Apparatus Measures Thicknesses Of Ice On Bars

Semiautomated apparatus measures diameters, at selected lengthwise positions, of nine vertical ice-coated bars in icing-research wind tunnel. Includes measuring head that travels on rails parallel to bar, driven by ball screw actuated by stepping motor. Position of measuring head along bar measured by string potentiometer, providing position feedback for closed-loop control circuit. Circuit provides for smooth motion of measuring head, and used to select various programmed sequences of motions and measurements. Measurements needed to determine degree of uniformity of icing conditions for experiments on aircraft models.