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How to determine wind speed from the air?

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How to determine wind speed from the air?

Old 23rd Sep 2007, 17:36
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How to determine wind speed from the air?

Good evening,

I wish to know how it is possible to estimate the wind speed from windsock at the airport, or windmills, or even smoke from factories?

I mean i don't have much trouble estimating the direction of the wind, however i cannot estimate the speed.

Please help me with this,
Great day,


BeautifulClouds

Last edited by BClouds; 23rd Sep 2007 at 20:39.
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Old 23rd Sep 2007, 18:14
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Join Date: Feb 2000
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windsocks have a max wind rating, i.e when it is horizontal it is showing x knots or above. I think 15kt and 25kt spring to mind, depending on the size.

From FAA windsock specifications:

4.2.6 Windsock Extension. Test the windsock to assure that it extends fully when subjected
to a wind of 15 (+2,-1) knots (+3.7, -1.8) km/hr or (+2.3, -1.2 mph) ).
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Old 23rd Sep 2007, 18:16
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Hello.

Learn to sail!!! In addition to the "Observation" list below the boaty version will give observations based on water movement, spray and appearance of white horses on the wave ridges etc

This is how you can estimate wind speed by looking at stuff on the ground, see http://www.bbc.co.uk/dna/h2g2/A876864:

Edited to put a boaty one in:

http://www2.metoffice.gov.uk/weather...fortscale.html
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Old 23rd Sep 2007, 18:47
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windsocks have a max wind rating,
- and I think the Island of Tiree airport (in the Hebrides) is rated at 90kts and I was there when it tore.
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Old 23rd Sep 2007, 20:39
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Thank you very much for your help, on windsock, tree and water.

If anyone knows how to estimate wind speed from smoke (factories for example), and windmills, please let me know.

BClouds
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Old 24th Sep 2007, 15:18
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Mate, the windfarms aren't much good, they turn at an RPM decided by computers although obviously the wind speed will affect the max achievable RPM. Some will even be stopped!

As far as smoke goes, I usually estimate horizontal from the chimney as 25-30 knots and work progressively less until it goes straight up at less than 5 kts. I don't really fly in surface winds above 30kts so can't tell you about signs when it's greater than that!

HTH.

Blunty
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Old 24th Sep 2007, 17:48
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If you're hat blows off, it's too windy.
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Old 25th Sep 2007, 19:20
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...especially if you're in the airplane!
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