Anemometers

Instrument for measuring the speed of airflow. The most familiar instruments for measuring wind speeds are the revolving cups that drive an electric generator (useful range approximately 5 – 100 knots). For very low airspeeds, a unit in which revolving vanes operate a counter measures the airspeed. For strong, steady wind speeds (in wind tunnels and aboard aircraft in flight), a pitot-tube anemometer is often used; the pressure difference between the interior of the tube and the surrounding air can be measured and converted to airspeed.