This report describes the development effort involved in creating an instrument capable of measuring the speed (0 to 50 fps) and direction of an air-flow vector at any selected point ranging from 0 to 1000 ft above the earth's surface. The sensitive instrument element was an electrically heated thermistor rod producing an electrical signal variation as a result of the convective cooling action of the measured air flow. The electrical signal from the elevated instrument station was conveyed to the ground readout station by a transmission cable. The instrument was stably supported and selectively positioned in the air flow by a tethered kite-type balloon. The development resulted in a complete and practical field measuring instrument having good accuracy and response.
Prepared under signal Corps contract No. DA-36-039 SC-72314, Signal Corps Project No. 1052A, Department of Army Project No. 3-17-02-001
Ripken, John F.; Killen, John M..
Research and Development Studies for a Low-Level Free-Air Velocity Measuring System.
St. Anthony Falls Hydraulic Laboratory.
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