Wind Vanes

[Gina]

Just done a test - the high power magnet I've got doesn't affect the reed switches in the spare F.O. wind vane unit until it gets to within 2 inches of the reeds. So I don't anticipate any problem with the damping magnet and the reed switch in the anemometer - it will be too far away.

[Gina]

My latest thoughts on wind sensors.

New-Wind-Unit-4.png

[captzero]

Just out of interest, Davis have released a new wind vane which is now the standard on all new Vantage Pro systems.

Link is here ...... http://www.davisnet.com/

[steve]

Just out of interest, Davis have released a new wind vane which is now the standard on all new Vantage Pro systems.

Link is here ...... http://www.davisnet.com/

Interesting. And only $10 for one to upgrade existing systems. Probably $30 in the UK...

[Gina]

Been building my new wind vane today. Some alterations to cater for what materials I had available.

0-new-wind-vane-z.png

[Great Cornholio]

Gina. You do some amazing mods. I think vertical is the way to go. Being at a lot of airports I see lots of professional wind vanes. The common thing that they all have is that they are super long. As in 36 inches or more as a guess. I haven't seen any kind of dampers on them however something may be hidden from view in the mast. All of them still have a little bit of flutter or wobble (although I've never seen one do a complete 360 like my FO has done plenty of times)

The way to go may be light and long without any dampening. This way slight change in direction will be detected fast but the long moment arm should keep it from straying too far from out of the wind.

You say you have lots of trees so you probably have pretty turbulent airflow so no matter what unless you get way above the trees you may not be able to get a steady wind direction because there truly is no steady wind direction.

[Gina]

Thank you

The one I'm working on now is about a foot long with magnetic damping - but I'll be doing tests with and without damping. The vane itself is about 5in long and 4in high with a round shaped leading edge. I've made it as light as I can. I'll take some photos later.

[Gina]

Just done a quick test. Just held up in the wind by hand rather than on top of a mast. The wind is Force 4-5 gusting 6 and blustery. The FO at 20ft (6m) was swinging up to about 22 degrees either way. New vane about half as much without damping and slightly less with. I would expect the wind at about 8ft to be a lot more turbulent so initial results look good. I'm looking forward to trying it higher up and also in lower winds.

[Orion]

Just starting a new wind vane
The general idea is to remove the fins from the FO vane leaving the plastic splines and fix them inside the tube then add weight as necessary to the nose
will also raise the height of the wind vane to clear the anemometer as the arm will be that much longer I will also need to make the cable from the anemometer a bit longer

UPDATE Yes it was a bit heavy got made a bit smaller in the final version
See later post

[Gina]

That looks pretty substantial and maybe a bit heavy.

Just taken some measurements of mine... bearing centre to end of vane 12in, vane 6in long by 5in high. Vane made from thin plastic packaging and arm from other scrap plastic. All designed to be as light as possible. Counterweight is a magnet which also operates reed switches and about 3in from bearing centre. Total weight 96g (grammes).

[Gina]

I've been checking out operating distance of the reed switches to try and make sure the in-between positions work. One problem is that the distance to close is quite a bit less than the distance to open - a ratio of nearly 1:2. Of course, if the vane is waggling that might not be such a problem

I was originally thinking of using optical sensing but that requires power to run the IR emitters. More than available as parasitic power from the 1-wire network, I think. The reed switch circuit works fine with parasitic power. Anyway, I'll see how the reed switch method works and keep optical as a "backup".

[Gina]

Been checking rotational properties with magnet and radial reed switches. The angle between turning on and turning off is about 60 degrees. Going the other way the on/off positions were about 15 degrees different. So the difference between the two directions is not as much as I thought.

[Gina]

Further test results :-

Been checking the coverage for the various wind directions (compass points) with a view to using the overlap of adjacent 8 point reed switches to calculate in-between directions. The average "on" angle for each reed switch is 60 degrees and the reeds are placed at 45 degree increments. So the overlap is 15 degrees. The result is shown below. The 8 cardinal points are covered by 45 degrees but the others between by only 15. I would like them nearer equal. More experimenting to do.

00-vane-angles-2.png

[MickinMoulden]

Just starting a new wind vane
The general idea is to remove the fins from the FO vane leaving the plastic splines and fix them inside the tube then add weight as necessary to the nose
will also raise the height of the wind vane to clear the anemometer as the arm will be that much longer I will also need to make the cable from the anemometer a bit longer

Looks real neat. Great work.

[Great Cornholio]

Just done a quick test. Just held up in the wind by hand rather than on top of a mast. The wind is Force 4-5 gusting 6 and blustery. The FO at 20ft (6m) was swinging up to about 22 degrees either way. New vane about half as much without damping and slightly less with. I would expect the wind at about 8ft to be a lot more turbulent so initial results look good. I'm looking forward to trying it higher up and also in lower winds.

That test sounds pretty good. The air at 8 ft should be much more turbulent than at 20 ft. Due to the fact that the air hits more stuff at 8 ft than 20 ft.

I'd say that once you get that new vane in its normal home you will have pretty good results and that the vane will be pretty accurate. It will still wobble some but they all wobble some. Also keep in mind that there are some days that wind will vary in direction as much as 60 degrees or more. Those days make work fun...