Author Topic: Peet Bros wind vane and cup - Bigger = Better?  (Read 1167 times)

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Offline Big Sky Weather

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Peet Bros wind vane and cup - Bigger = Better?
« on: September 19, 2019, 01:13:24 PM »
I'm sure this is a rather simple question to answer based on the obvious, but does their "Size Matters" declaration ring true? If you look at the photo below, it shows how their wind vane and cup stack up to other brands. What if you took Brand "OS" from their chart and just modified the vane to have more surface area. Would it be more accurate? Same with the cups.... just use a larger cup? Or is this marketing hype? (I'd like to know who the brands are behind their comparison)

Offline galfert

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #1 on: September 19, 2019, 01:40:19 PM »
D = Davis (old Weather Monitor wind vane shown 7911)
L = La Crosse
OS = Oregon Scientific

I think size only matters to a certain point. If you get too big then a very low wind will not have the force to move cups or wind vane. Even if you get a strong wind if you have larger wind cups then there is more mass and more inertia to overcome...the cups will stay spinning longer well after the wind has settled. So without any scientific proof...just speaking my mind I think this sounds like baloney. I'm sure the opposite is true that if the cups and vane are too small then there might be less accuracy. So I think there is probably a sweet spot in size. What I do notice is that wind vanes like Kestrel and RM Young are pretty large in length and have a considerable tail section fins. Kestrel and RM Young make Peet Bros. look like the ones with the little hands if you know what mean.

« Last Edit: September 19, 2019, 01:55:46 PM by galfert »
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Offline Big Sky Weather

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #2 on: September 19, 2019, 02:36:45 PM »
D = Davis (old Weather Monitor wind vane shown 7911)
L = La Crosse
OS = Oregon Scientific

I think size only matters to a certain point. If you get too big then a very low wind will not have the force to move cups or wind vane. Even if you get a strong wind if you have larger wind cups then there is more mass and more inertia to overcome...the cups will stay spinning longer well after the wind has settled. So without any scientific proof...just speaking my mind I think this sounds like baloney. I'm sure the opposite is true that if the cups and vane are too small then there might be less accuracy. So I think there is probably a sweet spot in size. What I do notice is that wind vanes like Kestrel and RM Young are pretty large in length and have a considerable tail section fins. Kestrel and RM Young make Peet Bros. look like the ones with the little hands if you know what mean.

Thanks for weighing in. I'd like to see measured results that support their claim but it might not be out there. BTW, off-topic but since you're "here", Ambient has finally decided to send me a replacement rain/temp/hum assembly for my WS-2000. Should be here Saturday. Feels like an eternity when your station is down and you have significant weather come through.

Offline galfert

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #3 on: September 19, 2019, 02:51:44 PM »
Great hope it works out. Keep us informed. I'm particularly interested in hearing if you ever do connect a TNC to the WS-2000.
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Offline CW2274

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #4 on: September 19, 2019, 03:34:53 PM »
Davis sells two sizes. Here's the skinny from Prodata:

Large and small: Wind cups for VP2-type anemometers have been available in two cup sizes – small and large. The 7911 (WMII-type) units were originally small cups only (in ca 2000 and before). But for many years now both anemometer types have been sold only with large cups (though small cups are still available as spares) and large is the only size that is likely to be relevant to the great majority of users. Large cups start spinning at lower wind speeds than the smaller version and for general use there is no need ever to think of using small cups. Even for anemometers originally supplied with small cups, the large cups are the best replacement.

The only circumstance in which small cups were suggested was in localities where extremely high winds (eg hurricane force – 100mph and above) may be encountered because smaller cups may perform a little better under these extreme conditions, presumably because of their lower wind resistance, though this isn’t stated explicitly anywhere. The downside of small cups is obviously their more limited performance at more moderate wind speeds.

Offline galfert

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #5 on: September 19, 2019, 04:01:35 PM »
Being that the new Davis stuff is larger than the WMII 7911, I sure hope that the graphic posted to the thread is not still being prominently displayed by Peet Bros. website. Talk about outdated information. Also today who cares about Oregon Scientific and La Crosse. Lately all you hear is Davis, Acurite, and Ambient/Ecowitt.

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Offline Big Sky Weather

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #6 on: September 19, 2019, 09:12:43 PM »
I pulled it from this page, with it being accessible from a hyperlink in the text:

"...featuring exceptional response in all wind conditions, including very low wind speeds (typical starting threshold 1.5 mph! here's why)"

Offline miraculon

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #7 on: September 20, 2019, 08:25:32 AM »
No mention about bearing friction in either the vane or anemometer....

Large cups/vane to overcome high bearing friction might work, but low friction bearings with smaller cups/vane could be just as effective.

My R M Young Wind Monitor Jr. is much more sensitive to both direction and speed than my Davis VP2 vane. I suppose that the vane on the "big brother" standard Wind Monitor would be more responsive with direction, but the "propeller" design is the same.

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Offline Big Sky Weather

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #8 on: September 21, 2019, 08:08:25 PM »
Great hope it works out. Keep us informed. I'm particularly interested in hearing if you ever do connect a TNC to the WS-2000.

New assembly arrived this morning and the station is back online. Let's hope that was just a fluke and I get several years out of it. If not, I'll consider going to either Davis or Peet Bros. Question for you, if I use the GW1000, can the console from my 2000 still display the data? My wife likes it in the kitchen and if that should become obsolete then she'll lose interest in the whole thing.

Offline galfert

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Re: Peet Bros wind vane and cup - Bigger = Better?
« Reply #9 on: September 21, 2019, 08:12:09 PM »
Yes, the display continues to work with the GW1000. You can have as many displays as you want.
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