
paste or pellets into an anode chamber. Waste zinc oxide is pumped
into a waste tank or bladder inside the fuel tank, and fresh zinc
paste or pellets are taken from the fuel tank. The zinc oxide
waste is pumped out at a refueling station and sent to a recycling
plant. Alternatively, this term may refer to an electro-chemical
system in which zinc is used as a co-reactant to assist the
reformation of hydrocarbon fuels on an anode of a fuel cell.

Zinc-air batteries have properties of fuel cells as well as
batteries: the zinc is the fuel, the rate of the reaction can be
controlled by controlling the air flow, and used zinc/electrolyte
paste can be removed from the cell and replaced with fresh paste.
Research is being conducted in powering electric vehicles with
zinc-air batteries.


http://micro.magnet.fsu.edu/electromag/electricity/batteries/zincair.html
Zinc-air batteries produce electrochemical energy by using oxygen
straight from the air. Oxygen becomes the cathode reactant, and is
diffused directly into the battery. The air cathode uses an
aqueous alkaline electrolyte to catalytically promote the reaction
of oxygen, but is not depleted or transformed at discharge. The
cathode is compact, yet at the same time has an almost unlimited
capacity, and achieves high energy densities due to the additional
volume available for the zinc anode.

The advantages of a zinc-air battery include flat discharge
voltage, safety and environmental benefits, good shelf life, and
low cost. In addition, zinc-air batteries have high volumetric
energy density compared to most primary batteries. The
disadvantages of such batteries are that they rely on ambient
conditions, they dry out once exposed to outside air, they have
flooding potential, they have limited output, and their active
life is short. It is important to note that when zinc turns it
into zinc oxide it expands, and there must be adequate space
within the battery for this expansion. The main form of gas
transfer degradation is water vapor transfer.

[Ernest Christley]

Post by Orval Fairbairn

Post by Orval Fairbairn

Post by James Sleeman

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).

Look at the problem this way: In an all-electric machine, you carry ALL
of your energy supply with you: fuel and oxidizer -- to make electricity.
With any IC engine, you carry the fuel only -- the air is free (20%
oxygen), so, at 15:1 air/fuel ratio, you would need 90 lb of air for
each gallon of fuel.
Therefore, for a nominal 50 gallon fuel capacity (300 lb), you would
have to carry an additional 7500 lb of air.
That is a lot of weight for a 3000 lb aircraft!

DUH! I meant 4500 lb of air! That is still a lot of weight penalty.

Well, to be fair Orval, you do get the 90% efficiency in an electric
motor, vs the 30% in an IC engine. You'd only have to drop 1500lb of
useful load with the electric motor.

Isn't the useful load of most light airplanes somewhere between 600 and
2000lbs?

[Gattman]

Post by James Sleeman

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).

It depends on the demand. During the worldwide battlebots craze a few years
ago there were marked technological improvements in battery technology in
the course of about four years. I imagine hybrid vehicles are really going
to push the state of the tech. It might not be viable yet, but if there's
sufficient motivation and investment it could really happen.

That would rock. Even if the cost is the same, the reduction in sound would
be wonderful. You'd want a reserve battery for the purpose of getting you
home when your mains began to taper off, though.

-c

[Gig 601XL Builder]

Post by Gattman

Post by James Sleeman

Post by Larry Dighera
Electrically Powered Ultralight Aircraft

It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to
see them as viable in the distant future either).

It depends on the demand. During the worldwide battlebots craze a
few years ago there were marked technological improvements in battery
technology in the course of about four years. I imagine hybrid
vehicles are really going to push the state of the tech. It might
not be viable yet, but if there's sufficient motivation and
investment it could really happen.

Come on, it's not like there isn't sufficient motivation out there now and
it isn't coming from battlebots. If anyone comes up with a battery that can
power and automobile for 4 hours at highway speeds and is affordable to
produce they will be very wealthy.

If they can make one that is as efficient as a tank of gasoline they will
shortly become very, very wealthy.

[Gattman]

Post by Gig 601XL Builder
Come on, it's not like there isn't sufficient motivation out there now and
it isn't coming from battlebots. If anyone comes up with a battery that
can power and automobile for 4 hours at highway speeds and is affordable
to produce they will be very wealthy.
If they can make one that is as efficient as a tank of gasoline they will
shortly become very, very wealthy.

I agree. It's on the way. Wasn't too long ago that terms like "lithium
ion" and "nickle metal hydride" were unheard of to the common consumer.

Five or six years ago your choices were Hawker Genesis-style Sealed Lead
Acid or custom-built NiCad battery arrays which is what we used. NiMH and
lithium ion weren't available or affordable but the proliferation of power
chairs, stuff like the Segway, electric scooters and so forth have really
pushed the demand for lightweigh, high performance batteries.

-c

[Gig 601XL Builder]

Post by Gattman

Post by Gig 601XL Builder
Come on, it's not like there isn't sufficient motivation out there
now and it isn't coming from battlebots. If anyone comes up with a
battery that can power and automobile for 4 hours at highway speeds
and is affordable to produce they will be very wealthy.
If they can make one that is as efficient as a tank of gasoline they
will shortly become very, very wealthy.

