
Ask HN: New Jet Engine - ryanthedev
liquid nitrogen.  It’s abundant in our atmosphere, we can cool it using a vacuum.<p>Replace the jet fuel with a mix of water \ air \ liquid nitrogen.<p>Creates a lot of dense gas shooting through a nozzle at high velocity.
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gus_massa
To make liquid nitrogen, you need an special equipment. Imagine that it's like
a refrigerator, but more complex. So to run the equipment you will need a lot
of electricity.

You have to do the calculation of how much will it cost in electricity to
produce the liquid nitrogen necessary to have the same impulse of the usual
fuel.

Also, liquid nitrogen is very cold, mixing it with water will make a lot of
ice [1]. The ice is not good for the nozzles or whatever is in the "engine" of
the jet.

[1] Liquid nitrogen is quite cheap, something like $3 per gallon. You can get
some for free in the laboratory during a major degree in Physics. It's nice to
play with it, but be careful and follow the safety instruction. :)

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ryanthedev
Liquid nitrogen is actually very easy to make and very easy to melt. You can
buy a generator that can make 67 liters a minute of eBay.

The water would be hot though I’m open for debate on another source to rapidly
warm the liquid nitrogen.

I wish I had the time or the money and engineering ability to prove it out.
Hopefully some other inventor and build on this concept. It will work, my
biggest concern would be destroying the atmosphere, but I would predict we
would need a lot of nitrogen exhaust to displace enough oxegen.

Thanks for the feedback!

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jaclaz
>You can buy a generator that can make 67 liters a minute of eBay.

67 liters _per minute_?

How much would that cost? I thought that they are in the several tens of
thousands dollars for generators that can produse a few tens liters _per day_.

