Originally Posted by johndoe42
...you can fly a small bit faster than the exhaust velocity, due to the added mass of the burnt fuel.
Just as well I read your post to the end before commenting....
You're right, of course.
At the extreme of this air/fuel ratio, when reducing the air intake down to zero, you get a rocket engine.
Easier to understand, almost... you can use the "balloon" analogy. Nothing in, only "mass out".
What's not always stressed enough in the tale, is that for a jet engine it's very nearly all "mass in = mass out" (the added fuel
mass being pretty well negliable), so the energy added by the fuel HAS to be converted into velocity, so the nozzle is a vital part of the system.
CJ