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:
http://www.youtube.com/watch?v=Wksx-jmhY7c


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: 561-351-1190
website: www.ElectraFlyer.com
email:


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/2007/07/25/sonex1.png

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]

On Aug 5, 11:52 am, Larry Dighera > wrote:
> 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:http://www.youtube.com/watch?v=Wksx-jmhY7c
>
> 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: 561-351-1190
> website:www.ElectraFlyer.com
> email:
>
> 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.
>
> · 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 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
> 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

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]

On Sun, 05 Aug 2007 10:53:30 -0700, Phil > wrote
in m>:

>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

[James Sleeman]

On Aug 6, 4:52 am, Larry Dighera > wrote:
> 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.

[[email protected]]

On Aug 6, 1:14 am, James Sleeman > wrote:
> On Aug 6, 4:52 am, Larry Dighera > wrote:
>
> > 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

[Bill Daniels]

> wrote in message
ups.com...

> 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

[Larry Dighera]

On Mon, 06 Aug 2007 00:14:14 -0700, James Sleeman
> wrote in
om>:

>On Aug 6, 4:52 am, Larry Dighera > wrote:
>> 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.

>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.

>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

[Larry Dighera]

On Mon, 06 Aug 2007 05:39:01 -0700, wrote in
om>:

>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

[Orval Fairbairn]

In article om>,
James Sleeman > wrote:

> On Aug 6, 4:52 am, Larry Dighera > wrote:
> > 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!

[Gig 601XL Builder]

Larry Dighera wrote:
> On Mon, 06 Aug 2007 05:39:01 -0700, wrote in
> om>:
>
>> 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


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

[Larry Dighera]

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

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

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

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



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

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

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

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

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

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

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

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

[[email protected]]

> 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

[[email protected]]

In rec.aviation.piloting Gig 601XL Builder <wrDOTgiaconaATsuddenlink.net> wrote:
> Larry Dighera wrote:
> > On Mon, 06 Aug 2007 05:39:01 -0700, wrote in
> > om>:
> >
> >> 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


> 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.

[Phil]

On Aug 5, 1:12 pm, Larry Dighera > wrote:
> On Sun, 05 Aug 2007 10:53:30 -0700, Phil > wrote
> in m>:
>
> >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.

[[email protected]]

On Aug 6, 11:14 am, wrote:
> In rec.aviation.piloting Gig 601XL Builder <wrDOTgiaconaATsuddenlink.net> wrote:
>
> > Larry Dighera wrote:
> > > On Mon, 06 Aug 2007 05:39:01 -0700, wrote in
> > > om>:
>
> > >> 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
> > 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.

[Larry Dighera]

On Mon, 06 Aug 2007 09:42:46 -0700, wrote
in . com>:

>> 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. :-)

[[email protected]]

In rec.aviation.piloting Phil > wrote:
> On Aug 5, 1:12 pm, Larry Dighera > wrote:
> > On Sun, 05 Aug 2007 10:53:30 -0700, Phil > wrote
> > in m>:
> >
> > >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.

--
Jim Pennino

Remove .spam.sux to reply.

[Orval Fairbairn]

In article >,
Orval Fairbairn > wrote:

> In article om>,
> James Sleeman > wrote:
>
> > On Aug 6, 4:52 am, Larry Dighera > wrote:
> > > 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.

[Ken Finney]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
>
> > wrote in message
> ups.com...
>
>> 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.

[Ken Finney]

> wrote in message
...
> In rec.aviation.piloting Gig 601XL Builder <wrDOTgiaconaATsuddenlink.net>
> wrote:
>> Larry Dighera wrote:
>> > On Mon, 06 Aug 2007 05:39:01 -0700, wrote in
>> > om>:
>> >
>> >> 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
>
>
>> 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.

[Gattman[_2_]]

"Phil" > wrote in message
ps.com...


>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.

>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

[Gattman[_2_]]

"James Sleeman" > wrote in message
ups.com...
> On Aug 6, 4:52 am, Larry Dighera > wrote:
>> 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]

Gattman wrote:
> "James Sleeman" > wrote in message
> ups.com...
>> On Aug 6, 4:52 am, Larry Dighera > wrote:
>>> 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.

[brtlmj]

> 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.

> 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

[Gattman[_2_]]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...

> 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

[Ricky]

On Aug 6, 10:18 am, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> 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]

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

>In article >,
> Orval Fairbairn > wrote:
>
>> 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.

[James Sleeman]

On Aug 7, 3:39 am, Larry Dighera > wrote:
> 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.

[Maxwell]

"Larry Dighera" > wrote in message
...
>
> 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.

[Michael Ash]

In rec.aviation.soaring wrote:
> In rec.aviation.piloting Phil > wrote:
>> 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
Rogue Amoeba Software

[Bill Daniels]

"Michael Ash" > wrote in message
...
> In rec.aviation.soaring wrote:
>> In rec.aviation.piloting Phil > wrote:
>>> 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
> Rogue Amoeba Software

[Morgans[_2_]]

"Michael Ash" > wrote

> 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.
--
Jim in NC

[Michael Ash]

In rec.aviation.soaring Morgans > wrote:
>
> "Michael Ash" > wrote
>
>> 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. :)

--
Michael Ash
Rogue Amoeba Software

[[email protected]]

In rec.aviation.piloting Michael Ash > wrote:
> In rec.aviation.soaring wrote:
> > In rec.aviation.piloting Phil > wrote:
> >> 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.

> 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.

> 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.

--
Jim Pennino

Remove .spam.sux to reply.

[Adhominem]

James Sleeman wrote:

> 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-
--
The mail address works, but please notify me via usenet of any mail you send
to it, as it has a retention period of just a few hours.

[Gig 601XL Builder]

Gattman wrote:
> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
> ...
>
>> 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?

[Tim Ward[_1_]]

> wrote in message
...

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

<Snippage>
> --
> Jim Pennino
>
> Remove .spam.sux to reply.

You want to support this, somehow?

Tim Ward

[Larry Dighera]

On Mon, 06 Aug 2007 18:22:41 -0700, James Sleeman
> wrote in
. com>:

>On Aug 7, 3:39 am, Larry Dighera > wrote:
>> 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.

>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.

[Larry Dighera]

On Mon, 6 Aug 2007 20:43:47 -0500, "Maxwell" > wrote
in >:

>
>"Larry Dighera" > wrote in message
...
>>
>> 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.

>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.

[Michael Ash]

In rec.aviation.soaring wrote:
> In rec.aviation.piloting Michael Ash > wrote:
>> 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.

>> 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.

>> 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.

--
Michael Ash
Rogue Amoeba Software

[[email protected]]

In rec.aviation.piloting Tim Ward > wrote:

> > wrote in message
> ...

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

> <Snippage>
> > --
> > 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.

--
Jim Pennino

Remove .spam.sux to reply.

[Neil Gould]

Recently, Larry Dighera > posted:

> On Mon, 06 Aug 2007 18:22:41 -0700, James Sleeman
> > wrote in
> . com>:
>
>> On Aug 7, 3:39 am, Larry Dighera > wrote:
>>> 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.

> 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... ;-)

> 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"
> wrote in
>:

>Recently, Larry Dighera > posted:
>
[snip]
>> 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.

>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?

>
>> 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.

>
>> 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

[Gattman[_2_]]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...

> 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

[Neil Gould]

Recently, Larry Dighera > posted:

> On Tue, 7 Aug 2007 11:48:50 -0500, "Neil Gould"
> > wrote:
>
>> Recently, Larry Dighera > posted:
>>
> [snip]
>>> 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... ;-)

> 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?
;-)

>> 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.

>>> 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.

>>> 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

[Gig 601XL Builder]

Gattman wrote:
> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
> ...
>
>> 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

[[email protected]]

In rec.aviation.piloting Gig 601XL Builder <wrDOTgiaconaATsuddenlink.net> wrote:
> Gattman wrote:
> > "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
> > ...
> >
> >> 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.




--
Jim Pennino

Remove .spam.sux to reply.

[Gattman[_2_]]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...

> 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

[Gig 601XL Builder]

wrote:
>
> If you go to http://xtronics.com/reference/energy_density.htm you find
> the energy densities of a lot of things.
>
>
> Propane (liquid) 13,900 Wh/kg
> Diesel 13,762 Wh/kg
> gasoline 12,200 Wh/kg
> Ethanol 7,850 Wh/kg
> Methanol 6,400 Wh/kg
> Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
> Primary Zinc-Air 300 Wh/kg
> Lead Acid Battery 25 Wh/kg
>
> So batteries have to improve by a factor of 10 to match gasoline.
>

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

[Larry Dighera]

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

>If you go to http://xtronics.com/reference/energy_density.htm you find
>the energy densities of a lot of things.
>
>
>Propane (liquid) 13,900 Wh/kg
>Diesel 13,762 Wh/kg
>gasoline 12,200 Wh/kg
>Ethanol 7,850 Wh/kg
>Methanol 6,400 Wh/kg
>Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
>Primary Zinc-Air 300 Wh/kg
>Lead Acid Battery 25 Wh/kg
>
>So batteries have to improve by a factor of 10 to match gasoline.

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

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

[[email protected]]

In rec.aviation.piloting Gig 601XL Builder <wrDOTgiaconaATsuddenlink.net> wrote:
> wrote:
> >
> > If you go to http://xtronics.com/reference/energy_density.htm you find
> > the energy densities of a lot of things.
> >
> >
> > Propane (liquid) 13,900 Wh/kg
> > Diesel 13,762 Wh/kg
> > gasoline 12,200 Wh/kg
> > Ethanol 7,850 Wh/kg
> > Methanol 6,400 Wh/kg
> > Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
> > Primary Zinc-Air 300 Wh/kg
> > Lead Acid Battery 25 Wh/kg
> >
> > So batteries have to improve by a factor of 10 to match gasoline.
> >

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

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

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

--
Jim Pennino

Remove .spam.sux to reply.

[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.



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

>On Mon, 06 Aug 2007 06:33:20 -0700, Airjunkie >
>wrote in . com>:
>
>>Eric Raymond has been at it for a long time. Check it out at
>>www.solar-flight.com
>
>http://www.solar-flight.com/sslink.html
>
>Thank you for the information. His achievement is remarkable for the
>time. Imagine what he could do 17 years later with today's ~40%
>efficient photovoltaic cells and light weight lithium-ion polymer
>batteries:
>
>
>
>The Boeing Company <http://www.boeing.com/news/releases/index.html>
>Boeing Spectrolab Terrestrial Solar Cell Surpasses 40 Percent
>Efficiency
>
>ST. LOUIS, Dec. 06, 2006 -- Boeing [NYSE: BA] today announced that
>Spectrolab, Inc., a wholly-owned subsidiary, has achieved a new world
>record in terrestrial concentrator solar cell efficiency. Using
>concentrated sunlight, Spectrolab demonstrated the ability of a
>photovoltaic cell to convert 40.7 percent of the sun's energy into
>electricity. The U.S. Department of Energy's National Renewable Energy
>Laboratory (NREL) in Golden, Colo., verified the milestone.
>
>"This solar cell performance is the highest efficiency level any
>photovoltaic device has ever achieved," said Dr. David Lillington,
>president of Spectrolab. "The terrestrial cell we have developed uses
>the same technology base as our space-based cells. So, once qualified,
>they can be manufactured in very high volumes with minimal impact to
>production flow."
>
>High efficiency multijunction cells have a significant advantage over
>conventional silicon cells in concentrator systems because fewer solar
>cells are required to achieve the same power output. This technology
>will continue to dramatically reduce the cost of generating
>electricity from solar energy as well as the cost of materials used in
>high-power space satellites and terrestrial applications.
>
>"These results are particularly encouraging since they were achieved
>using a new class of metamorphic semiconductor materials, allowing
>much greater freedom in multijunction cell design for optimal
>conversion of the solar spectrum," said Dr. Richard R. King, principal
>investigator of the high efficiency solar cell research and
>development effort. "The excellent performance of these materials
>hints at still higher efficiency in future solar cells."
>
>Spectrolab is reducing the cost of solar cell production through
>research investments and is working with several domestic and
>international solar concentrator manufacturers on clean, renewable
>solar energy solutions. Currently, Spectrolab's terrestrial
>concentrator cells are generating power in a 33-kilowatt full-scale
>concentrator system in the Australian desert. The company recently
>signed multi-million dollar contracts for its high efficiency
>concentrator cells and is anticipating several new contracts in the
>next few months.
>
>Development of the high-efficiency concentrator cell technology was
>funded by the NREL's High Performance Photovoltaics program and
>Spectrolab.
>
>A unit of The Boeing Company, Boeing Integrated Defense Systems
><http://www.boeing.com/ids/index.html> is one of the world's largest
>space and defense businesses. Headquartered in St. Louis, Boeing
>Integrated Defense Systems is a $30.8 billion business. It provides
>network-centric system solutions to its global military, government,
>and commercial customers. It is a leading provider of intelligence,
>surveillance and reconnaissance systems; the world's largest military
>aircraft manufacturer; the world's largest satellite manufacturer; a
>foremost developer of advanced concepts and technologies; a leading
>provider of space-based communications; the primary systems integrator
>for U.S. missile defense; NASA's largest contractor; and a global
>leader in sustainment solutions and launch services.
>###

[Larry Dighera]

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

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

That's only true if you overlook Randall Fishman's electrically
powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
Sonex proof-of-concept Waiex aircraft
(http://www.sonexaircraft.com/press/releases/pr_072407.html).

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

[[email protected]]

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

> >If you go to http://xtronics.com/reference/energy_density.htm you find
> >the energy densities of a lot of things.
> >
> >
> >Propane (liquid) 13,900 Wh/kg
> >Diesel 13,762 Wh/kg
> >gasoline 12,200 Wh/kg
> >Ethanol 7,850 Wh/kg
> >Methanol 6,400 Wh/kg
> >Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
> >Primary Zinc-Air 300 Wh/kg
> >Lead Acid Battery 25 Wh/kg
> >
> >So batteries have to improve by a factor of 10 to match gasoline.

