Electriflying

On Jun 25, 4:48*am, hierophant wrote:
On Fri, 24 Jun 2011 16:37:52 -0000, wrote:
Vaughn wrote:

wrote in message
...
Vaughn wrote:
How long to recharge for the next student?

You have just identified the real issue!

Nope, there is still the cost of a new, FAA certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150.

On Fri, 24 Jun 2011 13:18:08 -0700 (PDT), george wrote:

On Jun 25, 4:48*am, hierophant wrote:
On Fri, 24 Jun 2011 16:37:52 -0000, wrote:
Vaughn wrote:

wrote in message
...
Vaughn wrote:
How long to recharge for the next student?

You have just identified the real issue!

Nope, there is still the cost of a new, FAA certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150.

The strange thing is, the price for the 150/152 engine, is also about the
same price as a used 150. *In the flight training world, these things are
amortized and built into the training hourly rate. *If the electric trainer
isn't cheaper, it won't sell except in nitch situations where its silence or
(perhaps) novelty are factors.

Vaughn

It isn't all that strange when you concider that a 1990 Toyota Corolla goes
for about $3k while a rebuilt to new specs engine for it costs about $2.5k.

Anyway, back to airplanes...

The only electric airplane that is even close to being practical is a self
launched glider.

And since we are already close to the fundemental limits of physics and
chemistry on batteries, that isn't going to change without a blinding
breakthrough in the science of portable electric storage.

Please get off this topic before "MarkIV" returns. heh

I think he now calls himself Tom

Really? Well, there's a fella at Cox Communications that has a
standing arrest warrant for "Tom" if he ever as much as shows his
manic mania on Usenet again.

Seems "Tom" or Mark or whomever had a couple of friends who fingered
him in S.C. Peg leg and all.

wrote in message
...
Vaughn wrote:

wrote in message
...
Vaughn wrote:
How long to recharge for the next student?

You have just identified the real issue!

Nope, there is still the cost of a new, FAA certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150.

The strange thing is, the price for the 150/152 engine, is also about the
same price as a used 150. In the flight training world, these things are
amortized and built into the training hourly rate. If the electric
trainer
isn't cheaper, it won't sell except in nitch situations where its silence
or
(perhaps) novelty are factors.

Vaughn

It isn't all that strange when you concider that a 1990 Toyota Corolla
goes
for about $3k while a rebuilt to new specs engine for it costs about
$2.5k.

You are the one who said "Nope, there is still the cost of a new, FAA
certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150." I
simply pointed out that is really no different from the flight training
150/152, which will also require expensive powerplant investment every few
years.

Anyway, back to airplanes...

You are the one who got us away from airplanes...

The only electric airplane that is even close to being practical is a self
launched glider.

Unproven.


And since we are already close to the fundemental limits of physics and
chemistry on batteries,

Unproven


Vaughn

In article ,
"Vaughn" wrote:

wrote in message
...
Vaughn wrote:

wrote in message
...
Vaughn wrote:
How long to recharge for the next student?

You have just identified the real issue!

Nope, there is still the cost of a new, FAA certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150.

The strange thing is, the price for the 150/152 engine, is also about the
same price as a used 150. In the flight training world, these things are
amortized and built into the training hourly rate. If the electric
trainer
isn't cheaper, it won't sell except in nitch situations where its silence
or
(perhaps) novelty are factors.

Vaughn

It isn't all that strange when you concider that a 1990 Toyota Corolla
goes
for about $3k while a rebuilt to new specs engine for it costs about
$2.5k.

You are the one who said "Nope, there is still the cost of a new, FAA
certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150." I
simply pointed out that is really no different from the flight training
150/152, which will also require expensive powerplant investment every few
years.

Anyway, back to airplanes...

You are the one who got us away from airplanes...

The only electric airplane that is even close to being practical is a self
launched glider.

Unproven.


And since we are already close to the fundemental limits of physics and
chemistry on batteries,

Unproven


Vaughn

pretty good empirical evidence, though! If we weren't near the limits of
battery chemistry, we would have had an order of magnitude of change in
battery performance over the last century, since there have been major
needs for such performance: submarines, spacecraft, aircraft,
automobiles, laptop computers.

The last have made their major advances in the expansion of storage and
computing speed, while reducing their power requirements. The batteries
haven't advanced that far.

Vaughn wrote:

wrote in message
...
Vaughn wrote:

wrote in message
...
Vaughn wrote:
How long to recharge for the next student?

You have just identified the real issue!

Nope, there is still the cost of a new, FAA certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150.

The strange thing is, the price for the 150/152 engine, is also about the
same price as a used 150. In the flight training world, these things are
amortized and built into the training hourly rate. If the electric
trainer
isn't cheaper, it won't sell except in nitch situations where its silence
or
(perhaps) novelty are factors.

Vaughn

It isn't all that strange when you concider that a 1990 Toyota Corolla
goes
for about $3k while a rebuilt to new specs engine for it costs about
$2.5k.

You are the one who said "Nope, there is still the cost of a new, FAA
certified battery pack every
3 to 5 years, which will likely be in the ballpark price of a used 150." I
simply pointed out that is really no different from the flight training
150/152, which will also require expensive powerplant investment every few
years.

Umm, what I was pointing out is that a new power plant for an old vehicle
of any type is likely to be near the used price of the old vehicle.

Anyway, back to airplanes...

You are the one who got us away from airplanes...

The only electric airplane that is even close to being practical is a self
launched glider.

