Comment by Galxeagle
Not clear to me from the article - what's the different between an 'open rotor' engine and a turboprop (https://en.wikipedia.org/wiki/Turboprop)? At face value, both seem to be jet engines with propellers used on single-aisle planes?
There is still a jet stream coming out of the engine propelling the aircraft. Unlike a turboprop where only the propellor generates thrust.