Introduction: "Easy" Made Railgun
Claim : I do not take any responsibility for anything that happens. This is a project for people who have electricity knowledge background. Do not attempt this unless you have experience with high voltage.
First of all, I would like to thanks my parent, my uncle Paul. I made my design easy and cheap but remain the power compare to others.
I am NOT a English native speaker, so sorry for the grammar.....
Alright, let's jump into the topic
This railgun is very success, it has a finial speed of 205 m/s. compare to the final speed of 148m/s without electrical part, it is not very efficient but it still a decent result. The main problem is I don't have enough capacitor.
Electromagnetic Rail Propulsion System is a kinetic energy device which uses the electromagnetic launch technology. Traditional canons are pushed by gunpowder gas pressure to launch the projectile; a Electromagnetic Rail Propulsion System uses the ampere’s force in the electromagnetic system to launch the projectile. A Electromagnetic Rail Propulsion System is based on similar principles to the homopolar motor. The Electromagnetic Rail Propulsion System is made by a pair of parallel conducting rails, along which a sliding projectile which is accelerated by the electromagnetic effects of a current that flows down one rail, into the projectile and then back along the other rail. One of important measurements of a kinetic device is speed. The traditional device uses chemical explosive to generate force to push the projectile and its maximum speed can only reach 1.7 km/s. Unfortunately, the initial speed of the conventional artillery is restricted by many factors. For example, if you want to increase conventional artillery’s initial speed, the gun pressure has to increase. But theory and practice show that when ammunition quality and an projectile mass ratio is greater than 5 then speed increase at a much slower rate. Transformers 2, the movie shows how the NAVY uses Electromagnetic Rail Propulsion System to attack the transformer which was destroying a pyramid. Electromagnetic Rail Propulsion System projectile once reaches 10Km/s at before. Because of the high speed, Electromagnetic Rail Propulsion System can use in many different fields; like catapult a plane or shoot a flying missile.
for more information about railgun please go to wikipedia http://en.wikipedia.org/wiki/Railgun
If you have any question, please leave a common or E-mail me firstname.lastname@example.org
如果你知道哔哩哔哩，去哔哩哔哩看吧 发个弹幕投个硬币 http://www.bilibili.com/video/av1119424
Step 1: Prepare Material
- Body material: Phenolic (Garolite 11)
The body material is Phenolic (Garolite 11). G11 is the greatest material in Garolite series, It is military grade material. The reason I use Garolite 11 because it not conduct and it can bear the high heat, because of the resistance of the rail, there will be a lot of heat, also this kind of material has low coefficient of the thermal expansion.
- Rail material: copper beryllium & Projectile: Aluminum
I use copper beryllium as my rail material because it has high electric conduction; it can bear the high heat and low coefficient of the thermal expansion. The most important point is it has high hardness.
The material of projectile must be different from the material of rail. For projectile, copper, aluminum and molybdenum are the materials to choice. Due to price, molybdenum wouldn't work. So we left copper and aluminum.
First copper’s resistance is the half of aluminum. Second, output energy is depends on speed and mass. so I chose the aluminum as projectile and copper as rail material.For further explanation please download my thesis.
- Capacitor bank
I use 450v 1800uf * 8 aluminum capacitor and copper bar as the busbar
this is only 1.4KJ, and it is too small, I recommend you to buy more(I run out of my money.....this thing was killing me)
- Cable: 00AWG
- Air Tank(100 psi)
- transformer(110v to 300v )
- rectifier (Change AC to DC)
- Air Switch x 2
- DC voltmeter(1-600DC)
- AC Voltmeter(1-400AC)
- bleeding resistor
- radio control air valve(trigger the air tank)
- air tank adapter
- Arduino & Photo Gate(Optional)
Step 2: Design
- Projectile : only triangle or ladder-shaped ending is efficient. however φ=20°is most efficient choose. In reality the current cannot be uniformly distributed or you can say current density is not distributed formally; that because of the skin effect. That causes a lot of problems. First problem is local overheating which will weld the projectile to the rail. The second problem is high local resistance which make Electromagnetic Rail Propulsion System less efficient. Projectile needs to bear the high pressure; This is the kind of design that satisfy the theory.
- The internal resistance of the capacitor is the key of efficiency. Capacitors in series is the way less efficient than capacitor in parallel. Meanwhile, the capacitor in parallel has low voltage, which means I will spend less money on transformer. That is the reason that I chose the capacitor in parallel even if parallel capacitors have a high current.
- Special designed safety circuit is the design for discharge the capacitor
in another way but rail. Once the capacitor has fully charged, there are a lot of energy storage in capacitor, if we don't want to launch the projectile, we need to use a safety circuit to discharge the capacitor.
Spark section provide a discharge for unexpect event happen, in order to protect capacitors
- It is really easy to make this, just a pair of photo gate and arduino board, program is so easy because it is just a time calculation when the photogate triggered
Step 3: Make
Step 4: Assembly
Mill Channels into Base plate for rails
2. Mill holes into base plate for bolts 3. Mill Channels into Cover plate 4. Mill Holes into Cover plate for bolts 5. Mill RH Rail Plate 6. Mill Holes RH Rail Plate for bolts 7. Mill LH Rail Plate 8. Mill Holes LH Rail Plate for bolts 9. RH Air Channel Rail
10. RH Rail Cut to length 11. Mill groove for Terminal connection 12. Cut RH Terminal Bar to length 13. Mill groove for Terminal connection 14. Drill hole for Wire Lead 15. Thread Hole for wire lead
16. LH Rail Cut to length 17. Mill groove for Terminal connection 18. Cut RH Terminal Bar to length 19. Mill groove for Terminal connection 20. Drill hole for Wire Lead 21. Thread Hole for wire lead 22. Assemble the LH Terminal Connect to the LH Rail 23. Assemble the LH Terminal Connect to the LH Rail
24. Cut Aluminum Blocks 25. Rough mill Aluminum block to shape
26. Assemble RH Rail Plate to the Base plate 27. Assemble LH Rail Plate to the Base plate
28. Assemble RH Air Channel Rail to Base Plate 29. Assemble LH Air Channel Rail to Base plate 30. Place RH Rail into groove on Base Plate 31. Place LH Rail into groove on Base Plate
32. Measure Channel 33. Adjust Rough milled Aluminum to fit channel 34. Clamp assembly together 35. Drill locating holes through assembled pieces 36. Dowel pieces together 37. Run aluminum block through channel
38. Fit Cover Plate to assembly 39. Clamp cover down 40. Dowel the cover to the assembly 41. Bolt Rail Assembly Together 42.
43. Mount Rail Assembly to Upper Base 44. Cut Back Plate 45. Drill Hole for air hose 46. Thread Hole for Air Hose fitting 47. Attach Back Plate to Rail Assembly 48. Attach Air Hose 49. Cut wire to length 50. Attach Wire terminal to wire 51. Screw wire to RH Terminal Bar 52. Screw wire to LH Terminal Bar 53. Assembly switch to air tank 54. Secure air tank to Upper base
55. Assembly of the Electrical Components 56. Cut Bars for CAPACITORS 57. Drill Holes for screw Terminals 58. Drill Hole for wire Screw 59. Attach bars to Capacitors
Step 5: Have Fun!!
Railgun is really a fun project to do, just be sure you wear your face shield and lineman glove (it think it is necessary for accidentally touching).
The result of this railgun :
- Final velocity: 204 m/s
- Status of projectile : lightly damage
As you can see, this is not a one-day project, I had planned for half year. The theoretical background is important. So just be sure you know what you are doing.
Firing Video: https://www.youtube.com/watch?v=37-qByJBHco