Can Aircraft Be Far Behind?

and every 15 minutes everyone on the aircraft would have to get out and
get back in...
/old IT joke

Gig 601XL Builder wrote:
gatt wrote:

Battery technology is coming down in weight very rapidly. That's
encouraging.


Not really. If battery technology had kept up with computer technology over
the last 20 years you'd be able to power 747 accross the US with a batery
about the size of the one in your cell phone and it would cost about $5.00.

wrote in message
ups.com...
Actually, aircraft (specifically motor gliders) are far ahead!

See: http://www.nadler.com/public/Antares.html


It might take a little while before the power efficiency of batteries
equals the needs of a useful airplane...

Most GA airplanes aren't necessarily "useful." They're just flown around
for the hell of it. Imagine if you could log an hour of training or
practice or do a quick photo sortie without burning fuel.

I'm just disappointed that the Big Ass Rubber Band (tm) technology never got
past the balsa aicraft stage. Must be a big oil conspiracy.

-c

Larry Dighera wrote (rather quoted a comment from wired.com):
http://www.wired.com/news/wiredmag/0...l?tw=rss.index
The Tesla as it stands is obsolete if it doesn't use the new type
batteries from Altair[**]. It will be the laughingstock of the
business world if it delivers its current overly-complicated
battery system, with its computers and sensors and HVAC system.

Larry, just BTW, the Altair Nano batteries this guy is going on
don't pass the sniff test very well...

Tesla isn't using them because Tesla wants to ship cars
sometime this decade.

Altair claims that WRT conventional graphite electrode lithium-ion
batteries, their TiO nano-granule electrode lithium-ion batteries
have 3X the energy density, 60X the max charge rate, and 10X
the charge-cycle lifetime.

If these batteries actually existed in a form that would allow
Tesla to ship 200 cars this year, you would think that every
single cell phone and laptop in the universe would be running
on them, wouldn't you? I mean, *I* want my cell phone charge
to last 2 weeks instead of 5 days, *I* want to be able to charge
my laptop in 1 minute, and then have it last through an entire
8-hour flight, *I* want my cell phone battery to
last longer than the phone instead of having to replace the
battery after 18 months.

But yet I can't go to batteries.com and buy one of these
wonderful batteries that Tesla is so stupid for not using.
I think there *might* be a reason for that. :-)

BTW, this press release:
http://www.autobloggreen.com/2006/12...-phoenix-moto/

seems to indicate that Altair's entire production volume of batteries
to date is 10 35kWh battery packs for $750,000. It apparently
took 30 days (well, that includes Christmas) to deliver all 10 battery
packs.

I hope Altair and Phoenix are fabulously successful, but there is
good reason for skepticism.

-Jay-

Larry Dighera wrote:

wrote

Google says a Cessna 182 has about 16.2 m^2 of wing area, so you
might get around 1.6-2.4 kW from solar cells covering the wings.
You'd get a little more from the rest of the skin, but IMHO probably
not more than 50% additional, or 2.4 to 3.6 kW. That's 3.2 to 4.8 hp
that the cells are contributing.

Assuming your figures are correct, and given the specified cells, that
figure could be 200% to 300% of your figures. It could take a day to
fully recharge a exhausted battery in locations where city power was
unavailable.

Just what size battery are you thinking of? If you want to have a
battery that has the same capacity as the fuel tank in a 182, you would
need about 1000 kW-hr, or one 15 times the size of that in the Tesla
sports car.

The amount of power available from the sun is usually quoted in sun-days,
which is typically about 5 hours for the sunny areas in the south, like
west Texas.

Given a 5 hour sun-day, and a 5 kW solar panel arrangement, it would take
about 40 days to fully recharge the batteries, assuming 100 percent
efficiency of the charging circuit.

Further, batteries that can withstand high charge and discharge rates
often have associated high internal leakage, meaning that they lose their
charge rather quickly while sitting on the shelf. That means the charger
not only has to supply the charge itself, but also make up for the loss
from internal discharge. If you combine a realistic efficiency for the
charger with the realities of internal discharge, you might never see the
battery fully charged with the solar panels alone.