I agree. It's on the way. Wasn't too long ago that terms like
"lithium ion" and "nickle metal hydride" were unheard of to the
common consumer.
Five or six years ago your choices were Hawker Genesis-style Sealed
Lead Acid or custom-built NiCad battery arrays which is what we used.
NiMH and lithium ion weren't available or affordable but the
proliferation of power chairs, stuff like the Segway, electric
scooters and so forth have really pushed the demand for lightweigh,
high performance batteries.
-c

Do me a favor Gattman. What is the weight of the most effeicent battery that
could power an automobile at highway speed and how long will it do so and
how long to recharge?

[Gattman]

Post by Gig 601XL Builder
Do me a favor Gattman. What is the weight of the most effeicent battery
that could power an automobile at highway speed and how long will it do so
and how long to recharge?

Well, if I tried to answer that I'd sound like mx. I don't know what the
"most efficient" battery is for that purpose. It's a hell of a lot heavier
than the 250-250 pound machines I worked with. I think 4-6 SLAs--possibly
the least efficient--would pull a vehicle, but I doubt it would make highway
speed and if if it did it wouldn't be for more than a few minutes. Charge
time for each battery would probably be a couple of hours, maybe longer.

I bet it would weigh a hell of a lot more than a Rotax. Internal combustion
is still the most bang for the buck this side of nuclear.

I think the most realistic use of an electric motor in an aircraft would be
in the context of something like a glider, for maintaining altitude or
finding a thermal or just getting home. It would be fun to fly an
ultralight around the pattern under electrical power, but I wouldn't stray
very far.

-c

[Gig 601XL Builder]

Post by Gattman

Post by Gig 601XL Builder
Do me a favor Gattman. What is the weight of the most effeicent
battery that could power an automobile at highway speed and how long
will it do so and how long to recharge?

Well, if I tried to answer that I'd sound like mx. I don't know
what the "most efficient" battery is for that purpose. It's a hell
of a lot heavier than the 250-250 pound machines I worked with. I
think 4-6 SLAs--possibly the least efficient--would pull a vehicle,
but I doubt it would make highway speed and if if it did it wouldn't
be for more than a few minutes. Charge time for each battery would
probably be a couple of hours, maybe longer.
I bet it would weigh a hell of a lot more than a Rotax. Internal
combustion is still the most bang for the buck this side of nuclear.
I think the most realistic use of an electric motor in an aircraft
would be in the context of something like a glider, for maintaining
altitude or finding a thermal or just getting home. It would be fun
to fly an ultralight around the pattern under electrical power, but I
wouldn't stray very far.
-c

I understand and thank you for not MXing us. But the point isn't the weight
of the battery as compaired to a Rotax or any other engine. The issue I had
been getting at is the weight of the battery in comparison to the weight of
full load of gasoline.

Let's take my 601XL. 2 aluminum 12 gallon tanks each tank ways let's say 10
pounds add in 145 lbs of fuel and you have 165 pounds of transportable
energy that will produce ~100HP for about 4 hours.

My question to anyone is what is the lightest battery that is capable of
powering any motor that will produce the equivilent power for and equal
amount of time?

[Airjunkie]

check out the article on regenerative soaring at www.esoaring.com I
think I may have heard that Taras Kiceniuk will be giving a talk on
this subject at Tehachapi this Labor Day. He's been working on this
idea for a while...
Bill

[j***@specsol.spam.sux.com]

Post by Gig 601XL Builder

Post by Gattman

Post by Gig 601XL Builder
Do me a favor Gattman. What is the weight of the most effeicent
battery that could power an automobile at highway speed and how long
will it do so and how long to recharge?

Well, if I tried to answer that I'd sound like mx. I don't know
what the "most efficient" battery is for that purpose. It's a hell
of a lot heavier than the 250-250 pound machines I worked with. I
think 4-6 SLAs--possibly the least efficient--would pull a vehicle,
but I doubt it would make highway speed and if if it did it wouldn't
be for more than a few minutes. Charge time for each battery would
probably be a couple of hours, maybe longer.
I bet it would weigh a hell of a lot more than a Rotax. Internal
combustion is still the most bang for the buck this side of nuclear.
I think the most realistic use of an electric motor in an aircraft
would be in the context of something like a glider, for maintaining
altitude or finding a thermal or just getting home. It would be fun
to fly an ultralight around the pattern under electrical power, but I
wouldn't stray very far.
-c

I understand and thank you for not MXing us. But the point isn't the weight
of the battery as compaired to a Rotax or any other engine. The issue I had
been getting at is the weight of the battery in comparison to the weight of
full load of gasoline.
Let's take my 601XL. 2 aluminum 12 gallon tanks each tank ways let's say 10
pounds add in 145 lbs of fuel and you have 165 pounds of transportable
energy that will produce ~100HP for about 4 hours.
My question to anyone is what is the lightest battery that is capable of
powering any motor that will produce the equivilent power for and equal
amount of time?

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.

[Gig 601XL Builder]

Post by j***@specsol.spam.sux.com
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.

[j***@specsol.spam.sux.com]

Post by Gig 601XL Builder

Post by j***@specsol.spam.sux.com
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.

[Morgans]

Post by j***@specsol.spam.sux.com
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.

Are you sure about that?

I think I recall seeing someone do the calculations of how much solar energy
hits the top surface of a sailplane and wing, and it was still not enough to
motor without thermals, if it was all converted to electrical energy.

Anyone better in math, than me, want to take on that supposition?

[j***@specsol.spam.sux.com]

Post by Morgans

Post by j***@specsol.spam.sux.com
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.

Are you sure about that?
I think I recall seeing someone do the calculations of how much solar energy
hits the top surface of a sailplane and wing, and it was still not enough to
motor without thermals, if it was all converted to electrical energy.
Anyone better in math, than me, want to take on that supposition?

