My daughter needed to create a air powered "thing" for school and I found this instructable: http://www.instructables.com/id/Balloon-Hovercraft/ Since I didn't have a wooden spool, but I do have Autodesk Inventor and a 3D printer I decided we should design an adapter. We measured some CD's and our balloon and created a CD Balloon Hovercraft Adapter. The part prints easily and snaps into the center of the disc easily. Note: You will need a pretty smooth surface for this to work, we used our kitchen counter.