An ion thruster produces a flow of air even though it has no moving parts. A version of this seemingly impossible device is used on a larger scale to propel deep space probes for NASA. The advantage to this system over others is that you need only an electrical source to power the device and it has no moving parts so it is almost unbreakable. So why aren’t we using this to power our cars, boats, planes, and hovercrafts?

There are a few reasons, but they may not be the ones you think. The first idea you might have is that it’s just too expensive. This is certainly not the case: the device that I show you how to build today cost me less than $10 in new materials (I already had some solder, flux, wood, an NST, and Variac lying around). The second reason you might think of is that the device is just too complex. This would also be an incorrect assumption. As I said above, I am going to show you how to make this device today. It can take as little as 2 hours.

So why don’t we use this technology? Well, the primary reason is that the thrust of the device that I will show you how to construct is, simply put, miniscule. The 12,000 volts of power that the device runs on can only manage to lightly blow a piece of tissue paper. Nevertheless, it does produce a flow of air without any moving parts.

Today I will show you how to build your very own over-engineered and extremely dangerous fan out of little more than some copper pipe fittings, nails, and an NST (if you don’t know that NST stands for neon sign transformer, you should definitely learn more about the dangers of high voltage before you proceed). The device essentially is just two poles of an HV source. The poles are kept far enough away from each other so they ionize the surrounding air but do not arc. The ions produced flow towards the other pole of the voltage. Although the ions are all absorbed, the surrounding air that wasn’t ionized gains enough momentum so that it keeps going in the direction you aim for.

WARNING: The transformer used in this project produces voltages and current that CAN be LETHAL. If you are using a variable autotransformer to power your ion thruster, pushing the transformer beyond 120 volts is a VERY bad idea. Transformers can fail even when they are within their normal range of operating voltage. Only allow your transformer to operate in its normal voltage range. Take great care to safely discharge the transformer before approaching it. Never leave a transformer plugged in when you are not near the power cord.

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Project Steps

Gather supplies

Refer to the materials list.

Gather everything you need for the project and put everything in one place. A clean and organized workspace is essential to any good project.

Make sure that your wood is cut to size and has clean ends before you start.

Arrange the couplings.

First arrange your couplings in the pattern that you want the fan to be in. I chose a simple honeycomb pattern.

Apply a generous amount of flux to the connecting surfaces of each coupling.

Arrange the couplings with flux on a heat resistant surface (like a tile) and proceed to the next step.

Tip: When you heat the copper tube array, flux will go all over the tile. The hotter the flux gets, the lower it’s surface tension and the more it runs. Use a tile that you don’t want anymore.

Solder the couplings together

If you want, you can prevent the couplings from moving during soldering by tieing a wire around the assembly. I have not found this necessary.

Heat the tube assembly from all sides with a blowtorch. Heat everything for 15-20 seconds.

Gently apply solder by lightly pressing in between the adjoining surfaces of the tubes. The solder should melt very easily. If it doesn’t, heat for another 10 seconds and try again.

Before the solder fully hardens, lightly coat the wire in flux and apply it in between the tubes. If the solder is still liquid, the wire should bond to the structure.

Wait for the tube structure to solidify (about 2 minutes), then pick it up with a pair of pliers and cool it down with water.

The structure will have become discolored from the heating and the flux. This is absolutely fine.

Find the center of each cylinder

Take a small piece of paper and hold it over the cylinder assembly. Using a standard pencil (not mechanical), gently trace back and forth over the top of the assembly. You should notice that the outlines of the cylinders appear.

Once you have an outline of the cylinders, find the approximate center of each. I found that making two bisecting lines worked well for this. If you are so inclined, you can also check the position with a compass.

Assemble the cathode tower (Part 1)

Place the stencil that you just made on the piece of wood or acrylic that you want to use as the cathode tower. Make sure the holes will be centered on the board.

Transfer the centers of each tube to the board by pressing with a pin or a sharp pencil. With wood you should be able to just poke a hole through the paper.

Remove the stencil and define the markings by putting x’s over them.

Assemble the cathode tower (Part 2)

Using a drill bit that matches the size of your nails, carefully drill all 7 holes on the cathode tower. Be sure to keep the drill bit perfectly level. If you have a drill press or access to one, you should definitely use it.

Now would be a good time to sand the edges and the face of your cathode tower to get rid of those markings and sharp edges. You may also wish to sand the edges of the base at this time.

Add the nails

Take your copper plated nails and insert one into each of the holes that you drilled previously.

Push them most of the way in, but leave the heads sticking out about ¼”.

Wrap the other length of copper wire around each nail. Normally you would solder an electrical connection like this, but due to the high voltage and the eventual need to replace the nails in this application tightly wrapping the wire will be sufficient.

Press the nails in as far as they will go and proceed to the next step.

Find the length of the support tower

Take a wooden tower about the height of your cathode tower and cut a 45° point in it.

Position the tube array over the nails and find where the center of each tube is closest to the nail.

Position the tower’s pointed end where two tubes meet and mark where the base of the cathode tower is on the support tower. Trim the tower to the proper length and use any adhesive you like to join it to the tubes. I used hot glue because it is fast, insulating and easily removable if you make a mistake.

Attach the components to the base

Using whichever adhesive is your favorite, attach the cathode tower to the base, about 3 inches from the end.

When the adhesive is set, test the tube assembly’s height. If it needs to be shorter just sand it slightly. If it is good, affix the tube assembly to the base about 1 inch from the tips of the nails. Make sure it is centered properly.

Try it out!

Attach the HV leads of the transformer to the cathode tower and the tube assembly. Despite calling it the “cathode tower” there is no particular need for it to be the positive side since AC current switches polarity at a rate of 60Hz. MAKE SURE THE TRANSFORMER IS NOT PLUGGED IN WHEN YOU ARE NEAR IT!

If you have a variac I would suggest using it to see the effect of different voltages. Always be ready to unplug the transformer if the electricity starts to arc. Always keep your hand at least 10 inches away from any part that has electricity flowing through it. If all goes well, you should hear a humming noise and feel a light wind coming from the tubes!

If the electricity arcs, don’t worry. Just unplug and discharge the transformer, then adjust the nails so they are ¼” back from where they were. If you are using a variac, just set the voltage a bit lower.

If you don’t feel anything, move the nails closer, but keep in mind that the wind produced is extremely light. Use a tissue to check if there is any breeze.

If your transformer isn't wired already...

Check out Step 19 of this Nuclear Fusor project. Mr. Spangler does an excellent job of explaining it. Now that you have experience with high voltage, you might even consider trying the whole project.