In rough numbers, you get about 1 kW/m^2 of energy from the sun on
a clear day.

Current conversion technology is about 22% at best.

Technologies in the works are promising 50-60% (the check is in the
mail and I will respect you in the morning).

One presumes a sailplane is going to spend most of its time sailing
and only using the motor (with batteries) to get off the ground
and occassionaly cruise between thermals.

So most of the time you are just charging the batteries.

[Larry Dighera]

Post by j***@specsol.spam.sux.com
Current conversion technology is about 22% at best.
Technologies in the works are promising 50-60%

http://www.boeing.com/news/releases/2006/q3/060828a_nr.html
ST. LOUIS, Aug. 28, 2006 -- The Boeing Company [NYSE: BA] has signed a
contract to provide 600,000 solar concentrator cells to SolFocus,
Inc., a California-based renewable energy company that is developing
renewable terrestrial energy alternatives.

"Companies on the cutting edge of the renewable energy revolution come
to us because we are the world's leading manufacturer of solar cells,"
said Charles Toups, vice president of engineering for Boeing Space and
Intelligence Systems. "Our Spectrolab subsidiary has leveraged its
expertise in space photovoltaic products to create solar cells with
record-breaking efficiencies for Earth-based applications."

Under the 12-month contract from SolFocus, Inc. of Palo Alto, Calif.,
Spectrolab will build and deliver 600,000 solar concentrator cells
that will be used to convert the sun's rays into affordable
electricity for homes and businesses. The cells produced for SolFocus
will be capable of generating more than 10 megawatts of electricity,
or enough to power about 4,000 U.S. homes. With the average solar cell
efficiency above 35 percent at concentration, Spectrolab's
concentrator photovoltaic cells generate electricity at a rate that
can be more economical than electricity generated from conventional,
flat panel photovoltaic systems.

"Our mission is to deliver reliable solar-generated electricity at
wholesale energy prices, and Spectrolab's multi-junction concentrator
solar cells are key to making that possible," said Gary D. Conley, CEO
of SolFocus. "Spectrolab's cells will be integrated into our upcoming
solar concentrator field test program and then into the first phase of
active deployments."

A significant advantage of concentrator systems is that fewer solar
cells are required to achieve a specific power output, thus replacing
large areas of semiconductor materials with relatively inexpensive
optics that provide optical concentration. The slightly higher cost of
multi-junction cells is offset by the use of fewer cells. Due to the
higher efficiency of multi-junction cells used in the concentrator
modules, only a small fraction of the cell area is required to
generate the same power output compared to crystalline silicon or
thin-film, flat-plate modules.
=====================================================================

http://www.boeing.com/news/releases/2006/q3/060815b_nr.html

ST. LOUIS, Aug. 15, 2006 -- The Boeing Company [NYSE: BA] today
announced it has signed a multi-million dollar contract to supply
concentrator photovoltaic (CPV) cell assemblies to an Australian
company that produces renewable solar energy.

Under the contract with Solar Systems Pty. Ltd. of Hawthorn, Victoria,
Boeing will deliver 500,000 concentrator solar cell assemblies for use
at power stations that generate renewable energy for small, remote
Australian communities. Spectrolab, Inc. of Sylmar, Calif., a
wholly-owned Boeing subsidiary, will manufacture the cells. Deliveries
will begin later this year.

The solar cell assemblies will be capable of generating more than 11
megawatts of electricity -- enough to power 3,500 average-sized homes.
"For the past 50 years, Spectrolab has been a leader in space-based
solar cells," said Dr. David Lillington, president of Spectrolab, the
world's leading producer of space and terrestrial concentrating solar
cells. "We have leveraged our expertise in space photovoltaic products
and created terrestrial concentrating solar cells with record-breaking
efficiencies averaging above 35 percent. We are now partnering with
the best of industry and making great strides in reducing the cost of
solar energy to homes and businesses worldwide."

This contract with Solar Systems continues an earlier relationship
between the two companies. In April, Spectrolab and Solar Systems
brought the world's first full-scale ultra high efficiency 35-kilowatt
solar generator online in Australia. The system created a new
benchmark for solar concentrator systems both in system efficiency and
cost, and showed great promise for the future of renewable energy.

"The breakthrough demonstrated by this fully operating, full-scale
system shows the potential for CPV to dramatically change the
economics of solar power. We expect this to be the first commercial
phase of a very large and valuable relationship," said Solar Systems
Managing Director Dave Holland. "Our partnership with Spectrolab
represents a new level of cooperation toward the common goal of
meeting the community's power needs with clean, green electricity."

Solar Systems' concentrators resemble a satellite dish with curved
reflecting mirrors shaped to concentrate sunlight onto the solar
cells. A sun-tracking mechanism allows electricity to be produced from
morning to late afternoon. Small, remote communities are using a
number of concentrator dishes in "solar farms" for energy during the
day and switching to diesel generators at night.

A significant advantage of concentrator systems is that fewer solar
cells are required to achieve a specific power output. Large areas of
semiconductor materials now can be replaced with lower cost
concentration devices. The higher cost of ultra high efficiency
multi-junction cells is offset by the need for fewer cells. Because
multi-junction cells are so efficient, only a fraction of the cell
area is required to generate the same power as crystalline silicon or
thin-film flat-plate designs.
===============================================================

[Morgans]

Post by j***@specsol.spam.sux.com
In rough numbers, you get about 1 kW/m^2 of energy from the sun on
a clear day.
Current conversion technology is about 22% at best.
Technologies in the works are promising 50-60% (the check is in the
mail and I will respect you in the morning).
One presumes a sailplane is going to spend most of its time sailing
and only using the motor (with batteries) to get off the ground
and occassionaly cruise between thermals.
So most of the time you are just charging the batteries.

