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How Does a Windsock Work? And What Are They Used For?

What does a windsock do exactly?

A windsock, or anemoscope, is an instrument used in meteorology that indicates the direction and strength of the wind. The wind sleeve is attached to a vertical mast and fixed so it can rotate freely. It is usually a truncated cone shape, with a hole at each end, and normally coloured with stripes (typically red and white).

They have many applications and are used in airports, heliports, on highways or roads, and at industrial manufacturing facilities.

Characteristics of windsocks

The windsock has been specially designed as a simple and easy device to interpret the direction and strength of the wind.

The size of the windsock can vary, depending on the place where it is installed and the required visibility, and can range from something less than 1m to 4 m in length.

The widest part of the sleeve (cone) is attached to a ring, which is usually metallic so that it always remains open. This, in turn, is attached to a vertical mast in such a way that it can rotate freely in any direction.

When the wind hits the sleeve, it rotates allowing it to pass through the larger opening. Depending on the force of the wind, the sleeve rises up as it fills with air. The maximum inclination of the sleeve by the force of the wind is 90° with respect to the mast; that is to say, parallel to the surface of the ground. In some places, they must be calibrated so that at a certain wind speed, they are fully extended.

How does it show wind speed?

The windsock extends showing the direction of origin of the wind. Convention states that wind direction is indicated as the direction from which the wind originates. So, a windsock that points towards the south indicates a north wind (the wind comes from the north).

The speed of the wind is reflected in the angle of the windsock with respect to the pole it is attached to or other mounting assembly used. The position of the windsock cannot indicate the exact wind speed, but it is a very effective indicator.

The level of inflation and the inclination of the cone gives an approximate idea of ​​the wind speed. According to its inclination, the force of the wind can be estimated in the following way:

  • Vertical cone: loose or calm wind
  • 45° cone: a 45° angle indicates a considerable wind.
  • 90° horizontal cone: a 90° angle, with the sleeve fully extended, forming a right angle to the mast, means that the wind is very strong, especially if it remains fixed in that position.

Windsock applications

Wind sleeves are very useful at airports (the sleeves are usually illuminated for night use), heliports, aerodromes, hang gliding flight centres, on all types of viaducts located at high altitude, on roads where strong side air currents occur, as well as in industrial zones, mainly where chemical products are handled. They are especially useful for road safety, as they help to alert drivers to dangerous side winds on highways and roads.

Custom windsocks

Apart from the main windsock sleeve and pole, there is a range of windsock accessories available for specific windsock applications including telescopic, vehicle and wall mounting kits, among others.