The new Electric Cessna 172

In article ,
Vaughn wrote:

On 12/30/2012 1:16 PM, wrote:
If you look at the wing area of a 172 and calculate how much power you
can get, you find they aren't much good for charging the battery either
unless you go days between flights.

Agree. However, if someone wants to own a $200,000 plane and just wants
to fly it for an hour or so once a week it might work. Are there any
folks like that? Yes! But few of them would admit that to themselves
before buying a plane. It's a behavior they drift into later.

I can tell you that most of the non-FBO planes at my local airport
seldom fly. Even some of the FBO leasbacks sit unused for days at a time.


Also, solar panels aren't terribly vulnerable to hail. Otherwise, there
would be little point in mounting them on rooftops.
Rooftop solar panels are mounted at the latitude of the location to
receive maximum power, so a hailstone will hit at an angle of about 30
to 45 degrees from most of the US and tend to glance off.

The solar panels on a wing are going to be horizontal and will take a
direct hit from a hailstone.

There are many places in the US where it is not unusual for hailstones
to dent the tops of cars.

I have watched my share of hail, and seldom does it fall at a 90 degree
angle, so I doubt your theory. My home's panels are mounted at a less
than optimum angle because I am quite worried about hurricane winds and
not worried at all about hail, even though hail happens here.

Today's solar panels aren't glass and aren't terribly fragile. A
rooftop isn't a terribly friendly environment, yet panels last for
decades. I would judge that most PV panels are less prone to hail damage
than a typical aluminum wing skin, certainly no more.

Still, we agree that solar panels on a wing make little sense. They
would be costly, they would add little to the usefulness of the plane,
and they would add weight and complexity.

Also, nobody has remarked on those little wind turbines. Yes, I know
that they are an attempt to recover energy from the wingtip vortex, but
those things will add weight and drag. It would make far more sense to
reduce the vortex with winglets or a better wing design.

Further, adding blades to a prop is unlikely to improve its efficiency.

When you add the questionable solar panels, the questionable prop, and
the questionable wind turbines, I find myself thinking "vaporware".

Vaughn

.... and balonium technology!

On a straight economic matter, we'll be seeing battery improvements first in high demand areas like laptops and cell phones, and then cars. Only when those high volume needs are filled will rational people want to invest money in batteries as the prime energy source is airplanes.

In article ,
a wrote:

On a straight economic matter, we'll be seeing battery improvements first in
high demand areas like laptops and cell phones, and then cars. Only when
those high volume needs are filled will rational people want to invest money
in batteries as the prime energy source is airplanes.

There are still major chemical limitations on energy storage/weight
issues that preclude them from being a viable power source for aircraft
-- and cars.

On 2012-12-31, Orval Fairbairn wrote:
There are still major chemical limitations on energy storage/weight
issues that preclude them from being a viable power source for aircraft
-- and cars.

Well, not for cars - there are already all-electric cars with a 200 mile
range. With it being entirely normal for most households to have two or
more cars, it's entirely practical that one be electric in most instances,
since anything that demands cross-country driving can be done in the
other vehicle.

But for aircraft, batteries are a long way off from being viable (well,
for aircraft bigger than radio controlled ones - all of my RC aircraft
are electric, including helicopters weighing almost 7kg)

Dylan Smith wrote:
On 2012-12-31, Orval Fairbairn wrote:
There are still major chemical limitations on energy storage/weight
issues that preclude them from being a viable power source for aircraft
-- and cars.

Well, not for cars - there are already all-electric cars with a 200 mile
range. With it being entirely normal for most households to have two or
more cars, it's entirely practical that one be electric in most instances,
since anything that demands cross-country driving can be done in the
other vehicle.

That is 200 miles on the highway with the windows up and no air conditioning.

This makes them an expensive niche vehicle as is evindenced by their lack
of sales.


But for aircraft, batteries are a long way off from being viable (well,
for aircraft bigger than radio controlled ones - all of my RC aircraft
are electric, including helicopters weighing almost 7kg)

Absent some earth shaking new physics, batteries will never be viable
for a general purpose aircraft; motor gliders maybe, but something
equivelant to a C-172, nope.

In article ,
wrote:

Dylan Smith wrote:
On 2012-12-31, Orval Fairbairn wrote:
There are still major chemical limitations on energy storage/weight
issues that preclude them from being a viable power source for aircraft
-- and cars.

Well, not for cars - there are already all-electric cars with a 200 mile
range. With it being entirely normal for most households to have two or
more cars, it's entirely practical that one be electric in most instances,
since anything that demands cross-country driving can be done in the
other vehicle.

That is 200 miles on the highway with the windows up and no air conditioning.

.... and in daylight and moderate temperatures. As soon as the mercury
drops into the 40s or below (Deg F), their ability to store and deliver
a charge goes into the tank. Add cabin heating, defrost, etc. and it
only gets worse.


This makes them an expensive niche vehicle as is evindenced by their lack
of sales.


But for aircraft, batteries are a long way off from being viable (well,
for aircraft bigger than radio controlled ones - all of my RC aircraft
are electric, including helicopters weighing almost 7kg)

Absent some earth shaking new physics, batteries will never be viable
for a general purpose aircraft; motor gliders maybe, but something
equivelant to a C-172, nope.

For self-launching sailplanes, which don't need a big "fuel tank," --
yes.

On 01/01/13 07:44, wrote:
Dylan Smith wrote:
On 2012-12-31, Orval Fairbairn wrote:
There are still major chemical limitations on energy storage/weight
issues that preclude them from being a viable power source for aircraft
-- and cars.

Well, not for cars - there are already all-electric cars with a 200 mile
range. With it being entirely normal for most households to have two or
more cars, it's entirely practical that one be electric in most instances,
since anything that demands cross-country driving can be done in the
other vehicle.

That is 200 miles on the highway with the windows up and no air conditioning.

And in daylight and preferably no hills

On 2012-12-31, wrote:
Well, not for cars - there are already all-electric cars with a 200 mile
range. With it being entirely normal for most households to have two or
more cars, it's entirely practical that one be electric in most instances,
since anything that demands cross-country driving can be done in the
other vehicle.

That is 200 miles on the highway with the windows up and no air conditioning.

The typical use pattern of a car is driving a few miles twice a day
and then sitting stationary for at least 14 hours in a driveway which
is more than enough hours to charge off a normal power socket. Even
with the windows down and the AC on full blast there's no issue with
range for the typical daily use of a car.

With most households owning two or more cars, the other car can be used
for any cross-country journeys.

Dylan Smith wrote:
On 2012-12-31, wrote:
Well, not for cars - there are already all-electric cars with a 200 mile
range. With it being entirely normal for most households to have two or
more cars, it's entirely practical that one be electric in most instances,
since anything that demands cross-country driving can be done in the
other vehicle.

That is 200 miles on the highway with the windows up and no air conditioning.

The typical use pattern of a car is driving a few miles twice a day
and then sitting stationary for at least 14 hours in a driveway which
is more than enough hours to charge off a normal power socket. Even
with the windows down and the AC on full blast there's no issue with
range for the typical daily use of a car.

That isn't the typical pattern around here unless by "a few miles" you
mean 50 to 100 miles.

Perhaps you can point to a nation wide study that shows some national
average numbers?

With most households owning two or more cars, the other car can be used
for any cross-country journeys.

For most households, the second car is an old car or a utility vehicle
like a pickup.

Most people want to use the new car for trips.

The bottom line is that electric cars are NOT selling and likely will
not sell until the range goes up and the price comes down considerably.

On 12/31/2012 12:45 AM, Orval Fairbairn wrote:
There are still major chemical limitations on energy storage/weight
issues that preclude them from being a viable power source for aircraft
-- and cars.

It's time to wake up and smell the kilowatts Orval. "Preclude" is a
pretty daring word to use when you consider that electric cars and
aircraft are on the consumer market today.

Electric cars are here. That simple fact was driven home to me last
week when I visited California, where electric cars and their charging
stations are becoming a regular sight.

I have read your arguments here many times, and I agree with you that
the case for electric airplanes is harder to make. We especially agree
about that "new electric 172". (Can something that hasn't even been
built truly be considered "new"?) Still, recent improvements in the
technology is making special purpose electric aircraft look tempting.
Glider launch is an early application that is quickly gaining traction
in the marketplace.

In short; in the face of an improving technology, only a fool uses words
like "never" and "preclude".