That is why I specified cruising with the motor without thermals; to get a
feel on how the extra surface area and high aspect ratio (efficiency) would
mimic a cross country, motor cruise.

[Larry Dighera]

On Tue, 7 Aug 2007 21:08:12 -0400, "Morgans"

Post by Morgans
That is why I specified cruising with the motor without thermals; to get a
feel on how the extra surface area and high aspect ratio (efficiency) would
mimic a cross country, motor cruise.

It's beginning to look like the 21st century indeed:

http://www.solar-impulse.com/en/index.php
Bertrand Piccard and the EPFL unveil project to fly around the
world in a solar powered airplane

Lausanne, Switzerland -- A team of aviators and scientists led by
Dr. Bertrand Piccard, the first man together with Brian Jones to
circle the earth non-stop in a balloon in 1999, announced plans in
Lausanne, Switzerland Friday to develop an aircraft powered by the
sun and capable of circling the earth. The Piccard team envisions
being able to spend full nights in the air by 2007. Piccard will
be assisted by Jones, his co-pilot in their Breitling Orbiter 3
balloon, and André Borschberg, engineer and jet plane pilot. Their
new project, dubbed Solar Impulse , is aimed at demonstrating the
role of high technology in sustainable development. The EPFL
(Swiss Federal Institute of Technology in Lausanne/ Ecole
Polytechnique Fédérale de Lausanne ) is the official scientific
advisor to the project. The EPFL conducted thermodynamic research
in support of the Piccard/Jones 1999 balloon flight, and is the
official scientific advisor to Alinghi , current holder of yacht
racing's prestigious America's Cup.

EPFL, November 28th 2003


------------------------------------------------------------------

http://radio.weblogs.com/0105910/2004/04/01.html

Solar Impulse Will Circle the Globe in 2009

Bertrand Piccard, the Swiss adventurer who was one of the two
first men to fly around the world non-stop in a balloon in 1999,
wants to achieve the same goal again. But next time, he will use a
pollution-free, single-pilot solar-powered aircraft. The plane,
named Solar Impulse, will look like a glider, but its 70-meter
wingspan will exceed the one of a Boeing 747. Universe Today says
a prototype will be ready next year and that the plane should be
ready for its flight around the world in 2009.

The proposed aircraft resembles a glider, but with a mammoth
70-metre wingspan, exceeding that of a Boeing 747. Completely
covered by solar cells and equipped with possibly two tail-mounted
propeller engines, the plane will be capable of unassisted
take-off and will carry the necessary batteries for night flying.
...

----------------------------------------------------------------


http://www.universetoday.com/am/publish/solar_plane_around_earth.html
Solar Plane Will Attempt to Go Around the Earth

Summary - (Mar 31, 2004) The European Space Agency will be
supplying technology to assist adventurer Bertrand Piccard's
attempt to fly a solar-powered plane around the world. Piccard was
part of the team that successfully flew a balloon around the
Earth. The solar powered plane will have a 70-metre wingspan
(larger than a Boeing 747), and carry enough batteries to be able
to fly in the night as well. The plane would fly at an altitude of
10 km; well above the clouds to capture all the available
sunlight. The first round-the-world attempt will be made some time
after 2009.

Full Story -
Image credit: ESA
ESA's Technology Transfer Programme is to supply state-of-the-art
technologies to assist adventurer Bertrand Piccard's flight around
the world in a single-pilot solar-powered aircraft, ...

The EPFL study says that current off-the-shelf lithium-ion
batteries provide just under 200 watt-hours per kilogram (Wh/kg),
enough to support a single-pilot plane, while a two-pilot solution
would require a capacity of at least 300 Wh/kg.

The plan is to design and construct the first prototype aircraft
in 2004-2005, with initial test flights in 2006. The next step is
to complete night flights in 2007, initially at least 36 hours
including one full night. From then on flying lengths are to be
increased. . Innovative solutions will be required to store the
necessary food and water while reduce weight to a minimum –
familiar problems for ESA engineers designing space missions.

When will the Solar Impulse fly around the world, non-stop? "It is
planned to cross the Atlantic in 2008 and fly around the world
with stop-overs in 2009," says André Borschberg, "To fly around
non-stop depends very much on how quickly we will have higher
energy density batteries…but not before 2009." ...

[Larry Dighera]

On Tue, 7 Aug 2007 18:09:36 -0400, "Morgans"

Post by Morgans
I think I recall seeing someone do the calculations of how much solar energy
hits the top surface of a sailplane and wing, and it was still not enough to
motor without thermals, if it was all converted to electrical energy.

Here's one that flew across the US seventeen years ago:
http://www.solar-flight.com/sslink.html

[Larry Dighera]

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

Post by Gig 601XL Builder
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/releases/pr_072407.html).

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

[Gig 601XL Builder]

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

Post by Gig 601XL Builder
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/releases/pr_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.

[g***@cox.net]

On Aug 7, 3:04 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>

Post by Gig 601XL Builder

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

Post by Gig 601XL Builder
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/releases/pr_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.

