Topic: The flycup anemometer...

[SLOweather]

I dunno how these things pop into my head...

As I was driving out the driveway, past the spinning copper anemometer I made on the belvedere cupola, I had a idea.

Picture a classic flyball governor:



A flyball governor generally has 2 hinged arms with weights on the end.

Like a cup anemometer, add a third arm and replace the balls with cups.

My experience with anemometer design is that RPM for a given wind velocity is inversely proportional to the perpendicular distance from the center of the cup to the shaft. In a standard design cup anemometer, short radius = higher RPM, longer radius = less RPM for the same wind speed.

So, a flycup anemometer should have a higher RPM at slow wind speeds. As the wind speed increases, the cups would start to fly out and the RMP/wind speed would drop.

Hmm, I might have to cobble one up just to see what happens...

[Old Tele man]

Sounds like it'd produce a logarithmic rather semi-linear wind speed curve. You could probably "fine-tune" that curve using small weights.

[W7DRM (old call was W3DRM)]

Chris, I agree, I don't know where you come up with these ideas either but WOW, you've done it yet again! 

Reading your description of how the rotation increases as the balls get closer to the center of axis reminds me of an ice skater spinning on their toe. They control the spin speed by moving their arms in and out - in to go faster and out to slow down.

The only thing is that to be able to calculate the spin speed you would have to be able to know the diameter of the spin access as it changes. In any case , it's another SLO experiment I am sure we will all enjoy watching evolve... Great job! 

[LFWX]

They use something very similar at the elementary school I work at.