A windsock (also called a wind cone) is a
conical
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines conn ...
textile tube
Tube or tubes may refer to:
* ''Tube'' (2003 film), a 2003 Korean film
* ''The Tube'' (TV series), a music related TV series by Channel 4 in the United Kingdom
* "Tubes" (Peter Dale), performer on the Soccer AM television show
* Tube (band), a ...
that resembles a giant
sock
A sock is a piece of clothing worn on the feet and often covering the ankle or some part of the calf. Some types of shoes or boots are typically worn over socks. In ancient times, socks were made from leather or matted animal hair. In the late ...
. It can be used as a basic indicator of
wind speed and direction, or as decoration. They are typically used at
airports to show the direction and strength of the wind to pilots, and at
chemical plant
A chemical plant is an industrial process plant that manufactures (or otherwise processes) chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transform ...
s where there is risk of
gaseous
leakage. They are also sometimes located alongside
highways at windy locations.
At many
airports, windsocks are externally or internally lit at
night.
Function
Wind direction is the direction in which the windsock is pointing. (Wind directions are conventionally specified as the
compass point from which the wind originates; so a windsock pointing due
north indicates a
south
South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west.
Etymology
The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...
erly wind). Wind speed is indicated by the windsock's
angle relative to the mounting
pole; in low winds it droops; in high winds it flies
horizontal
Horizontal may refer to:
*Horizontal plane, in astronomy, geography, geometry and other sciences and contexts
*Horizontal coordinate system, in astronomy
*Horizontalism, in monetary circuit theory
*Horizontalism, in sociology
*Horizontal market, ...
ly.
Alternating stripes of high visibility orange and white were initially used to help to estimate wind speed, with each stripe adding 3
knots
A knot is a fastening in rope or interwoven lines.
Knot may also refer to:
Places
* Knot, Nancowry, a village in India
Archaeology
* Knot of Isis (tyet), symbol of welfare/life.
* Minoan snake goddess figurines#Sacral knot
Arts, entertainme ...
to the estimated speed. However, some circular frame mountings cause windsocks to be held open at one end, indicating a velocity of 3 knots even when it is not present. A fully extended windsock suggests a wind speed of or greater.
Standards
Per
FAA standards, a properly functioning windsock orients itself to a breeze of at least and fully extends in wind of .
Per
Transport Canada standards, a wind fully extends the windsock; a wind raises it to 5° below the horizontal; and a wind raises it to 30° below the horizontal.
ICAO
The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international a ...
standards specify a truncated cone-shaped windsock at least 3.6 m long and 0.9 m in diameter at the large end. It should be visible and understandable from an altitude of 300 m and ideally be of a single colour. If it is necessary to use two colours, they should ideally be orange and white arranged in five alternating bands, with the first and last darker in tone. In wind speeds of or more they must indicate wind direction to within ±5°.
See also
*
Air sock
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...
*
Anemometer – meteorological device for measuring wind speed and direction
*
Draco (military standard)
The ("dragon" or "serpent", plural ) was a military standard of the Roman cavalry. Carried by the , the was the standard of the cohort, as the eagle () was that of the legion.
The may have been introduced to the Roman army after the Dacian war ...
-
military standard
In military organizations, the practice of carrying colours (or colors), standards, flags, or guidons, both to act as a rallying point for troops and to mark the location of the commander, is thought to have originated in Ancient Egypt som ...
carried by the
Roman cavalry.
*
Koinobori – Japanese decorative carp-shaped windsocks
References
Airport infrastructure
Meteorological instrumentation and equipment
Socks
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