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

Well, you have to look at total system weight.

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

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

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

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

DC motors have brushes but motor control is simpler.

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


--
Jim Pennino

Remove .spam.sux to reply.

[Gig 601XL Builder]

Larry Dighera wrote:
> On Tue, 7 Aug 2007 14:51:55 -0500, "Gig 601XL Builder"
> <wrDOTgiaconaATsuddenlink.net> wrote in
> >:
>
>> all this talk of electric airplanes while a nice thought is
>> something that at best is way in the future.
>
> That's only true if you overlook Randall Fishman's electrically
> powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
> Sonex proof-of-concept Waiex aircraft
> (http://www.sonexaircraft.com/press/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.

[Gig 601XL Builder]

Larry Dighera wrote:
> On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
> >:
>
>> If you go to http://xtronics.com/reference/energy_density.htm you
>> find the energy densities of a lot of things.
>>
>>
>> Propane (liquid) 13,900 Wh/kg
>> Diesel 13,762 Wh/kg
>> gasoline 12,200 Wh/kg
>> Ethanol 7,850 Wh/kg
>> Methanol 6,400 Wh/kg
>> Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
>> Primary Zinc-Air 300 Wh/kg
>> Lead Acid Battery 25 Wh/kg
>>
>> So batteries have to improve by a factor of 10 to match gasoline.
>
> When you compare the efficiency of internal combustion Otto Cycle
> engines (30% - 40%) against electric motors (80% - 95%), it appears
> that a factor of five might be a more realistic comparison of their
> relative merits. Then there is the issue of power plant weight...
>
> Electric motors don't lose power in thin air either. With regard to
> reliability, electric motors have only one moving part compared to
> scores of moving parts for IC engines, their failure rate should be
> substantially greater than IC engines.

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

http://www.baldor.com/products/detail.asp?1=1&catalog=D50100P&product=DC+Motors&family=General+Purpose%7Cvw%5FDCMotors%5FGeneralPu rpose

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

[George]

Gig 601XL Builder wrote:
> Larry Dighera wrote:
>> On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
>> >:
>>
>>> If you go to http://xtronics.com/reference/energy_density.htm you
>>> find the energy densities of a lot of things.
>>>
>>>
>>> Propane (liquid) 13,900 Wh/kg
>>> Diesel 13,762 Wh/kg
>>> gasoline 12,200 Wh/kg
>>> Ethanol 7,850 Wh/kg
>>> Methanol 6,400 Wh/kg
>>> Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
>>> Primary Zinc-Air 300 Wh/kg
>>> Lead Acid Battery 25 Wh/kg
>>>
>>> So batteries have to improve by a factor of 10 to match gasoline.
>> When you compare the efficiency of internal combustion Otto Cycle
>> engines (30% - 40%) against electric motors (80% - 95%), it appears
>> that a factor of five might be a more realistic comparison of their
>> relative merits. Then there is the issue of power plant weight...
>>
>> Electric motors don't lose power in thin air either. With regard to
>> reliability, electric motors have only one moving part compared to
>> scores of moving parts for IC engines, their failure rate should be
>> substantially greater than IC engines.
>
> Here is a 100hp electric motor. I don't know if it is typical for an
> electric motor but damn the thing weighs over half a ton. I might make the
> 601XL a little nose heavy. But it's priced right up there with a Lyc of
> equal power.
>
> http://www.baldor.com/products/detail.asp?1=1&catalog=D50100P&product=DC+Motors&family=General+Purpose%7Cvw%5FDCMotors%5FGeneralPu rpose
>
> 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

[[email protected]]

On Aug 7, 3:04 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>
wrote:
> Larry Dighera wrote:
> > On Tue, 7 Aug 2007 14:51:55 -0500, "Gig 601XL Builder"
> > <wrDOTgiaconaATsuddenlink.net> wrote in
> > >:
>
> >> all this talk of electric airplanes while a nice thought is
> >> something that at best is way in the future.
>
> > That's only true if you overlook Randall Fishman's electrically
> > powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
> > Sonex proof-of-concept Waiex aircraft
> > (http://www.sonexaircraft.com/press/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]

wrote:
> On Aug 7, 3:04 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>
> wrote:
>> Larry Dighera wrote:
>>> On Tue, 7 Aug 2007 14:51:55 -0500, "Gig 601XL Builder"
>>> <wrDOTgiaconaATsuddenlink.net> wrote in
>>> >:
>>
>>>> all this talk of electric airplanes while a nice thought is
>>>> something that at best is way in the future.
>>
>>> That's only true if you overlook Randall Fishman's electrically
>>> powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
>>> Sonex proof-of-concept Waiex aircraft
>>> (http://www.sonexaircraft.com/press/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."

[Gig 601XL Builder]

George wrote:
>>
>
> 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.

[Morgans[_2_]]

> wrote

> 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?
--
Jim in NC

[Larry Dighera]

On Tue, 07 Aug 2007 20:54:59 GMT, wrote in
>:

>In rec.aviation.piloting Larry Dighera > wrote:
>> On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
>> >:
>
>> >If you go to http://xtronics.com/reference/energy_density.htm you find
>> >the energy densities of a lot of things.
>> >
>> >
>> >Propane (liquid) 13,900 Wh/kg
>> >Diesel 13,762 Wh/kg
>> >gasoline 12,200 Wh/kg
>> >Ethanol 7,850 Wh/kg
>> >Methanol 6,400 Wh/kg
>> >Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
>> >Primary Zinc-Air 300 Wh/kg
>> >Lead Acid Battery 25 Wh/kg
>> >
>> >So batteries have to improve by a factor of 10 to match gasoline.
>
>> When you compare the efficiency of internal combustion Otto Cycle
>> engines (30% - 40%) against electric motors (80% - 95%), it appears
>> that a factor of five might be a more realistic comparison of their
>> relative merits. Then there is the issue of power plant weight...
>
>Well, you have to look at total system weight.

Agreed.

>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.

>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.

>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.

>> 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 ...

>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.

[George]

Gig 601XL Builder wrote:
> George wrote:
>> 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

[Ash Wyllie]

James Sleeman opined

>On Aug 7, 3:39 am, Larry Dighera > wrote:
>> 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?

[[email protected]]

In rec.aviation.piloting Larry Dighera > wrote:



> 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.

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.

--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Morgans > wrote:

> > wrote

> > 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.


--
Jim Pennino

Remove .spam.sux to reply.

[Larry Dighera]

On Tue, 7 Aug 2007 16:12:16 -0500, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote in
>:
>
>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%5FGeneralPu rpose
>
> 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.

[Larry Dighera]

On Tue, 07 Aug 2007 14:34:36 -0700, wrote in
om>:

>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]

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

>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, 07 Aug 2007 23:14:59 GMT, wrote in
>:

>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.
================================================== =============

[Ernest Christley]

Orval Fairbairn wrote:
> In article >,
> Orval Fairbairn > wrote:
>
>> In article om>,
>> James Sleeman > wrote:
>>
>>> On Aug 6, 4:52 am, Larry Dighera > wrote:
>>>> 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?

[kontiki]

wrote:

>
> 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.

[kontiki]

Gattman wrote:

> 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.

[kontiki]

Larry Dighera wrote:
>
> 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.

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.

[Morgans[_2_]]

<jimp> wrote

> 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.
--
Jim in NC

[Larry Dighera]

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

>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 Wed, 08 Aug 2007 01:05:16 GMT, kontiki >
wrote in >:

>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

[James Sleeman]

On Aug 8, 2:21 am, Larry Dighera > wrote:
> 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.

[Maxwell]

"Larry Dighera" > wrote in message
...
>
> 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

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

>
> 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.

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.

[Snowbird]

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

Flight training in the pattern is an obvious first application.

[Snowbird]

"kontiki" wrote
>
> 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 Wed, 8 Aug 2007 01:12:26 -0500, "Maxwell" > wrote
in >:

>
>"Larry Dighera" > wrote in message
...
>>
>> 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.
>
>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?

[Gig 601XL Builder]

Larry Dighera wrote:

>
>
> 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.

[Darrel Toepfer]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote:

> 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...

[Gig 601XL Builder]

Darrel Toepfer wrote:
> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote:
>
>> 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...


Why should I. I'm not the one making the claim.

[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.

[[email protected]]

On Aug 7, 3:49 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>
wrote:
> wrote:
> > On Aug 7, 3:04 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>
> > wrote:
> >> Larry Dighera wrote:
> >>> On Tue, 7 Aug 2007 14:51:55 -0500, "Gig 601XL Builder"
> >>> <wrDOTgiaconaATsuddenlink.net> wrote in
> >>> >:
>
> >>>> all this talk of electric airplanes while a nice thought is
> >>>> something that at best is way in the future.
>
> >>> That's only true if you overlook Randall Fishman's electrically
> >>> powered ultralight (http://www.electraflyer.com) and Mr. Monnett's
> >>> Sonex proof-of-concept Waiex aircraft
> >>> (http://www.sonexaircraft.com/press/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.

[Darrel Toepfer]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote:

> Why should I. I'm not the one making the claim.

But your the "bubble burst"r... ;-)

[Larry Dighera]

On Wed, 08 Aug 2007 07:20:22 -0700, wrote in
. com>:

>
>> > 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.

[[email protected]]

On Aug 8, 8:35 am, Larry Dighera > wrote:
> On Wed, 08 Aug 2007 07:20:22 -0700, wrote in
> . com>:
>
>
>
> >> > 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]

Larry Dighera wrote:
> 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.

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.

[Gig 601XL Builder]

Larry Dighera wrote:
> On Wed, 08 Aug 2007 07:20:22 -0700, wrote in
> . com>:
>
>>
>>>> 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.

[Gig 601XL Builder]

Darrel Toepfer wrote:
> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote:
>
>> Why should I. I'm not the one making the claim.
>
> But your the "bubble burst"r... ;-)

Exactly! To have the guys bubble fixed he needs to be the one that keeps an
eye out for the flight.

[Larry Dighera]

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

>Larry Dighera wrote:
>> 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.
>
>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.

>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.

[Larry Dighera]

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

>Larry Dighera wrote:
>> On Wed, 08 Aug 2007 07:20:22 -0700, wrote in
>> . com>:
>>
>>>
>>>>> 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]

Larry Dighera wrote:
>>
>
> 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? http://www.ausbcomp.com/~bbott/cars/cugnot.jpg.

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]

> 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]

On Tue, 07 Aug 2007 17:51:27 GMT, "Neil Gould"
> wrote in
>:

>Recently, Larry Dighera > posted:
[...]
>> 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.

>>>> 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]

Recently, Larry Dighera > posted:

> On Tue, 07 Aug 2007 17:51:27 GMT, "Neil Gould"
> > wrote in
> >:
>
>> Recently, Larry Dighera > posted:
> [...]
>>> 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.

>>>>> 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.

> 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

[Maxwell]

"Larry Dighera" > wrote in message
...
>>
>>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.

[Dana M. Hague]

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

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

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

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

-Dana

--
--
If replying by email, please make the obvious changes.
-------------------------------------------------------------------------------
The number of elected federal officials is limited to congress, the president and the vice president. That's only 537 people. The federal bureaucracy numbers in the millions.....

[Morgans[_2_]]

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

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

Some of the newer Lithium iron cells, maybe, but they also cost a LOT more.

Still, electric flight, like many have said, still have a way to go.
--
Jim in NC

[Gig 601XL Builder]

Morgans wrote:
> "Dana wrote>
>> The major problem is the weight of the batteries, still far heavier
>> than gasoline. Also the lithium polymer batteries used are still
>> quite expensive (over $10,000 for enough for a half hour flight) and
>> somewhat dangerous (sort them out and they can explode!)
>
> Damn straight! No way am I going to strap a bunch of lithium polymer
> batteries to my butt.
>
> Some of the newer Lithium iron cells, maybe, but they also cost a LOT
> more.
> Still, electric flight, like many have said, still have a way to go.

And as if we need more proof of this.

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

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

[Larry Dighera]

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

>On Tue, 07 Aug 2007 14:58:07 GMT, Larry Dighera >
>wrote:
>
>>If a 14 HP electric propulsion system weighing 46 lbs could be
>>constructed, apparently it would permit the use of PPGs by pilots up
>>to 180 lbs.
>
>A PPG is a LOT more efficient than a powered parachute (PPC), but
>still far less efficient than a rigid wing. Still, several electric
>PPG's have been flown. The primary goal here is noise and vibration
>reduction, a worthy goal when the engine is strapped to the pilot's
>back.
>
>The major problem is the weight of the batteries, still far heavier
>than gasoline. Also the lithium polymer batteries used are still
>quite expensive (over $10,000 for enough for a half hour flight) and
>somewhat dangerous (sort them out and they can explode!)
>
>-Dana

That's interesting information. Thank you.


