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Richard Marble
9th January 2009, 06:53
The best place to put a turbine on my farm is in the middle of a hay field.

I’m not planning on having to climb a tower to work on my turbine. I also hate to loose a bunch of hay field because of guy wires supporting a tower. A small area I could cut around however.

I was thinking that with the right engineering I might be able to build a three legged tower that could be guyed off most of the time as a precaution or for tipping up and down but the guy wires could be removed to mow around in the summer.

Or maybe a lattice tower with guy wires used to tip the tower up and down.

Or maybe a monopole using outrigers like a sailboat mast with guy wires closer to the pole.


Anybody ever seen anything that I could use?

Rob Beckers
9th January 2009, 09:16
Hi Richard,

I don't have an answer for your question, but wanted to present a few comments on regular guyed tilt-up towers. For a 100' tilt-up tower that we use with the Scirocco the four guy wire anchor points extend out 43' from the center. For a 60' tower this is 21' (in other words, the foot-print from guy-to-guy is twice this). Not sure how large a field you have, maybe it is not as much of a loss-of-area as you thought.

You can also raise up the anchor points on concrete, using sonotube forms, making it easier to mow around them. Putting bright yellow plastic covers over guy wires (like the utility does) will help seeing and avoiding them. How often do you mow? If memory serves me from my days as a youth growing up around farms it's only twice a season for hay. Working around the anchor points may not be that much hardship. Keep in mind that the guy wires (and anchor points) are all in two narrow planes. The space between the wires is easily accessible.

Personally I'm a proponent of tilt-up towers; they make installation and maintenance so much easier. Not to mention that it's safer (climbing and working at altitude is inherently dangerous), especially if you have in mind to do the maintenance yourself. Tilt-ups are also a good price-point for towers. Self-supports have gotten very expensive due to the ever rising steel prices, and tilt-ups only cost a little bit more than a non-tilting guyed tower.

-RoB-

Ralph Day
12th January 2009, 06:50
Hi Richard and Rob
Perhaps Mario will post about his pipe tilt up towers. I'm not sure if he's posted pictures and such before, or maybe Rob has pictures from the 2007 tour.

Ralph

Robin Gilks
15th January 2009, 05:58
I've been working on a solution to the same problem. What I've done is split the paddock into 4 with two fence runs at 90 degrees so that the guy wires run down the fence lines. This has the advantage of being able to restrict grazing so that the grass has a chance to recover as the stock is moved round. It also means that the guys don't get hung up on the roll-over bar on the tractor.

The original idea was to use fence posts as the guy anchors - I even spaced the posts so that I had a set of four 10m out from the pivot - but a trial run convinced me that a couple of tons of concrete would be a much better bet. I'll hook into the posts as a extra precaution since they will be dragging 7 strands of HT wire even if they get lifted out :)

Ralph Day
15th January 2009, 10:04
I have an 80' guyed tower for my H80 wind turbine. When it goes up and down the guys drop and flop where they may...in a clear area. If they were to get hung up on fencing or posts, then when raising again you could have a big problem. If a wire is snagged then when pullingup it would stop the upward motion...if you're lucky. If unlucky it would probably cause the tower to bend one way and fail. Might be best to make the whole footprint a paddock, fence it all in and let the animals control the grass. Make a gateway where the pull line and gin pole go and you're away.

The total area for guying an 80'tower is only 80'x80', not a lot to lose, unless you have a restricted area for putting the tower up.

Good luck.

Ralph

Stellar Gellar
20th April 2009, 04:57
Wow nice idea. Im also planning to put one on my farm too.:cheesy:

Dan Lenox
20th April 2009, 09:09
Richard,

I have to agree with Rob about freestanding towers, I have a 70' lattice tower for my 17' diameter wind turbine, and I have to say that I am ready to convert to tilt-up tower.

Yearly maintenance seems to be a necessity.

I am curious about tilt-ups, if you do not want to keep gin pole connected then do you have to run additional guys on that side? One set for the gin pole and one for fixed guys?

Dan

PS: anyone interested in 70' HD70 AN Wireless tower? It has step bolts, 3/8" lifeline, custom 12' telescoping stub and davit crane... It's value is easily $6.5k and can take up to 20' turbine.

Rob Beckers
20th April 2009, 09:35
Hi Dan,

The tilt-ups I've worked with do not have any additional or separate guy wires on the side of the gin pole. However, they use the gin pole as an attachment point for that side's guys (and have a single point connecting the gin pole to the anchor on that side). So, if you want to be able to take the gin pole off you would have to find a way to transfer that set of guys directly to a ground anchor point. The equalizer plate (where the guy wires come together) would need two attachment points, so you can switch, and it would need to be detached from the gin pole. Take a look at the picture below to get a better idea of what I'm talking about. That's a 4" ARE tilt-up, and the guy on the left is Robert, the owner of ARE. This was taken during a workshop there. Loads of fun!

