RM YOUNG propeller anemometer 27106 from the United States

The 27106 propeller anemometer uses a fast response propeller and a high-quality speed generator sensor to generate a DC voltage that is linearly proportional to the air velocity. Airflow from any direction can be measured, however, propellers only respond to airflow components parallel to their axis of rotation. The off-axis response is very close to a cosine curve with appropriate polarity; Due to the vertical airflow, the propeller does not rotate. The output signal is suitable for various signal converters and data recording devices. Standard expanded polystyrene (EPS) propellers provide maximum sensitivity at low wind speeds. The optional carbon fiber thermoplastic (CFT) propeller can be used for a wider range and durability.

specification
08274 Polystyrene Propeller (EPS):
Diameter: 22 centimeters
Pitch: 29.4cm air duct per revolution
Range: 0-25 meters per second (55 miles per hour)
Threshold: 0.3 meters per second (0.6 miles per hour)
Distance constant: * 1.0 meter (3.2 feet)
08254 Carbon Fiber Thermoplastic Propeller (CFT):
Diameter: 20 centimeters
Pitch: 30.0 centimeters per rotation of wind diameter
Range: 0-35 meters per second (80 miles per hour)
Threshold *: 0.4 meters per second (0.8 miles)
Distance constant *: 2.1 meters (6.9 feet)
Signal output:
Standard: Speed generator transducer - analog DC voltage proportional to wind component. Polarity indicates the direction of rotation. 1800 RPM (500 mV)=8.8 meters per second (19.7 miles per hour).
Optional: Photochopper sensor, 10 pulses/rev. 1800 RPM (300 Hz)=8.8 meters per second (19.7 miles per hour).
Ability requirements:
Standard: The anemometer and speed generator are self powered.
Optional: Anemometers with photocatchers require 5-15 VDC at 11mA.
Dimension:
43 centimeters (17 inches) long w/installation. , with a shell diameter of 2.5 centimeters (1 inch). Propeller diameter: (see previous text)
Installation: 3/4 "pipe thread adapter and MS type connector (connected to anemometer)
Weight:
0.5 kg (1.1 pounds), transportation weight 1 kg (2.2 pounds)