How to create a Spiral / Helical Sheet Metal Model that can be flattened

If you want to create a spiral / helical sheet metal model, using the sweep feature + insert bends will not do the job.

You will need to use two different size helix / spiral paths:

Spiral/Helical Path

Then, convert these curves to 3D sketch entities:

Converted to 3D curves

Now, use lofted bend to create sheet metal:

Lofted Bend

Helical Sheet Metal Model

Flattened state:

Flattened Model