Ion drive for aircraft imminent.

On 11/7/2016 7:39 PM, wrote:
In sci.physics mike wrote:
On 11/7/2016 1:46 PM, wrote:
In sci.physics Phil Hobbs wrote:
On 11/07/2016 01:37 PM, wrote:
In sci.physics Robert Clark wrote:

snip

If you know of a means to provide 50,000 V at *lightweight* then you will
have solved the problem of an independently flying lifter, using the
macrosized wires currently used. You would need about a power to weight
ratio for the power source of better than 1 watt per gram, while being able
to provide these ca. 50,000 V voltages.

Bob Clark

Trivial; look at any camera flash unit built in the last several decades.

However you have totally missed the point; voltage and the weight of the
converter is irrelevant as it is the total power that determines the
weight of it all.

BTW, here are some real world power to weight ratios:

Boeing 777 engine 10 kW/kg
1985 Chevy Celebrity 300 W/kg -- So for a 1000 kg car, that's 402
horsepower? Sign me up!

Cheers

Phil Hobbs

No, that is the power to weight ratio of the engine, not the power to
weight ratio of the car.


Power is a red herring. What's important is the total energy produced
by the
engine AND the fuel supply.
It doesn't get the least bit interesting until the engine can lift
itself and a FULL tank of whatever powers it AND the vehicle AND the
payload to reach the destination.
I can't imagine that ever happening 1000 feet off the ground on this ole
earth at a cost anywhere near the cost of other forms of transportation.

Are you trying to say airplanes aren't going to make it in the commercial
world?


Yep, that's exactly what I'm saying: "Airplanes with ion drive are not
going to make it in the commercial world." Whatever technology can make
that work will be FAR less costly applied to something that rolls along
the roadway.

But that misses the point that it's ENERGY that's the concern. Doesn't
matter how light or powerful the airplane engine is if it still can't lift
enough fuel to reach the destination. It takes a given amount of energy
to get from here to there. Changing the engine only affects the efficiency
of the process that converts the available fuel source to whatever it takes
to motivate the vehicle. Maybe we'll see terrestrial ion engines, but
the efficiency
improvement won't be huge.

If we had an electric fuel source of sufficient energy/weight ratio,
we'd already have electric airplanes.

If you're gonna spend millions of dollars to fling an object into
space at escape velocity, it makes sense to have a nuclear power
source that applies tiny thrust for a long time using minimal reaction
mass to continue the flight to places unknown.
For a terrestrial flight to New York, not so much.

So, what am I missing?

In sci.physics mike wrote:
On 11/7/2016 7:39 PM, wrote:
In sci.physics mike wrote:
On 11/7/2016 1:46 PM, wrote:
In sci.physics Phil Hobbs wrote:
On 11/07/2016 01:37 PM, wrote:
In sci.physics Robert Clark wrote:

snip

If you know of a means to provide 50,000 V at *lightweight* then you will
have solved the problem of an independently flying lifter, using the
macrosized wires currently used. You would need about a power to weight
ratio for the power source of better than 1 watt per gram, while being able
to provide these ca. 50,000 V voltages.

Bob Clark

Trivial; look at any camera flash unit built in the last several decades.

However you have totally missed the point; voltage and the weight of the
converter is irrelevant as it is the total power that determines the
weight of it all.

BTW, here are some real world power to weight ratios:

Boeing 777 engine 10 kW/kg
1985 Chevy Celebrity 300 W/kg -- So for a 1000 kg car, that's 402
horsepower? Sign me up!

Cheers

Phil Hobbs

No, that is the power to weight ratio of the engine, not the power to
weight ratio of the car.


Power is a red herring. What's important is the total energy produced
by the
engine AND the fuel supply.
It doesn't get the least bit interesting until the engine can lift
itself and a FULL tank of whatever powers it AND the vehicle AND the
payload to reach the destination.
I can't imagine that ever happening 1000 feet off the ground on this ole
earth at a cost anywhere near the cost of other forms of transportation.

Are you trying to say airplanes aren't going to make it in the commercial
world?


Yep, that's exactly what I'm saying: "Airplanes with ion drive are not
going to make it in the commercial world." Whatever technology can make
that work will be FAR less costly applied to something that rolls along
the roadway.

I doubt there is any technology that could ever make it work in an
atmosphere.

But that misses the point that it's ENERGY that's the concern. Doesn't
matter how light or powerful the airplane engine is if it still can't lift
enough fuel to reach the destination. It takes a given amount of energy
to get from here to there. Changing the engine only affects the efficiency
of the process that converts the available fuel source to whatever it takes
to motivate the vehicle. Maybe we'll see terrestrial ion engines, but
the efficiency
improvement won't be huge.

