Strain gage operated wind velocity and direction indicator


Most all wind indicators are of the conventional moving airfoil and rotatable vane type. In recent years it has been popular to replace or reduce moving parts with electronic circuitry. If only the electrons move, perhaps a move can be made toward a maintenance free unit. From bathroom scales to wind tunnel testing, strain gages have replaced the moving balance and other substantial movement transducers. Why have we not had a large spin off of consumer items originating from professional wind tunnel techniques measuring air flow? This paper reveals some of the problems encountered in designing such a device. The dynamic characteristics of wind, from less than one mile per hour to 100, is enough of a range to cause serious calibration problems. Also, the drift caused by high amplifier gains is critical. The amplifier needed for the transducer makes it difficult to maintain calibrated stability at low air velocities. Another factor is the engineering of digital solid state logic to interpret the gage's analog voltages into direction of the air flow. A final question asked, can the cost be competitive with traditional anemometers or wind direction indicating devices? A unit was designed, built, and tested in a wind tunnel up to a Reynolds number of one million. The following paper shows the concept, circuitry, and results of this experiment.


Technology and Construction Management

Document Type

Conference Proceeding

Publication Date


Journal Title

Instrumentation in the Aerospace Industry, Proceedings of the ISAAerospace Instrumentation Symposium