We also haven't added up the cost and weight of the batteries yet, not to
mention the cost and weight of the solar panels.

The Tesla Motors engine weighs less than 70 lbs per their specs.

The Tesla motor will also not be sized for a continuous duty. They are
relying on the fact that an automobile only needs horsepower for short
bursts of acceleration, and practically loafs along the rest of the time.
Just think about how little you need to depress the accelerator pedal
when cruising along in your car.

An aircraft needs to have a power source that can provide high power for
long periods. Electric motors would therefore have to be sized
appropriately. In the case of industrial 3 phase motors, they typically
weigh 1 lb. per horsepower. Therefore, a motor large enough to power a
182 would weigh close to 200 lb.

Clearly, GM lacks the creative insight to produce a viable
electric car. It's like teaching an elephant to dance.

Not at all. GM has the imagination, it's just that the technology is not
there yet. It is too expensive, and there are too many limitations for
it to complete with internal combustion engines as things stand today.

Agreed. But lithium technology is used in millions of laptop
computers worldwide. It's mainstream, and proven (despite Sony's
manufacturing anomalies).

Yes, and it is very expensive. Even with cheaper lead-acid batteries, a
replacement set of batteries (800 lb.) for the Toyota RAV was something
like $15,000. Lithium batteries are something like 4 times that cost
today, or $60,000 for a set of batteries for a car. How many people will
spend that kind of money?

James Robinson wrote:
Larry Dighera wrote:

Clearly, GM lacks the creative insight to produce a viable
electric car. It's like teaching an elephant to dance.

Not at all. GM has the imagination, it's just that the technology is
not there yet. It is too expensive, and there are too many
limitations for it to complete with internal combustion engines as
things stand today.


Speaking of GM. Here's their newest electric concept car.

http://www.canada.com/topics/finance...4600aa&k=45978

Check out the batteries from A123 Systems:
http://www.a123systems.com/html/technology.html

Li Ion batteries made with iron at 1/5 the price, twice the power and
half the weight of conventional Li Ions.
They are already on the market and are starting to show up in
DeWalt's/Bosch 36V cordless tools.
They have a weight to Watt ratio less than 1 lb / 1500W ( .9 to be
exact).

Scheeesch if their stock ever goes public, I'll be standing in long
line of buyers.


Agreed. But lithium technology is used in millions of laptop
computers worldwide. It's mainstream, and proven (despite Sony's
manufacturing anomalies). Yes, and it is very expensive. Even with cheaper lead-acid batteries, a
replacement set of batteries (800 lb.) for the Toyota RAV was something
like $15,000. Lithium batteries are something like 4 times that cost
today, or $60,000 for a set of batteries for a car. How many people will
spend that kind of money?

JD writes:

They have a weight to Watt ratio less than 1 lb / 1500W ( .9 to be
exact).

A watt is not a measure of energy storage. Perhaps you are thinking
of watt-hours or something similar?

Also, the greater the energy density, the greater the potential hazard
(as already exists with many lithium batteries).

--
Transpose mxsmanic and gmail to reach me by e-mail.

On Jan 10, 3:16 pm, Mxsmanic wrote:
JD writes:
They have a weight to Watt ratio less than 1 lb / 1500W ( .9 to be
exact).A watt is not a measure of energy storage. Perhaps you are thinking
of watt-hours or something similar?

Also, the greater the energy density, the greater the potential hazard
(as already exists with many lithium batteries)
--
Transpose mxsmanic and gmail to reach me by e-mail.

These Li-Ions don't have the same safety problem as the conventional
because of the Iron.
from their website on this subject:

"A123 M1 cells are intrinsically safe and eliminate the risk of
explosions and thermal runaway associated with conventional Lithium-Ion
batteries that use oxide active materials. To achieve this, the active
materials in A123's technology are not combustible and do not release
oxygen if exposed to high temperature or in the event of battery
failure or mechanical abuse."