Aircraft engines don't lift anything.

If we had an electric fuel source of sufficient energy/weight ratio,
we'd already have electric airplanes.

If you're gonna spend millions of dollars to fling an object into
space at escape velocity, it makes sense to have a nuclear power
source that applies tiny thrust for a long time using minimal reaction
mass to continue the flight to places unknown.
For a terrestrial flight to New York, not so much.

So, what am I missing?

--
Jim Pennino

On 11/3/2016 9:00 AM, Robert Clark wrote:
Yes, that's a good example. Electric, battery-powered airplanes and
helicopters already exist.

Toys.


However, the key point is according to the
mathematics you can get even better power-to-thrust ratio with ionic
propulsion using ionizing wires at the nanoscale than helicopters
achieve.

what math ? got a url ?


As important as is the fact that you would no longer need heavy transformers
to produce tens of thousands of volts, even more important is the high
thrust-to-power ratio you can get by only using low voltages.

This page describes the operation of the "lifters":

Ionocraft.
3. Mechanism.
"A generalized one-dimensional treatment gives the equation:

F = I*d/k,
where
F is the resulting force, measured in dimension ML/T^2
I is the current flow of electric current, measured in dimension I.
d is the air gap distance, measured in dimension L.
k is the ion mobility coefficient of air, measured in dimension T^2 I/M
(Nominal value 2·10^−4 m^2/ Vs).

"In its basic form, the ionocraft is able to produce forces great enough to
lift about a gram of payload per watt,[6] so its use is restricted to a
tethered model. Ionocraft capable of payloads in the order of a few grams
usually need to be powered by power sources and high voltage converters
weighing a few kilograms, so although its simplistic design makes it an
excellent way to experiment with this technology, it is unlikely that a
fully autonomous ionocraft will be made with the present construction
methods. Further study in electrohydrodynamics, however, show that different
classes and construction methods of EHD thrusters and hybrid technology
(mixture with lighter-than-air techniques), can achieve much higher payload
or thrust-to-power ratios than those achieved with the simple lifter design.
Practical limits can be worked out using well defined theory and
calculations.[7] Thus, a fully autonomous EHD thruster is theoretically
possible."
https://en.wikipedia.org/wiki/Ionocraft#Mechanism

Since the power is P = I*V, amperage times voltage, the key thrust to power
ratio is F/P = d/kV. So if the air gap distance d remains the same, reducing
the voltage increases the thrust-power ratio. Then theoretically IF the
lifter is able to operate at hundreds of volts instead tens of thousands of
volts you could increase the thrust/power ratio hundred(s) of times.

Note that you can't just arbitrarily use a low voltage. You need sufficient
voltage to initiate air ionization. Experiments have confirmed that for
wires at the nanoscale you do get the important corona inception (air
ionization) for voltages in the only 100's of volts range. However, it is
very important to note that when you reduce the voltage and wire diameter
the thrust is also reduced. Indeed to get thrust sufficient for large scale
objects you would then need to use millions to billions of the nanowires.

Since the wires are only nanometers wide there is no problem in regards to
their fitting beneath a transport craft. But the large number of wires
required would be a consideration in regards to the wires corona regions.
You can't pack the wires too close together and maintain maximum thrust
since interaction between the separate corona's reduces thrust. Among
amateur experimenters that have built them, a lot of experimentation has
gone into the best geometry to maximize thrust. A common arrangement is the
triangular shape, with larger lifters constructed using this basic shape as
cells to build up to larger devices.

The reason you don't have just have a bunch of parallel wires bunched close
together with the lifters is because of the corona region interaction at
small distance. Then there would have to be a significant degree of
experimentation to determine how close the nanowires could be packed while
maintaining maximum thrust.

In regards to the comparison of the thrust/power ratio of the lifters
compared to helicopters. This is a parameter known as power loading for
hovering transports. For helicopters it's commonly in the range of 6 to 10
lb/hp:

Helicopter Aerodynamics and Performance.
http://images.slideplayer.com/12/349...s/slide_51.jpg

This is about 3.6 to 6 grams-thrust/watt. The lifters currently made using
macroscale wires get about 1 gram-thrust per watt in thrust/power ratio. So
if the nanowire lifters really were able to manage a hundred times better
thrust/power ratio than current lifters, that would be a major advance for
hovering transport craft. Even if the nanowire lifters only improve the
thrust/power ratio over current lifters by a factor of 10, that would still
be an improvement over current helicopters.

