Why it's so hard to build a jet engine

Re:Why it's so hard to build a jet engine by iancmceachern on Friday February 28, 2025 @07:43PM (#43214129)

They are not temperature constrained at altitude. It's much colder up there.

They are air, oxygen really, constrained.

You are right that the electric motors themselves won't suffer from the same oxygen starvation, but as the other commenter noted, the props or impeller blades will. They need something to push, there isn't much up there.

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Re:Why it's so hard to build a jet engine by numpad0 on Friday February 28, 2025 @11:38PM (#43215960)

I think he's talking about aerodynamic heating. Turbines compress air, and exhaust generates more thrust than resistance, so it's sort of obvious that compressor stages can be temperature limited where the airframe that hosts it is temperature constrained or something.

I'm not sure how it has to do with electric propulsion, though - I'd think systems like NERVA is a more exciting solution in this kind of domain(jk).

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