Preliminary Tests of an Ultrasonic Thermoanemometer for Aircraft Measurements

Abstract

A prototype of an ultrasonic thermoanemometer, specially designed for aircraft measurements, has been developed. By measuring the transit time of ultrasonic pulses, one can deduce the speed of sound and then the air temperature (or the aircraft speed) at hundredth of a second intervals. In order to avoid the problems inherent to vibrations and to reduce the number of measurement paths, the flow has been channeled so as to be unidirectionnal. Wind tunnel studies allowed us to define a convenient geometry. Preliminary flight tests (up to 200 km h?1) have been conducted.