Can Aircraft Be Far Behind?

"mad8" wrote:

James Robinson wrote:

The batteries weigh 900 lb., and put out 75 HP for an hour. You
wouldn't get too far on that in a C150.

you would save a noticeable amount of weight from not needing to carry
fuel (avgas is something like 6lbs per galon, so that would be approx
300lbs "offset" (not saved, but shifted to battery cell weight)
also, no oil (so thats a few more pounds)
and electric motors are fairly light compared to internal combustion
blocks

Yes. If you saw my other post, I added up those numbers. You remove a bit
more than 400 lb total with the gasoline engine, and add more than 1000 lb.
with the batteries and electric motor, for a net add of 600 lb. That is
more than the aircraft can handle.

You also drop from a 4hr 30 minute endurance to a 60 minute endurance.

You really can't beat the energy density and low cost of liquid petroleum
fuels with today's technology.

"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Larry Dighera wrote:
http://www.teslamotors.com/

Well they say the motor weighs 70 pounds and produces 248 HP but I can't
find anything about the weight of the batteries.

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

-c

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.

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.

Recently, Larry Dighera posted:

http://www.teslamotors.com/

I even suspect that cars fitting this description beyond shape or color
are a long way off. The endurance/performance claims by this outfit are
for some reason not able to be produced by the major car companies (or
anyone else?). Why is that? I didn't see any reference to the specific
design of the motor, and if I had a lot of time on my hands, I'd do a
patent search. I'll just remain skeptical until shown more details.

Neil

On Tue, 09 Jan 2007 16:35:40 GMT, "Neil Gould"
wrote in
:

Recently, Larry Dighera posted:

http://www.teslamotors.com/

I even suspect that cars fitting this description beyond shape or color
are a long way off.

Tesla Motors has apparently sold 200 of their all electric roadsters
which are scheduled for delivery late this summer. You can reserve on
for delivery next year.

The endurance/performance claims by this outfit are
for some reason not able to be produced by the major car companies (or
anyone else?). Why is that?

Battery technology is advancing rapidly. However, GM, and their Volt
prototype, are so mired in corporate bureaucracy, that they can't even
turn a profit with their IC products.

I didn't see any reference to the specific
design of the motor, and if I had a lot of time on my hands, I'd do a
patent search. I'll just remain skeptical until shown more details.

Neil


I'm hopeful, but I don't blame you for being skeptical.

Electrically powered vehicles are the only hope to reduce the transfer
of wealth from the western world to the middle east, and reduce global
warming. If the US doesn't find some breakthrough technology soon,
we'll all be speaking Farsi before long. :-(

Recently, Larry Dighera posted:

On Tue, 09 Jan 2007 16:35:40 GMT, "Neil Gould" wrote:
I didn't see any reference to the specific
design of the motor, and if I had a lot of time on my hands, I'd do a
patent search. I'll just remain skeptical until shown more details.


I'm hopeful, but I don't blame you for being skeptical.

Electrically powered vehicles are the only hope to reduce the transfer
of wealth from the western world to the middle east, and reduce global
warming. If the US doesn't find some breakthrough technology soon,
we'll all be speaking Farsi before long. :-(

I agree with you that we need to develop alternative energy methods and
supplies. However, I am not convinced that we are as close to a practical
solution for electric-only vehicles as the promotional material on that
site suggests. If the information suggested by James Robinson is accurate,
the vehicle will not achieve its stated performance or endurance figures.
For one thing, a 75 hp/hr. battery won't deliver 200 kW for very long.

Neil

On Tue, 09 Jan 2007 18:20:07 GMT, "Neil Gould"
wrote in
:

If the information suggested by James Robinson is accurate,

Assuming 746 watts / horsepower, and the Tesla Motor's ~56 kWh
capacity, Robinson's 75 Hp for one hour assertion seems accurate.

the vehicle will not achieve its stated performance or endurance figures.

I don't know specifically to which figures you are referring, but the
Tesla roadster will probably easily meet it's acceleration figure.

For one thing, a 75 hp/hr. battery won't deliver 200 kW for very long.

Perhaps the Tesla roadster doesn't need to develop 75 Hp during it's
entire run time, and there's the issue of regenerative braking, but
these things are not germane to electrically powered aircraft which
typically must produce 75% rated Hp continuously in cruise flight.

Unlike automobiles, aircraft not only require motive power to propel
them forward, but they are not afforded the luxury of a roadway to
support their weight, and I would presume aircraft drag is
considerably more than an automobile.

Recently, Larry Dighera posted:

On Tue, 09 Jan 2007 18:20:07 GMT, "Neil Gould"
wrote in
:

If the information suggested by James Robinson is accurate,

Assuming 746 watts / horsepower, and the Tesla Motor's ~56 kWh
capacity, Robinson's 75 Hp for one hour assertion seems accurate.

the vehicle will not achieve its stated performance or endurance
figures.

I don't know specifically to which figures you are referring, but the
Tesla roadster will probably easily meet it's acceleration figure.

For one thing, a 75 hp/hr. battery won't deliver 200 kW for very
long.

Perhaps the Tesla roadster doesn't need to develop 75 Hp during it's
entire run time, and there's the issue of regenerative braking,

I imagine that the average power consumption can exceed 75 hp/hr in
typical city driving, and unless the Altair battery is used, regenerative
braking won't provide much of a recovery.

but
these things are not germane to electrically powered aircraft which
typically must produce 75% rated Hp continuously in cruise flight.

True. I think there may be some solutions in the future, but I'm skeptical
that the Tesla motor is that solution.

Unlike automobiles, aircraft not only require motive power to propel
them forward, but they are not afforded the luxury of a roadway to
support their weight, and I would presume aircraft drag is
considerably more than an automobile.

I think aerodynamic drag is greater in an automobile than an airplane, but
much more of the auto motor's energy can be used for overcoming that drag
since it doesn't have to provide the energy for lift.

Neil

"Larry Dighera" wrote in message
...
On Tue, 09 Jan 2007 18:20:07 GMT, "Neil Gould"
...
Perhaps the Tesla roadster doesn't need to develop 75 Hp during it's
entire run time, and there's the issue of regenerative braking, but
these things are not germane to electrically powered aircraft which
typically must produce 75% rated Hp continuously in cruise flight.

Unlike automobiles, aircraft not only require motive power to propel
them forward, but they are not afforded the luxury of a roadway to
support their weight, and I would presume aircraft drag is
considerably more than an automobile.


That's probably not a good assumption.

From http://www.t18.net/resources/T-18%20orig%20hdbk.doc page 34

An O-290 Powered T-18 can get 20+ miles per gallon at 170+ mph true air
speed

Not many gasoline powered cars can match this.

--
Geoff
The Sea Hawk at Wow Way d0t Com
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