So I'm an amature rocket scientist. while having a conversation with a friend on a nozzles we though of a new nozzle:
Its a double nozzle where it expands a lot and then compress. I want to put this to the test on a R-candy but is it work the time and effort? I think it will lose a good portion of its energy by the time it comes out. My friend says that the Bernoulli's principle will cause it to go faster hence the lost of energy doesn't matter. What do you think?