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Windsock strength?


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I'm getting conflicting information about what a standard windsock will indicate in terms of wind strength. I've heard that the standard modern aerodrome primary white windsock, aka "Wind Direction Indicator" (according to CASA), is horizontal at wind strengths greater than 30 knots. However, I've also heard 15 knots is the correct number.

 

Can anyone shed some light?

 

 

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It's a little more complicated, as in theory White socks were a lighter strength and yellow socks were higher rated if I have that the right way around.

 

Probem is that not all wind sock manufacturers stuck to the standard.

 

I was of the belief that white was 20 knots and yellow 30 when blowing horizontal.

 

 

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WINDSOCK: The windsock not only gives a good indication of the direction but can also give a fair idea of the wind speed. Use the Primary windsock - that's the white one. The old style canvas windsocks that were used in the past were just horizontal at 30 knots.

 

A Primary Wind Indicator in 15+ knots of wind The modern lightweight windsock is horizontal with a windspeed of 15 knots or more. 5° below the horizontal would indicate 10 knots and 30° below the horizontal would indicate 6 knots. A windspeed of 3 knots or more will cause the windsock to rotate about its shaft and indicate the wind direction. Source: Transport Canada Civil Aviation AGA - 5.0 Markers, Markings, Signs and Indicators and FAA Advisory Circular 150/5345-27D - FAA Specification for Wind Cone Assemblies.

 

above copied from the Schoefields newsletter

 

 

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Windsock info.

 

The signal thing is that CASA regard it as a "wind direction indicator." , and no more. There is probably NO standard out there for wind strength. When you fly over the aerodrome you cannot discern the angle that the sock presents to the horizontal anyhow. The only time that you can get an idea of the wind strength is by the crab angle you need on final to maintain the centreline, If The wind has a significant crosswind component. Nev..

 

 

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From website of windsock manufacturer

 

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8 & 12 Foot Windsocks.

 

Wind Socks of 8 & 12 Foot.

 

These are available in white, or yellow, and are also available in a choice of standard weight or heavy duty versions. the heavy duty version being for places of extreme wind, cyclone prone, or tropical areas.

 

The 8 & 12 foot windsocks are calibrated for Aviation use, fitted with an internal hoop and four large attach eyelets, and is supplied with heavy duty cable ties to attach to a 2ft diameter frame for the 8ft windsock, or a 3ft frame for the 12ft version.

 

The heavy duty windsock will outlast the standard weight by an estimated 50% under the same give conditions.

 

The standard weight windsock is slightly more 'active' in very light wind conditon.

 

12ft windsocks are the 'standard' for use at licenced and council airstrips and airports.

 

 

It is quite possible that there are several 'primary' windsocks at an airport, (one for each runway, and often one near the end of each runway.

 

Colour choice of windsocks for non commercial use is simply a matter of what stands out the best against the background colour as seen from the air. Yellow is easier to see against a background of sky, or as seen from the ground. Both colours illuminate well with the 12 volt lighting option, as the materials used have good fibre optic qualities.

 

 

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