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Robert Clark

Fri Aug 12 2016, 03:22AM

Registered Member #58454 Joined: Thu Feb 18 2016, 06:33AM
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Posts: 23

I'm researching the ionocraft, commonly called a "lifter":

These require tens of thousands of volts. Usually heavy iron cored transformers are used to create the high voltages. But this means the power supply is heavy and the ionocraft can't lift them.
But how lightweight can an air cored transformer be? Less than 1 gram weight per watt power output would be ideal.

Bob Clark

Sulaiman

Fri Aug 12 2016, 09:33AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

have you looked here ?

a few random thoughts;

how will you stabilise a free-floating lifter ?
could you consider a helium baloon to neutralise most of the weight, and give stability?

copper wire is dense, consider aluminium or carbon ?

how will you remotely control the power?

I believe that the power-to-weight ratio of a high frequency ferrite=cored transformer is better than air-cored,

everyone knows that UFOs get their power from the mothership,
maybe 'wireless power transfer' is practical at short-range?

Robert Clark

Fri Aug 12 2016, 01:14PM

Registered Member #58454 Joined: Thu Feb 18 2016, 06:33AM
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Posts: 23

Thanks for the response. That link you provided is one that all researchers on the lifters have read. In that page, like with all other researchers, they use iron cored transformers to get the high voltage. But these are too heavy for the lifters to raise.

You can stabilize the lifter by actively varying the angles of the collector plates at the bottom.

The air core transformers look light to me because all they consist of is wires, no iron core. But perhaps this results in low power efficiency.

I was not aware you could get a high frequency iron core transformer. I thought air cored was used for that.

Do you have an example of an iron core that can get better than 1 watt per gram power to weight ratio?

Bob Clark

Mads Barnkob

Fri Aug 12 2016, 01:56PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

You would have to build a high frequency high voltage switch mode power supply, that could use a small planar high voltage transformer with multiplier stages after.

High frequency implies that you do not use iron core transformers anymore, but ferrite cores of different material composition depending on your switching frequency. But you are properly most likely to be with the spectrum of MnZn cores.

Finn Hammer

Sat Aug 13 2016, 05:13AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

Robert,

It would help a lot if you would come forward and describe what you want the lifter to do, for example: "I want to build a lifter that can fly by itself and be remotely controlled".

Since you are so concerned about the weight of the power supply, I assume that you want to float it on the lifter.
Is this a correct assumption?.
In that case, you also have to float the power source, batteries, they are heavy too. Have you considered that?
And grounding of that power supply? Drag a ground wire after the lifter?

Cheers, Finn Hammer

Robert Clark

Sat Aug 13 2016, 06:46AM

Registered Member #58454 Joined: Thu Feb 18 2016, 06:33AM
Location:
Posts: 23

Finn Hammer wrote ...

Robert,
It would help a lot if you would come forward and describe what you want the lifter to do, for example: "I want to build a lifter that can fly by itself and be remotely controlled".
Since you are so concerned about the weight of the power supply, I assume that you want to float it on the lifter.
Is this a correct assumption?.
In that case, you also have to float the power source, batteries, they are heavy too. Have you considered that?
And grounding of that power supply? Drag a ground wire after the lifter?

Cheers, Finn Hammer

Thanks for the response. Yes, I want a lifter that can fly independently without being attached to a power supply left on the ground. This would be a completely new, practical form of transportation. Silent, with no moving parts, completely emission free.

I have looked at the batteries part of the equation. Surprisingly, high power density batteries do exist. They are used for example for radio controlled airplanes and helicopters where you need high power at lightweight to drive the propellers or rotors. I've seen battery power(watts) to weight(grams) ratios of better than 10 to 1, i.e., these batteries can put out more than 100 watts of power at only a 10 gram weight.

Since the lifters can raise in the range of 1 gram in weight, i.e., the thrust, per 1 watt of power input, this would be well within the requirements to get an independently flying lifter.

It's the high voltage power supply that is the stumbling block to getting them to fly independently. Do a google image search on "lifters", "power supply", and "high voltage". You'll see the lifters are quite light, in the range of a few grams, but the power supplies are large and heavy in the range of a few kilograms.

Bob Clark

Finn Hammer

Sat Aug 13 2016, 09:02AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

Bob,
When The typical power supply is heavy like a brick, it is only because The Random experimenter does not know better.
Try to have a look at The supply nested inside a taser stick, The small handheld units that advertise megavolts, but dont deliver close to that, still, rectify, and you might be flying.

Cheers, Finn Hammer

Sulaiman

Sat Aug 13 2016, 09:04AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

can you specify the eht psu a little better ?
e.g. voltage and current and weight required

I suspect that mechanical movements to achieve stability is a poor choice because
. it will add significantly to the overall weight
. the craft will no longer have no moving parts
. for a triangular lifter you could use three separate inverters with variable outputs

Finn : I believe that there is no need for an earth wire,
it is just the p.d. between corona wire and the rest that is required

Robert Clark

Sat Aug 13 2016, 01:49PM

Registered Member #58454 Joined: Thu Feb 18 2016, 06:33AM
Location:
Posts: 23

Sulaiman wrote ...

can you specify the eht psu a little better ?
e.g. voltage and current and weight required
I suspect that mechanical movements to achieve stability is a poor choice because
. it will add significantly to the overall weight
. the craft will no longer have no moving parts
. for a triangular lifter you could use three separate inverters with variable outputs
Finn : I believe that there is no need for an earth wire,
it is just the p.d. between corona wire and the rest that is required

The specs of the lifters built by one lab are here:

You see the best thrust to power they could manage was about 1 gram thrust per watt of power. For instance the basic triangular Super Cell V1.0 lifter listed there got .15N thrust, about 15 gram-force, using 14 watts of input power.

This particular one used rather higher voltage though of 54 kV. So the amperage was 14W/54,000kV = 0.25 mA.

Bob Clark

Robert Clark

Sat Aug 13 2016, 01:55PM

Registered Member #58454 Joined: Thu Feb 18 2016, 06:33AM
Location:
Posts: 23

Finn Hammer wrote ...

Bob,
When The typical power supply is heavy like a brick, it is only because The Random experimenter does not know better.
Try to have a look at The supply nested inside a taser stick, The small handheld units that advertise megavolts, but dont deliver close to that, still, rectify, and you might be flying.

Cheers, Finn Hammer

I think these work by using capacitors which are known to be able to put out high power but only for a short pulse for a few seconds. We need a power supply to work for several minutes continuous.

Bob Clark

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