Longitudinal scan, cam shaped, turntable rotor for magnetic recording

In a reel-to-reel longitudinally scanned tape transport or recorder, a length of media is positioned to fly in transducing relationship with a transducing head. The transducing head is mounted on a rotatable turntable rotor. The rotor includes a substantially circular member with concentric horizontal surfaces projecting in separate vertical planes. A cam shaped contour is fabricated on one of the horizontal surfaces with the transducing means positioned at the peak or crown of said cam shaped surface. There is a gradual roll off between the crown and the lowest point of the cam shaped surface. The roll off creates a converging channel which allows a sufficient volume of air to enter the interface between the media and the head and a diverging channel which allows the air to be bled off.