How to cut out a series of Helix to form channels?

After better understanding what you were wanting here is how I would do it.

  1. Step 1:

    Create a spiral (not a helix)

  2. Step 2:

    open a sketch and convert the spiral curve to a sketch entity.

  3. Step 3:

    project the sketch onto the conical face.

  4. Step 4:

    make a plain at an end point of the new curve that is perpendicular to the curve.

  5. Step 5:

    make a circle and sweep cut along the curve

  6. Step 6:

    circular pattern