bobbythekid Posted June 8, 2016 Share Posted June 8, 2016 Can you calculate the exit velocity of a 25kg ferrous slug from a linear electromagnetic accelerator of a length of about one thousand metres when applied in a vacuum when superconductive electromagnets are used? Bonus question: Can you calculate the level of energy required (joules or volts, your choice) Extra question: Can you calculate the cost of this product? we can assume that there is not coating or anything, just a bare kilometre long linear electromagnetic accelerator. include source if possible. Link to comment Share on other sites More sharing options...
swansont Posted June 8, 2016 Share Posted June 8, 2016 Without being given any of the technical details, the answer is "no". Link to comment Share on other sites More sharing options...
Raider5678 Posted June 8, 2016 Share Posted June 8, 2016 (edited) Can you give me some more information, Top speed of the slug Acceleration rate Power of the electromagnetic accelerator Also, to have enough liquid nitrogen alone would cost a fortune. About 400 trillion dollars. Per minute. Edited June 8, 2016 by Raider5678 1 Link to comment Share on other sites More sharing options...
EdEarl Posted June 8, 2016 Share Posted June 8, 2016 https://en.wikipedia.org/wiki/Railgun#Mathematical_formula Link to comment Share on other sites More sharing options...
swansont Posted June 8, 2016 Share Posted June 8, 2016 Also, to have enough liquid nitrogen alone would cost a fortune. About 400 trillion dollars. Per minute. Oh, baloney. Liquid nitrogen is fairly cheap. The LHC pre-cools their superconductors with liquid nitrogen (9000 metric tonnes) before using the much more expensive liquid helium. http://www.symmetrymagazine.org/article/december-2014/lhc-filled-with-liquid-helium and the LHC is a much more ambitious project than a railgun, even if the latter is a km long. Link to comment Share on other sites More sharing options...
John Cuthber Posted June 8, 2016 Share Posted June 8, 2016 Can you calculate the exit velocity of a 25kg ferrous slug from a linear electromagnetic accelerator of a length of about one thousand metres when applied in a vacuum when superconductive electromagnets are used? Quite possibly less than it would be if you didn't use superconducting magnets. At high field strengths things stop superconducting, so by imposing a condition that the magnets are superconducting, you are limiting the field strength. Since a coil gun doesn't need to power the magnets for a long time, the energy savings you get from superconductors are less important. Also, if I'm allowed to use a non magnetic stainless steel as the "ferrous" slug, then the answer might be "pretty much zero". What question are you trying to answer? Link to comment Share on other sites More sharing options...
Raider5678 Posted June 8, 2016 Share Posted June 8, 2016 Oh, baloney. Liquid nitrogen is fairly cheap. The LHC pre-cools their superconductors with liquid nitrogen (9000 metric tonnes) before using the much more expensive liquid helium. http://www.symmetrymagazine.org/article/december-2014/lhc-filled-with-liquid-helium and the LHC is a much more ambitious project than a railgun, even if the latter is a km long. I don't really know a lot about liquid nitrogen, i figured it would take quite a bit of It to cool even a small section... Then again I'm probably wrong. Link to comment Share on other sites More sharing options...
imatfaal Posted June 9, 2016 Share Posted June 9, 2016 Can you give me some more information, Top speed of the slug Acceleration rate Power of the electromagnetic accelerator Also, to have enough liquid nitrogen alone would cost a fortune. About 400 trillion dollars. Per minute. Liquid nitrogen is cheap. In a vacuum the top speed is pretty much unlimited until you start getting relativistic and I do not want to be on the same continent as a 25kg slug travelling at relativistic speeds wrto the earth. But you are right the OP needs to provide far more info or maybe search the net for some of the presently operating rail guns etc (the US Navy has a doozy that was featured here a year or so ago) BTW Railguns - tbomk - are not simple linear accelerators and rely on the slug forming an electrical contact with both rails, the (huge) current flowing in this circuit causes magnetic fields, and with currents flowing in magnetic field you get force Link to comment Share on other sites More sharing options...
Enthalpy Posted June 13, 2016 Share Posted June 13, 2016 There are varied designs for electromagnetic guns. A common one indeed has just two rails "shorted" (and this is difficult) by the round. The strong current makes itself the induction as it passes in the rails. The main limit is the quality of the moving contact. It's usually graphite since the rest is worse, and it vaporizes, which contributes by the plasma to a contact, but loses power and erodes the rails and the round, destroying the round if exaggerating. Forces on the rails are bad but easier to cope with. One other design switches many coils after an other, preferibly overlapping, to attract a ferromagnetic round. In both cases, I too fear that superconductors are worse than metals because they limit the induction. Coils could also repel the round acting as a short-circuited loop. As far as I know (and I ignore much) this design is less good as a gun. But it's standard at lithotriptors to repel a conductive membrane as a sound transmitter. An inventor wanted to accelerate D-T rounds that way for fusion, and last time I checked it, the design failed because of superconductor limitations. Link to comment Share on other sites More sharing options...
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