Flight Evaluation: Rosemount Orthogonal Low Airspeed System Low Airspeed Sensor

Tests were conducted on the Rosemount Engineering Company Model 853 orthogonal true airspeed sensor to determine its suitability for operational and flight test use as an airspeed system for helicopters. The sensor has no moving parts, and operates on the principle that differential pressures, measured between a pair of orthogonal chambers, are proportional to the airspeed in a given direction. Flight tests at Edwards Air Force Base, California, were started on 24 January 1974 and were continued as additional hardware became available.