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Electrothermal Ramjet

  1. Jul 8, 2013 #1
    Time to propose another crazy idea: the electrothermal ramjet. I was reading about Project Pluto today. I find it interesting that there is no combustion involved; just the compression of air then the expansion by heat from a nuclear fission reaction. What if we could use coils (or some other way to dissipate heat) of metal with electricity flowing through it to produce heat? Of course, there would need to be massive amounts of electrical energy to generate the heat needed for the expansion. I thought tungsten might be a reasonable material for heat dissipation because of its high liquefaction point, but it is very dense; an engine using large amounts of tungsten would likely not produce a positive thrust to weight ratio.

    The engine would have the shape of a typical ramjet, and at the point of highest there would be coils of some conductor. Electricity would run through the coils and produce heat. This would expand the air, and force it out of the back, producing thrust.

    So what do you think? power considerations aside of course
  2. jcsd
  3. Jul 8, 2013 #2


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    That's not unlike what already exists or what happened in Project Pluto , only you would need such a large amount of electricity that you would either need major advances in battery technology or else a way to generate a lot of it in a small space with little weight on board, such as with the nuclear reactor already used.
  4. Jul 10, 2013 #3


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    The rate of cooling of the resistive coils would be tremendous. One problem might be a stall of the ram air intake flow. The instant reduction in cooling would result in immediate vaporisation of the coils.

    It might be a good idea to find some way of recovering the heat from the exhaust after the ram jet has passed so it can be reused rather than left behind.
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