Bob Clark

--
----------------------------------------------------------------------------------------------------------------------------------
Finally, nanotechnology can now fulfill its potential to revolutionize
21st-century technology, from the space elevator, to private, orbital
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:

Nanotech: from air to space.
https://www.indiegogo.com/projects/n...ce/x/13319568/
----------------------------------------------------------------------------------------------------------------------------------

On Tue, 8 Nov 2016 07:13:09 -0000, wrote:

In sci.physics mike wrote:
On 11/7/2016 7:39 PM, wrote:
In sci.physics mike wrote:
On 11/7/2016 1:46 PM, wrote:
In sci.physics Phil Hobbs wrote:
On 11/07/2016 01:37 PM, wrote:
In sci.physics Robert Clark wrote:

snip

If you know of a means to provide 50,000 V at *lightweight* then you will
have solved the problem of an independently flying lifter, using the
macrosized wires currently used. You would need about a power to weight
ratio for the power source of better than 1 watt per gram, while being able
to provide these ca. 50,000 V voltages.

Bob Clark

Trivial; look at any camera flash unit built in the last several decades.

However you have totally missed the point; voltage and the weight of the
converter is irrelevant as it is the total power that determines the
weight of it all.

BTW, here are some real world power to weight ratios:

Boeing 777 engine 10 kW/kg
1985 Chevy Celebrity 300 W/kg -- So for a 1000 kg car, that's 402
horsepower? Sign me up!

Cheers

Phil Hobbs

No, that is the power to weight ratio of the engine, not the power to
weight ratio of the car.


Power is a red herring. What's important is the total energy produced
by the
engine AND the fuel supply.
It doesn't get the least bit interesting until the engine can lift
itself and a FULL tank of whatever powers it AND the vehicle AND the
payload to reach the destination.
I can't imagine that ever happening 1000 feet off the ground on this ole
earth at a cost anywhere near the cost of other forms of transportation.

Are you trying to say airplanes aren't going to make it in the commercial
world?


Yep, that's exactly what I'm saying: "Airplanes with ion drive are not
going to make it in the commercial world." Whatever technology can make
that work will be FAR less costly applied to something that rolls along
the roadway.

I doubt there is any technology that could ever make it work in an
atmosphere.

But that misses the point that it's ENERGY that's the concern. Doesn't
matter how light or powerful the airplane engine is if it still can't lift
enough fuel to reach the destination. It takes a given amount of energy
to get from here to there. Changing the engine only affects the efficiency
of the process that converts the available fuel source to whatever it takes
to motivate the vehicle. Maybe we'll see terrestrial ion engines, but
the efficiency
improvement won't be huge.

Aircraft engines don't lift anything.

Harriers aren't aircraft? Well, they do look a little like bricks.
;-)

In sci.physics Robert Clark wrote:
On 11/3/2016 9:00 AM, Robert Clark wrote:
Yes, that's a good example. Electric, battery-powered airplanes and
helicopters already exist.

Toys.


However, the key point is according to the
mathematics you can get even better power-to-thrust ratio with ionic
propulsion using ionizing wires at the nanoscale than helicopters
achieve.

what math ? got a url ?


As important as is the fact that you would no longer need heavy transformers
to produce tens of thousands of volts, even more important is the high
thrust-to-power ratio you can get by only using low voltages.

How many times must you be told you do NOT need heavy transformers to
produce high voltages?

Camera flash units produce tens of thousands of volts.

This page describes the operation of the "lifters":

Ionocraft.
3. Mechanism.
"A generalized one-dimensional treatment gives the equation:

F = I*d/k,
where
F is the resulting force, measured in dimension ML/T^2
I is the current flow of electric current, measured in dimension I.
d is the air gap distance, measured in dimension L.
k is the ion mobility coefficient of air, measured in dimension T^2 I/M
(Nominal value 2·10^−4 m^2/ Vs).

And what is the magnitude of I?

"In its basic form, the ionocraft is able to produce forces great enough to
lift about a gram of payload per watt,[6] so its use is restricted to a
tethered model. Ionocraft capable of payloads in the order of a few grams
usually need to be powered by power sources and high voltage converters
weighing a few kilograms, so although its simplistic design makes it an
excellent way to experiment with this technology, it is unlikely that a
fully autonomous ionocraft will be made with the present construction
methods. Further study in electrohydrodynamics, however, show that different
classes and construction methods of EHD thrusters and hybrid technology
(mixture with lighter-than-air techniques), can achieve much higher payload
or thrust-to-power ratios than those achieved with the simple lifter design.
Practical limits can be worked out using well defined theory and
calculations.[7] Thus, a fully autonomous EHD thruster is theoretically
possible."
https://en.wikipedia.org/wiki/Ionocraft#Mechanism

Since the power is P = I*V, amperage times voltage, the key thrust to power
ratio is F/P = d/kV. So if the air gap distance d remains the same, reducing
the voltage increases the thrust-power ratio. Then theoretically IF the
lifter is able to operate at hundreds of volts instead tens of thousands of
volts you could increase the thrust/power ratio hundred(s) of times.

