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Temporary tower for anemometer

Discussion in 'Home Power and Microgeneration' started by WhyMe, Aug 27, 2005.

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  1. WhyMe

    WhyMe Guest

    I bought a wind speed data logging kit to see if wind power is worth
    it for my area. I'd like to build a cheap temporary tower 40-60 feet
    high. My plan is to put the pipe in a 5 gallon bucket fill it with
    concrete and then bury the bucket in the earth. I would also use guy
    wires every 15-20 feet connected to screw in earth anchors. Could
    someone suggest what pipe I could use for this temporary tower? Is
    this a good plan for a temporary tower?
     
  2. SQLit

    SQLit Guest


    Cheap 40 foot tower?? seems non inclusive to me.

    Check with your local electrical contractors that have bucket/auger trucks.
    Might be easier and cheaper to just set a pole where you want to do your
    testing. When your done they can pull it out if the your testing fails the
    results your looking for. If not and you chose the right pole your tower is
    almost finished.


    FYI poles are usually sunk 20 to 40% of their length into the ground
    depending on conditions.
    Your idea of a 5 gallon bucket with concrete is a waste of time and money in
    my opinion.
    Guy wire attachments are usually set into the ground at least 4 feet. Guy
    wire is a bear to work with and takes a lot of muscles. A come-a-long will
    work but it will take you all weekend to do one set of 3 guys.

    Have fun and do not hurt anyone or anything
     
  3. Vaughn

    Vaughn Guest

    You want to use a telescoping TV antenna mast. They come complete with
    attachments for light guy wire every 10 feet. I greatly prefer to attach them
    to a building if possible, and then guy them every ten feet above the building.

    Another possibility is to go to the library and look at a copy of The Radio
    Amateur's Handbook. In the back, you will find plans for building wooden masts
    using ordinary materials you can buy at any Home Depot.

    Vaughn
     
  4. Guest

    Sounds fine to me. What's your max expected windspeed and prop diameter?

    V mph makes 0.00256V^2 lb/ft^2, eg 6.4 psf at 60 mph. If a 4' prop with
    12.6 ft^2 of swept area pushes 80 pounds max (less, given Betz) with
    guy wires every 10' up to 10' below the top, it needs to resist about
    10x80 = 800 ft-lb = M = fI/C = 25KPir^4/(4r) = 19635r^3, so r = 0.34",
    for solid pipe... 3/4" schedule 40 galvanized pipe with 1.05" OD makes
    I = Pi/4((1.05/2)^4-(3/4/2)^4) = 0.044 in^4, so M = 25Kx0.044/(1.05/2)
    = 2101 ft-lb, over twice the requirement.

    The lower guy wires might have spreaders, with no ground connection.

    Nick

    Join PE Drew Gillett and PhD Rich Komp and me for a workshop on Solar House
    Heating and Natural Cooling Strategies at the first Pennsylvania Renewable
    Energy Festival on Saturday September 24, 2005 near Allentown. See

    http://www.paenergyfest.com/workshop-info.shtml
     
  5. Me

    Me Guest


    I like to use Extension Ladders for tempoary towers. They aren't too
    expensive and can be used for something other than just as a tempoary
    tower. They are easily guyed and I usually just bury the bottom foot in
    the ground after it is erected.


    Me
     
  6. JoeSixPack

    JoeSixPack Guest


    Sure, if you're loaded or like to waste money like the government. Here's
    what I'd do: buy a helium balloon for each time you want to test the wind.
    Release it and calculate the wind velocity at various levels.
     
  7. WhyMe

    WhyMe Guest

    Thank you everyone who gave advice. I really need some! ;-)

    OK. I should build a tall tower that would hold the turbine and use it
    to test the wind. But I'm looking for a cheap way to get a *fair*
    reading of the wind where I live. I can't afford to lose money on
    something that isn't feasable where I am. I already have looked at the
    wind maps for my general area, 10-11 mph 5.5-6 m/s at 30 meters and
    12-13 mph 5.5-13.4 m/s at 50 meters. But I want to log the information
    at my site which is at the top of a hill. I bought a wind data logger
    from http://www.inspeed.com the $99 PC connected data logger. If I put
    up a temporary tower of 1 section of 20 foot pipe would that give me a
    reasonable reading of the wind power on my land? I know the higher up
    you go the more power and more stable the wind is. I just need to
    satisfy myself that it is feasible where I live to install a wind
    turbine.
     
