I was just watching this video...
...and it got me thinking: a propeller shoves back air, and this creates a forward force on the prop. The prop attached to a shaft, and the prop is tugging on the shaft. Both the shaft and the prop are rotating.
The airframe on the other hand is (relatively) stationary. Yet the airframe depends on the rotating prop to pull it in the desired direction of trust.
This means there is an interface somewhere, between the rotating shaft and the rest of the engine, and that interface transfers all the thrust of the propshaft to the engine, and then the engine in turn transfers that force to the air frame.
That to me sounds like the mother of all bearings! What does such a bearing look like?! Or is there some other mechanical principle/device in play?