A typical small aircraft engine produces about 140 kW, so at 500 V your
current is a bit under 300 A.

A typical small helicopter engine is about twice that size, so double
the current for a helicopter.

That means the conductors from the power supply must be huge and you
have to have hundreds, if not thousands, of emmitters to get the
individual currents down to levels that won't vaporize them.

Even if you mangaged to pull all that off, you now have a huge RFI
generator destroying all radio communication over a wide ares which
the FCC would never allow to be operated.


--
Jim Pennino

On 11/7/2016 11:13 PM, wrote:


Aircraft engines don't lift anything.


OK, how about, "Aircraft engines,
when properly fixtured,
can result in objects disengaging contact with the earth?"

In sci.physics mike wrote:
On 11/7/2016 11:13 PM, wrote:


Aircraft engines don't lift anything.


OK, how about, "Aircraft engines,
when properly fixtured,
can result in objects disengaging contact with the earth?"

How about the engine on fixed wing aircraft provides thrust to overcome
total drag to accelerate the aircraft to an airspeed sufficient to
provide enough lift from the wings to overcome the force of gravity?

How about the engine of a helicopter provides power to spin rotating
wings to a speed sufficient to develop enough lift to overcome the
force of gravity? For the purpose of this discussion assume that the
angle of attack of the rotor blades has been set appropriately.



--
Jim Pennino

On Tue, 8 Nov 2016 22:05:29 -0000, wrote:

In sci.physics mike wrote:
On 11/7/2016 11:13 PM, wrote:


Aircraft engines don't lift anything.


OK, how about, "Aircraft engines,
when properly fixtured,
can result in objects disengaging contact with the earth?"

How about the engine on fixed wing aircraft provides thrust to overcome
total drag to accelerate the aircraft to an airspeed sufficient to
provide enough lift from the wings to overcome the force of gravity?

How about the engine of a helicopter provides power to spin rotating
wings to a speed sufficient to develop enough lift to overcome the
force of gravity? For the purpose of this discussion assume that the
angle of attack of the rotor blades has been set appropriately.

There is more than one aircraft with a thrust to weight ratio greater
than unity, not to mention a rocket or two.

In sci.physics krw wrote:
On Tue, 8 Nov 2016 22:05:29 -0000, wrote:

In sci.physics mike wrote:
On 11/7/2016 11:13 PM, wrote:


Aircraft engines don't lift anything.


OK, how about, "Aircraft engines,
when properly fixtured,
can result in objects disengaging contact with the earth?"

How about the engine on fixed wing aircraft provides thrust to overcome
total drag to accelerate the aircraft to an airspeed sufficient to
provide enough lift from the wings to overcome the force of gravity?

How about the engine of a helicopter provides power to spin rotating
wings to a speed sufficient to develop enough lift to overcome the
force of gravity? For the purpose of this discussion assume that the
angle of attack of the rotor blades has been set appropriately.

There is more than one aircraft with a thrust to weight ratio greater
than unity, not to mention a rocket or two.

Yes, there certainly are but they are niche aircraft in the overall
scheme of things and an extremely small percentage of aircraft.

Maybe you'd like to include ornithopters in the discussion of engines
for flying machines.

Rockets are rockets.

https://en.wikipedia.org/wiki/Aircraft



--
Jim Pennino

On Wed, 9 Nov 2016 00:13:29 -0000, wrote:

In sci.physics krw wrote:
On Tue, 8 Nov 2016 22:05:29 -0000, wrote:

In sci.physics mike wrote:
On 11/7/2016 11:13 PM, wrote:


Aircraft engines don't lift anything.


OK, how about, "Aircraft engines,
when properly fixtured,
can result in objects disengaging contact with the earth?"

How about the engine on fixed wing aircraft provides thrust to overcome
total drag to accelerate the aircraft to an airspeed sufficient to
provide enough lift from the wings to overcome the force of gravity?

How about the engine of a helicopter provides power to spin rotating
wings to a speed sufficient to develop enough lift to overcome the
force of gravity? For the purpose of this discussion assume that the
angle of attack of the rotor blades has been set appropriately.

There is more than one aircraft with a thrust to weight ratio greater
than unity, not to mention a rocket or two.

Yes, there certainly are but they are niche aircraft in the overall
scheme of things and an extremely small percentage of aircraft.

Maybe you'd like to include ornithopters in the discussion of engines
for flying machines.

Why not? The whole thread is already pretty silly.

Rockets are rockets.

https://en.wikipedia.org/wiki/Aircraft

Oh, Ion engines aren't be proposed for rockets, too? Never mind.