Can Aircraft Be Far Behind?

http://www.teslamotors.com/

Theres no soul to me in that, its batteries that make it go... theres
no mechanical engineering there (don't take that too literally), but in
an IC engine there's movement theres combustion, there's things
spinning about, in this electric motor things just are.

The brilliance of it, the raw humanity behind it isn't there anymore...
it's just a high tech toy.

On Tue, 9 Jan 2007 18:12:31 -0600, "Danny Deger"
wrote in
:

I think the 75 hp for an hour is very close. Not enough for
an airplane in my opinion.


How much horsepower does a Cessna 150 equipped with a Continental
O-200 power plant develop at 75% cruise power?

Take a look at the chart here
http://www.teslamotors.com/performance/performance.php, and notice
that at ~8,000 RPM the Tesla electric motor will develop nearly 200
Hp. Now what's your opinion?

On 9 Jan 2007 17:14:14 -0800, "
wrote in
.com:

http://www.teslamotors.com/

Theres no soul to me in that, its batteries that make it go...

It's true, that petroleum was once alive (I'll leave the soul aspect
to those who have been inculcated to need religiosity), but lithium
batteries are the child of man's genius none the less.

theres no mechanical engineering there (don't take that too literally), but in
an IC engine there's movement theres combustion, there's things
spinning about,

According to information at the link above, there are about 100
"things" moving. That's one hundred times more opportunity for an
internal combustion engine part to fail in flight. Or don't you find
that fact significant?

in this electric motor things just are.

Right. One moving part, the rotor.

The brilliance of it, the raw humanity behind it isn't there anymore...
it's just a high tech toy.

The romance is a subjective point of view. If one is a machinist,
s/he probably shares your view. If one is an electrician or EE, s/he
sees the beauty of simplicity and efficiency.

But I understand what you mean. It's like comparing a player piano to
an electronic keyboard. Something is lost to progress.

"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
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

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...


Kirk
66

Larry Dighera wrote:
If an aircraft were covered in Spectrolab* triple-junction solar
cells, fuel would be free during the daylight, quiet, and pollution
free.

You get something like 1 kW/m^2 of energy from the sun under good
conditions, like being on the equator on a clear day in the summer. I
think current PV cells are somewhere around 10% to 15% efficient, so
that's 100-150 watts per square meter. 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.

Also, does the solar cell factory run on solar cells?

What is the weight of the Continental O-200 complete with its
manifolding, muffler, oil, and fuel?

http://en.wikipedia.org/wiki/Continental_O-200 says about 170 lbs (77
kg) dry for just the engine.

For an electric drive, in addition to the weight of the motor and
batteries, you'll also need to figure in the weight of the inverter
that changes DC into three-phase AC. Some of these inverters are
air-cooled and some are liquid-cooled.

http://www.wired.com/news/wiredmag/0...l?tw=rss.index
Tesla has managed to produce an impractical and exorbitantly
expensive vehicle just as a revolutionary new battery has appeared
on the scene.

I've only been involved in hybrid cars for about six years, but I've
already seen a few "revolutionary new batteries" come and go. Many of
these batteries turn out to be quite good at ensuring a steady flow of
press releases out and money in, but never quite manage to push any
actual electrons.

Matt Roberds

According to information at the link above, there are about 100
"things" moving. That's one hundred times more opportunity for an
internal combustion engine part to fail in flight. Or don't you find
that fact significant?

Thats the brilliance of it... theres hundreds of moving parts, it's by
no means efficient or refined, yet there are more incidents and
accidents cause by the failure of natures most sofisticated creature at
piloting the plane than there are incidents and accidents caused by the
brute under the cowling.

According to information at the link above, there are about 100
"things" moving. That's one hundred times more opportunity for an
internal combustion engine part to fail in flight. Or don't you find
that fact significant?

I don't think my last post went through correctly so here it goes
again...

The brilliance of those hundreds of moving parts that fail is just in
the fact that they hardly ever do... pilots and humans, some of the
most sophisticated animals nature has created fail more often than
engines do, the simplicity of the electric motor won't get rid of those
accidents.

Larry Dighera wrote:

On Tue, 09 Jan 2007 10:19:00 -0600, James Robinson
wrote in :

Larry Dighera wrote:

"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote:

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.

