Forums > Kitesurfing General

Best hand-held wind meter?

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Created by Knickers > 9 months ago, 4 Nov 2008
getfunky
WA, 4485 posts
7 Nov 2008 11:23AM
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Paradox said...

hoskoau said...

Q?: Will a wind meter held 2m or so above the ground (on a flat-ish beach) generally be reading 3-4 kts lighter than the breeze blowing 20m or so higher?


The simple solution would be to attach the wind meter to the kite and find out.

The higher up you go the windier it gets. This is a well known fact when designing skyscrapers.


There are a lot of graphs and formula's used for turbine and structures design that indicate the wind is approx 30% stronger at 20m over that at 2m (15kts@2m is 20kts@20m). Atlhough these figures are likely to represent average land based values. I would think it is probably less of a factor over water where the surface drag is less.

I would think you are about spot on with a 3-4 kt difference over the water getfunky.

[EDIT] PS love your windmeter SG, I never really considered buying one but I am now seriously tempted to make one of these. If you found the right spot you could attach the fan 10m up a pole somewhere near your local and conceal some wires coming out around ground level. you would just need to hook up the trusty multi when you turn up - the whole crew could use it .....




Ta paradox.

I have been tempted at times to buy a meter but always though it was going to still be a guestimate even with the meter.

Really tops idea with the PC fan and multi-meter. Funny, a week ago I found a brand new mm in my shed that I have had for years and never used. Next verge collection I am gettin me a home made wind meter!! Super functional but nice n daggy lookin too - just the way I like it!!

sandgroper
WA, 368 posts
23 Dec 2008 8:34PM
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From: galeforce
Sent: Monday, 22 Dec 2008 5:22 AM
Subject: Interested in your diy wind meter

Hi sandgroper,

I was browsing the forums and came along your profile. I saw the pics of your diy wind meter and thought I would like to have one of them. How accurate is it? So I've gone and pulled a fan out if an old computer and got a cheap multi-meter, but I cant hook it up right and cant work out the setting on the multi-meter has to be on.

What setting shout the multi-meter be on and is it red to red black to black when connecting the fan to the multi-meter?

Thanks, galeforce.


From: sandgroper
Sent: Tuesday, 23 Dec 2008 7:23 AM
Subject: Re: Interested in your diy wind meter

Red to red, black to black, but it doesnt matter all that much. Set MM to read AC current at about 100mA - 200mA for 25knots.

It will vary between fans, but if you dont get any reading at all on the lowest AC current setting the the fan is by definition, stuffed. It is a prerequisite that you use a working fan.

To calibrate, get someone to drive you at a fixed speed (say 40kph) on a day with no wind and stick he fan out the window. Note the MM reading and you're all done.


From: galeforce
Sent: Tuesday, 23 Dec 2008 5:52 AM
Subject: Re: Interested in your diy wind meter

Ok sounds good I will give it a go. Such a smart idea though =). Thanks again galeforce.


And BTW, it as accurate as anything you'll pay $100+ for.

Gorgo
VIC, 5101 posts
24 Dec 2008 2:28PM
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All hand-held wind-meters are inaccurate. You are measuring the wind blowing at ground level with the flow distorted by the ground and everything around it. The only way to get an accurate reading would be to put one up a 10m pole with no part of the pole or support interfering with the meter.

The most effective way of judging the wind is to walk around a bit and look and listen.

If you are standing facing the wind and you can hear a definite solid wind blowing noise then it is probably windy enough to go kiting using your light wind gear.

If there's white caps all over the place and sand and **** blowing about then you might want to use your small kite.

If the wind is blowing offshore then there won't be any white caps, unless it's really ****ing strong.

If you really must buy a wind meter then the small Hall are are about the best available www.hallwindmeter.com/gliders.php They never break. The batteries never go flat. They read fairly consistently.

galeforce
VIC, 35 posts
25 Dec 2008 10:39PM
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Sandgroper's diy wind meter actually works quite well. And it is pretty consistent with its readings. Anyway it saved me 50 bucks. Thanks Sandgroper!



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"Best hand-held wind meter?" started by Knickers