[Gig 601XL Builder]

Post by g***@cox.net
On Aug 7, 3:04 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>

Post by Gig 601XL Builder

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

Post by Gig 601XL Builder
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/releases/pr_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.

I really hate to burst your bubble but, from the Sonex link above.

"Initial top speeds will reach approximately 130 mph, and endurance is
expected to range between 25-45 minutes or longer, depending upon power
usage on each individual flight."

[Darrel Toepfer]

Post by Gig 601XL Builder
I really hate to burst your bubble but, from the Sonex link above.
"Initial top speeds will reach approximately 130 mph, and endurance is
expected to range between 25-45 minutes or longer, depending upon power
usage on each individual flight."

Be sure to let us kneaux when it flies...

As of OshGosh, it hadn't...

[g***@cox.net]

On Aug 7, 3:49 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>

Post by Gig 601XL Builder

Post by g***@cox.net
On Aug 7, 3:04 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>

Post by Gig 601XL Builder

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

Post by Gig 601XL Builder
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/releases/pr_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.

I really hate to burst your bubble but, from the Sonex link above.
"Initial top speeds will reach approximately 130 mph, and endurance is
expected to range between 25-45 minutes or longer, depending upon power
usage on each individual flight."- Hide quoted text -
- Show quoted text -

I also read that but "Expected to be" isn't a claim and 45 minutes is
not what I would call significant duration.

[Larry Dighera]

Post by g***@cox.net

Post by Gig 601XL Builder

Post by g***@cox.net
I have not seen any significant flight duration claim on the Sonex,
which speaks well for the design team.

I really hate to burst your bubble but, from the Sonex link above.
"Initial top speeds will reach approximately 130 mph, and endurance is
expected to range between 25-45 minutes or longer, depending upon power
usage on each individual flight."- Hide quoted text -
- Show quoted text -

I also read that but "Expected to be" isn't a claim and 45 minutes is
not what I would call significant duration.

Would you characterize 12 seconds ad significant?

http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur’s first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville’s second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.

[g***@cox.net]

Post by Larry Dighera

Post by g***@cox.net

Post by Gig 601XL Builder

Post by g***@cox.net
I have not seen any significant flight duration claim on the Sonex,
which speaks well for the design team.

I really hate to burst your bubble but, from the Sonex link above.
"Initial top speeds will reach approximately 130 mph, and endurance is
expected to range between 25-45 minutes or longer, depending upon power
usage on each individual flight."- Hide quoted text -
- Show quoted text -

I also read that but "Expected to be" isn't a claim and 45 minutes is
not what I would call significant duration.

Would you characterize 12 seconds ad significant?
http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur's first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville's second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.

I guess I should have clarified that my comments refer to the here and
now where 12 seconds and\or 45 minutes are both insignificant in terms
of useful flight duration. While any duration is important the first
time achieved it will only become marketable when it has reached a
practical use point. Hopefully today's developments will lead to
something in the future that is but for now they are interesting
engineering experiments. Most people should and do applaud the efforts
while some think the future is already here. For those adventurers we
have $100,000 cars and underpowered trikes available right now.
I'm going to hold off for a little while longer.

[Gig 601XL Builder]

Post by Larry Dighera

Post by g***@cox.net

Post by Gig 601XL Builder

Post by g***@cox.net
I have not seen any significant flight duration claim on the Sonex,
which speaks well for the design team.

I really hate to burst your bubble but, from the Sonex link above.
"Initial top speeds will reach approximately 130 mph, and endurance
is expected to range between 25-45 minutes or longer, depending
upon power usage on each individual flight."- Hide quoted text -
- Show quoted text -

I also read that but "Expected to be" isn't a claim and 45 minutes is
not what I would call significant duration.

Would you characterize 12 seconds ad significant?
http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur's first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville's second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.

I would now but when the best previous powered flight it was ZERO in both
time and distance anything >0 was significant. And, unfortunately, for the
electric powered airplane folks they have to be compared at least to what I
can build in my garage and attach a 1960's vintage Corvair engine too.

Sonex's electric airplane especially has to be judged against that criteria
because they already make a plane that I can build in my garage and hang a
Corvair engine on.

[Larry Dighera]

On Wed, 8 Aug 2007 10:55:38 -0500, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote in

Post by Gig 601XL Builder

Post by Larry Dighera

Post by g***@cox.net

Post by Gig 601XL Builder

Post by g***@cox.net
I have not seen any significant flight duration claim on the Sonex,
which speaks well for the design team.

I really hate to burst your bubble but, from the Sonex link above.
"Initial top speeds will reach approximately 130 mph, and endurance
is expected to range between 25-45 minutes or longer, depending
upon power usage on each individual flight."- Hide quoted text -
- Show quoted text -

I also read that but "Expected to be" isn't a claim and 45 minutes is
not what I would call significant duration.

Would you characterize 12 seconds ad significant?
http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur's first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville's second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.

I would now but when the best previous powered flight it was ZERO in both
time and distance anything >0 was significant. And, unfortunately, for the
electric powered airplane folks they have to be compared at least to what I
can build in my garage and attach a 1960's vintage Corvair engine too.
Sonex's electric airplane especially has to be judged against that criteria
because they already make a plane that I can build in my garage and hang a
Corvair engine on.

Electrically powered flight is in its infancy just as powered flight
was in 1903.

[Gig 601XL Builder]

Post by Larry Dighera
Electrically powered flight is in its infancy just as powered flight
was in 1903.

