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i was wondering about setting up an air speed indicator. on a tall pole at an airstrip. 3 sets of spinning cups .but i would want each level of spinning cups to represent STARTING at a different air speed . eg bottom level approx 1mt dia.
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Tony,Not a bad idea, you will need some friction on the system to stop it from starting at a lower level than you desire.It"s back to the gyrocopter moving the car on its handbrake question.You have a couple of things to overcome when you want something to move - first is friction, the next is inertia.Have a look in the "engineers toolbox" for an idea of the static friction if you are using plain bushes or sleeve bearings, and then have a look at the rolling resistance of bearings that you will acutally use, it may be in the SKF catalogue. You may have to just calibrate it by putting it on the roof of your car or similar and then driving along the road at a desired speed - set up a friction ring with a *spring* preload on it and lockable mechanical adjustment.. you could use a tapered thrust bearing with a spring pushing down as a friction and bearing thing.. I might do a sketch and email it to you if you post yours here or email me at : nicholas.tomlin
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Here is a cheap full blown weather station. only $148.50 inc GST.http://www.envioustechnology.com.au/...e=WWS10Regards SamL...............
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Back in the ole days a wind sock would give you an aproximate wind speed. When socks were made of canvass, they were heavy and so, they suffered brewers droop in light windsie at 20 kts they stuck staight out, at 5 kts they were floppy. these new lightweight socks do it to some degree but require much less wind speed to blow them straight.If you are worried about windspeed, dont! just worry about wind direction and keep an eye on your airspeed, that"s all that matters.Nowdays, with the return of weather, if I walk outside and the wind is blowing steady, I"ll go for a fly, if it is gusty and thermally, there is allways something to do around the farm...why get crap bumped out of yourself when tomorrow might be smooth and clear?Mark.
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just thinking laterally here.Messing around with different cups and different frictions would be a nightmare .How about using exactly the same cups at each level but have increasing length arms they are mounted to. (maybe even adjustable length while you are trimming it in set up)With the same resistance in each system a cup mounted to a long arm would be turned easier (ie lower wind speed) by the wind than a shorter arm.if the theory worked it would be simple reliable system.cheers Art
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thanks guys,and
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