Ion drive for aircraft imminent.

tto:

[CUT]

old.

EM-drive is much better :)

-really-does-work

Bye Jack

1.2 milliNewtons of thrust per kW energy input. At any sane terrestrial speed, that's less than half of two thirds of f*#k all.

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.

1. 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

"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."

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.

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

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A helicopter...a real one that is....can weigh as little as 1300 to 1600 pounds for a 2 place piston, like a Robinson R22 ( guessing the weight) to a BK 117 like I fly which grosses out at 3200 Kgs to the huge Russian machines that are up to over 100,000Kgs. The Mil V-12 is the largest I believe. Whatever their weight they are sure to consume huge amounts of fuel whatever they do.

1300 lb = 589,670 grams or about 589,670 watts required using your conversion ratio,

assume you are using a max of 1 micro amp through your nano wires, then the voltage needs to be W = V * I or 589,670 = V * 10^-6 or

58,967,000,000 Volts

unfortunatly, this amount of voltage breaks down air insulation for several thousand feet, so the explosion and arc over will wipe out the wires.

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

>

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.

And what is the magnitude of I?

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

Or if you can make it work on a reduced voltage to each wire then you need billions of wires in parallel and a huge supply current. And it is current in a power supply that necessities big heavy wires, not voltage because of I^2*R.

--
Jim Pennino

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 Tuesday, November 8, 2016 at 9:46:22 AM UTC-8, snipped-for-privacy@specsol.spam.sux.com wrote: ...

...

Normal camera flash tubes run off about ~300V plus a trigger pulse of ~4kV.

kevin

OK, Tazers produce tens of thousands of volts and don't have heavy transformers.

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

All that's needed is government funding to get the efficiency up and the price down. A few $T ought to get Elon's interest.

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.

--
Jim Pennino

You sure about that? My stun gun has a heavy transformer...heavy relative to the energy it can supply. I don't think you could suspend it, and the energy source using the energy it could supply for very long.

Why not? The whole thread is already pretty silly.

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

From start to end...

Where is the word "rocket" in the subject of this thread?

--
Jim Pennino

Where would you put the Harrier in that definition? Doesn't it have the ability (albeit rather lightly loaded) to take-off vertically on thrust from the engine alone?

rick jones

--
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