That matters not. It still has to be compared to what it is supposed to
replace. Would you want an electric car that was the technological equal to
this? Loading Image....

The otherside of that is that we can expect to wait until 2110 for electric
flight to catch up to where we are now with gasoline powered flight.

[Anthony W]

Post by Larry Dighera
Would you characterize 12 seconds ad significant?
http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur’s first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville’s second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.

In 1903 it was but times change...

Tony

[Larry Dighera]

Post by g***@cox.net
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.

Of course. But it seems it's getting closer all the time.

[Larry Dighera]

Post by j***@specsol.spam.sux.com
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.

[j***@specsol.spam.sux.com]

Post by Larry Dighera

Post by j***@specsol.spam.sux.com
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.

Post by Larry Dighera
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.

[Larry Dighera]

Post by j***@specsol.spam.sux.com

Post by Larry Dighera

Post by j***@specsol.spam.sux.com
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.

Agreed.

Post by j***@specsol.spam.sux.com
A 100 HP electric motor is not going to be particularly light

The ~100 HP Continental O-200 is about 170 lbs. If you look at the
motors offered by AstroFlight, it looks like they weigh about one
pound per horsepower, but that doesn't include the controller,
charger, etc.

Post by j***@specsol.spam.sux.com
and the power cables are going to weigh a whole lot more than fuel lines
for example.

True, but there are several trade offs: No oil cooler nor oil, No
gascolator nor fuel pump, etc... But the electric motor will require
a controller, a charging system, wiring, etc. It's difficult to
speculate about the weight without more specific information.

Post by j***@specsol.spam.sux.com
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.

It's difficult to say.

Post by j***@specsol.spam.sux.com

Post by Larry Dighera
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.

But the controller has no moving parts either except perhaps a cooling
fan and contractor. I would guess the electrical propulsion system to
be potentially more reliable than an IC system, but there is the Sony
LI battery recall issue ...

Post by j***@specsol.spam.sux.com
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.

Today, brushless DC motors, or even three-phase induction motors, are
used.

Sonex mentions a brushless DC motor:

http://www.greencarcongress.com/2007/07/sonex-aircraft-.html#more
Using a purpose-built AeroConversions brushless DC
cobalt motor, controller, and highly efficient battery ...

... the design team, in collaboration with Bob Boucher of Astro
Flight, Inc. (http://www.astroflight.com/), has designed and built
a completely new AeroConversions motor.

This motor is the most powerful, lightest-weight, and efficient
unit of this type ever produced. It is a 3 phase, 270 volt, 200
amp motor that will be over 90 percent efficient.


This works out to about 75 continuous HP by my calculations.

It will be interesting to see what the future brings.

[j***@specsol.spam.sux.com]

Post by Larry Dighera
Today, brushless DC motors, or even three-phase induction motors, are
used.
http://www.greencarcongress.com/2007/07/sonex-aircraft-.html#more
Using a purpose-built AeroConversions brushless DC
cobalt motor, controller, and highly efficient battery ...
... the design team, in collaboration with Bob Boucher of Astro
Flight, Inc. (http://www.astroflight.com/), has designed and built
a completely new AeroConversions motor.
This motor is the most powerful, lightest-weight, and efficient
unit of this type ever produced. It is a 3 phase, 270 volt, 200
amp motor that will be over 90 percent efficient.
This works out to about 75 continuous HP by my calculations.
It will be interesting to see what the future brings.

I'm not totally convinced the internal controllers electronics for
a brushless DC motor are going to be that reliable at these power
and heat levels.

Time will tell.

The Civic hybrid uses a brushless DC motor, so there's a test bed
for that level of power.

[Gig 601XL Builder]

Post by Larry Dighera

Post by j***@specsol.spam.sux.com
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/detail.asp?1=1&catalog=D50100P&product=DC+Motors&family=General+Purpose%7Cvw%5FDCMotors%5FGeneralPurpose

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

[George]

Post by Gig 601XL Builder

Post by Larry Dighera

Post by j***@specsol.spam.sux.com
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/detail.asp?1=1&catalog=D50100P&product=DC+Motors&family=General+Purpose%7Cvw%5FDCMotors%5FGeneralPurpose
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

[Gig 601XL Builder]

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

None would be safer, though you might find some people who would have a
problem with calling it an airplane if it couldn't get off the ground.

[George]

Post by Gig 601XL Builder

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

None would be safer, though you might find some people who would have a
problem with calling it an airplane if it couldn't get off the ground.

That was my point, if it can't fly, how can it crash?? <vbg>

George

[Larry Dighera]

On Tue, 7 Aug 2007 16:12:16 -0500, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote in

Post by Gig 601XL Builder
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/detail.asp?1=1&catalog=D50100P&product=DC+Motors&family=General+Purpose%7Cvw%5FDCMotors%5FGeneralPurpose
Catalog Number: D50100P
Description: STOCK MOTOR,368AT,100HP,1750/2000RPM,DPFG
Ship Weight: 1,118 lbs.
List Price: $21,195
Multiplier Symbol: N2

Right. Those are the type I used to install in the early '70; that
was about forty years ago. Today the situation is a bit different.

