I have now been in the “thinking box” for quite some time regard issue, also sleepless nights :lol: #-o
And i now have come up with the finale solution, also for the turbulence issue if this also is affecting the break downs of the wind direction potensiometer.
Now i have cut of aprox 40% of the wind vane tail to 35 k/grams . See photo.
Also grinded the bronze end down to get weight balance correct.
I now this will affect quickness for change in wind direction in low wind conditions, but i think it will indicate good above 6-8 m/s anyway.
Also it will not “hopefully” turn the quick small movement side to side as much as the original one.
Will change the wind vane as soon as weather allow it today or tomorrow.
Weather window open up this evening, so have been up on roof to change original davis wind vane to “special modified” wind vane 35 k/grams at 18:25.
Will see the next days if any changes, if any usable wind is around.
That’s a interesting idea. I imagine there may be some loss of directional accuracy at very low speeds but that’s not your issue. I think I would have tried adding (balanced) mass to increase its inertia. I look forward to seeing the results
Thanks for input niko
The modified vane has been in work since yesterday 18:25, see photo.
Surprisingly the modified vane seems for now even worse, but its also lighter (35 k/grams) then the original davis that is 43 k/grams.
Will see when more wind shows up.
Maybe think out a “slow down” breaker #-o
Mounting it higher then 2m from roof top is not easy on the roof tiles ether, if alu pipe is longer the pipe will flex in the wind… then need support wires aso… wife will kill me :roll:
I also been thinking about adding more mass to the wind vane niko.
Could try adding mass to original one, compare to original 43 k/grams.
Can the potensiometer stand the extra weight??
Weather allows for more modifying today.
So adding mass as niko suggested.
For testing i now have modified one original davis wind van, adding more mass, from original 43 k/grams to 174 k/grams. See photo.
A little bit bumpy look with nuts mounted on it due to the weight balance, but hope it does the job calming down the wind van quick small side to side movement.
Tested/compare to original wind vane in garage using air compressor, adding mass makes more “stability” on the van.
Original one was flexing quickly side to side, the more mass wind vane was calmer in the garage test.
The more mass wind vane was mounted today at 11:25 before lunch.
See during today how its performing in “real life”.
The first test i did by cut of aprox 40% of wind van wing surface was 35 k/grams after modifying, and was looking worse then original reg small quick side to side movement.
Any chance the issue is being caused by turbulence? Your pictures show a lot of roofs nearby that could be disturbing the natural wind flow. Just thinking out loud, maybe more height for the anemometer would provide some relief to the quick changes you’re graphing.
Thanks for input NorCal Dan.
as i mention further down in post: Mounting it higher then 2m from roof top is not easy on the roof tiles ether, if alu pipe is longer the pipe will flex in the wind… then need support wires aso… wife will kill me :roll:
Get it higher up is no option at present time.
Since im living in a long slope down to sea 146 m over sea level, lot of wind turbulence up the long slope, a lot of houses, to get free of turbulence i prob have to have a pipe 25 metres high.
See photo of old position on balcony, 7,5 meters- 2 meters over roof top.
This will be positioned left-down compare to present position at this time.
But of course swaying a lot, when the wind was over 40 m/s last winter, the alu pipe almost broke in two If to support this layout with wires, i have to connect wires at my neighbour house wall [-X and he will prob be werry happy
Hi All.
Looks like the side to side has gotten little better with more mass on the wind vane.
On photo- before red line is the cut of vane used 35 kgram, on red arrow side is the more mass vane in use 175 kgram.
Will run like this for a while, hope some more wind.
That does look a little better. Be interesting to see how it goes…
It would be difficult to mechanically damp it, you might do something magnetic but that would risk affecting the speed sensor. Averaging would be another solution but I don’t think the Davis has that possibility.
Hi.
Thanks for input niko.
mechanically damp it would actually be the right solution to the issue, but how?? maybe some “spring” load adjusable from the rotating wind vane to the plastic housing pushing on a steel ring some how, one idea??
Averaging i think is not a solution since the issue is only mechanically, not software.
I also wonder how this wind vane 175 kgrams will hold up with 40 m/s wind, will it get loos and fly away?
Here is graph photo since mounted yesterday, actually looking good so far i believe.
On photo- before red line is the cut of vane used 35 kgram, on red arrow side is the more mass vane in use 175 kgram.
Seems like its wind from south that has most turbulence (all houses up hill), east-north almost strait line.
Need more wind to be sure.
A user on the Cumulus forum added magnetic damping to their home brew wind vane - to good effect iirc. Just an aluminium disk and strong permanent magnet. Mounting it to the Davis sensor would be the challenge I think.
Thanks for input @mcrossley , alot to read there on forum.
good idea.
Will order some magnets 5mm X 3mm on ebay, need to figure out a plan how to mount 1 or 4 magnet in a X to wind vane and a magnetic ring or similar to the “housing” or opposite.
Not a magnetic ring, an Aluminum disk (eddy current brake). This is what I was also suggesting. My concern is that the magnets (use neodymium ones) will affect the magnetic sensor in the speed part of the unit.
Thanks fore info and clearing this up niko, good info
Can i use like normal aluminum? or does it have to be (eddy current brake) aluminum, where to get it small and round?? E-bay has like almost nothing so small fore use #-o
Regular aluminum. I don’t know where to get a ready made disk, I would find any aluminum sheet and cut a circle out of it, probably just use a hole saw. I can buy small sheets from the hardware store, but otherwise I would look for a cheap baking sheet or something like that.
Ok, regular aluminum i have here at home, just ordered 10 pc of 5mm x 3 mm neodymium magnets.
When magnets arrive i will find a way to mount it on the wind vane.
If to support this layout with wires, i have to connect wires at my neighbour house wall [-X and he will prob be werry happy 