Total weight is indicated as ~2,400 lbs (including air
conditioning). Given its 1:10 power to weight ratio, I'd say, if it
had wings instead of the beefy structure it requires to meet road
safety standards, it would fly. It wouldn't require any fuel.
Recharges fully in 3.5 hours.

The batteries weigh 900 lb., and put out 75 HP for an hour.

I didn't see those numbers on the Tesla Motors web site. Have you got
a source for that information? There is a chart here, but it is more
about marketing than engineering:
http://www.teslamotors.com/performance/performance.php

Your numbers seem to conflict to some degree with these:

http://en.wikipedia.org/wiki/Tesla_Roadster#Battery
Battery:
6,831 Lithium ion battery cells
About 450 kg
Full-charge time of three and a half hours
~56 kWh capacity

The conversion factor for kg to lb is 2.205, so 450 kg is 992.25 lb.
Therefore, it's actually closer to 1,000 lb. of batteries, according to
those specs.

The conversion factor for kWh to HP-hr is 1.34, so 56 kWh is the
equivalent of 75.04 HP-hr

Here is the page on the Tesla Motors web site that I found the comment
that the batteries weighed 900 lb.

http://www.teslamotors.com/blog1/ind...9&js_enabled=1

I found the 56 kWh number on another page, and simply converted it to
horsepower, since those are the units that most GA pilots would be
familiar with.

You wouldn't get too far on that in a C150.

With a C-150 gross weight of ~1,600 lbs, it's considerably lighter
than the Tesla Roadster. But an aircraft wouldn't require many of the
car's systems such a transmission, electric windows, heavy running
gear (springs, 17" wheels and tires, disk brakes, power assist
steering, etc), and the Tesla motor weighs less than 70 lbs. What is
the weight of the Continental O-200 complete with its manifolding,
muffler, oil, and fuel?

Well, let's look at some numbers. A gasoline aero engine of that size is
typically about 2 lb. per HP, so a 100 HP engine would weigh about 200
lb. I believe the O-235 is listed at 215 lb., with supplies, so it's in
the ballpark.

In comparison, three phase motors typically weigh about 1 lb. per
horsepower. That would mean a 100 hp motor would weigh about 100 lb. I
suspect that the Tesla's motor weighs less, because it is rated for less
continuous duty than would be necessary on an aircraft. An automobile
engine practically loafs along when on the highway at constant speed, and
only needs to have power for short bursts of speed. An aircraft engine,
on the other hand, operates at high power for hours on end.

The fuel and tanks would also be unnecessary with an electrically-powered
aircraft. A typical C-150 has something like a 26 gallon capacity. At 6
lb. per gallon, that would be 136 lb. Add roughly 20 percent to that to
account for the weight of the tanks, or 27 lb, for a total of about 165
lb. for the fuel plus the tanks. The grand total being 215 + 165 = 380
lb. Some additional amount could be added for fuel lines, filters and
pumps, but they would be relatively small. As a round number, lets say
everything weighs 400 lb.

So, if we take out the IC engine, and replace it with the batteries used
in the Tesla, and an appropriate electric motor, we would take out 400
lb., and add 900 plus 100 lb. for the batteries and motor, assuming the
ligher weight, plus some additional for the electrical control system an
wiring. Even without the control system, we would have a net gain in
weight of about 600 lb. Considering that a C150 has a usable capacity of
only 370 lb. or so with full fuel, The electically-powered aircraft would
already be more than 200 lb. overloaded, and we haven't even considered
the pilot, passenger, or baggage. Doesn't sound too practical, does it?

Larry Dighera wrote:

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. :-(

There are alternatives that are perfectly practical, and technically
feasible. They just aren't economic, or any better environmentally.

One of the closest is the liquafaction of coal. We have vast supplies in
North America, and it is a relatively straight-forward process to convert
it to liquid fuel. (see the Fischer-Tropsch process) The Germans and South
Africans used synfuels made from coal when they couldn't get cheaper
petroleum products. They worked well.

There are a number of environmental issues, but the biggest problem is that
fuel produced from coal is somewhat more expensive than petroleum based
fuels, and few will pay extra for them. OPEC knows how much synfuels are
to make, and they carefully keep the price of crude below those costs, so
there is little risk of a competitive supply.