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

[Big John]

Gig

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

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

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


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

>Morgans wrote:
>> "Dana wrote>
>>> The major problem is the weight of the batteries, still far heavier
>>> than gasoline. Also the lithium polymer batteries used are still
>>> quite expensive (over $10,000 for enough for a half hour flight) and
>>> somewhat dangerous (sort them out and they can explode!)
>>
>> Damn straight! No way am I going to strap a bunch of lithium polymer
>> batteries to my butt.
>>
>> Some of the newer Lithium iron cells, maybe, but they also cost a LOT
>> more.
>> Still, electric flight, like many have said, still have a way to go.
>
>And as if we need more proof of this.
>
>TOKYO: Japan's Toyota Motor Corp. will delay by one or two years the rollout
>of new high-mileage hybrids with lithium-ion batteries because of safety
>concerns, reported a newspaper.
>
>Toyota's decision was prompted by worries that the batteries could overheat,
>catch fire or even explode, the Wall Street Journal on Thursday reported in
>its online edition, quoting unnamed Toyota executives.
>

[Gig 601XL Builder]

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



Is this the story you are talking about John? If so what is an "LG Chem
cell?"
http://www.autobloggreen.com/2007/06/05/breaking-gm-awards-two-battery-development-contracts-for-chevy/


Big John wrote:
> Gig
>
> Just saw where GM bought a battery company here in US that has
> developed batteries that do not catch fire or expload like current
> Lithium Polymer's.
>
> GM expects to have a plug in auto on market at least two years before
> Toyota can get their batteries sorted out and their auto on the
> market.
>
> Big John
> *************************************************

[Gig 601XL Builder]

Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT TO:
> GM on the cutting edge of anything is a little funny. And I'm sure
> Sony didn't think their batteries would do this...
> http://www.youtube.com/watch?v=WeWq6rWzChw
>
>
>
> Is this the story you are talking about John? If so what is an "LG
> Chem cell?"
> http://www.autobloggreen.com/2007/06/05/breaking-gm-awards-two-
> battery-development-contracts-for-chevy/
>

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

[Ken Finney]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...
> Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT TO:
>> GM on the cutting edge of anything is a little funny. And I'm sure
>> Sony didn't think their batteries would do this...
>> http://www.youtube.com/watch?v=WeWq6rWzChw
>>
>>
>>
>> Is this the story you are talking about John? If so what is an "LG
>> Chem cell?"
>> http://www.autobloggreen.com/2007/06/05/breaking-gm-awards-two-
>> battery-development-contracts-for-chevy/
>>
>
> GM doing this also kind of proves my point that the new battery technology
> is coming from somewhere with a lot more money in play than the ultralight
> and LSA market.
>
>

"LG" is Lucky Goldstar, a Korean conglomerate.

[Gig 601XL Builder]

Ken Finney wrote:
> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
> ...
>> Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT TO:
>>> GM on the cutting edge of anything is a little funny. And I'm sure
>>> Sony didn't think their batteries would do this...
>>> http://www.youtube.com/watch?v=WeWq6rWzChw
>>>
>>>
>>>
>>> Is this the story you are talking about John? If so what is an "LG
>>> Chem cell?"
>>> http://www.autobloggreen.com/2007/06/05/breaking-gm-awards-two-
>>> battery-development-contracts-for-chevy/
>>>
>>
>> GM doing this also kind of proves my point that the new battery
>> technology is coming from somewhere with a lot more money in play
>> than the ultralight and LSA market.
>>
>>
>
> "LG" is Lucky Goldstar, a Korean conglomerate.

So it is just another version of a Li-Ion battery and not a "new"
technology?

[Ken Finney]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...
> Ken Finney wrote:
>> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
>> ...
>>> Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT TO:
>>>> GM on the cutting edge of anything is a little funny. And I'm sure
>>>> Sony didn't think their batteries would do this...
>>>> http://www.youtube.com/watch?v=WeWq6rWzChw
>>>>
>>>>
>>>>
>>>> Is this the story you are talking about John? If so what is an "LG
>>>> Chem cell?"
>>>> http://www.autobloggreen.com/2007/06/05/breaking-gm-awards-two-
>>>> battery-development-contracts-for-chevy/
>>>>
>>>
>>> GM doing this also kind of proves my point that the new battery
>>> technology is coming from somewhere with a lot more money in play
>>> than the ultralight and LSA market.
>>>
>>>
>>
>> "LG" is Lucky Goldstar, a Korean conglomerate.
>
> So it is just another version of a Li-Ion battery and not a "new"
> technology?

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

[Gig 601XL Builder]

Ken Finney wrote:
> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
> ...
>> Ken Finney wrote:
>>> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
>>> ...
>>>> Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT
>>>> TO:
>>>>> GM on the cutting edge of anything is a little funny. And I'm sure
>>>>> Sony didn't think their batteries would do this...
>>>>> http://www.youtube.com/watch?v=WeWq6rWzChw
>>>>>
>>>>>
>>>>>
>>>>> Is this the story you are talking about John? If so what is an
>>>>> "LG Chem cell?"
>>>>> http://www.autobloggreen.com/2007/06/05/breaking-gm-awards-two-
>>>>> battery-development-contracts-for-chevy/
>>>>>
>>>>
>>>> GM doing this also kind of proves my point that the new battery
>>>> technology is coming from somewhere with a lot more money in play
>>>> than the ultralight and LSA market.
>>>>
>>>>
>>>
>>> "LG" is Lucky Goldstar, a Korean conglomerate.
>>
>> So it is just another version of a Li-Ion battery and not a "new"
>> technology?
>
> Yes. GM is also working with another company, A123, on their
> "nano-phosphate" technology, but it is just a different flavor of Li-
> Ion.

So what makes them think that these are going to be any less likely to
explode than the others? I think Toyota is taking the right path holding off
on the battery powered cars. Let GM eat the first thousand or so lawsuits.

[Ken Finney]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...
> Ken Finney wrote:
>> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
>> ...
>>> Ken Finney wrote:
>>>> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
>>>> ...
>>>>> Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT
>>>>> TO:
>>>>>> GM on the cutting edge of anything is a little funny. And I'm sure
>>>>>> Sony didn't think their batteries would do this...
>>>>>> http://www.youtube.com/watch?v=WeWq6rWzChw
>>>>>>
>>>>>>
>>>>>>
>>>>>> Is this the story you are talking about John? If so what is an
>>>>>> "LG Chem cell?"
>>>>>> http://www.autobloggreen.com/2007/06/05/breaking-gm-awards-two-
>>>>>> battery-development-contracts-for-chevy/
>>>>>>
>>>>>
>>>>> GM doing this also kind of proves my point that the new battery
>>>>> technology is coming from somewhere with a lot more money in play
>>>>> than the ultralight and LSA market.
>>>>>
>>>>>
>>>>
>>>> "LG" is Lucky Goldstar, a Korean conglomerate.
>>>
>>> So it is just another version of a Li-Ion battery and not a "new"
>>> technology?
>>
>> Yes. GM is also working with another company, A123, on their
>> "nano-phosphate" technology, but it is just a different flavor of Li-
>> Ion.
>
> So what makes them think that these are going to be any less likely to
> explode than the others? I think Toyota is taking the right path holding
> off on the battery powered cars. Let GM eat the first thousand or so
> lawsuits.

They don't so much explode, as burn. One of the thingsthat many don't
realize is that a "battery", by definition, is made up of cells. One bad
cell tends to take out other cells around it and damage the battery. So, if
your reliability goal is "1 in 1000 battery failures" and you have 1000
cells in each battery, you actually need a cell failure rate of less than "1
in a million". I'm willing to drive a car with Li-Ion batteries, I can run
away from the fire. Ford experimented with Sodium-Sulphur batteries years
ago, pretty difficult to run away from one of those fires. On the other
hand, I've personally had a car with a gasoline engine catch on fire, so
their failure rate isn't zero.

[Morgans[_2_]]

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

Close, but not quite accurate.

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

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

[Dave[_5_]]

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


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

David Johnson

[[email protected]]

On Aug 10, 5:12 pm, Dave > wrote:
> Are
>
> > you able to provide links to any forums or web sites related to this
>
> Check this out:http://www.calcars.org/news-archive.html
>
> David Johnson

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

[Larry Dighera]

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

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

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

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

Thank you for the link. It is spectacular.


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

Story: http://www.theinquirer.net/default.aspx?article=32550
http://news.com.com/Dell+takes+heat+over+battery+recall/2009-1044_3-6105828.html

Video:
http://www.youtube.com/watch?v=WeWq6rWzChw&mode=related&search=#

Explanation of cause:
http://reviews.cnet.com/4660-10165_7-6625980.html
http://www.prnewstoday.com/release.htm?cat=computer-electronics&dat=20060824&rl=LATH05424082006-1
The recall arises because, on rare occasions, microscopic metal
particles in the recalled battery cells may come into contact with
other parts of the battery cell, leading to a short circuit within the
cell. Typically, a battery pack will simply power off when a cell
short circuit occurs. However, under certain rare conditions, an
internal short circuit may lead to cell overheating and potentially
flames. The potential for this to occur can be affected by variations
in the system configurations found in different notebook computers.

[cavelamb himself[_3_]]

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

1) weight

2) power

3) scale

[Bill Daniels]

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

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

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

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

Bill Daniels

Some Lithium cells can suffer thermal runaway and fire. Others are
extremely
> wrote in message
oups.com...
> On Aug 10, 5:12 pm, Dave > wrote:
>> Are
>>
>> > you able to provide links to any forums or web sites related to this
>>
>> Check this out:http://www.calcars.org/news-archive.html
>>
>> David Johnson
>
> Lithium Polymer batteries are widely used in RC planes, cars, etc and
> are known to be potentially dangerous. Most runaway fires occur during
> charging but it has also occurred to a lessor degree during discharge
> and even storage. Vented charging safety bags are recommended for this
> reason. There is a video on this link that shows the explosive power
> of small LiPo's. Consider the size differance of these batteries to
> the one hung under the trike in one of the first posts or those that
> could be installed in the wings of a sailplane.
> http://www.liposack.com/video.html
>

[Barnyard BOb]

"Snowbird" wrote:

>"kontiki" wrote
>>
>> Yeah sure, but its not practical for anything but an hour or two of
>> playing around on a Saturday afternoon.
>
>Flight training in the pattern is an obvious first application.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Well, well.
Looks who is still alive.

Hi there.


- Barnyard BOb -

[Gig 601XL Builder]

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

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

[Ken Finney]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...
> Ken Finney wrote:
>> I'm willing to
>> drive a car with Li-Ion batteries, I can run away from the fire.
>
> Are you going to park it in your garage while you sleep at night?
>

Well, people park Fords in their garages!

;^)

[Ken Finney]

"Morgans" > wrote in message
...
>
> "Ken Finney" > wrote
>>
>> Yes. GM is also working with another company, A123, on their
>> "nano-phosphate" technology, but it is just a different flavor of Li-Ion.
>
> Close, but not quite accurate.
>
> The common lithium ion battery outgases oxygen in the process of burning,
> which then feeds conventional fires and helps consume the other cells.
>
> The 123 batteries are a different chemistry that do not outgas oxygen,
> thus do not catastrophically fail.
>

Thanks for the info!

[Gig 601XL Builder]

Ken Finney wrote:
> "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
> ...
>> Ken Finney wrote:
>>> I'm willing to
>>> drive a car with Li-Ion batteries, I can run away from the fire.
>>
>> Are you going to park it in your garage while you sleep at night?
>>
>
> Well, people park Fords in their garages!
>
> ;^)

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

[Dana M. Hague]

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

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

Try http://electricppg.com

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

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

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

[Dana M. Hague]

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

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

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

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

[Bill Daniels]

"Dana M. Hague" <d(dash)m(dash)hague(at)comcast(dot)net> wrote in message
...
> On Sat, 11 Aug 2007 15:35:25 GMT, Larry Dighera >
> wrote:
>
>>I would assume that the source of these Li-ion Polymer battery fires
>>is excessive electrical current flowing through the battery either
>>from too high a charging rate, too high a discharge rate, or a short
>>internal (as in the case of the Sony laptop cells) or external, or
>>being over charged. Perhaps it would be prudent to install a circuit
>>breaker of fuse to prevent too high a current and a timer to
>>disconnect a forgotten charger.
>
> I imagine the root of the problem is very low internal resistance
> which, while making them very efficient, also allows the current to
> "run away". Good circuit design can alleviate many of the issues, but
> safety if the batteries are damaged in a crash is still an issue.
>
> -Dana
> --

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

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

Bill Daniels

[Larry Dighera]

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

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

I would think the hazard somewhat less than gasoline.

[Gig 601XL Builder]

Larry Dighera wrote:
> On Mon, 13 Aug 2007 17:39:44 -0400, Dana M. Hague
> <d(dash)m(dash)hague(at)comcast(dot)net> wrote in
> >:
>
>> safety if the batteries are damaged in a crash is still an issue.
>
> I would think the hazard somewhat less than gasoline.

The battery can produce it's own ignition source.

[Larry Dighera]

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

>Larry Dighera wrote:
>> On Mon, 13 Aug 2007 17:39:44 -0400, Dana M. Hague
>> <d(dash)m(dash)hague(at)comcast(dot)net> wrote in
>> >:
>>
>>> safety if the batteries are damaged in a crash is still an issue.
>>
>> I would think the hazard somewhat less than gasoline.
>
>The battery can produce it's own ignition source.
>

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

[CanalBuilder]

Larry Dighera wrote:
> On Tue, 14 Aug 2007 08:40:29 -0500, "Gig 601XL Builder"
> <wrDOTgiaconaATsuddenlink.net> wrote in
> >:
>
>> Larry Dighera wrote:
>>> On Mon, 13 Aug 2007 17:39:44 -0400, Dana M. Hague
>>> <d(dash)m(dash)hague(at)comcast(dot)net> wrote in
>>> >:
>>>
>>>> safety if the batteries are damaged in a crash is still an issue.
>>> I would think the hazard somewhat less than gasoline.
>> The battery can produce it's own ignition source.
>>
>
> You have a point. While a source of ignition (sparking wires, hot
> muffler?) is required to ignite post-crash gasoline fumes, it would
> take an un-fused short circuit or significant deformation of a battery
> to potentially ignite a lithium battery. Granted, if the crash occurs
> as a result of fuel exhaustion, there is little fire hazard, while the
> lithium would always be aboard.
>
>
How much of a fire hazard would a paper battery be?

http://www.energy-daily.com/reports/Beyond_Batteries_Storing_Power_In_A_Sheet_Of_Paper _999.html

[Larry Dighera]

On Wed, 15 Aug 2007 12:23:00 GMT, CanalBuilder
> wrote in
>:

>How much of a fire hazard would a paper battery be?
>
>http://www.energy-daily.com/reports/Beyond_Batteries_Storing_Power_In_A_Sheet_Of_Paper _999.html

That is an interesting device indeed. Given these quotes from the
article:

Rensselaer researchers infused this paper with aligned carbon
nanotubes, which give the device its black color. The nanotubes
act as electrodes and allow the storage devices to conduct
electricity. The device, engineered to function as both a
lithium-ion battery and a supercapacitor, can provide the long,
steady power output comparable to a conventional battery, as well
as a supercapacitor's quick burst of high energy. ...

Along with use in small handheld electronics, the paper batteries'
light weight could make them ideal for use in automobiles,
aircraft, and even boats. The paper also could be molded into
different shapes, such as a car door, which would enable important
new engineering innovations.

"Plus, because of the high paper content and lack of toxic
chemicals, it's environmentally safe," Shaijumon said. ...

"Plus, because of the high paper content and lack of toxic
chemicals, it's environmentally safe," Shaijumon said.

"It's a way to power a small device such as a pacemaker without
introducing any harsh chemicals - such as the kind that are
typically found in batteries - into the body," Pushparaj said.

I find the article to be somewhat contradictory in its characterizing
a lithium-ion battery as containing no harsh chemicals. And its claim
of using carbon electrodes in a supercapacitor seem very
counterintuitive for a low impedance device. It reads like an April
Fools Day hoax.

[Charles Vincent]

wrote:
> In rec.aviation.piloting Tim Ward > wrote:
>
>> > wrote in message
>> ...
>
>>> The advantage from the electric engine at cruise is that it uses zero
>>> energy.
>
>> <Snippage>
>>> --
>>> 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.
>

To carry more weight at the same speed and altitude takes more power, so
you have to account for the energy expended kiting you deadweight
electric takeoff system around the sky as well. Sizing an engine for
cruise has been done, if only backwards. Think JATO. Most JATO's are
actually RATO (rocket assisted takeoff). I expect RATO would beat an
electric system based on energy density and the fact that when it is
done you have reduced your weight by the fuel. I also suspect for a
given amount of thrust the rocket will be lighter than an electric motor
and associated clutches and gearing. In my opinion, at this point in
time it is just as practical for a homebuilt as well as in not.


Charles

[[email protected]]

In rec.aviation.piloting Charles Vincent > wrote:
> wrote:
> > In rec.aviation.piloting Tim Ward > wrote:
> >
> >> > wrote in message
> >> ...
> >
> >>> The advantage from the electric engine at cruise is that it uses zero
> >>> energy.
> >
> >> <Snippage>
> >>> --
> >>> 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.
> >

> To carry more weight at the same speed and altitude takes more power, so
> you have to account for the energy expended kiting you deadweight
> electric takeoff system around the sky as well. Sizing an engine for
> cruise has been done, if only backwards. Think JATO. Most JATO's are
> actually RATO (rocket assisted takeoff). I expect RATO would beat an
> electric system based on energy density and the fact that when it is
> done you have reduced your weight by the fuel. I also suspect for a
> given amount of thrust the rocket will be lighter than an electric motor
> and associated clutches and gearing. In my opinion, at this point in
> time it is just as practical for a homebuilt as well as in not.

Well, that's true enough, but the above was about hybrid cars.

--
Jim Pennino

Remove .spam.sux to reply.

[cavelamb himself[_4_]]

wrote:
>
>>To carry more weight at the same speed and altitude takes more power, so
>> you have to account for the energy expended kiting you deadweight
>>electric takeoff system around the sky as well. Sizing an engine for
>>cruise has been done, if only backwards. Think JATO. Most JATO's are
>>actually RATO (rocket assisted takeoff). I expect RATO would beat an
>>electric system based on energy density and the fact that when it is
>>done you have reduced your weight by the fuel. I also suspect for a
>>given amount of thrust the rocket will be lighter than an electric motor
>>and associated clutches and gearing. In my opinion, at this point in
>>time it is just as practical for a homebuilt as well as in not.
>
>
> Well, that's true enough, but the above was about hybrid cars.
>


No, it's not true enough.

To carry more weight at the same speed and altitude requires more LIFT.

A higher CL - and/or more wing area.

THEN, to overcome the increased drag, THEN you need more power.

But more power by itself won't satisfy the constraints...

[Charles Vincent]

wrote:
> In rec.aviation.piloting Charles Vincent > wrote:
>> wrote:
>>> In rec.aviation.piloting Tim Ward > wrote:
>>>
>>>> > wrote in message
>>>> ...
>>>>> The advantage from the electric engine at cruise is that it uses zero
>>>>> energy.
>>>> <Snippage>
>>>>> --
>>>>> 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.
>>>
>
>> To carry more weight at the same speed and altitude takes more power, so
>> you have to account for the energy expended kiting you deadweight
>> electric takeoff system around the sky as well. Sizing an engine for
>> cruise has been done, if only backwards. Think JATO. Most JATO's are
>> actually RATO (rocket assisted takeoff). I expect RATO would beat an
>> electric system based on energy density and the fact that when it is
>> done you have reduced your weight by the fuel. I also suspect for a
>> given amount of thrust the rocket will be lighter than an electric motor
>> and associated clutches and gearing. In my opinion, at this point in
>> time it is just as practical for a homebuilt as well as in not.
>
> Well, that's true enough, but the above was about hybrid cars.
>

Well in cruise in a car, more weight does not increase your aerodynamic
drag like it does on an airplane, but it does increase your rolling
resistance in the real world, so there is no free lunch. Different
tradeoffs for different missions. I guess that is why cheetahs and
sparrows look so different.

Charles

[[email protected]]

In rec.aviation.piloting cavelamb himself > wrote:
> wrote:
> >
> >>To carry more weight at the same speed and altitude takes more power, so
> >> you have to account for the energy expended kiting you deadweight
> >>electric takeoff system around the sky as well. Sizing an engine for
> >>cruise has been done, if only backwards. Think JATO. Most JATO's are
> >>actually RATO (rocket assisted takeoff). I expect RATO would beat an
> >>electric system based on energy density and the fact that when it is
> >>done you have reduced your weight by the fuel. I also suspect for a
> >>given amount of thrust the rocket will be lighter than an electric motor
> >>and associated clutches and gearing. In my opinion, at this point in
> >>time it is just as practical for a homebuilt as well as in not.
> >
> >
> > Well, that's true enough, but the above was about hybrid cars.
> >


> No, it's not true enough.

> To carry more weight at the same speed and altitude requires more LIFT.

> A higher CL - and/or more wing area.

> THEN, to overcome the increased drag, THEN you need more power.

> But more power by itself won't satisfy the constraints...

So if I add 1 pound to a 2400 pound gross aircraft loaded to 2300 pounds,
it would be impossible to cruise at the same speed and altitude without
the 1 pound unless I added wing area?

How about 50 pounds?

--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Charles Vincent > wrote:
> wrote:
> > In rec.aviation.piloting Charles Vincent > wrote:
> >> wrote:
> >>> In rec.aviation.piloting Tim Ward > wrote:
> >>>
> >>>> > wrote in message
> >>>> ...
> >>>>> The advantage from the electric engine at cruise is that it uses zero
> >>>>> energy.
> >>>> <Snippage>
> >>>>> --
> >>>>> 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.
> >>>
> >
> >> To carry more weight at the same speed and altitude takes more power, so
> >> you have to account for the energy expended kiting you deadweight
> >> electric takeoff system around the sky as well. Sizing an engine for
> >> cruise has been done, if only backwards. Think JATO. Most JATO's are
> >> actually RATO (rocket assisted takeoff). I expect RATO would beat an
> >> electric system based on energy density and the fact that when it is
> >> done you have reduced your weight by the fuel. I also suspect for a
> >> given amount of thrust the rocket will be lighter than an electric motor
> >> and associated clutches and gearing. In my opinion, at this point in
> >> time it is just as practical for a homebuilt as well as in not.
> >
> > Well, that's true enough, but the above was about hybrid cars.
> >

> Well in cruise in a car, more weight does not increase your aerodynamic
> drag like it does on an airplane, but it does increase your rolling
> resistance in the real world, so there is no free lunch. Different
> tradeoffs for different missions. I guess that is why cheetahs and
> sparrows look so different.

Unless the added weight is enough to deform the tires, the increase
in rolling resistance in the total energy expediture can't be found.

--
Jim Pennino

Remove .spam.sux to reply.

[Charles Vincent]

cavelamb himself wrote:
> wrote:
>>
>>> To carry more weight at the same speed and altitude takes more power,
>>> so you have to account for the energy expended kiting you
>>> deadweight electric takeoff system around the sky as well. Sizing
>>> an engine for cruise has been done, if only backwards. Think JATO.
>>> Most JATO's are actually RATO (rocket assisted takeoff). I expect
>>> RATO would beat an electric system based on energy density and the
>>> fact that when it is done you have reduced your weight by the fuel.
>>> I also suspect for a given amount of thrust the rocket will be
>>> lighter than an electric motor and associated clutches and gearing.
>>> In my opinion, at this point in time it is just as practical for a
>>> homebuilt as well as in not.
>>
>>
>> Well, that's true enough, but the above was about hybrid cars.
>>
>
>
> No, it's not true enough.
>
> To carry more weight at the same speed and altitude requires more LIFT.
>
> A higher CL - and/or more wing area.
>
> THEN, to overcome the increased drag, THEN you need more power.
>
> But more power by itself won't satisfy the constraints...
>
>
The original remark said "To carry more weight at the same speed and
altitude takes more power" -- which you have now taken the time to
substantiate with more detail. It never said it was the only factor,
and didn't need to, to rebut the earlier claim. I do not understand how
you arrive at it not being true. Frankly, I would expect any one
engaged in building or flying an airplane to understand those
relationships, and based on the FAA's published pilot exam questions and
other materials, it seems they agree.

Charles

[Charles Vincent]

wrote:
> In rec.aviation.piloting cavelamb himself > wrote:
>> wrote:
>>>> To carry more weight at the same speed and altitude takes more power, so
>>>> you have to account for the energy expended kiting you deadweight
>>>> electric takeoff system around the sky as well. Sizing an engine for
>>>> cruise has been done, if only backwards. Think JATO. Most JATO's are
>>>> actually RATO (rocket assisted takeoff). I expect RATO would beat an
>>>> electric system based on energy density and the fact that when it is
>>>> done you have reduced your weight by the fuel. I also suspect for a
>>>> given amount of thrust the rocket will be lighter than an electric motor
>>>> and associated clutches and gearing. In my opinion, at this point in
>>>> time it is just as practical for a homebuilt as well as in not.
>>>
>>> Well, that's true enough, but the above was about hybrid cars.
>>>
>
>
>> No, it's not true enough.
>
>> To carry more weight at the same speed and altitude requires more LIFT.
>
>> A higher CL - and/or more wing area.
>
>> THEN, to overcome the increased drag, THEN you need more power.
>
>> But more power by itself won't satisfy the constraints...
>
> So if I add 1 pound to a 2400 pound gross aircraft loaded to 2300 pounds,
> it would be impossible to cruise at the same speed and altitude without
> the 1 pound unless I added wing area?
>
> How about 50 pounds?
>

No. You can increase the angle of attack, which increases the lift ( to
a limit) and also increases the drag, which must be overcome with more
power. If your speed drops, so does the lift. If you could increase
your aspect ratio, you could get more lift at the same speed at the same
power I think. So I guess Richard is flying a swing wing texas
parasol.;') For the rest of us, we have to add power to carry more
weight at the same speed and altitude. Since most planes lose weight
while in flight in the real world, you actually have the opposite issue.

Charles

[Morgans[_2_]]

> wrote

> Unless the added weight is enough to deform the tires, the increase
> in rolling resistance in the total energy expediture can't be found.

Bull hockey.

Just because it is not noticeable, or measurable by the lack of sensitivity
with the instrument you are currently not using, does not mean that it does
not exist.

More weight on the bearings will cause more rolling resistance. That is
fact, not open to dispute. If you say it is, I want to buy the rights to
the bearings you are using, so I can patent them and make a fortune.
--
Jim in NC

[[email protected]]

In rec.aviation.piloting Charles Vincent > wrote:
> wrote:
> > In rec.aviation.piloting cavelamb himself > wrote:
> >> wrote:
> >>>> To carry more weight at the same speed and altitude takes more power, so
> >>>> you have to account for the energy expended kiting you deadweight
> >>>> electric takeoff system around the sky as well. Sizing an engine for
> >>>> cruise has been done, if only backwards. Think JATO. Most JATO's are
> >>>> actually RATO (rocket assisted takeoff). I expect RATO would beat an
> >>>> electric system based on energy density and the fact that when it is
> >>>> done you have reduced your weight by the fuel. I also suspect for a
> >>>> given amount of thrust the rocket will be lighter than an electric motor
> >>>> and associated clutches and gearing. In my opinion, at this point in
> >>>> time it is just as practical for a homebuilt as well as in not.
> >>>
> >>> Well, that's true enough, but the above was about hybrid cars.
> >>>
> >
> >
> >> No, it's not true enough.
> >
> >> To carry more weight at the same speed and altitude requires more LIFT.
> >
> >> A higher CL - and/or more wing area.
> >
> >> THEN, to overcome the increased drag, THEN you need more power.
> >
> >> But more power by itself won't satisfy the constraints...
> >
> > So if I add 1 pound to a 2400 pound gross aircraft loaded to 2300 pounds,
> > it would be impossible to cruise at the same speed and altitude without
> > the 1 pound unless I added wing area?
> >
> > How about 50 pounds?
> >

> No. You can increase the angle of attack, which increases the lift ( to
> a limit) and also increases the drag, which must be overcome with more
> power. If your speed drops, so does the lift. If you could increase
> your aspect ratio, you could get more lift at the same speed at the same
> power I think. So I guess Richard is flying a swing wing texas
> parasol.;') For the rest of us, we have to add power to carry more
> weight at the same speed and altitude. Since most planes lose weight
> while in flight in the real world, you actually have the opposite issue.