Here's a small electric motor manufactured by the same fellow, Bob
Boucher, who designed the Sonex motor:


http://www.astroflight.com/store/store-type-tem.html?item=products:af-990&sid=0001Hcv4by3CKHwWtA02470

Cobalt 90 Direct Drive Motor
Cobalt 90 Direct Drive Motor, 30 to 40 cells, 1500W

Astro 90 Cobalt Motor p/n 690
Model No. p/n 690
Name 90 Cobalt
Armature Winding 10 turns
Armature Resistance 0.111 ohms
Magnet Type Sm Cobalt
Bearings Ball Bearings
Motor Speed /volt 256 rpm/volt
Motor Torque/amp 5.3 in-oz /amp
Voltage Range 24 to 48 volts
No Load Currrent 3 amps
Maximum Continuous Current 35 amps
Maximum Continuous Power 1200 watts
Motor Length 3.7 inches
Motor Diameter 2.1 inches
Motor Shaft Diameter 0.25 inches
Prop Shaft Diameter 5/16 inch
Motor Weight 32 oz


Expected Performance of Cobalt 90
Battery Prop Amps Watts Rpm
36 Nicads 14x7 20 amps 800 watts 9,000 rpm
36 Nicads 14x10 25 amps 1000 watts 8,500 pm
36 Nicads 15x10 30 amps 1200 watts 8,000 rpm
36 Nicads 16x10 35 amps 1400 watts 7,500 rpm


This is a small motor, as you can see, but it uses ~1,500 watts, so at
720 watts per horsepower, that's about two horsepower, and it weighs
32 oz, or about two pounds. That works out to about one horsepower
per pound for this type of motor. I have no idea if a one hundred
horsepower motor of this type would weigh 100 lbs or not, but it seems
reasonable.

[Gig 601XL Builder]

Post by Larry Dighera
I have no idea if a one hundred
horsepower motor of this type would weigh 100 lbs or not, but it seems
reasonable.

That's why I showed the first 100HP electric motor I could find. They
obviously don't make a 100HP motor of the type you showed or you would have
quoted it's specs.

I doubt they add the extra 1000 lbs just for the fun of it.

[Larry Dighera]

On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote in

They obviously don't make a 100HP motor of the type you showed or you would have
quoted it's specs.

Take a look at the ~75 HP electric motor installed in the Sonex Waiex:
http://www.sonexaircraft.com/news/images/airventure07/e-flight_5947.jpg

Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.

You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

[Gig 601XL Builder]

Post by Larry Dighera
On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote in

They obviously don't make a 100HP motor of the type you showed or
you would have quoted it's specs.

http://www.sonexaircraft.com/news/images/airventure07/e-
flight_5947.jpg
Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.
You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

Of course I don't. But they might as well be at this point becuse the
electric motor they have has never been off the ground.

I wish the Sonex guys well and will praise the hell out of them if they do
what they are trying to do. But, as I said in a earlier post, I just don't
see this big of a technological leap coming from a company whose last major
enginnering feat was converting a VW engine for aircraft.

If and when it happens it will be either a bunch of guys from MIT or Cal
Tech or as the offshoot of a much more profitable electric motor project.

[Larry Dighera]

On Wed, 8 Aug 2007 10:48:40 -0500, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote in

Post by Gig 601XL Builder

Post by Larry Dighera
On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote in

They obviously don't make a 100HP motor of the type you showed or
you would have quoted it's specs.

http://www.sonexaircraft.com/news/images/airventure07/e-
flight_5947.jpg
Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.
You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

Of course I don't. But they might as well be at this point becuse the
electric motor they have has never been off the ground.

The motor was apparently designed by Bob Boucher. He also designed
the motors Dr. Paul MacCready used to fly across the English channel
solely under power from the sun, and other successful AeroVironment
electrically powered aircraft commissioned by NASA. If anyone can
design a proper electric motor for aviation, Mr. Boucher should be
able to; he has the past successes to prove it.

Post by Gig 601XL Builder
I wish the Sonex guys well and will praise the hell out of them if they do
what they are trying to do. But, as I said in a earlier post, I just don't
see this big of a technological leap coming from a company whose last major
enginnering feat was converting a VW engine for aircraft.
If and when it happens it will be either a bunch of guys from MIT or Cal
Tech or as the offshoot of a much more profitable electric motor project.

Perhaps.

[Gattman]

Post by Gig 601XL Builder
Let's take my 601XL. 2 aluminum 12 gallon tanks each tank ways let's say
10 pounds add in 145 lbs of fuel and you have 165 pounds of transportable
energy that will produce ~100HP for about 4 hours.
My question to anyone is what is the lightest battery that is capable of
powering any motor that will produce the equivilent power for and equal
amount of time?

Well, depending on which end of the gearbox it's measured, 40+ pounds of
NiCAD batteries got between 1-4 HP at maybe 70% motor power for 20 minutes
max before the battery output began to taper off. For perspective, the
Etek motor used on the ultralight in the link is probably about twice as
powerful as the motors we were using, so maybe for a ballpark measurement I
could double the battery time for the same weight. Theoretically if you
managed and cooled your batteries correctly you could get ~30 minutes for
that 40 pounds of batteries, or maybe two hours if you quadrupled it for
your ~160 pounds. Max.

Too much weight for an ultralight, and no way it's gonna get near 100HP.
Again, that's just a ballpark estimate.

-c

[kontiki]

Post by Gattman
I agree. It's on the way. Wasn't too long ago that terms like "lithium
ion" and "nickle metal hydride" were unheard of to the common consumer.

It takes a lot of energy to manufacture those batteries ... and recycle
them when they are used up. You have to factor that into the equation.

