Buid a coil or helix with a varying pitch

[MAGNUT45]

Inventor 2009.
A want to create a coil/helix of a magnet winding.
I need the pitch to gradually increase per revolution
Is there a way I can do this?

Thanks!

 

[Jabberwocky]

At our company (Inventor 2008) we fake this by making multiple coils, basically one for each pitch segment. It is very time consuming but does look correct once you're finished. You can set up parameters to help the coils smoothly transition but I don't know of an actual variable pitch helix like SolidWorks has.