Yea.. I'm not real sure about the units here... but they do site a
power density of 2700W/Kg see:
http://www.a123systems.com/html/tech/power.html

JD wrote:
Yea.. I'm not real sure about the units here... but they do site a
power density of 2700W/Kg see:
http://www.a123systems.com/html/tech/power.html

They're pretty clearly talking about power density, not
energy density. Both their language and their units
reflect power density.

Power density isn't the issue for long-distance cruising.
It might be somewhat relevant if you were wanting to
build the fastest possible dragster for a 100 yard sprint.
But energy density is the problem that most battery
powered vehicles have when compared to petroleum
powered vehicles, especially for long distance cruising.

"Larry Dighera" wrote in message
...
On Tue, 9 Jan 2007 21:24:33 -0500, "Capt. Geoffrey Thorpe" The Sea
Hawk at wow way d0t com wrote in
:
...
From http://www.t18.net/resources/T-18%20orig%20hdbk.doc page 34

(Perhaps you'd be good enough to cut and paste the reverent section
into a follow up. I'm uneasy opening MS Word documents from anonymous
sources.)

Gee, I can't imagine why...

Not sure how the formatting will come out but here is data for one T-18:



CRUISE PERFORMANCE



Standard Temperature, Lean Mixture, 135 BHP used as 100% Power Base



% TAS %
TAS

POWER RPM MPH GPH MPG POWER RPM MPH GPH MPG



SEA LEVEL 2000 FT



50 2060 137 5.6 24.5 50 2100
137 5.6 24.4

60 2320 154 6.6 23.3 60 2360
154 6.6 23.2

70 2490 165 7.5 21.9 70
2540 166 7.6 21.8

75 2550 170 8.0 21.2 75
2600 171 8.1 21.2

80 2610 174 8.4 20.6 80
2660 175 8.5 20.6

90 2730 181 9.3 19.4 90
2780 182 9.4 19.4

100 2820 187 10.2 18.4 100 2870
188 10.3 18.3

114 2910 194 11.3 17.2 107 2910
192 10.8 17.8





% TAS %
TAS

POWER RPM MPH GPH MPG POWERRPM MPH GPH MPG



4000 FT 6000 FT



50 2120 137 5.6 24.3 50
2140 137 5.7 24.2

60 2390 154 6.7 23.1 60
2420 155 6.7 23.1

70 2570 167 7.6 21.9 70
2600 168 7.7 21.9

75 2640 172 8.1 21.2 75
2670 174 8.1 21.4

80 2710 176 8.6 20.6 80
2740 179 8.6 20.8

90 2810 183 9.4 19.4 90
2840 186 9.5 19.6

100 2910 189 10.3 18.3 94 2880
188 9.8 19.1





% TAS %
TAS

POWER RPM MPH GPH MPG POWER RPM MPH GPH MPG



8000 FT 10000 FT



50 2160 137 5.7 24.1 50
2180 136 5.7 23.9

60 2440 156 6.7 23.2 60
2450 158 6.7 23.5

70 2620 172 7.7 22.4 70
2650 176 7.7 22.8

75 2700 178 8.2 21.8 75
2730 183 8.2 22.3

80 2780 183 8.7 21.2 80
2810 188 8.7 21.6

86 2830 189 9.2 20.6



Power and fuel flow data are based on Lycoming performance charts for the
0-290-D2, dependent upon Manifold Pressure, RPM, OAT, and Pressure Altitude.
Speeds based on speed course calibrated airspeed system.




fwiw:

t18.net is a pretty good place to get infomation. By T-18 builders for T-18
builders

The guy who wrote the aircraft handbook that I copied this from is a very
meticulous Aero engineer who used to work in flight test for one of the big
aerospace companies in the U.S. He puts a lot of effort into the details -
his O-290 T-18 is as fast as many of the O-360 powered T-18's And, knowing
how he works - I would trust his data before I would trust any of mine...


--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
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