How is thrust generated by a propeller? I get confused sometimes because I hear different theories of how propellers generate thrust.


One is that the propeller pushes air back to provide thrust.
Another is the blades generate lift creating a high pressure behind the blade pushing the aircraft forward.


Is it just one of these true or is it both? For you guys its the same way of generating thrust, but to me its two ways thats my confusion. And why does a propeller need to generate lift if it just accelerates air backwards to provide thrust. That question is my main confusion.
It's the same thing, it changes only the point of view, see Newton's third law: for each action there is an equal and opposite reaction, i.e. to create thrust, the engine has to push air backwards. Pushing the air backwards means that the air is pushing you forward and this, in the reference system of the propeller blade, is lift.