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DIY Lifter - An Electrohydrodynamic Thruster (EHDT)
The diagram below shows a EHDT in its most basic form. It consists of a fine wire, suspended above a sheet of Aluminium foil, by a lightweight insulating support such as balsa wood. If a high voltage DC source is connected as shown, a thrust will be produced, propelling the device in the direction of the positive wire. This thrust is due the motion of air, or any other dielectric (insulating) fluid around the device, as described below.
WARNING: This project requires the use of dangerous high voltage electricity!
The top sharp electrode ionizes the air. If the electrode is positive, free electrons in the vicinity will accelerate towards it, and strip off other electrons from the air molecules around the sharp wire. A cloud of heavy positive charges is thus formed, and the avalanche of electrons approaching the sharp electrode account for the corona & ionization current.
In their mad rush from the ion emitter to the smooth negative electrode, the positive ions bump into neutral air molecules-air particles without electric charge. The force exerted on them by the electric field is offset by the force of friction caused by collisions of the ions with the neutral air molecules. As a result, ions drift through the air gap with an approximately constant velocity Vd, that is proportional to the electric field given by Vd=kE, where the proportionality constant K is called the ion mobility, the highest the value the more mobile (faster) and the less friction is offered.
EHDT Construction Details
Gently fold over the top a long edge so you are left with a long rounded edge, and a long sharp edge opposite. The rounded edge will be closest to the corona wire.
Fold the strip into three equal sections, plus a little extra for sticking the ends together.
Using a small amount of glue, attach three lightweight balsa wood supports, and stick the two short edges of the foil together to form a triangle.
Loop a thin wire around the supports so that it is a few centimeters from the foil, and leave a long wire for connection to the power supply.
Connect another long wire to the foil, in a position away from the other trailing wire.
Flying the Lifter
The voltage required to power the lifter will depend upon its size but it is usually above 10kV. By moving the top corona wire closer to the foil, more thrust can be produced. If it is too close arcs will jump between the electrodes, causing it not to fly.
Place the thruster on an insulating surface (a table), and away from any metal objects.
Attach the two wires to the table so that the thruster can hover, whilst being held down by the wires.
Making a HV DC power supply for the lifter
For a tiny Lifter the output of a plasma globe PSU and a HV diode can be used, but for a larger device a larger transformer may be needed.
The picture on the left is of the inside of the plasma globe, and you can make the output of this DC by connecting it to a HV diode.
For larger lifters, a simple adjustable supply can be made by driving an high voltage coil with a power pulse modulatorand then rectifying the output with a high voltage diode and capacitor as shown here. The diode D1 should be rated for high voltage such as 20kV, 100mA as to withstand current pulses from accidental shorts. The capacitor C1 should also be rated for 20kV. The capacitor is not essential but it can help improve performance and add some protection for the diode. The capacitance can be any value, but bigger is better.
The pulse modulator allows you to vary the output voltage very easily so that you can get more control over the performance of the lifter.
The information provided here can not be guaranteed as accurate or correct. Always check with an alternate source before following any suggestions made here.
ElectroHydroDynamic Propulsion
The transformers in CRT screens give a DC output because they usually have a built in voltage doubler.
If your propulsion systems were used more, we would save a lot of money.
Could you give me some dimensions, my transformer is a 10kv 25-30mA or alternately i have a flyback, which would you reconmend.
Have they ever tried to use a small tesla coil as power source or would this just be over kill.
thank you very much.
thanks!
Something else that might help is that I know I found it on your site somewhere, but I'm not sure where.
Thanks!!
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But where does the power go in?
More current or voltage makes more thrust upt to certain limits. Too much and energy is just wasted.
Attatching multiple units together is an effective way.
and if an Wimshurst machine cant power it than wut else can power on of this other than wut u have posted.
There are many different ways to make and power a thruster. Google the term 'lifter' to find many examples.
copper is a much better conducter
The most lightweigt PSU I have used was made by removing the globe from a plasma globe and placing a HV diode or rectifier arrangement on the output so that it gives about 15kV DC (depending on size of original plasma globe). This will only give enough current to fly the tinyest of EHDT like shown in the video.
i now got some money t spend and gonna tinker with some of this stuff ill share iny thing new with you.
i dont know how i found this site but im happy i did this is a great site
but quite low ampige since i am going from mains is that anoth to power a descent sized one and if not could u sugest a power supply design that would give alot more power i was thinking of makeing a much larger one useing 3 of them attached to gether and my final question is there a formula u could give me to find the thrust of givin size voltage and current.
thanks
The simplest way is to use a voltage multiplier to step up the mains.
Formula available here
Thanks
You need thousands of volts DC for an EHD lifter to work
ALIENBLUESTAR
What energy it that then?
Oh yeah, rubber bands!!..
It seems as though it would be cheap and easy to manage.
Of course, it would have to be far larger than this.
Without an iron coil, the transformer you mention would not be very efficient.
You could probably send quite a lot of power by microwaves although it is not likely to be practical, or cost effective. I think the weight of any conversion hardware would be quite high. maybe with future nano-material technology, something better could be done.
Thanks in Advance
You could use a voltage doubler circuit to both convert it to DC and to double the voltage.