>>1471600It requires a lot of redundancy and this is easier with modern technology.
Also constrained airflow is messy to tweak, simply using an impeller gives half the thrust of a propeller (without lots of fine tuning):
https://www.youtube.com/watch?v=wg8ZbiC9IBwAlso there lots of concerns similar to ones found in rockets and supersonic airplanes, like managing air pressure:
https://en.wikipedia.org/wiki/Venturi_effect >>1472480I doubt they could even build this craziness at the time.
