Has a fixed-wing aircraft ever been built that featured multiple turbines powering a single propeller? Has a fixed-wing aircraft ever been conceived, prototyped or built that features multiple turbines powering a single propeller? The concept of a twin-engine aircraft with a single propeller is intriguing to me. Picturing something like a Pilatus PC-12 with two engines under the hood and a single prop might have some advantages. I come from a fixed-wing background and know little about helicopters, but if something exists I suspect it is a rotor wing.
The LearAvia LearFan 2100 used two separate PT-6B to drive a single pusher propeller through a common gearbox.


LearFan 2100 in flight (picture source)

If you want to know why its official first flight date is December 32, 1980, read here.


LearFan 2100 engine arrangement (picture source)

This engine arrangement was the LearFan's eventual undoing when the FAA denied it a proper certification because of concerns that the single gearbox constituted a single point of failure.