Physics Help Forum Railgun Math Simulator

 Electricity and Magnetism Electricity and Magnetism Physics Help Forum

Dec 18th 2011, 12:44 PM   #1
Junior Member

Join Date: Dec 2011
Posts: 3
Railgun Math Simulator

Hey all
Im a second year engineering student bored as hell in the second week of a 3 month vacation. So i decided to try and build a small railgun capable of launching a projectile(20-40g) to about 400km/h.

Attached is a excel file. It is a sort of simulation.

Cells in Blue must be typed in by user.
Cells in Green list the Current/Mass needed to achieve desired values.
The Cell in red must get its values from the table at a given point ( you choose )

This all makes alot more sense with the simulator.
Please try it out! Any suggestions are welcome! Point out all the mistakes i made ( there must be a few ) and be critical please. This is a dangerous undertaking and i want to be as sure as possible about the math.

Thank You!
Attached Files
 Railgun.xls (68.0 KB, 40 views)

 Dec 21st 2011, 09:00 AM #2 Physics Team     Join Date: Jun 2010 Location: Morristown, NJ USA Posts: 2,326 Quite ambitious. Looks like you'll need a power supply of about 4 megawatts to reach your goal (volts x amps), able to deliver about 50,000 joules of energy (volts x amps x time).
 Dec 22nd 2011, 04:21 AM #3 Junior Member   Join Date: Dec 2011 Posts: 3 Yes i know it is quite ambitious, but do think it is possible? does the simulator 'simulate' accurately? i was thinking about 6 capacitors would do the job? Each of them about 6800uF and 450V in parallel. I'm currently studying chemical engineering, and I thus do not have the necessary textbooks to supply me with answers. If you think it not possible, what weight and speed do you think i can achieve? Thanks for replying. Last edited by Fr1ki; Dec 22nd 2011 at 04:25 AM.
 Dec 22nd 2011, 07:35 AM #4 Physics Team     Join Date: Jun 2010 Location: Morristown, NJ USA Posts: 2,326 Might be possible, but incredibly risky. You're talking lethal amounts of current and energy, so this is not something to do on a whim. Finding capacitors of the size you need and rated for > 450 violts is a bit tricky - I found one from a supplier like in the attached picture. Note they are about $1000 each and require a signed safety affidavit! And getting 10,000 amps to the device will require massive cables - I don't know how you would connect them. I suspect that superconducting cables would be the only practical way - and now you're really talking big$$! Attached Thumbnails  Jan 4th 2012, 12:19 AM #5 Junior Member Join Date: Dec 2011 Posts: 3 I was searching around the web alot and talking with various engineers where I am doing vacation work, and all of them say that I do not need large cables at all. They say that the current pulse is so quick, that it will hardly even warm up a thin wire. But the longer the pulse needed, the thicker the wire has to be. Which kind of makes sense to me. And, I have been searching around, and I will go with a 220V capacitor bank. The reason for this is that it is WAY cheaper ($20-\$50 each), and, in my country, we use 220V outlets. So I will charge them with a diesel generator. Or that is the idea at least. So the paramenters of the simulator has changed a bit. I will only require about 5500 amps but I must use a 12g projectile.

 Tags math, railgun, simulator

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post jaiii Physics Software 3 Oct 24th 2018 03:22 AM ilovemath General Physics 1 Feb 8th 2013 02:03 PM Singularitarian Quantum Physics 8 Nov 24th 2009 11:06 PM AniMuS Thermodynamics and Fluid Mechanics 0 Jul 7th 2009 06:02 AM Tabassum Kinematics and Dynamics 2 Jan 31st 2009 12:30 AM