Editing Anemometer (section)

===Vane anemometers===
One of the other forms of mechanical velocity anemometer is the ''vane anemometer''. It may be described as a [[windmill]] or a propeller anemometer. Unlike the Robinson anemometer, whose axis of rotation is vertical, the vane anemometer must have its axis parallel to the direction of the wind and is therefore horizontal. Furthermore, since the wind varies in direction and the axis has to follow its changes, a [[weather vane|wind vane]] or some other contrivance to fulfill the same purpose must be employed.

A ''vane anemometer'' thus combines a propeller and a tail on the same axis to obtain accurate and precise wind speed and direction measurements from the same instrument.<ref name= WMO>{{cite web|url=http://www.eumetcal.org/resources/ukmeteocal/rapid_cyclo/www/english/glossary/vaneanem.htm|title=Vane anemometer|author=World Meteorological Organization|author-link=World Meteorological Organization|work=Eumetcal|access-date=6 April 2014|archive-url=https://web.archive.org/web/20140408221107/http://www.eumetcal.org/resources/ukmeteocal/rapid_cyclo/www/english/glossary/vaneanem.htm|archive-date=8 April 2014|url-status=dead}}</ref> The speed of the fan is measured by a revolution counter and converted to a windspeed by an electronic chip. Hence, volumetric flow rate may be calculated if the cross-sectional area is known.

In cases where the direction of the air motion is always the same, as in ventilating shafts of mines and buildings, wind vanes known as air meters are employed, and give satisfactory results.<ref>{{Cite book|last=Various|url=https://books.google.com/books?id=iUFjDwAAQBAJ&q=In+cases+where+the+direction+of+the+air+motion+is+always+the+same%2C+as+in+ventilating+shafts+of+mines+and+buildings%2C+wind+vanes+known+as+air+meters+are+employed%2C+and+give+satisfactory+results.&pg=PP8|title=Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1|date=2018-01-01|publisher=Prabhat Prakashan|language=en}}</ref>

<gallery caption="Vane anemometers" class="center">
File:Wind speed and direction instrument - NOAA.jpg|Vane style of anemometer
File:Prop vane anemometer.jpg|[[Helicoid]] propeller anemometer incorporating a [[wind vane]] for orientation
File:Anemometer-IMG 4734-white.jpg|Hand-held low-speed vane anemometer
File:Digital_Handheld_Anemometer.jpg|Hand-held digital anemometer or Byram anenometer.
</gallery>