What's the difference between a pulsejet and a PDE? A pulsejet is just the
old V-1 Buzzbomb engine; a pipe with a kerosene burner and a one way flapper on
the front. Simplicity itself. Which is why it's still interesting while
inefficient. short-lived flappers are the hangup.
The PDE is a potential thing of beauty; a rocket engine which uses discrete
supersonic explosions rather than continuous combustion whith subsonic exhaust.

^
//^\\
~~~ near space elevator ~~~~
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