Gee, you mean all I gotta do is tweek the trim and throttle a bit?

Who'd have guessed it? :-)


--
Jim Pennino

Remove .spam.sux to reply.

[Phil]

On Aug 15, 8:18 am, Larry Dighera > wrote:
> On Wed, 15 Aug 2007 12:23:00 GMT, CanalBuilder
> > wrote in
> >:
>
> >How much of a fire hazard would a paper battery be?
>
> >http://www.energy-daily.com/reports/Beyond_Batteries_Storing_Power_In...
>
> That is an interesting device indeed. Given these quotes from the
> article:
>
> Rensselaer researchers infused this paper with aligned carbon
> nanotubes, which give the device its black color. The nanotubes
> act as electrodes and allow the storage devices to conduct
> electricity. The device, engineered to function as both a
> lithium-ion battery and a supercapacitor, can provide the long,
> steady power output comparable to a conventional battery, as well
> as a supercapacitor's quick burst of high energy. ...
>
> Along with use in small handheld electronics, the paper batteries'
> light weight could make them ideal for use in automobiles,
> aircraft, and even boats. The paper also could be molded into
> different shapes, such as a car door, which would enable important
> new engineering innovations.
>

IF these can be made practical, they sound ideal for use in an
airplane. They are light, and they can be shaped in just about any
way to fit inside the airframe. Suppose they were integrated into the
airframe and wings such that a large percentage of the airplane
consisted of battery. It might be possible to get enough capacity
there for a practical general aviation electric plane.

[cavelamb himself[_4_]]

Charles Vincent wrote:

> No. You can increase the angle of attack, which increases the lift ( to
> a limit) and also increases the drag, which must be overcome with more
> power. If your speed drops, so does the lift. If you could increase
> your aspect ratio, you could get more lift at the same speed at the same
> power I think. So I guess Richard is flying a swing wing texas
> parasol.;') For the rest of us, we have to add power to carry more
> weight at the same speed and altitude. Since most planes lose weight
> while in flight in the real world, you actually have the opposite issue.
>
> Charles


Don't be snotty, Charles.


Since the subject is an electrically powered aircraft, the weight issue
is not trivial. That's been my issue with this thread from the start.

The constraints given here were to fly at the same speed and altitude
but at a higher weright.

You can increase lift via increased angle of attack only as far as
CLmax. No Farther. (You seem to have that part right)

Beyond that any increased weight will require increased wing area.

Aspect ratio alone won't answer is most cases.

And - an electric powered plane would NOT lose weight in flight.

No electrons are "consumed" - no change in battery weight.

[Morgans[_2_]]

"Phil" > wrote
>
> IF these can be made practical, they sound ideal for use in an
> airplane. They are light, and they can be shaped in just about any
> way to fit inside the airframe. Suppose they were integrated into the
> airframe and wings such that a large percentage of the airplane
> consisted of battery. It might be possible to get enough capacity
> there for a practical general aviation electric plane.
>
I can see the headlines, now.

Plane (or car) crashes, and the car's structure electrocutes the occupants.
<g>
--
Jim in NC

[Larry Dighera]

On Fri, 17 Aug 2007 11:28:06 -0700, Phil > wrote
in . com>:

>It might be possible to get enough capacity
>there for a practical general aviation electric plane.

It might indeed. But I'd have to know more about the paper battery
specifications before I could render any sort of judgment. I guess
we'll have to wait until more information is disclosed. Let's see
.....



http://www.eetimes.com/news/semi/rss/showArticle.jhtml?articleID=201800045&cid=RSSfeed_eetimes_semiRSS

Paper battery is rechargeable

R. Colin Johnson
EE Times
(08/14/2007 9:42 AM EDT)

PORTLAND, Ore. — Rensselaer Polytechnic Institute researchers
said they have developed a paper-thin battery by immersing a
carpet of vertical nanotubes in an ionic liquid electrolyte. The
result is a cellulose paper that stores electrical energy.

The RPI team produced a supercapacitor by placing a second
nanotube electrode on the other side of the paper. They then added
a lithium electrode atop the paper, creating what they claim is a
paper-thin rechargeable battery.

"The carbon nanotubes are embedded in the paper, and the
electrolyte is soaked into the paper, so it really looks, feels
and weighs about the same as paper," said RPI professor Robert
Linhardt.

The supercapcitor and rechargeable battery are the result of a
year and half of collaborative research among three RPI labs. One
lab was making carbon nanotube-based structures, which were
adapted to serve as a battery electrode. By growing the nanotubes
vertically on a sheet, liquid cellulose was poured between the
"forest of nanotubes" to form the battery. Another lab added a
lithium-based top electrode to create either a rechargeable
battery
or a supercapacitor by adding a second nanotube electrode.

Ionic liquids first dissolved the cellulose, turning it into a
gel.
The fluids also serve as the battery electrolyte, carrying ions
from one side of the paper battery to the other.

Each sheet of battery-paper generated about 2.4 volts with a power
density of about 0.6 milliamps/cm2. For higher voltages, paper can
be stacked. For more current, the sheets can be expanded to larger
areas. The battery-paper operates from minus 100 degrees up to 300
degrees Fahrenheit, and can deliver quick surges of current, the
RPI researchers claim. It can also be rolled twisted or cut into
many shapes.

So far, the RPI researchers have only cycled their paper batteries
through 100 rechargings. But they claim no deterioration in
performance has been detected after recharging. Next, they plan
long-term testing of the batteries to determine the maximum number
of rechargings, and to optimize the design for higher power
densities. ...



http://www.uberreview.com/2007/08/flexible-battery-developed-by-rensselaer-polytechnic-institute.htm
It does not function better than existing batteries on the market
and at present it is extremely expensive to produce.


http://news.rpi.edu/update.do?artcenterkey=2280
Contact: Michael Mullaney
Phone: (518) 276-6161
E-mail:

“We’re not putting pieces together – it’s a single, integrated
device,” he said. “The components are molecularly attached to each
other: the carbon nanotube print is embedded in the paper, and the
electrolyte is soaked into the paper. The end result is a device
that looks, feels, and weighs the same as paper.”




Can someone make the necessary conversions to compare the power
density of about 0.6 milliamps/cm2 for the paper battery to secondary
lithium-ion Polymer batteries at 130 - 1200 Wh/kg*?



* http://xtronics.com/reference/energy_density.htm

[Larry Dighera]

The original paper battery article is available on-line:

http://www.pnas.org/cgi/content/abstract/0706508104v1?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=paper+battery&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT
Proceedings of the National Academy of Sciences of the United States
of America

Published online before print August 15, 2007
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0706508104


This Article

Full Text (PDF)
Articles by Pushparaj, V. L.
Articles by Ajayan, P. M.


Engineering
Flexible energy storage devices based on nanocomposite paper

To whom correspondence should be addressed.

Pulickel M. Ajayan, E-mail:

[cavelamb himself[_4_]]

Morgans wrote:
> "Phil" > wrote
>
>>IF these can be made practical, they sound ideal for use in an
>>airplane. They are light, and they can be shaped in just about any
>>way to fit inside the airframe. Suppose they were integrated into the
>>airframe and wings such that a large percentage of the airplane
>>consisted of battery. It might be possible to get enough capacity
>>there for a practical general aviation electric plane.
>>
>
> I can see the headlines, now.
>
> Plane (or car) crashes, and the car's structure electrocutes the occupants.
> <g>

LOL!

These paper batterise are light because they are so small.

By the time they make a battery will a few megawatts capacity, it's NOT
going to be all that light.

Lighter than Lead/Acid? Probably.

But light enough to fly? It might be a while...

[Charles Vincent]

cavelamb himself wrote:


> Don't be snotty, Charles.
>
>
> Since the subject is an electrically powered aircraft, the weight issue
> is not trivial. That's been my issue with this thread from the start.
>
> The constraints given here were to fly at the same speed and altitude
> but at a higher weright.
>
> You can increase lift via increased angle of attack only as far as
> CLmax. No Farther. (You seem to have that part right)
>
> Beyond that any increased weight will require increased wing area.
>
> Aspect ratio alone won't answer is most cases.
>
> And - an electric powered plane would NOT lose weight in flight.
>
> No electrons are "consumed" - no change in battery weight.
>
>

Not really being snotty at all. Frankly, I was in the process of
deleting screenfulls of messages on the topic of electric powered
airplanes being as the subject really holds no interest for me. For
some reason I happened to read "The advantage from the electric engine
at cruise is that it uses zero energy" on one message just as I deleted
it. Pulling it back from the trash, I felt compelled to respond to it.
My mistake. For some reason you are in turn compelled to nit pick my
correct assertion because it did not completely cover the relevant
aerodynamic theory. In my opinion, it covered enough, but not following
the thread, I have no idea what sort of debate has been raging. As I
stated elsewhere, I just didn't expect that information required for
even the most basic pilot ticket would be the subject of any debate
here. In the end, to fly at the same speed and altitude but at a higher
weight requires more power be applied, whether you use that power to
drag the same wing at a higher angle of attack or a bigger wing doesn't
change that. Or you could use more power to drag the wing at a higher
speed to generate the lift you needed. All of this ignores the fact
that for internal combustion aircraft powerplants, the weight per HP
goes down as the power goes up. Last time I looked at it, the opposite
is true of electric motors. I don't think an electric assist for an IC
engine is going to be viable for aircraft in the near future.


Charles

[cavelamb himself[_4_]]

Charles Vincent wrote:

> cavelamb himself wrote:
>
>
>> Don't be snotty, Charles.
>>
>>
>> Since the subject is an electrically powered aircraft, the weight issue
>> is not trivial. That's been my issue with this thread from the start.
>>
>> The constraints given here were to fly at the same speed and altitude
>> but at a higher weright.
>>
>> You can increase lift via increased angle of attack only as far as
>> CLmax. No Farther. (You seem to have that part right)
>>
>> Beyond that any increased weight will require increased wing area.
>>
>> Aspect ratio alone won't answer is most cases.
>>
>> And - an electric powered plane would NOT lose weight in flight.
>>
>> No electrons are "consumed" - no change in battery weight.
>>
>>
>
> Not really being snotty at all. Frankly, I was in the process of
> deleting screenfulls of messages on the topic of electric powered
> airplanes being as the subject really holds no interest for me. For
> some reason I happened to read "The advantage from the electric engine
> at cruise is that it uses zero energy" on one message just as I deleted
> it. Pulling it back from the trash, I felt compelled to respond to it.
> My mistake. For some reason you are in turn compelled to nit pick my
> correct assertion because it did not completely cover the relevant
> aerodynamic theory. In my opinion, it covered enough, but not following
> the thread, I have no idea what sort of debate has been raging. As I
> stated elsewhere, I just didn't expect that information required for
> even the most basic pilot ticket would be the subject of any debate
> here. In the end, to fly at the same speed and altitude but at a higher
> weight requires more power be applied, whether you use that power to
> drag the same wing at a higher angle of attack or a bigger wing doesn't
> change that. Or you could use more power to drag the wing at a higher
> speed to generate the lift you needed. All of this ignores the fact
> that for internal combustion aircraft powerplants, the weight per HP
> goes down as the power goes up. Last time I looked at it, the opposite
> is true of electric motors. I don't think an electric assist for an IC
> engine is going to be viable for aircraft in the near future.
>
>
> Charles
>

I guess I was just over reacting to the swing wing parasol comment.

And yes, I can see your point.
Higher Cl - or bigger wing. Either will require more power.
Which was my point as well.

Yep. A lot of this thread has been - well - fanciful?


Richard

[[email protected]]

In rec.aviation.piloting Charles Vincent > wrote:
> cavelamb himself wrote:


> Not really being snotty at all. Frankly, I was in the process of
> deleting screenfulls of messages on the topic of electric powered
> airplanes being as the subject really holds no interest for me. For
> some reason I happened to read "The advantage from the electric engine
> at cruise is that it uses zero energy" on one message just as I deleted
> it. Pulling it back from the trash, I felt compelled to respond to it.

Have either of you guys heard of the term "thread drift"?

Both of you are responding to the part of the thread that drifted off
to the topic of hybrid CARS and how they get good mileage.

--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Morgans > wrote:

> > wrote

> > Unless the added weight is enough to deform the tires, the increase
> > in rolling resistance in the total energy expediture can't be found.

> Bull hockey.

> Just because it is not noticeable, or measurable by the lack of sensitivity
> with the instrument you are currently not using, does not mean that it does
> not exist.

Perhaps you would like a rephrase:

Unless the added weight is enough to deform the tires, the increase
in rolling resistance compared to the total system energy expediture
is so small that it is negligible.

Or how about:

Unless the added weight is enough to deform the tires, the increase
in rolling resistance compared to the total system energy expediture
has about the same effect as ****ing in Lake Tahoe.

--
Jim Pennino

Remove .spam.sux to reply.

[Charles Vincent]

wrote:
> In rec.aviation.piloting Charles Vincent > wrote:
>> cavelamb himself wrote:
>
>
>> Not really being snotty at all. Frankly, I was in the process of
>> deleting screenfulls of messages on the topic of electric powered
>> airplanes being as the subject really holds no interest for me. For
>> some reason I happened to read "The advantage from the electric engine
>> at cruise is that it uses zero energy" on one message just as I deleted
>> it. Pulling it back from the trash, I felt compelled to respond to it.
>
> Have either of you guys heard of the term "thread drift"?
>
> Both of you are responding to the part of the thread that drifted off
> to the topic of hybrid CARS and how they get good mileage.
>

Fair enough.

