Rotorwash Wind Sensor Evaluation

Abstract : This project's purpose was to assess and document the ability of the Qualimetrics, Inc. model 2132 wind sensor (a cup and vane type sensor) to measure a rotorwash flow field as compared to the TSI, Inc. model 204D ion beam deflection sensor. The tests concentrated on the sensor's ability to capture dynamic characteristics of a helicopter rotorwash flow field. The project was conducted from April to November 1992 and consisted of quantitative laboratory and field testing. The laboratory testing included 9.5 hours of wind tunnel test time, subjecting each sensor to three step input tests at velocities of 20 knots, 50 knots, and 80 knots. Field test data were collected during one hour of SH-60B helicopter hover time at heights of 15 and 25 feet above ground level at distances of 35 and 70 feet from the wind sensors. Aircraft gross weights ranged between 19,600 and 20,500 pounds. All field test data were obtained in ambient wind conditions of approximately 8 knots at 40 degrees relative to the aircraft nose, -40 feet pressure altitude in an ambient temperature of 85 deg F. Laboratory data analysis indicates the model 2132 cup and vane sensor's time constant values were significantly higher than those of the model 204D ion beam sensor and varied relative to wind tunnel velocity settings. This indicates the model 2132 sensor's ability to accurately capture oscillations in a dynamic flow field is significantly less than the model 204D sensor. The model 2132 sensor did detect periodic or pulsating velocity magnitudes, but failed to capture significant oscillations as compared to the model 204D sensor. Flight Test, SH- 60B Helicopter, Helicopter, Wind Speed Sensor, Rotorwash, Wind Tunnel Test