[ExI] Electromagnetic launcher efficiency

[spike]

>.From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of Anders Sandberg
Subject: [ExI] Electromagnetic launcher efficiency

 

>.Just a quick question I hope Spike, Keith or some of you others already
know the answer to:

>.What is the theoretical limit to electromagnetic launcher efficiency?

>.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. -- Anders Sandberg,

 
 
Anders, I don't know where I last saw the equations on that, but it is an
interesting question.  
 
A few years ago I went with the fam to Disneyland California Experience,
where they have a maglev launched roller coaster.  I stood and watched it
for half an hour.  After each launch, they have sprayers that cool the
track.  I tried to estimate the amount of energy being dissipated by the
amount of steam that comes off, but it was hopeless.  What I needed was some
kind of IR thermometer, which would allow me to find the temperature of the
track after the launch, then estimate the mass of the steel, then use the
specific heat of iron.  I could estimate the mass of the roller coaster and
the speed it was going at the end of the launch event, estimate half the
waste energy goes into the track and half goes into the rollercoaster and
the air, and get it that way.
 
Or we could just look up actual data, that might work too.
 
spike
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