These batteries have high energy per unit volume but they cost a lot
of money because it takes a lot of energy to produce them.

[Maxwell]

Post by Larry Dighera
Personally, I'd like to see an electrically powered parachute
(http://skyhighflying.com/homepage.html) design attempted. Surly the
lighter weight would require less power. It would seem that
lithium-ion polymer batteries are a potential enabling technology.

They might be lightweight and strong, but I think they would be far too
inefficent. All the canopies I have been around have had a very poor L/D
when compared to something like a sailplane.

I always assumed they were so popular because they were so strong, portable
and quick to set-up. But I'm thinking their fuel mileage would be very poor.

[Larry Dighera]

Post by Maxwell

Post by Larry Dighera
Personally, I'd like to see an electrically powered parachute
(http://skyhighflying.com/homepage.html) design attempted. Surly the
lighter weight would require less power. It would seem that
lithium-ion polymer batteries are a potential enabling technology.

They might be lightweight and strong, but I think they would be far too
inefficent. All the canopies I have been around have had a very poor L/D
when compared to something like a sailplane.

The web site below mentions an L/D of four to one.

Post by Maxwell
I always assumed they were so popular because they were so strong, portable
and quick to set-up. But I'm thinking their fuel mileage would be very poor.

I would be more interested in the specific horsepower required to
operate powered parachutes than their efficiency. This web site
mentions 50 HP to 65 HP:
http://www.all-about-powered-parachutes.com/faq.htm

There is a 14 HP Powered Paraglider (PPG) engine offered here:
http://www.poweredparasports.com/Paramotors%20&%20Trikes.htm#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.

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.

[kontiki]

Post by Larry Dighera
http://www.poweredparasports.com/Paramotors%20&%20Trikes.htm#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.
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.

Yeah sure, but its not practical for anything but an hour or two of
playing around on a Saturday afternoon. You can't carry anything or
go anywhere to accomplish anything except maybe brag about how little
energy you used goofing off for a few hours. Its like blasting around
on a jet ski... basically a total waste of energy without producing
any useful work or benefit to mankind.

Don't get me wrong, I love new technology and if you can afford to
spend money on extra curricular stuff like aimlessley cruising about
in solar powered paragliders or jet skis fine. But don't think you
are doing the world a big favor because you used something other
than gasoline to power it.

[Larry Dighera]

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

I'll bet you would have said something similar to the Wrights. :-)
Where's you vision, man?

Now here's an electrically powered aircraft that really is playing
around: http://www.nesail.com/videos/jazz.wmv

[Snowbird]

Post by kontiki
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.

[Maxwell]

Post by Larry Dighera
I would be more interested in the specific horsepower required to
operate powered parachutes than their efficiency. This web site
http://www.all-about-powered-parachutes.com/faq.htm

That's what I have seen. We even have a tandem trike locally that uses a
Subaru.

Post by Larry Dighera
http://www.poweredparasports.com/Paramotors%20&%20Trikes.htm#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.
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.

I would think that would be close to the bare minimum. I flew a fixed wing
hang glider on 10 HP for a while back in the 70s. A Manta Fledgling, and it
was very underpowered. Maybe 100 fpm climb or so.

[Larry Dighera]

Post by Maxwell

Post by Larry Dighera
http://www.poweredparasports.com/Paramotors%20&%20Trikes.htm#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.
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.

I would think that would be close to the bare minimum. I flew a fixed wing
hang glider on 10 HP for a while back in the 70s. A Manta Fledgling, and it
was very underpowered. Maybe 100 fpm climb or so.

I would guess the rigid wing would have a higher L/D than a powered
parachute's 4:1, so it might require less power. Does that sound
correct in your experience?

[Maxwell]

Post by Larry Dighera

Post by Maxwell
I would think that would be close to the bare minimum. I flew a fixed wing
hang glider on 10 HP for a while back in the 70s. A Manta Fledgling, and it
was very underpowered. Maybe 100 fpm climb or so.

I would guess the rigid wing would have a higher L/D than a powered
parachute's 4:1, so it might require less power. Does that sound
correct in your experience?

Indeed, quite a bit less from my experience. I think my Fledge was supposed
to be around 10:1.

[Paul Hanson]

A technology I have not seen even mentioned in this
lengthy (but very good) thread is that of carbon nonotube
enhanced ultracapacitors, which have the promise of
the energy density of the latest lithium polymers,
but almost infinite discharge cycles and can be recharged
in seconds. What would make a whole heap of sense (to
me at least), would to develop an electric tow plane
based around this technology. Quiet, efficient, hardly
affected by density altitude, quick as refueling with
avgas when charges are needed, etc. This would get
our fleet of non-powered aircraft off the ground just
fine, without angering the encroaching land developments
and such. An efficient/viable electric towplane, that's
what we need. I'm sure other developments would stem
from it too of course.
Hats off to all people/groups considering alternatives
at this point, and down with the naysayers!
Paul Hanson

Post by Maxwell

Post by Larry Dighera

Post by Maxwell
I would think that would be close to the bare minimum.
I flew a fixed wing
hang glider on 10 HP for a while back in the 70s. A
Manta Fledgling, and
it
was very underpowered. Maybe 100 fpm climb or so.

I would guess the rigid wing would have a higher L/D
than a powered
parachute's 4:1, so it might require less power.
Does that sound
correct in your experience?

Indeed, quite a bit less from my experience. I think
my Fledge was supposed
to be around 10:1.

"Do the usual, unusually well"--Len Niemi