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Parts of an ionocraft
An ionocraft itself is very easy and cheap to make but it takes a lot of adjusting to make it fly. Here are its main components:
1: 42swg (0.1mm) wire strung around the three vertical supports and connected to the high voltage cable. This acts as the sharp component needed in order to make the ionocraft fly. We tried thicker, 30swg wire and found out that it does not work well because it held the ionocraft on the platform due to its rigidity and also since it was thicker, it was not as sharp which meant it would produce less lift. The wire can be fine-tuned by moving it up and down along the balsa supports and find the correct place for it, thus making the ionocraft fly.
2: 1/16 inch pieces of balsa wood that support the whole structure. We used balsa wood because it is extremely lightweight and fairly strong. There are also pieces of balsa along the top of the foil skirt that give a flat surface for the foil to rest on. This is the other component, the blunt end, that is required to generate lift
3: One long strip of normal kitchen aluminium foil. Although this ionocraft will work if we reverse the polarity, I decided to attach the skirt to the ground because it is safer to have the high voltage components as far away from the base plate as possible to avoid short circuits.
How an ionocraft works
Two conductive materials, usually metals, are placed near each other. One of them has to be sharp (in our case this is the very thin wire) and the other one has to be blunt (kitchen foil folded over a flat balsa beam). Then the high voltage is attached to the sharp object and the ground to the blunt object. The polarity does not matter but I decided to put the ground on the foil skirt to keep the high voltage far away from the landing platform. Once high voltage is applied to the sharp object, it becomes positively charged and the blunt object becomes negatively charged 
The charges are packed closer together on the sharp object than they are on the blunt object. Once the power is turned on, an electric field forms between the two
objects and I have represented it by drawing lines from a positive charge to a negative charge. The closer together the lines are, the stronger the electric field is. The electric field is stronger near the sharp object because the charges are packed closer together.
The atoms in the air between the two objects also have positive protons and negative electrons. The electric field is so strong near the sharp object that is can sometimes pull negative electrons from the atom. Like charges repel, unlike charges attract. Since the electron that was pulled away from the neutral atom is negatively charged, it gets attracted to the positive sharp object. The atom that is left behind becomes positively charged due to one of its negative electrons getting pulled away and gets attracted towards the negative blunt end. This type of atom is called an ion. So far, ionocraft does not move because all forces cancel out.
In the air near the blunt object there are many neutral atoms that do not interact with the electric field. The ions that are travelling in the direction of blunt object can sometimes collide with the neutral atoms in the air. This slows the ions down but makes the neutral atom go in the direction of the blunt object also. Since the neutral atom is not connected to the electric field and the ion is, the ionocraft moves in the overall direction of the sharp object, opposite to the direction of travel of the ion. The neutral atoms in the air that have been knocked in the direction of the blunt object by the ions keep on going past it. This is the ion wind even though most of it is not made of ions and it can be felt by carefully putting your finger near the bottom of the foil skirt.
In short:
An ionocraft moves because of ions that are connected to the device through an electric field bump into atoms in the air, causing the device to move in the direction of the sharp object.
Building the ionocraft
Here is how I built the 30+ prototypes and the final ionocraft that is on display:
1. Firstly, cut out a sheet of foil measuring 5cm by 30cm and trim 6 pieces of balsa supports to 9cm with a sharp blade. The exact dimensions are not important as they do not impact performance.
2. Glue 3 pieces of 9cm balsa 1cm below the top of the foil while making sure 0.2cm of space is left between the struts. There should be 2-3 cm of extra foil on the end.
3. Fold over the 1cm of foil onto the horizontal struts below and glue into place the remaining three vertical balsa supports in the places left in the previous spot.
4. Apply glue on the spare 2-3cm of foil and fold everything together into a triangle. Attach the very thin wire to the top of the lifter.
5. Finally, sellotape thin pieces of thread to the small protruding landing legs and the ground wire to the foil skirt.
Once this is built, it will probably not fly straight away because a lot of very fine adjustments must be made. Try to move the thin wire that is spun around the top of the lifter as close as possible to the foil skirt without making any arcs. If the wire is too close, then the ark will burn the balsa and if it is too far away, not enough lift will be generated. It is also important that the wire is relatively straight and is following the triangular shape of the foil skirt. Another useful tip is to place this in a dark room and inspect the corona (this is a blue-purple glow that appears in the space between the foil and the wire due to ions moving from the sharp object, the wire to the blunt object, the foil). If there is a corona on one side but not on the others, move the wire closer to the foil slightly on those sides.
We have built many prototypes because we were experimenting with different wire thicknesses and other building techniques as well as the fact that the we moved the wire too close to the foil on some prototypes and the vertical balsa supports ended up burning and snapping due to the powerful electric arc.
The power supply
In order for the ionocraft to work, a power supply that can provide 30 kilovolts (30,000 volts) at 250 microamps (0.00025 amps) is required. A cathode tube TV meets all of these requirements. A cathode tube TV is one of those old ones that have a massive back compartment and we got one from eBay for 5£. Firstly, we located the high-voltage wire leading to the cathode tube, cut its connection to the tube and rerouted it outside of the case for easy access. Next, we we secured the high voltage wire onto a glass jar in order for it to avoid contact with the grounded base plate. There is a possibility that the TV may overheat if we run it for an hour without breaks so we decided to implement a timer that would regulate how long the TV is on or off for. The timer uses two sockets, one to power the timer itself and another one which later leads off to the TV power. Inside the timer box, there is a button and if you press it an n amount of times, the power to the TV will be on for those n second and off for those n seconds. We also attached a discharge stick which we touch to the high voltage components after the power is off to make them safe to touch because it we don’t, the capacitors may still be storing power in them.Both of the grounded components, the discharge stick and the ground wire have 240 kilohms resistors that are rated for 2 watts that installed in order to protect the monitor from high current sparks that may damage TV.
Ionocrafts in real life
Studies on ionocrafts date back to 1920 when Thomas Brown built one and incorrectly claimed he found a way of modify gravity using an electric field. The term “ionocraft” was introduced in 1960, when experiments on Electrohydrodynamics (producing thrust without combustion or moving parts) was at its peak. These experiments have shown that an ionocraft can’t work in a vacuum (if you read the “how an ionocraft works” section of this poster you will understand why). There are not many practical uses for these lifters because they need a massive amount of electricity and they do not produce enough thrust. It would be impossible to make an ion-powered airplane with our current power generation methods.
Ion engines
An ionocraft IS NOT an ion engine because they work in different ways. In simple terms, an ion engine works by propelling xenon gas atoms at very high speeds (150,000 km/h) out of the back of the spacecraft. Thrust is produced because of Sir Isaac Newton’s third Law that states: every action has an equal and opposite reaction. Ion engines therefore work in a vacuum and are used on many modern spacecraft and deep space probes because they are much more efficient than normal liquid fuel rocket engines. They produce a very small amount of thrust (slow acceleration) when compared with rocket engines but they can go on working for many months due to very low xenon consumption and renewable electricity that comes from solar panels. Ion engines are also safer than rockets because there is no risk of explosions due to the fuel being electricity and a inert gas (xenon). In order to get these ion engine spacecraft into space, a normal solid or liquid fuel rocket is needed because an ion engine does not produce enough thrust to get itself into space. Picture of xenon atoms getting propelled out of an ion engine:
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