Here is the corrected helix.

Cool, except it still isn't precisely correct.  Like you said earlier,
there's a helix thrown by each blade, therefore there should be two on
the drawing (a three bladed prop would have three helixes, and so on).
I've no problem with omitting the extra helix(es) for clarity, but you
should put that in the caption.

Also, the core element which the spiral circles (the prop tip path?)
does not actually exist as a drag element.  You could remove it, or if
removing it would hurt the clarity, can you reduce it to a thin solid
line?

And finally, for all the marbles, the helix needs to gradually get
bigger, with vortex helix tube also getting bigger and more diffuse.  I
don't imagine you'll make those changes, but I did want to have it
recorded.

Russell

All good points.
No problem up until the getting bigger bit :)
I don't think that is possible in Rhino.