That's ingenious. It's one of those rare mechanisms that are hard to come up with but obvious once you learn of them. I recommend everyone to watch this video.
(The presentation spends a lot of time explaining tail rotors, which this invention does not need. Skip to about halfway to see how it works.)
https://en.wikipedia.org/wiki/Tip_jet
As with all cool concepts "Zee Germans" had the idea https://en.wikipedia.org/wiki/Focke-Wulf_Triebfl%C3%BCgel