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Comment by thom_nic | Hacker News Reader

This idea of an electrical-arc jet engine is new to me. Can you point to any published material on such a design or prototype? Very intriguing.

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Nobody who has taken a course in energy conversion (an second or third level thermodynamics course) would even bother to propose this. It is not coincidental that all mechanical engineers take this course, and mechanical engineers are also the people who design engines.

If you take a course in energy conversion, and also an economics course, then you would consider this.

https://en.wikipedia.org/wiki/Nuclear-powered_aircraft

Some joules are more expensive than others :)

The nuclear aircraft did not fail because nuclear power was too expensive, they failed because reactors were too heavy. If you read more about the American nuclear aircraft programs, you will find that they were most interested in using the heat from Nuclear reactions to warm up air; they did not propose to generate electricity with which to heat or push air (because it is too complex and inefficient).

Right. A nuclear reactor generates massive amounts of heat from fission, then uses that heat to boil water (sometimes heavy water for better radiation shielding) to make steam to cause turbines to spin, which generates the electricity. (in fact, fossil fuel burning plants also use this steam-electric model)

If the end goal is to generate heat, then there's no good reason to add those additional steps.

Using an RTG producing electricity as a heat source in a Brayton-cycle engine was on my Jet-Pro final exam in college.

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