how to model helical turbine rotor ?

i hope this answer can help you.
i have no idea for the dimension

  1. Step 1:

    Sketch square on top plane

  2. Step 2:

    Extrude it and Set the Draft Angle

  3. Step 3:

    create a new sketch on face plane like picture

  4. Step 4:

    Revolve the sketch

  5. Step 5:

    create a new sketch on face like picture

  6. Step 6:

    create a 2nd sketch (line) on face plane

  7. Step 7:

    sweep the sketch with option Twist Along Path

  8. Step 8:

    Create circular pattern

  9. Step 9: