Major Tom: you are correct, but I tried to indicate that I didn't think the spirals were reflective of the airflow, just the pattern of compression caused by the blades. If there had been significant tangential airflow it would not spiral, it would move at a tangent since once the air leaves the rotating blade it must continue in a straight line.

The images I posted were really with the intent to show where the concept of spiral flow might have come from - they are NOT flow patterns but are often mis-labelled as such because they fit with the preconception.

As noted, any propeller that put substantial tangential momentum into its slipstream would be a very lousy propeller (inefficient).