Charles

[Charles Vincent]

Morgans wrote:
> > wrote
>
>> Unless the added weight is enough to deform the tires, the increase
>> in rolling resistance in the total energy expediture can't be found.
>
> Bull hockey.
>
> Just because it is not noticeable, or measurable by the lack of sensitivity
> with the instrument you are currently not using, does not mean that it does
> not exist.
>
> More weight on the bearings will cause more rolling resistance. That is
> fact, not open to dispute. If you say it is, I want to buy the rights to
> the bearings you are using, so I can patent them and make a fortune.

If a bird craps on your windshield, it is more likely to noticeably
influence your aerodynamic drag than rolling resistance.....I took Jim's
"can't be found" to mean lost in the noise. According to SAE studies,
aerodynamic drag accounts for 60% of the resistance that must be
overcome for highway cruise, with tires being 25% and driveline friction
making up the last 15%.

I suspect an electric motor and associated batteries however, are going
to deform the tires. The power companies that I work with are doing
studies on a number of electric vehicles. I have been told that they
run some interesting tires and pressures.

Charles

[cavelamb himself[_4_]]

wrote:
> In rec.aviation.piloting Charles Vincent > wrote:
>
>>cavelamb himself wrote:
>
>
>
>>Not really being snotty at all. Frankly, I was in the process of
>>deleting screenfulls of messages on the topic of electric powered
>>airplanes being as the subject really holds no interest for me. For
>>some reason I happened to read "The advantage from the electric engine
>>at cruise is that it uses zero energy" on one message just as I deleted
>>it. Pulling it back from the trash, I felt compelled to respond to it.
>
>
> Have either of you guys heard of the term "thread drift"?
>
> Both of you are responding to the part of the thread that drifted off
> to the topic of hybrid CARS and how they get good mileage.
>

Look again, Jim.

It seems to have drifted back on thread.

[[email protected]]

In rec.aviation.piloting cavelamb himself > wrote:
> wrote:
> > In rec.aviation.piloting Charles Vincent > wrote:
> >
> >>cavelamb himself wrote:
> >
> >
> >
> >>Not really being snotty at all. Frankly, I was in the process of
> >>deleting screenfulls of messages on the topic of electric powered
> >>airplanes being as the subject really holds no interest for me. For
> >>some reason I happened to read "The advantage from the electric engine
> >>at cruise is that it uses zero energy" on one message just as I deleted
> >>it. Pulling it back from the trash, I felt compelled to respond to it.
> >
> >
> > Have either of you guys heard of the term "thread drift"?
> >
> > Both of you are responding to the part of the thread that drifted off
> > to the topic of hybrid CARS and how they get good mileage.
> >

> Look again, Jim.

> It seems to have drifted back on thread.

This is probably a historic moment.

Normally what happens when thread drift begins is that it increases
at an increasing rate such that what was originally zepplin aerodynamics
becomes the best recipe for strawberry preserves...

--
Jim Pennino

Remove .spam.sux to reply.

[Dan Luke[_2_]]

"Charles Vincent" wrote:

>> Just because it is not noticeable, or measurable by the lack of sensitivity
>> with the instrument you are currently not using, does not mean that it does
>> not exist.
>>
>> More weight on the bearings will cause more rolling resistance. That is
>> fact, not open to dispute. If you say it is, I want to buy the rights to
>> the bearings you are using, so I can patent them and make a fortune.
>
> If a bird craps on your windshield, it is more likely to noticeably
> influence your aerodynamic drag than rolling resistance.....I took Jim's
> "can't be found" to mean lost in the noise. According to SAE studies,
> aerodynamic drag accounts for 60% of the resistance that must be overcome
> for highway cruise, with tires being 25% and driveline friction making up
> the last 15%.

Pardon the intrusion on this interesting discussion, but just how *does* added
weight in a car impose extra load on the powerplant besides via bearing
friction and tire deformation?

Added weight means the powerplant is doing more work to maintain the same
speed; there's no way around it, the laws of physics demand it. So where's
the extra power going?

--
Dan
T-182T at BFM

[cavelamb himself[_4_]]

Dan Luke wrote:

> "Charles Vincent" wrote:
>
>
>>>Just because it is not noticeable, or measurable by the lack of sensitivity
>>>with the instrument you are currently not using, does not mean that it does
>>>not exist.
>>>
>>>More weight on the bearings will cause more rolling resistance. That is
>>>fact, not open to dispute. If you say it is, I want to buy the rights to
>>>the bearings you are using, so I can patent them and make a fortune.
>>
>>If a bird craps on your windshield, it is more likely to noticeably
>>influence your aerodynamic drag than rolling resistance.....I took Jim's
>>"can't be found" to mean lost in the noise. According to SAE studies,
>>aerodynamic drag accounts for 60% of the resistance that must be overcome
>>for highway cruise, with tires being 25% and driveline friction making up
>>the last 15%.
>
>
> Pardon the intrusion on this interesting discussion, but just how *does* added
> weight in a car impose extra load on the powerplant besides via bearing
> friction and tire deformation?
>
> Added weight means the powerplant is doing more work to maintain the same
> speed; there's no way around it, the laws of physics demand it. So where's
> the extra power going?
>

To accellerate...

[Phil]

On Aug 17, 2:19 pm, "Morgans" > wrote:
> "Phil" > wrote
>
> > IF these can be made practical, they sound ideal for use in an
> > airplane. They are light, and they can be shaped in just about any
> > way to fit inside the airframe. Suppose they were integrated into the
> > airframe and wings such that a large percentage of the airplane
> > consisted of battery. It might be possible to get enough capacity
> > there for a practical general aviation electric plane.
>
> I can see the headlines, now.
>
> Plane (or car) crashes, and the car's structure electrocutes the occupants.
> <g>
> --
> Jim in NC

I know you're only half serious, but yes, that would have to be
considered. That's a risk in hybrid autos as well. EMTs and
firefighters are taking special training to handle the wrecks of these
cars. And the gasoline we use for our current airplanes poses the
risk of incinerating the occupants in a crash. I am not sure that an
electric plane would actually pose more risk. I would think that the
increased reliability of the propulsion system would decrease the risk
overall. How many people are killed every year in crashes caused by
engine failures?

[Matt Whiting]

Dan Luke wrote:
> "Charles Vincent" wrote:
>
>>> Just because it is not noticeable, or measurable by the lack of sensitivity
>>> with the instrument you are currently not using, does not mean that it does
>>> not exist.
>>>
>>> More weight on the bearings will cause more rolling resistance. That is
>>> fact, not open to dispute. If you say it is, I want to buy the rights to
>>> the bearings you are using, so I can patent them and make a fortune.
>> If a bird craps on your windshield, it is more likely to noticeably
>> influence your aerodynamic drag than rolling resistance.....I took Jim's
>> "can't be found" to mean lost in the noise. According to SAE studies,
>> aerodynamic drag accounts for 60% of the resistance that must be overcome
>> for highway cruise, with tires being 25% and driveline friction making up
>> the last 15%.
>
> Pardon the intrusion on this interesting discussion, but just how *does* added
> weight in a car impose extra load on the powerplant besides via bearing
> friction and tire deformation?
>
> Added weight means the powerplant is doing more work to maintain the same
> speed; there's no way around it, the laws of physics demand it. So where's
> the extra power going?
>

Heating the brakes. :-)

Matt

[[email protected]]

In rec.aviation.piloting Dan Luke > wrote:

> "Charles Vincent" wrote:

> >> Just because it is not noticeable, or measurable by the lack of sensitivity
> >> with the instrument you are currently not using, does not mean that it does
> >> not exist.
> >>
> >> More weight on the bearings will cause more rolling resistance. That is
> >> fact, not open to dispute. If you say it is, I want to buy the rights to
> >> the bearings you are using, so I can patent them and make a fortune.
> >
> > If a bird craps on your windshield, it is more likely to noticeably
> > influence your aerodynamic drag than rolling resistance.....I took Jim's
> > "can't be found" to mean lost in the noise. According to SAE studies,
> > aerodynamic drag accounts for 60% of the resistance that must be overcome
> > for highway cruise, with tires being 25% and driveline friction making up
> > the last 15%.

> Pardon the intrusion on this interesting discussion, but just how *does* added
> weight in a car impose extra load on the powerplant besides via bearing
> friction and tire deformation?

It takes more power to accelerate the car to cruise speed in a given time.

F=ma

> Added weight means the powerplant is doing more work to maintain the same
> speed; there's no way around it, the laws of physics demand it. So where's
> the extra power going?

Ummm, no, quite the opposite.

The laws of physics say once an object is in motion it takes no energy
to maintain the velocity UNLESS there is some other force at work
that would cause the velocity to decrease.

Since at a constant speed, the a in F=ma is zero, the force is zero
no matter the mass.

Once at speed in a car (or airplane or rocket ship) the only energy
needed to maintain speed is that equal to any drag forces that
would otherwise slow the car down.

Have you looked at the current crop of high mileage cars?

They all have very aerodynamic profiles to get the air drag down.

--
Jim Pennino

Remove .spam.sux to reply.

[Ernest Christley]

wrote:

> The laws of physics say once an object is in motion it takes no energy
> to maintain the velocity UNLESS there is some other force at work
> that would cause the velocity to decrease.
>
> Since at a constant speed, the a in F=ma is zero, the force is zero
> no matter the mass.
>
> Once at speed in a car (or airplane or rocket ship) the only energy
> needed to maintain speed is that equal to any drag forces that
> would otherwise slow the car down.
>
> Have you looked at the current crop of high mileage cars?
>
> They all have very aerodynamic profiles to get the air drag down.
>

They also have very narrow, hard tires. Unfortunately, the DOT has laws
against solid rubber tires or they could be made even harder.

Your analysis would be mostly correct if we were talking about trains.
I've stood beside a loaded one and watched it deform the tracks. A car
on the road is like a machine rolling across a mattress. Extra weight
pushes the tire down into the mattress and increases the drag. The
energy is going into deforming the tires and heating them. Ask any over
the road trucker what happens when you're hauling 40-tons and you don't
keep your tire pressure up. Tends to light up the night.

[[email protected]]

In rec.aviation.piloting Ernest Christley > wrote:
> wrote:

> > The laws of physics say once an object is in motion it takes no energy
> > to maintain the velocity UNLESS there is some other force at work
> > that would cause the velocity to decrease.
> >
> > Since at a constant speed, the a in F=ma is zero, the force is zero
> > no matter the mass.
> >
> > Once at speed in a car (or airplane or rocket ship) the only energy
> > needed to maintain speed is that equal to any drag forces that
> > would otherwise slow the car down.
> >
> > Have you looked at the current crop of high mileage cars?
> >
> > They all have very aerodynamic profiles to get the air drag down.
> >

> They also have very narrow, hard tires. Unfortunately, the DOT has laws
> against solid rubber tires or they could be made even harder.

> Your analysis would be mostly correct if we were talking about trains.

My analysis of what?

The biggest source of drag on a car is air followed by tires.

Of course the makers are going to put hard tires on as well as
streamline the vehicle to get mileage up.

The less drag, the less gas the vehicle uses.

What's your point?

--
Jim Pennino

Remove .spam.sux to reply.

[Charles Vincent]

wrote:

>
> The biggest source of drag on a car is air followed by tires.
>
> Of course the makers are going to put hard tires on as well as
> streamline the vehicle to get mileage up.
>
> The less drag, the less gas the vehicle uses.
>
> What's your point?
>

That is only true in cruise on the highway. In stop and go city driving
driveline friction is the majority, followed by inertia. Air and tire
is a small percentage combined.

Charles

[[email protected]]

In rec.aviation.piloting Charles Vincent > wrote:
> wrote:

> >
> > The biggest source of drag on a car is air followed by tires.
> >
> > Of course the makers are going to put hard tires on as well as
> > streamline the vehicle to get mileage up.
> >
> > The less drag, the less gas the vehicle uses.
> >
> > What's your point?
> >

> That is only true in cruise on the highway. In stop and go city driving
> driveline friction is the majority, followed by inertia. Air and tire
> is a small percentage combined.

Inertia is not drag.

Inertia is F=ma.

In stop and go driving, F=ma dominates.

If it didn't, hybrids converting the F in deceleration into energy in
the batteries instead of heat in the brakes wouldn't get their high
mileage numbers.


--
Jim Pennino

Remove .spam.sux to reply.

[Morgans[_2_]]

"Phil" <> wrote

> I know you're only half serious,

Yep, only half, until you really start to think about it.

> but yes, that would have to be
> considered. That's a risk in hybrid autos as well. EMTs and
> firefighters are taking special training to handle the wrecks of these
> cars. And the gasoline we use for our current airplanes poses the
> risk of incinerating the occupants in a crash. I am not sure that an
> electric plane would actually pose more risk.

I think there is a higher risk, perhaps by many times.

Ever seen a LiPo Battery have a catestrophic failure? One of the primary
ways a LiPo can be caused to fail in that way is physical damage. Ask the
electric RC guys. Most of them would never think of putting even a slightly
physically damaged LiPo back into service, unless it was a really cheap
plane that they wanted to see destroyed.

Now imagine a battery many thousands (or even a few hundred) times larger,
and larger capacity to match.

I'll take my chances with the gasoline fire, thanks, ANY day. That speaks
nothing of the chance of electrocution, or chemical burns or injury due to
the cell's chemestry.

> I would think that the
> increased reliability of the propulsion system would decrease the risk
> overall. How many people are killed every year in crashes caused by
> engine failures?

How much more reliable is an electric of that size ( to run a decent sized
airplane with decent performance) and power going to be, especially if it is
designed with lightness as a major design consideration? That remains yet
to be seen.

OK, even if we give the electric a given reliability superiority, that is
not going to save all that many lives. Most power failures in I.C. powered
airplanes are not that big of deal, and many times never even reported. Far
more die due to stupid pilot tricks (a broad spectrum category to lump a
bunch of other things together) than loss of power.