Unproven.

Antares 20E, Alisport Silent 2 Targa, Pipsistrel Taurus.

Some have been around for decades.

And since we are already close to the fundemental limits of physics and
chemistry on batteries,

Unproven

Basic physics and chemistry.

If you don't believe it, get a physics or chemistry degree and you will find
out why it is true.



--
Jim Pennino

Remove .spam.sux to reply.

wrote in message
...
If you don't believe it, get a physics or chemistry degree

Do you have yours? You are the one trying to make this case, not me.

Myself, I neither agree nor disagree, but am cautiously impressed with the
advances I have seen in the last few years.

Vaughn

Vaughn wrote:

wrote in message
...
If you don't believe it, get a physics or chemistry degree

Do you have yours? You are the one trying to make this case, not me.

Myself, I neither agree nor disagree, but am cautiously impressed with the
advances I have seen in the last few years.

It is easy enough to Google for.

Start here, a plain english overview of energy storage:

http://www.thebulletin.org/web-editi...age-technology




--
Jim Pennino

Remove .spam.sux to reply.

In article ,
"Vaughn" wrote:

wrote in message
...
If you don't believe it, get a physics or chemistry degree

Do you have yours? You are the one trying to make this case, not me.

Myself, I neither agree nor disagree, but am cautiously impressed with the
advances I have seen in the last few years.

Vaughn

Well, Vaughn, all you have to do is a simple back-of-the-envelope
calculation to see it.

First, calculate the fuel and air consumed in an internal combstion
engine:
1. fuel, at 6 lb/gal
2. air, at f/a ratio of 1:15.

This means that, for every pound of fuel, you consume 15 pounds of air.
You may use kilograms, if you please.

For a 20 gallon tank, you have 120 lb of fuel and use 1800 lb of air to
propel yourself through the air.

If you are using batteries, you now have to carry the equivalent of both
the fuel and the consumable air to do the same job, or almost a ton of
consumables. That is why battery technology is against a wall of
diminishing returns and is not a practical soultion to aircraft
propulsion.

Orval Fairbairn wrote:
In article ,
"Vaughn" wrote:

wrote in message
...
If you don't believe it, get a physics or chemistry degree

Do you have yours? You are the one trying to make this case, not me.

Myself, I neither agree nor disagree, but am cautiously impressed with the
advances I have seen in the last few years.

Vaughn

Well, Vaughn, all you have to do is a simple back-of-the-envelope
calculation to see it.

First, calculate the fuel and air consumed in an internal combstion
engine:
1. fuel, at 6 lb/gal
2. air, at f/a ratio of 1:15.

This means that, for every pound of fuel, you consume 15 pounds of air.
You may use kilograms, if you please.

For a 20 gallon tank, you have 120 lb of fuel and use 1800 lb of air to
propel yourself through the air.

If you are using batteries, you now have to carry the equivalent of both
the fuel and the consumable air to do the same job, or almost a ton of
consumables. That is why battery technology is against a wall of
diminishing returns and is not a practical soultion to aircraft
propulsion.

100LL avgas has a specific energy of 44 MJ/kg not counting the air to
burn it.

The best theoretical battery has a specific energy of 2.54 MJ/kg.

So even ignoring the air, to get the same energy from a thoretical
battery that doesn't exist yet as 120 lb of 100LL, you would need a bit
over 2,000 lbs worth of battery.

If you factor in the fact that electric motors are about twice as efficient
in energy coversion as gasoline engines, you still need around 1000 lb
worth of battery.

That is why you hear people say batteries have to improve by an order of
magnitude, i.e. get 10 times better, before they will be generally practical
to power vehicles.

And phyiscs and chemistry says you can't do it.



--
Jim Pennino

Remove .spam.sux to reply.

On 2011-06-25, Orval Fairbairn wrote:
pretty good empirical evidence, though! If we weren't near the limits of
battery chemistry, we would have had an order of magnitude of change in
battery performance over the last century, since there have been major
needs for such performance: submarines, spacecraft, aircraft,
automobiles, laptop computers.

Well, we have had an order of magnitude change. The first long life
rechargable battery (as in lasts many charge cycles), the lead acid
battery, has an energy density of 41 watt hours per kilogram.

The latest long life rechargable battery, the lithium polymer,
has an energy density of 128 watt hours per kilogram. That's pretty
close to an order of magnitude. (You could nit-pick and say the
lithium battery was invented a long time ago, but that lithium
battery was not rechargable and is a far cry from a modern Li-Poly).

Also the performance just within lithium polymer batteries has increased
enormously. Ten years ago, the maximum discharge rate of any kind
of rechargable lithium battery didn't exceed 1 to 2 C (1C = a current
equal to the amp hour capacity of the battery, so if you had a 10aH
Li-Ion with a maximum discharge of 1C, it would mean it could
give at most a current of 10 amps). I have a LiPoly battery here
that has a maximum discharge rate of 60C continuous, 120C peak.
It's the size of a cigar packet and can start a car engine. This just
wasn't possible even 10 years ago.

Additionally, UC San Diego is working on a battery that is expected
to give an energy density of around 1kWh per kilogram (an order of
magnitude better than current lithium rechargable batteries). It
remains to be seen what C rating it will have, which is enormously
important for anything that moves. Lithium cobalt oxide batteries
in the lab have a 500 watt hour/kg energy density. From past performance
it typically is about 10 years from being a "yeah it works in the lab"
to a commercial product.