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Just a quick question I hope Spike, Keith or some of you others
already know the answer to:<br>
<br>
What is the theoretical limit to electromagnetic launcher
efficiency?<br>
<br>
As far as I can tell from the literature, the quenchgun people seem
to claim that a superconducting coilgun storing all its energy in
the coils is optimal: <br>
<blockquote>"The quenchgun is analogous to the Carnot engine in
thermodynamics the ideal launcher capable of achieving the maximum
theoretically possible efficiency. "<br>
</blockquote>
<a class="moz-txt-link-freetext" href="http://adsabs.harvard.edu/full/1992NASSP.509B.117S">http://adsabs.harvard.edu/full/1992NASSP.509B.117S</a><br>
However, presumably the magnetic fields will not all couple to the
projectile. And I would really need to get a number of that
efficiency - I cannot find the old papers cited, since they are all
80s conference proceedings. <br>
<a class="moz-txt-link-freetext" href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900012490_1990012490.pdf">http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900012490_1990012490.pdf</a>
<br>
claims "nearly all energy is transmitted", but I cannot figure out
how nearly the nearly is. <br>
<br>
Normal railguns obviously have energy losses from ohmic resistance.
The calculations in <br>
<a class="moz-txt-link-freetext" href="http://ilin.asee.org/Conference2008/SESSIONS/Lumped%20Parameter%20Modeling%20of%20the%20Ideal%20Railgun.pdf">http://ilin.asee.org/Conference2008/SESSIONS/Lumped%20Parameter%20Modeling%20of%20the%20Ideal%20Railgun.pdf</a><br>
seem to imply that if everything was superconducting the efficiency
would be 1, which I find doubtful.<br>
<br>
Real electromagnetic launchers have far bigger energy losses of
course, but I am interested in the theoretical limit. Assume you can
get as much superconductors, perfect timing and energy as you like.
<br>
<br>
<pre class="moz-signature" cols="72">--
Anders Sandberg,
Future of Humanity Institute
Philosophy Faculty of Oxford University </pre>
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