Nope, lots of problems to consider before we start considering an electric
aircraft. Lots more than we can maybe even consider, at the moment, even if
we were to figure out a way to make a practical airplane electric powered,
don't you think?
--
Jim in NC

[Charles Vincent]

wrote:
> In rec.aviation.piloting Charles Vincent > wrote:
>> wrote:
>
>>> The biggest source of drag on a car is air followed by tires.
>>>
>>> Of course the makers are going to put hard tires on as well as
>>> streamline the vehicle to get mileage up.
>>>
>>> The less drag, the less gas the vehicle uses.
>>>
>>> What's your point?
>>>
>
>> That is only true in cruise on the highway. In stop and go city driving
>> driveline friction is the majority, followed by inertia. Air and tire
>> is a small percentage combined.
>
> Inertia is not drag.
>
> Inertia is F=ma.
>
> In stop and go driving, F=ma dominates.
>
> If it didn't, hybrids converting the F in deceleration into energy in
> the batteries instead of heat in the brakes wouldn't get their high
> mileage numbers.
>
>
Yes Jim, I knew the difference, and I see you know too. I had assumed
you also knew the difference between aerodynamic drag and rolling
friction when you lumped then together in your statement "The biggest
source of drag on a car is air followed by tires." I figured you were
using drag in a more generalized way rather than jumping to the
conclusion you just didn't know the difference. Since you are insisting
on being pedantic, then I will have to point out that inertia is really
just the m in F=ma, the formula just establishes a relationship between
the property of mass called inertia and force and acceleration. I
expect that the manufacturers are working to reduce all of the
"retarding" forces on their vehicles, which benefit them without regard
to the motive source. Electric vehicles can have an advantage in the
regime where inertia is the dominate "retarding" force and a
disadvantage where it is not.

Charles

[Ernest Christley]

wrote:
> In rec.aviation.piloting Ernest Christley > wrote:
>> wrote:
>
>>> The laws of physics say once an object is in motion it takes no energy
>>> to maintain the velocity UNLESS there is some other force at work
>>> that would cause the velocity to decrease.
>>>
>>> Since at a constant speed, the a in F=ma is zero, the force is zero
>>> no matter the mass.
>>>
>>> Once at speed in a car (or airplane or rocket ship) the only energy
>>> needed to maintain speed is that equal to any drag forces that
>>> would otherwise slow the car down.
>>>
>>> Have you looked at the current crop of high mileage cars?
>>>
>>> They all have very aerodynamic profiles to get the air drag down.
>>>
>
>> They also have very narrow, hard tires. Unfortunately, the DOT has laws
>> against solid rubber tires or they could be made even harder.
>
>> Your analysis would be mostly correct if we were talking about trains.
>
> My analysis of what?
>
> The biggest source of drag on a car is air followed by tires.
>
> Of course the makers are going to put hard tires on as well as
> streamline the vehicle to get mileage up.
>
> The less drag, the less gas the vehicle uses.
>
> What's your point?
>

The point is that weight matters...even in land-locked vehicles.

[[email protected]]

In rec.aviation.piloting Ernest Christley > wrote:
> wrote:
> > In rec.aviation.piloting Ernest Christley > wrote:
> >> wrote:
> >
> >>> The laws of physics say once an object is in motion it takes no energy
> >>> to maintain the velocity UNLESS there is some other force at work
> >>> that would cause the velocity to decrease.
> >>>
> >>> Since at a constant speed, the a in F=ma is zero, the force is zero
> >>> no matter the mass.
> >>>
> >>> Once at speed in a car (or airplane or rocket ship) the only energy
> >>> needed to maintain speed is that equal to any drag forces that
> >>> would otherwise slow the car down.
> >>>
> >>> Have you looked at the current crop of high mileage cars?
> >>>
> >>> They all have very aerodynamic profiles to get the air drag down.
> >>>
> >
> >> They also have very narrow, hard tires. Unfortunately, the DOT has laws
> >> against solid rubber tires or they could be made even harder.
> >
> >> Your analysis would be mostly correct if we were talking about trains.
> >
> > My analysis of what?
> >
> > The biggest source of drag on a car is air followed by tires.
> >
> > Of course the makers are going to put hard tires on as well as
> > streamline the vehicle to get mileage up.
> >
> > The less drag, the less gas the vehicle uses.
> >
> > What's your point?
> >

> The point is that weight matters...even in land-locked vehicles.

In cars, weight matters most in acceleration and doesn't matter in
any significant amount with modern tires in cruise.

--
Jim Pennino

Remove .spam.sux to reply.

[Morgans[_2_]]

<jimp> wrote

> This is probably a historic moment.
>
> Normally what happens when thread drift begins is that it increases
> at an increasing rate such that what was originally zepplin aerodynamics
> becomes the best recipe for strawberry preserves...

LoL !

Thanks, I needed that!
--
Jim in NC

[Morgans[_2_]]

"Dan Luke" <> wrote

> Pardon the intrusion on this interesting discussion, but just how *does*
> added weight in a car impose extra load on the powerplant besides via
> bearing friction and tire deformation?

It isn't. He failed to include bearing resistance (only tire deformation)
in the original assessment of increased rolling resistance.
--
Jim in NC

[Phil]

On Aug 18, 12:24 am, "Morgans" > wrote:

> Nope, lots of problems to consider before we start considering an electric
> aircraft. Lots more than we can maybe even consider, at the moment, even if
> we were to figure out a way to make a practical airplane electric powered,
> don't you think?
> --
> Jim in NC

Oh, definitely. We are nowhere near a practical electric airplane.
But I think the potential is there (no pun intended), and I hope they
keep working on it.

[[email protected]]

In rec.aviation.piloting Morgans > wrote:

> "Dan Luke" <> wrote

> > Pardon the intrusion on this interesting discussion, but just how *does*
> > added weight in a car impose extra load on the powerplant besides via
> > bearing friction and tire deformation?

> It isn't. He failed to include bearing resistance (only tire deformation)
> in the original assessment of increased rolling resistance.

I didn't include it because the increase in wheel bearing friction (the
only bearing friction effected by weight) is negligable in modern
vehicles.

The total bearing friction, i.e. all the bearings in the vehicle is
around 10% of the total drag forces trying to slow a car.

Adding a little weight to a 2000 to 3000 pound car causes an insignificant
change in the wheel bearing friction.


--
Jim Pennino

Remove .spam.sux to reply.

[Montblack]

wrote)
> Normally what happens when thread drift begins is that it increases at an
> increasing rate such that what was originally zepplin aerodynamics becomes
> the best recipe for strawberry preserves...


So you're saying zeppelins should take advantage of jam-jet propulsion
technology?

....when in season, of course


Paul-Mont
Usually needs to snow twice before I get the drift ~~~~

[[email protected]]

On Aug 11, 9:47 pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> ...
> I've already made a cell holder for A123 Systems "A1" cells. That's the
> lithium phosphate nano cathode one used in 36V DeWalt power tools. You can
> buy a couple of new DeWalt 36V power packs for $50 or so on Ebay. Then,
> dismantle the pack to retrieve the individual cells. My pack will be 13.8
> volts and 11AH weighing 3 pounds. It will be the same size as a 7AH 12V SLA
> but weigh less than half as much.

Don't forget to add a brick of lead to the bottom of your
new battery pack, to keep the CG in the right place ;-)
Best Regards, Dave "YO"

[Montblack]

wrote)
> In cars, weight matters most in acceleration and doesn't matter in any
> significant amount with modern tires in cruise.


Speculate please:

1. Two 3,600 lb cars - good tires
2. Traveling 60 mph (no wind)
3. 4cly - 150 hp (Honda Accords)
3. Flat highway in North Dakota
4. Fuel flow meters hooked up to both vehicles

(Honda #1)
Driver ................ 105 lbs
Fuel .................... 15 lbs
TOTAL .............. 120 lbs (1/30th of 3,600 lb car)

(Honda #2)
Driver ................. 300 lbs
Passengers ........ 700 lbs
Luggage ............. 100 lbs
Fuel ................... 100 lbs
TOTAL ............. 1,200 lbs (1/3 of 3,600 lb car) ....BTW, BTDT! <g>

If both vehicles were monitored for 50 miles, would their fuel flow be
(approx) the same, in cruise?


Paul-Mont

[Montblack]

("Charles Vincent" wrote)
> According to SAE studies, aerodynamic drag accounts for 60% of the
> resistance that must be overcome for highway cruise, with tires being 25%
> and driveline friction making up the last 15%.


Semi:
Tires ........... 18
Footprint ..... big per tire
Weight ....... 80,000 lbs
Drag .......... HUGE!!
MPG .......... 5 (loaded)

Minivan:
Tires ........... 4
Footprint ..... smaller per tire
Weight ....... 4,000 lbs (for easy math)
Drag .......... MUCH less + no cab/trailer drag
MPG .......... 22

I've never really understood why an 800 lb motorcycle/rider gets (only) 50
mpg and a fully loaded semi can get (about) 5 mpg?

Motorcycle:
Tires ........... 2
Footprint ..... very small per tire
Weight ....... 800 lbs (with rider)
Drag .......... It's a motorcycle! <g>
MPG ........... 50


Paul-Mont

[Matt Whiting]

Montblack wrote:
> ("Charles Vincent" wrote)
>> According to SAE studies, aerodynamic drag accounts for 60% of the
>> resistance that must be overcome for highway cruise, with tires being 25%
>> and driveline friction making up the last 15%.
>
>
> Semi:
> Tires ........... 18
> Footprint ..... big per tire
> Weight ....... 80,000 lbs
> Drag .......... HUGE!!
> MPG .......... 5 (loaded)
>
> Minivan:
> Tires ........... 4
> Footprint ..... smaller per tire
> Weight ....... 4,000 lbs (for easy math)
> Drag .......... MUCH less + no cab/trailer drag
> MPG .......... 22
>
> I've never really understood why an 800 lb motorcycle/rider gets (only) 50
> mpg and a fully loaded semi can get (about) 5 mpg?
>
> Motorcycle:
> Tires ........... 2
> Footprint ..... very small per tire
> Weight ....... 800 lbs (with rider)
> Drag .......... It's a motorcycle! <g>
> MPG ........... 50

Motorcycles have a terrible coefficient of drag given their shape and
the shape of the rider. A fully faired bike is much better, but still
much worse than most cars. My K1200LT is one of the better motorcycles
and its Cd is above 0.5 with the windshield fully lowered and I believe
it is closer to 0.6 with the windshield at the highest setting.

So even with the relatively small frontal area as compared to a car
(although not as much smaller as you might think as the bike is taller
than most cars), the drag coefficient is so high that the total drag is
quite high in comparison.

Matt

[Matt Whiting]

Montblack wrote:

> I've never really understood why an 800 lb motorcycle/rider gets (only) 50
> mpg and a fully loaded semi can get (about) 5 mpg?
>
> Motorcycle:
> Tires ........... 2
> Footprint ..... very small per tire
> Weight ....... 800 lbs (with rider)
> Drag .......... It's a motorcycle! <g>
> MPG ........... 50
>
>
> Paul-Mont

Check this: http://www.bgsoflex.com/airdragchart.html

Matt

[Morgans[_2_]]

"Montblack" <> wrote

> So you're saying zeppelins should take advantage of jam-jet propulsion
> technology?

Oh, isn't that a sweet idea?
--
Jim in NC

[[email protected]]

In rec.aviation.piloting Montblack > wrote:
> wrote)
> > In cars, weight matters most in acceleration and doesn't matter in any
> > significant amount with modern tires in cruise.


> Speculate please:

> 1. Two 3,600 lb cars - good tires
> 2. Traveling 60 mph (no wind)
> 3. 4cly - 150 hp (Honda Accords)
> 3. Flat highway in North Dakota
> 4. Fuel flow meters hooked up to both vehicles

> (Honda #1)
> Driver ................ 105 lbs
> Fuel .................... 15 lbs
> TOTAL .............. 120 lbs (1/30th of 3,600 lb car)

> (Honda #2)
> Driver ................. 300 lbs
> Passengers ........ 700 lbs
> Luggage ............. 100 lbs
> Fuel ................... 100 lbs
> TOTAL ............. 1,200 lbs (1/3 of 3,600 lb car) ....BTW, BTDT! <g>

> If both vehicles were monitored for 50 miles, would their fuel flow be
> (approx) the same, in cruise?

A pulled out of my ass, wild assed guess is that since you are
increasing the load by 33%, then yes, you will see a difference,
and at that loading the tires will be visibly deformed.

Now, would you care to calculate the energy required to accelerate
3720 pounds to 60 mph versus accelerating 4800 pounds to 60 mph?

Assume gasoline is 45 megajoules per kilogram and the engine is 38%
efficient.

You may neglect all drag for this calculation and express the energy
in kilograms of gasoline.



--
Jim Pennino

Remove .spam.sux to reply.

[[email protected]]

In rec.aviation.piloting Montblack > wrote:
> ("Charles Vincent" wrote)
> > According to SAE studies, aerodynamic drag accounts for 60% of the
> > resistance that must be overcome for highway cruise, with tires being 25%
> > and driveline friction making up the last 15%.


> Semi:
> Tires ........... 18
> Footprint ..... big per tire
> Weight ....... 80,000 lbs
> Drag .......... HUGE!!
> MPG .......... 5 (loaded)

> Minivan:
> Tires ........... 4
> Footprint ..... smaller per tire
> Weight ....... 4,000 lbs (for easy math)
> Drag .......... MUCH less + no cab/trailer drag
> MPG .......... 22

> I've never really understood why an 800 lb motorcycle/rider gets (only) 50
> mpg and a fully loaded semi can get (about) 5 mpg?

