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Flyback driver and a lifter

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Antonio

Mon May 19 2008, 07:07PM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644

I have built a flyback driver to power a "lifter", and other experiments:

The driver generates a ramp current at the base of the power transistor using an inductor, and recovers most of the energy stored at the inductor at the end of the cycle.
The constructed circuit, being tested with an electrometer:

A "lifter", with the structure made with plastic transparency foil:

Flying:

A bit more of power is needed for reliable results, but it worked.

Coronafix

Tue May 20 2008, 02:35AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Nice one Antonio! I built one once out of balsa though, then it arced over and the thing caught fire.
I always thought it was interesting how Jean-louis Naudin found that by pulsing the DC HV into the lifter it
increased the efficiency. He only tried it up to 100Hz, but he found that 70Hz was the best.
Would be a simple rotary spark gap perhaps?

Antonio

Wed May 21 2008, 12:14AM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644

Since ionic wind is a quite nonlinear function of the applied voltage, it seems possible that pulses can be better than pure DC. My power supply produces significant 120 Hz pulsing due to the quite low capacitance that I put after the rectifier. Maybe this is good, not bad. Some shaking caused by the pulses also helps in the takeoff. I would like to find a way to reduce ozone generation. These things are not good for the health...

Coronafix

Wed May 21 2008, 12:43AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

He has a chart that shows the input power dropping down until it reaches 70Hz then going back up slightly until 100Hz, not sure where 120Hz would be. They also tested asymmetrical capacitors in a high vacuum recently and it worked contrary to popular opinion, perhaps Brown was correct all along.
I don't know how you would decrease the ozone, perhaps something to "soak" it up?

Avi

Wed May 21 2008, 02:01AM

Registered Member #580 Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410

if it holds together with just the top triangle, you can just about halve the weight by removing the bottom one.

Tesladownunder

Wed May 21 2008, 02:16AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Goldsphere wrote ...

He has a chart that shows the input power dropping down until it reaches 70Hz then going back up slightly until 100Hz, not sure where 120Hz would be. They also tested asymmetrical capacitors in a high vacuum recently and it worked contrary to popular opinion, perhaps Brown was correct all along.
I don't know how you would decrease the ozone, perhaps something to "soak" it up?

Naudin's site has so much pseudoscience in it, that I would not regard it as a reliable source of information. and there are so many other effects of electrostatic attraction that I do not believe the vacuum stuff. You are not going to get a high vacuum with balsa in the cavity anyway.
I have not seen any evidence that pulsed DC works better than DC. In the marginal lift situation you don't want to lose your lift for part of the cycle. The problem is that peak voltage limits how close your wires get. Anything less than that means you have less lift.
This is why half wave rectified DC wont work until you add a capacitor.
My lifter page is here. I think mine is the only one on the net that is in constant public display for 2 years.
Pic shows my 80kV lifter lifting its own weight in payload (4.6g)

TDU

Coronafix

Wed May 21 2008, 11:04PM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

I know that his site has a lot of pseudoscience on it, but I don't think that should distract from the obvious amount of research he has put into lifters. In fact, I have not seen anyone else who has done the amount of research and documentation that Jean-Louis has done. The fact that he actually recreates pseudoscience devices in order to test them for some possible anomaly as the inventor has claimed, should just highlight more the scientist that he is, but instead gets constantly flamed for it. If more web pages followed his lead on the scientific documentation including graphs and videos, the web would be more enjoyable for us science minded types, but alas some prefer showmanship to increase traffic.
I really don't understand how supposed scientific minds can "poo poo" an idea or statement before even trying to recreate it. The experiment wouldn't be difficult as I have stated.
Meanwhile here is something about the vacuum testing.

Avi

Thu May 22 2008, 12:02AM

Registered Member #580 Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410

His own documentation on lifters speaks of operating with additional non scientifically proven (amounts?) of partucular forces.
Anyway can we not speak of this anymore and back to the topic!

Coronafix

Thu May 22 2008, 12:57AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Yeh, I know his conclusions are not what you would expect, but his data seems honest.
Anyway, the vacuum stuff,

Antonio, what voltage and current do you think you are getting from your output?

Antonio

Thu May 22 2008, 01:24AM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644

I will make more precise measurements, but I estimate about 25 kV without much load, based on spark length between balls and simulations.

Measurements:
Open circuit: 25 kV (9.5 mm sparks between 3.8 cm balls)
With 40 MOhms of load: 25 kV (0.63 mA)
With 5 MOhms of load: 11.5 kV (2.3 mA)
With lifter, in series with 5 MOhms of resistance: 25 kV
Return current from the lifter: 0.5 mA

But I need a bit more of voltage, or a lighter lifter (really the lower triangle is not needed), to get something more reliable.

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