ion gun in regular air

[Gyro]

One thing I should perhaps mention is that lifters require asymmetrical electrodes. When I was experimenting with mine, I tried swapping the polarity. The direction of thrust remains the same. Efficiency was better with the small (wire) electrode +ve irrc.

[helius]

At low electrode potentials, lifters must ionise lots of air, that's the sharp vertical line on the left.

Was the horizontal axis of your graph supposed to be labeled in kV instead of V?
At such "low potentials" as shown you will get no ionization at all! The potential required is closer to 25,000 V.

[aussie_laser_dude]

One thing I should perhaps mention is that lifters require asymmetrical electrodes.

In pretty much every lifter guide, paper, website, design etc you learn that the better the asymmetry, the better it lifts. Fair enough, they have good experimental evidence to show this consistently is an important factor in their designs. I doubt they could make a lifter that lifts with symmetric electrodes. Better ionisation and asymmetrical positioning of initial ions to give an assymetrically applied force are two reasons why you'd need asymmetrical electrodes. I'm saying everyone is using a design that's easy to make, not one that best utilises the physics. I stand firm, symmetrical electrodes can work.

I tried swapping the polarity. The direction of thrust remains the same. Efficiency was better with the small (wire) electrode +ve irrc

Hehe, this was fun to figure out. Same direction of force with reverse polarity is due to positive vs negative ion acceleration. Figuring out why it gives more thrust in one polarity took me a bit longer to understand, I won't spoil the puzzle. Do you have numbers on the the difference? (force, volts, current, electrode shape and separation for each polarity)

Was the horizontal axis of your graph supposed to be labeled in kV instead of V?

It's V, if you read the title, this is the total power for lifting a "mass" (it's a pretty heavy mass). It's the general shape of the curve that's important, not the vertical scale which will vary with lifters, typically in W rather than MW.

At such "low potentials" as shown you will get no ionization at all! The potential required is closer to 25,000 V.

Exactly! This is the best forum ever, so many thinkers.
Quoting myself:

The low part of the curve (high efficiency of Force to Power consumption) is inaccessible with current lifter designs.

I'm not suggesting the engineering is simple to get around this problem, but I've got ideas. I'd like to first verify experimentally that what seems impossible is actually doable. I'd like some help from some electricity savy people on this forum with an experimental setup to make some basic measurements and test physical models, i asked before but I'll try again with slightly better diagrams.
[see attachment]

[Gyro]

I tried swapping the polarity. The direction of thrust remains the same. Efficiency was better with the small (wire) electrode +ve irrc

Hehe, this was fun to figure out. Same direction of force with reverse polarity is due to positive vs negative ion acceleration. Figuring out why it gives more thrust in one polarity took me a bit longer to understand, I won't spoil the puzzle. Do you have numbers on the the difference? (force, volts, current, electrode shape and separation for each polarity)

No, I don't have figures, it was pretty unscientific (I was just interested to see if it actually worked) - It just seemed to take a tad more voltage to become airborne with reverse polarity and was probably a a little noisier, it just seemed to struggle a bit more (it was still flying easily before it reached flashover though). There was also maybe a bit more ozone production, but it was pretty smelly whichever polarity (this was 14 years ago so my memory has faded a bit).

Electrode geometry is clearly a very strong influence on the thrust produced - I'd like to see you achieve results with symmetrical electrodes, but it seems to me that you're throwing away an awful lot of 'geometry based advantage'. These things operate at very close to flashover voltage as it is.


Edit: You can see construction, electrode shape etc. in the photo and video in my thread that I linked previously (and below), just a basic triangular, wire and foil one.

Edit1: As far as dimensions and spacing go, I think length of side was about 100mm, electrode spacing about 20mm, and the skirt of the bottom electrode about 10mm (probably sub-optimal). Same dimensions for both polarities. The PSU topped out at 25kV @ maybe 0.5 -1mA.

[Marco]

I suspect positive wires give better lift because OH- and O2- are heavier than H+.

[aussie_laser_dude]

I suspect positive wires give better lift because OH- and O2- are heavier than H+.

Yeah I think it's something like this, I'm not 100% sure what cations and anions form, but I'm pretty sure it's to do with the asymmetry in mass of cations vs anions. One interesting experiment that could be done would be to take a flexible, plastic, transparent tube and place two ring shape electrodes inside, say 10cm apart and apply 1kV (a weak, non ionising electric field). The tube could then be made into a close loop with a small feather sticky taped inside the tube to measure airflow. Background radiation would generate a small concentration of ions in the tube and the tiny electrical current of the drifting anions/cations would result in a net force on the air. Over minutes / hours the air would build up speed and the feather could be seen pushed by the wind. This force would be dependent on electrode polarity, as opposed to the dominant force measured standard lifter designs. I'd do this experiment right now but I have little money and currently no lab or equipment If anybody is bored, here's a chance to discover a new electricity/air phenomena (I think it's new?), that uniform electric fields weakly push air.