> Motorcycle:
> Tires ........... 2
> Footprint ..... very small per tire
> Weight ....... 800 lbs (with rider)
> Drag .......... It's a motorcycle! <g>
> MPG ........... 50


The coefficient of drag for motorcycles is usually pretty bad unless
they are faired, and it still ain't great.

The power required to overcome drag is 1/2(p*v^3*A*C)

p is the densitity of the fluid
v is the airspeed
A is the area
C is the coefficient of drag


--
Jim Pennino

Remove .spam.sux to reply.

[Matt Whiting]

wrote:

> The coefficient of drag for motorcycles is usually pretty bad unless
> they are faired, and it still ain't great.

Yes.


> The power required to overcome drag is 1/2(p*v^3*A*C)

No. It is v^2 unless they have changed the physics since I was an aero
engineering student back in the 70s.

Matt

[[email protected]]

In rec.aviation.piloting Matt Whiting > wrote:
> wrote:

> > The coefficient of drag for motorcycles is usually pretty bad unless
> > they are faired, and it still ain't great.

> Yes.


> > The power required to overcome drag is 1/2(p*v^3*A*C)

> No. It is v^2 unless they have changed the physics since I was an aero
> engineering student back in the 70s.

Yes.

The drag goes up with the square of velocity, the POWER required to
overcome the drag goes up as the cube.

Force: Fd = 1/2(p*v^2*A*C)

Power: Pd = Fd * v = 1/2(p*v^3*A*C)

--
Jim Pennino

Remove .spam.sux to reply.

[Matt Whiting]

wrote:
> In rec.aviation.piloting Matt Whiting > wrote:
>> wrote:
>
>>> The coefficient of drag for motorcycles is usually pretty bad unless
>>> they are faired, and it still ain't great.
>
>> Yes.
>
>
>>> The power required to overcome drag is 1/2(p*v^3*A*C)
>
>> No. It is v^2 unless they have changed the physics since I was an aero
>> engineering student back in the 70s.
>
> Yes.
>
> The drag goes up with the square of velocity, the POWER required to
> overcome the drag goes up as the cube.
>
> Force: Fd = 1/2(p*v^2*A*C)
>
> Power: Pd = Fd * v = 1/2(p*v^3*A*C)

Ah, yes, I didn't read "power" when I looked at the formula. Sorry
about that.

Matt

[dirigible designer]

On Aug 6, 3:16 pm, brtlmj > wrote:
> > 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;
>
That is why aircraft engines are so powerful and light; they're
depended-on to fight gravity as well as wind resistance.
Which leads us to the case of airships! They float. They don't
have to work to stay at altitude, they just hang there. Their engines
don't have to hold them up.
But, and it's a big but, since they are so big, they have more
wind resistance than airplanes. Since wind resistance is the log, or
cube? of wind speed, their hull-speeds are quite limited and their
engines remain relatively small as a result.
Enter the less-powerful electric motors! Enter solar photo-
voltaic cells! The big surface area of airships are ideal for mounting
solar arrays. And if you have a cloudy day and don't charge your
batteries up to snuff, well, you will not have to go to ground, as in
an airplane, because you are afloat in your element and you drift with
the breeze for awhile.
Words to the wise about the future of flight. High cheers from
Allen the airshipman

[Larry Dighera]

On Sun, 19 Aug 2007 09:53:32 -0700, dirigible designer
> wrote in
om>:

>On Aug 6, 3:16 pm, brtlmj > wrote:

Actually, these are my words from earlier in this message thread. See:
Message-ID: >.

>> > 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;
>>
>That is why aircraft engines are so powerful and light; they're
>depended-on to fight gravity as well as wind resistance.
> Which leads us to the case of airships! They float. They don't
>have to work to stay at altitude, they just hang there. Their engines
>don't have to hold them up.
> But, and it's a big but, since they are so big, they have more
>wind resistance than airplanes. Since wind resistance is the log, or
>cube? of wind speed, their hull-speeds are quite limited and their
>engines remain relatively small as a result.
> Enter the less-powerful electric motors! Enter solar photo-
>voltaic cells! The big surface area of airships are ideal for mounting
>solar arrays. And if you have a cloudy day and don't charge your
>batteries up to snuff, well, you will not have to go to ground, as in
>an airplane, because you are afloat in your element and you drift with
>the breeze for awhile.
> Words to the wise about the future of flight. High cheers from
>Allen the airshipman

Thank you for mentioning electrically powered airships.

Lighter Than Air craft are excellent candidates for electric power as
is evidenced by:


http://en.wikipedia.org/wiki/Airship
In 1883, the first electric-powered flight was made by Gaston
Tissandier who fitted a 1-1/2 horsepower Siemens electric motor to
an airship. The first fully controllable free-flight was made in a
French Army airship, La France, by Charles Renard and Arthur
Constantin Krebs in 1884 . The 170 foot long, 66,000 cubic foot
airship covered 8 km (5 miles) in 23 minutes with the aid of an
8-1/2 horsepower electric motor.




http://missilethreat.com/missiledefensesystems/id.12/system_detail.asp
...
In September 2003, the Missile Defense Agency (MDA) and the North
American Aerospace Defense Command (NORAD) awarded a $40 million
development contract to Lockheed Martin to build the High Altitude
Airship prototype. Lockheed Martin currently manufactures the
Goodyear blimps that can be seen over big sporting events. These
blimps are approximately 200 feet long with a volume of 200,000
cubic feet. By contrast, the HAA prototype will be 500 feet long,
160 feet in diameter, with a volume of 5.2 million cubic feet,
i.e. more than 25 times the size of the average Goodyear blimp.

MDA plans to deploy the HAA at an altitude of 65,000 feet where
the air is one-twentieth the density that it is near the ground.
One of the biggest challenges facing MDA and Lockheed Martin is
how to get the HAA from the ground to its area of deployment,
since the helium gas inside will expand more than fifteen times as
the blimp rises. To solve this problem, the HAA will be filled
mostly with air when it is close to the ground. As it rises, the
air inside the blimp will be forced out and helium from five small
inner balloons will replace it. This “balloon-within-a-balloon”
concept will allow the HAA to maintain its football-like shape
throughout all stages of flight.

Once deployed, the HAA will generate its own power supply from
thin-film photovoltaic solar cells. It will require 10 kilowatts
of electricity to run its 4,000-pound radar system. The prototype
HAA will include batteries to keep the electricity flowing at
night, although the final version will most likely use lightweight
fuel cells. Four electrically powered engines will each drive two
30-foot-wide propellers that will provide the blimp’s forward
thrust. The propellers will allow the HAA to hover within a mile
of its assigned location, thus maintaining its fixed
“geostationary” nature. ...



http://www.aiaa.org/aerospace/images/articleimages/pdf/LTA.pdf
Zeppelin Luftschifftechnik in Germany resorted to a unique method
of delivering its NT-07 airship to a Japanese customer. The
semirigid air-ship was flown to Italy and, fully inflated, was
put on board a BPDockship for the journey to Kobe, Japan. Tail
surfaces and forward engines were removed. Zeppelin is leasing
another NT-07 to the DeBeers diamond company for two years. It
also was delivered by ship, to South Africa. The air-ship will be
equipped to examine geological formations in southern African
countries. Zeppelin carried 11,000 passengers on sightseeing
flights in Germany during 2004. Work is proceeding on the
development of the 19-passenger NT-14. First flight is expected in
early 2008. Zeppelin has acquired the intellectual property of the
defunct CargoLifter organization.

This will become part of an LTAinstitute for coordinating
activities on scientific and predevelopment levels applicable to
all types of airships. It will be headquartered in
Friedrichshafen.

Japan’s Aerospace Exploration Agency completed its series of eight
flights with the above-mentioned 223-ft-long, 370,755-ft,
un-manned research airship. The objective of these flights was to
verify flight control, operation, and tracking technologies from
takeoff to landing. Geostationary flight at 13,000 ft was realized
with the aid of electrically powered propellers. Data obtained
will be applied to JAXA’s further research into high-altitude
airships.

Another approach to this subject, a “bal-loon robot,” was
investigated by Japan’s National Institute of Advanced Industrial
Science and Technology (AIST). A 92-ft-long model carrying a 3-kg
payload was launched to an altitude of 55,700 ft. Power for
propulsion was supplied by batteries. Data transmission failure
prevented verification of station keeping.

AIST has built a 43-ft-long nonrigid propelled by cycloidal
propellers driven by electricity supplied by batteries. This
unmanned airship can be used for aerial observation and
monitoring of hazardous areas.




http://mae.pennnet.com/Articles/Article_Display.cfm?Section=Archives&Subsection=Display&ARTICLE_ID=150899&KEYWORD=blimp
Latest generation of military airships to use solar electric power
by J.R. Wilson

Peterson AFB, Colo. — The North American Aerospace Defense Command
(NORAD) has joined forces with the U.S. Army and other agencies to
develop the 21st-century High Altitude Airship to help defend U.S.
airspace, control its borders, and possibly provide global
surveillance capability to military theater commanders.

"It's an old idea with new technology applied," explains U.S. Navy
Cmdr. Pat Lyons, chief of ISR and NORAD J-5 Directorate. "This
airship is unmanned, untethered, and electric powered. We expect
it to be composed of solar cells, a fuel cell, and electrolyzer
for nighttime operations."

The new airship's command-and-control links most likely will
involve satellite communications channels. All of these
technologies will probably enable the airship to remain on station
for as long as one year, Lyons says.

Electric power
The airship will be electrically powered — possibly using a
hydrogen fuel cell — with DC brushless motors and propellers as
the likely propulsion system, although the final design will be up
to the contractor; Lyons says there are several other possible
concepts for program managers to consider. That includes the
number of motors, which also would determine the number of
propellers.

"The concepts we've seen show speeds up to 100 knots for the
objective airship," Lyons explains. "The winds at 70,000 feet are
fairly benign; you're above the weather and the jet stream, but
occasionally, depending on where you are, they can get up to 100
knots, building for 24 hours, peaking for a day, then diminishing
for a day. With a 100-knot airspeed, the airship can remain
geostationary," Lyons says.

A variety of sensors are being considered for the airship's
Advanced Concept Technology Demonstration (ACTD), including a
small communications relay. In operation, the vehicle could be
used to enable communications 600 or more miles apart, including
over a mountain. Currently, ground troops with handheld
communications must post a relay unit on a water tower or other
tall structure to avoid losing contact in the field. ...

Military & Aerospace Electronics August, 2002
Author(s) : J.R. Wilson

[Montblack]

wrote)
> The coefficient of drag for motorcycles is usually pretty bad unless they
> are faired, and it still ain't great.
> The power required to overcome drag is 1/2(p*v^3*A*C)
>
> p is the densitity of the fluid
> v is the airspeed
> A is the area
> C is the coefficient of drag


80-ft length of the semi
(vs.)
8-ft length of the motorcycle

Does this play (much) of a role here?

Is that role expressed (adequately/sufficiently) in the above formula,
through "C" ...drag?


Paul-Mont
<http://www.totalmotorcycle.com/motorcyclespecshandbook/1MotorcycleManufacturer.htm>
Fun site - make / model / year. My Yamahoppers were both in there.

[[email protected]]

In rec.aviation.piloting Montblack > wrote:
> wrote)
> > The coefficient of drag for motorcycles is usually pretty bad unless they
> > are faired, and it still ain't great.
> > The power required to overcome drag is 1/2(p*v^3*A*C)
> >
> > p is the densitity of the fluid
> > v is the airspeed
> > A is the area
> > C is the coefficient of drag


> 80-ft length of the semi
> (vs.)
> 8-ft length of the motorcycle

> Does this play (much) of a role here?

> Is that role expressed (adequately/sufficiently) in the above formula,
> through "C" ...drag?

The C is the catchall variable that is determinded by the object's
overall shape and for all but the most simple shapes (i.e. flat plate,
sphere, etc.) determined by measurement.

As to what length does specifically, it depends.

Smooth sides are going to be less "draggy" than lumpy sides.

A flat back end is going to be more "draggy" than a tapered back end.


--
Jim Pennino

Remove .spam.sux to reply.

[Robert Bonomi]

In article >,
Montblack > wrote:
wrote)
>> Normally what happens when thread drift begins is that it increases at an
>> increasing rate such that what was originally zepplin aerodynamics becomes
>> the best recipe for strawberry preserves...
>
>
>So you're saying zeppelins should take advantage of jam-jet propulsion
>technology?

*NOT* recommended. Real-world experience has established that jam-jet
combinations are not desirable.

This is a true story. I don't have a cite for it, but this was reported in
the Wall Street Journal at the time; that's where I encountered it.
Time: late 60s, early 70s. Dateline: West Germany, outside a U.S. Air Base
there. A local resident was bothered by the noise of the military jets as
they came low over his house for landings.

Being a reasonable man, he politely asked the the USAF to do something
to reduce the noise levels. He was brushed off. REPEATEDLY. He went
through the entire hierarchy, all the way to the base commander. No luck.

Being a determined man, he decided "this means war". He then purchased a
12th-century catapult which he set up in his back yard.

He then proceeded to launch _cherry_pies_ at the aircraft passing overhead.

After he scored his third *direct*hit* within a period of a few weeks, the
Air Force sued for peace.

Apparently the engine overhaul required after a jet engine ingested a pie
was _very_ expensive.


I can just imagine the maintenance-log entries. And what the bean-counters
back at the five-sided funny-farm had to say upon review.

[Montblack]

("Robert Bonomi" wrote)
> Being a determined man, he decided "this means war". He then purchased a
> 12th-century catapult which he set up in his back yard.
>
> He then proceeded to launch _cherry_pies_ at the aircraft passing
> overhead.
>
> After he scored his third *direct*hit* within a period of a few weeks, the
> Air Force sued for peace.


“I was wondering if you could tell me where the phrase pie in the sky came
from?”

http://www.worldwidewords.org/qa/qa-pie1.htm
Pie in the sky :-)


Paul-Mont