Easy way to count rpm on a vawt

[Norm]

   I noticed that an avi was posted, a vawt with

6 blades one had a small red patch, but it was

still spinning too fast to count by eye...

   This would be especially nice for youngsters

making the Pico Turbine, it calls for a wooden

dowel for the axle, about 8 inches.......

now if it were about 2 ft higher you could paint

a highly visible spiral stripe on the top exposed

extended axle a lead or 'thread' of 1 per inch,

the eye can easily follow the spiral from bottom

to top quickly jumping back down to the bottom

when you reach the top....24 turns per cycle,

setting a timer for 10 seconds it, the rpm could

be easily determined, or so I would imagine.

  Similar to using good ol' nut and threaded rod

method.

                 ( :>) Norm.

 

[Devo]

A stiff card or piece of mylar placed to "click" against something works well to-like the old bike tire trick when we were kids. This way you can look directly at the second hand while listening to the clicks.4 clicks a second,240 rpm.......

Just another way...

Devo

[electrondady1]

those blades all look the same at 120 rpm norm so i stuck a piece of that red tape on so i could count from inside the house

[Norm]

  Fun...isn't it? Just something about a spinning

windmill....

            ( :>) Norm.

[robfirth]

I wish I had that problem. I mounted a 2 foot cardboard windmill on a bicycle rim and but it on a 3 foot stick. Maybe it should be higher. tried to count the rpm. It was 0.

winds where between 3-6 mph today, usually between 5-8

[elvin1949]

Rob

i saw in a earlier post you say you were in louisiana.

What part i am in leesville.

later

elvin

[electrondady1]

a spining windmill looks like hope !

[robfirth]

I am in Baton Rouge. Leesville is between Alexandria and Texas, right?

Good news about the wind here...my cardboard windmill moved today. Actually went so fast I couldn't count rpm. about 120 to 240 rpm in a good gust. rest of the time it stood still. 6-8 mph winds today. I don't think it will be out there long, because the wind is probably here because it is about to rain. Rain + Cardboard = Mess

[elvin1949]

 right location.

paint the rotor [cheap wally-world paint]it will last a little longer.

later

elvin

[electrondady1]

unless i can make some sort of break through in my geni design it looks as though i must stack up the vawt moduals . i can use a different colored vane(buckets) if i off set each layer it should produce a spiral effect like norm was talking about.