IntroductionHave you ever wanted to use the forces of electromagnetism to launch a projectile? The coil gun is a relatively new invention compared to the older and different types built. A coil gun is a projectile accelerator consisting of one or more coils wrapped around a barrel and when you add electricity, these coils becomes electromagnets. Most coil guns will launch the projectile to high velocities but can be tweaked so it does not fire at high velocities. Another concept of the coil gun is called a Rail Gun. The rail-gun is strictly used in military due to the fast speed of the projectile at 8,600 km/h or 5343.792mph(2.4 kilometers per second). The rail gun launches a 7 pound projectile at “hypersonic velocities”. The coil gun operates using electromagnets which is enameled copper wire wrapped around the barrel and has an electric current going through it making it an electromagnet. Electromagnets are used daily coming from a doorbell, junk yards, to even rock concerts. Some of the most important parts of this coil gun are the:Arduino uno, 3D printer, Stepper motor, IR Photo-diodes, IR LEDs, resistors, Fast Fuse and the batteries. The 3D printer is a huge part in this project and without it, this project would be harder. The printer prints out all of the base parts to the coil gun. The Arduino Uno is a microprocessor which drives the Nema 17 Stepper Motor to initiate the coin movement. The IR LEDs send out white light and when the coin passes under it, it blocks out the light from the IR Photo-Diode (receiver) causing the next coil to turn on. The resistors are used to reduce current flow and divide voltages to the coils. Fast Fuses are being used in this project to increase safety to withstand surge currents when turned on/off. Electromagnets are simply coil wire wrapped around an iron or air core. If it is wrapped around an air core then it is called a solenoid. When electricity is brought to the coil, it becomes energized thus making an electromagnet. Unlike the typical magnet, electromagnets are temporary and can be enabled or disabled through a switch or unplugging the wires from a power source. There are two main types of electromagnets, AC and DC. DC is what makes this coilgun, DC is usually used to pick up or hold object while AC is used to demagnetize objects like TV screens. AC magnets changes flux density as the current goes through it. The polarity of this object will also flip when the current changes every half cycle. The AC currents will actually be reduced compared against the DC magnet. The importance to an electromagnet is the ability to control things within this, including: flux density, polarity of the field, and even the shape of the field. The magnitude of the current flowing can be strengthened or weakened by the magnetic flux density, while the polarity is determined by which may the flow is going and the shape of the field is determined by the shape of the core which this coil is wrapped around. A big use of electromagnets are transformers. Transformers are just two electromagnets coupled together and no isolation between the two. The electrical field can be determined by doing the following equation:E=F/q where “E” is the Electric field strength, “F” is Force and “Q” is the charge. According to Columbus’s Law, means adding more charge will lead to more electric force. Columbus’s Law says “The strength of the electric field of magnetism between two points charges, is directly proportional to the product of the magnitudes of charges and oppositely proportional to the distance between them.” To find the strength of an electromagnet, use Magneto Motive Force (m.m.f)=IxN ampere turns. M.M.F is the current, I is the flow through the coils, and N is number of turns within the coil. The strength is then determined by ampere turns. The more turns there are the more strength it has. Literature Review The first coil gun when it was fired, sounded even louder than a .22 round being fired. The launcher had 1 long continuous coil from start of the barrel to the end. One long coil like this will in theory weaken the strength of the gun and with multiple stages, after each stage it would speed up therefore reaching higher velocities(if tuned right). The most recent coilgun was done at Rutgers School of Engineering and this project’s results reworded are increasing the layers would only increase the resistance of the coil, therefore weakening the current. The output voltage in this project was 230V leaving the object traveling between 15-20m/s. Launching the object through all 3 stages lead to 40-50m/s with a boost converter bringing the voltage to ~400V. This device only launched 1 object due to the coils being discharged and having to charge them again and every object has to be manually loaded into the solenoid (air core). The results of most coilguns are that the object launches farther and faster due to more voltage (over 4x the amount). Fictional Concept”Arc Reactors” are a fictional design introduced in “Iron Man” used to power things creating 8 gigajoules of power per second. While this not a real thing, it is relatable to a Multi-Isotope Radio-Decay cell. The closest thing to this is called the ITER Fusion Reactor. The ITER will work by smashing two isotopes of hydrogen, deuterium, and tritium producing helium and a free neutron. When these are mashed together, the leftover mass is then converted to energy. The “Arc Reactor” is a circle likely because there are charged particles moving in a circular pattern being contained by a magnetic field produced by an electromagnet. The magnetic fields can then curve these particles. The arc reactor used palladium which is known as a “cold” fusion. Palladium isotope Pd-103 produces Rh-104 using electron capture, which means one electron is taken in by the nucleus, which merges with a proton then creating a neutron and an energetic photon.3D Printer3D printers is a machine which can make a physical, 3D object by melting filament(plastic) into multiple layers on top of each other. The process starts by making or downloading the models on a computer or using a 3D scanner. To prepare a model, it will need to be sliced which can usually happen through software like Cura on a PC. When it is sliced, the printer will then need to be calibrated by steps/mm. After the printer, the model can be moved from the PC to the printer by USB, data transfer cable(DTC) or Wi-Fi. It uses some materials that are used in this project like the Arduino Uno and the Nema Stepper Motor. Additional Background2.1 Projectile Analysis The first thing to do in an analysis is to find the right material that will be launched in the coil gun. The coil will need to be the minimum size which is equal to the length of the quarter to solve the suckback issue. Projectiles that are lighter will require less energy to launch according to the work kinetic energy theorem. If the object is too small then the magnetization will not increase any more, leading to the flux density not increasing fast enough. If the mass is too heavy then it could not be magnetized at all. The dimensions of the quarter have to be relatively close to the coils to get the flux linkage at its max, or the field could be in the air and not magnetizing the object. For a solenoid, the diameter of the coil and object have to be as close as possible without letting the object touch the acrylic glass to slow it down due to friction. There are three constraints to keep in mind while winding the coils and choosing the right projectile. The first constraint is when a projectile is fired, that it should have at least three times the coils diameter or more. The second constraint is that the coil should not be shorter than the object because if the object is longer than the coil, when one end gets through the coil there is 1 end being magnetized and 1 end not being magnetized or could even be pulled back. The type of material we need has to be ferromagnetic meaning it has a high susceptibility to magnetization. Diamagnetic is useless in this analysis, diamagnetic is caused by negative susceptibility which means that the magnetization of the objected weakened the magnetic field of the coils. B= U?(1+X)H). Ferromagnetic has a larger susceptibility than most other objects so it should work for this project. The object being fire should never be able to take in electricity and if the object is conductive then it needs to be a low rating of conductivity. If the object is conductive then it can be used to add more resistance to said object. The currents inside of the object would oppose the magnetic field (Lenz’s Law) which makes kinetic energy to heat. SummaryThe object has to be a non conductive ferromagnetic material with a length smaller than the coil, and roughly around 3x as small in length and has to be close to the diameter of the coil. The coil gun will shoot quarters (aluminum disk) and soft iron or a soft ferrite material because these have low eddy current loss, low hysteresis, and an average field permeability.