-RoB-

Ric Murphy
20th April 2009, 17:51
Hey Dan,
I wondered how long it would be before you got tired of climbing. I have a 70', 4" tilt up tower with 4 sets of guys. The anchor spacing for each set of guys is 35' from center however my gin pole is only 21' (standard length of pipe). So I have a 5th anchor point just for the gin pole. The same 3 guys that go to the gin pole are shared with the main anchor on that side. The guy lengths are cut for the main anchor. Attached to each of those 3 guys is a short "pigtail" clamped to the guys. When lowering the tower I release the turnbuckle of the guys one at a time and transfer to the gin pole attaching to the pigtail. Not sure if I'm explaining well. There are some pictures in this post.
http://www.greenpowertalk.org/showthread.php?t=4598
Additional pix in this post starting at post #48, page 2
http://www.greenpowertalk.org/showthread.php?t=675&page=2
My 4" gin pole slides over a 3-1/2" stub at the base of the main tower. Easy to remove in order to cut the grass (good thing since it's in the middle of my yard!!)
Ric

Dan Lenox
20th April 2009, 18:50
Ric/Rob

I wouldn't actually say that I am tired of climbing, actually I like it. The problem is that I'm getting up in years and in 5 yrs or so when I will be turning 60 I just don't see myself being *able* to.

I still say that I don't care for the esthetics of guyed towers, and *love* my freestanding tower, I just have to look into the near future and my physical capabilities. Having said that I'm sure that I will adjust to the guys - hopefully I can get my tower sold and get this new one up before end of fall. To that end I am willing to cut a good deal for someone that wants a freestanding tower.

Thanks for the posted pics, I've studied the details of your tower and everything else that I can lay my hands on, never can have too many details and pictures. I plan on making mine out of 10" tubing (copying OtherPower guys) due to the size of my turbine and the windy location that I live in.

Sorry if this thread got hijacked... But at least it is relevant.

Dan

Mario De Castris
21st April 2009, 01:15
Hello all,

It has been a long time since posting. Here are a couple pictures of my homemade tilt down towers, one freestanding the other freestanding with guide wires, both towers are raised and lowered with a hand crank.

Mario

P.S. I will be posting about Net metering as soon I have some numbers on how my system is doing

618

619

620

621

Steven Fahey
21st April 2009, 01:21
Hi Dan,

As you may have heard, I recently had trouble with my tilt-up tower. Sounds like a sure bet that if you built a tilt-up, you would do an excellent job, with a proper winch, so I don't need to get into that.

I took a different approach to anchoring around the gin pole than what Rob pictured there. I anchored all four corners the same way - one top cable, one middle cable to each anchor point directly into the ground. This was for a 45' tall tower so your 70' or so would merit up to 4 guy wires.

The gin pole of my tower simply remained attached when the tower was up, the end resting on a block on the ground, rather inert. I could take it off any time, but I chose not to; never needed or wanted to. The philosophy was that all the anchoring hardware only does anchoring. Conversely, the lifting hardware doesn't do double-duty as anchor hardware.

This philosophy may undergo some evolution as I consider how to build my second tower.

If I was any more serious than I already am about wind power, I would be tempted by your tower for sale.

Locating a tower in an open field is an excellent location, but when guy wires are involved, it is an open invitation to accidents. You the tower owner won't always be the person driving the tractor round the anchors and tower base. Seeding, spraying, cutting, tilling... there are many passes over a field, depending on the crop. Every guy wire anchor increases the likelihood of an accident.

Balance that risk with the cost of raising the tower with a crane, and climbing up periodically.

Dan Lenox
21st April 2009, 10:04
Steven,

Used the wrong terminology - I'm not making a tilt-up, but a guyed tower that is hinged at the bottom.

The OtherPower guys used 10"od 1/8" wall tubing, I will use three 20' sections so it will be guyed at each tubing juncture as well as at top, giving me 3 guy wires on all four sides, for a total height of about 65'. A bit lower than current tower, but seeing that I am at the top of the mountain ridge from the towers perspective all tree tops stop at about the 25' level...

Due to the elevation of my property I have to tilt the tower 'up-hill', so the gin pole needs to be removable as it would otherwise be about 5' in the air at the tie-down point. A little to obtrusive.

You still acquiring data about wind turbines? Since mine is now down, I will be measuring what I have more closely and increasing offset from yaw bearing, as well as increasing air gap, and playing with tail and vane so it furls better. When done will be sure to send you updated information for your spread sheet.

Dan

Steven Fahey
21st April 2009, 15:06
Then I guess you will go with a gin pole separate from the tower anchors etc.
Good, that gives you freedom to have a gin pole any length you like, or that comes apart in smaller pieces, etc.

One of the things I started trying to do with my spreadsheet was making a performance estimator, just to see if simple Ohm's law rules would make reasonable preditions with a variety of real-world examples. I haven't gotten very far but it's mostly because who knows the exact resistance of their stator coils? Unless you measure it with an ohm-meter that is accurate down to 0.1 Ohm or so... Oh well it was worth a try. It does work well for my motor conversions, because phase resistance is usually in the several ohms area.

If you make changes then reporting their effects would be very valuable. Changing one variable and monitoring the effect is the scientific way. Thank you.