  8. wmbjk

    wmbjk Guest

    If you want to build a cheap temporary tower, here's one way - a
    hinged base, one stick of 2" schedule 40, and one stick of 1.5"
    schedule 40. That would give you 42'. Free standing will be bendy but
    OK, some guy wires would be nice at about the 30' level. Ideally you'd
    sleeve and weld the sticks together, but for temporary you can
    probably get away with using a threaded coupling and a bushing. A
    steel conduit-coupling might be better than a cast pipe-coupling. You
    could use angle iron (perhaps 3"X3/8") for the base (set in concrete),
    one 1/2" bolt for the hinge pin, and another to lock the tower in the
    up position.

    Here's a photo of a similarly constructed windsock tower.
    http://citlink.net/~wmbjk/images/windsock.JPG Sock is 18"X96", pole is
    close to 30' tall. It only bends a little in a stiff wind. The brace
    at the bottom doesn't hold anything up, it's attached to a
    counterweight so that I can raise and lower the pole by myself.
    Concrete is about 18" in diameter, 36" deep. I dug most of the hole
    using a powered chisel, which should give you some idea of the ground
    hardness. Better to pour the concrete into the bare hole than to
    backfill against a bucket.

    Wayne
     
  9. JoeSixPack

    JoeSixPack Guest

    This just goes to prove that you won't necessarily get good advice on here.
    In the real world, it wouldn't be considered wise to buy a wind logger and a
    tower just to get an idea of the wind in your area. The expense is out of
    all proportion to the information you need to make a decision about wind
    power. The data you would get from mounting your anemometer on the roof
    could easily be extrapolated to give you a good idea of the wind velocities
    at higher levels. Trees, hills and buildings create a boundary layer zone
    near the ground which reduced wind velocity nearer the ground. It's an easy
    assumption that the higher the tower, the more wind you can harvest. It's
    really a classic case of overkill.
     
  10. wmbjk

    wmbjk Guest

    *If* he'd said that he even *had* a roof at the desired location, then
    using only a plumb bob and an ordinary house cat, he could do a drop
    test and see how far Kitty drifts. Whether data extrapolated from such
    testing would be meaningful could make for a classic Usenet
    discussion.
    Thank you Captain Obvious.
    Why assume when we can easily read from Whyme's post instead? He wrote
    "I know the higher up you go the more power and more stable the wind
    is."
    Actually, he's following the advice of experts. His plan is smart,
    workable, and affordable. All he asked for was specific advice about
    minimizing the cost of a tower. The fact is that if he's so inclined,
    a trip to a good scrap yard and a Saturday's work will have him
    collecting useful data.

    Wayne
     
  11. JoeSixPack

    JoeSixPack Guest

    Reminiscent of NASA spending millions to develop a ballpoint pen to work in
    zero gravity, when a pencil would have worked just fine.
     
  12. JoeSixPack

    JoeSixPack Guest


    How about a big purple crayon?
     
  13. wmbjk

    wmbjk Guest

    Yes, scrap pipe and angle iron - the material of choice for all things
    NASA. If only we could get them to read your posts. With all the
    wisdom and the savings they could probably have a hydrogen-powered
    ship on Mars by next Tuesday.

    Wayne
     
  14. Nick Hull

    Nick Hull Guest

    Since I have lots of 30-40' bamboo, I'd make a bamboo tower, much like
    bamboo scaffolding.
     
  15. rick

    rick Guest

    What waste of money ????

    helium you can buy at K-mart. or Wal-mart
    Balloons easy to find.
    1 fishing pole with full load of line.

    sounds like a fun experiment

    Rick
     
  16. WhyMe

    WhyMe Guest

    I'm going to go with this plan. If it turns out wind power is worth it
    on my land I can use the 2" pipe for the wind turbine. Thanks for the
    great idea.
     
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