Author Topic: Tilt-up tower size limits?  (Read 1036 times)

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clflyguy

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Tilt-up tower size limits?
« on: May 10, 2006, 01:31:04 PM »
 Greetings everyone, my name is Gus and I have lurked long and learned much from this group.. This morning I decided to take the plunge and join.

 We are in the process of aquiring about 7-1/2 acres of former grazing land here in NE Fla and will be off-grid from the very beginning. The winds here are not steady by any means, except when a weather system is moving through, which seems to happen often enough to take advantage of in the summer. Fall, winter and spring are always windy with 3,5 and 7 day nor'easters moving through on a regular basis. In between those times though, and through the summer the winds are very light... SO, the five blade fiberglass 18' dia. geared up mill is born.

 The rotors and stator are finished. My friend Jack has a large lathe and was able to lighten up both of the f-150 rotors by about 6 pounds apiece, and in the process made a nice 1/16 wide by 1/8 high lip around the outside to retain the 1x2x1/2 neo's (thanks Dans). We went with 9 coils @ 68 turns of 16 guage inverter duty wire and 12 neo's per rotor. The stator started with a 2 layer mat shell then bondo thickened resin to retain coils. It has 4 mounting ears, due to the manner in which it's going to be used. I will try to include plans and pics as soon as I learn the finer points of posting on this board...

 AND FINALLY to the topic in the title.. I want to put up an approx. 95-100 ft tilt-up tapering pipe tower, starting with 4-1/2" pipe at the base and using full length (20') sections nested a few inches into the previous section and welded, i.e. 4-1/2",4",3-1/2",3",2-1/2"). The horiz. leg is 60' on the lifting side and will have the guy gang plate attached to it.

 My question (and my fear) is that this tower might be a little tall for the type, I would greatly value informed opinions (and even w.a.g's) on this aspect of the project.  Thanks in advance, and in retrospect- Gus
« Last Edit: May 10, 2006, 01:31:04 PM by (unknown) »

wdyasq

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Re: Tilt-up tower size limits?
« Reply #1 on: May 10, 2006, 08:13:06 AM »
The 5" X 60' pipe tower with 2 sets of guys seemed to have about all it wanted with a 5M/16' mill I helped errect.


Ron

« Last Edit: May 10, 2006, 08:13:06 AM by wdyasq »
"I like the Honey, but kill the bees"

nanotech

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Re: Tilt-up tower size limits?
« Reply #2 on: May 10, 2006, 12:06:50 PM »
I can help you with the pictures part.  Drop me an email to darrin.moore@gmail.com and I can host the pics and help with the HTML to post them here.
« Last Edit: May 10, 2006, 12:06:50 PM by nanotech »

RP

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Re: Tilt-up tower size limits?
« Reply #3 on: May 10, 2006, 09:08:45 PM »
By now I'd guess you figured out what "intro copy" does.  ;-)
« Last Edit: May 10, 2006, 09:08:45 PM by RP »

DanG

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Re: Tilt-up tower size limits?
« Reply #4 on: May 11, 2006, 05:24:42 AM »
How did you latch on to 95-foot as optimum height?


Not a WAG this one, the tower will make or break the fine mill you'll be flying.


Zubbly & others caught in the failure-proven tower engineering mindset (FUNK!) have happily adopted ROHN antenna sections for lofting homebuilts. Tilt-ups, fold-over, rigid, they're all good. Nor'easters shouldn't be a problem though if under a hurricane warning no good would come of leaving tower up...

-

« Last Edit: May 11, 2006, 05:24:42 AM by DanG »

clflyguy

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Re: Tilt-up tower size limits?
« Reply #5 on: May 11, 2006, 09:25:54 PM »
The 95' height was arrived at by measuring the mature trees in the immediate area and adding 35' for good air- pipe comes in 20' lengths but a little of it will be nested into each preceeding piece, therefore 95-100'. I considered the raidio tower idea early on, but being part scottish and having a welder decided the type for me. We just closed on the property today, but I have already aquired the survey and laid out the property lines and location of everything on my cad system (I"m a facilities designer for the railroad) including the dreaded "fall zone" should the unthinkable occur. Right now I'm in the final few days of preparing the old house for sale, cleaning painting etc. Work on the alternator, pivot and other small stuff is on hold until the house is ready for market. I can't wait to get started on my blades. My hobby since childhood has been model airplanes and airfoil design. I won't be hotwire cutting any foam for this mill though, since thin blades turn faster. They are solid f/g, 8' (2' dia. hub) 21" root chord @31 degrees, double concave taper to 4" tip chord (swept tips) @1-1/2 degrees. The 5 blade 18' dia. design is to extract as much energy as possible from the typical zephyr-like breezes we get here, but (hopefuly) prevent a lot of over speeding in the 30-45 mph range we see w/ the weather systems and very frequent thunder storms. (I was in the service and 19, stationed in Va. before I ever knew it could rain without lightning and thunder)  --it's been a long day, so I will bid everyone a good eve,   Gus
« Last Edit: May 11, 2006, 09:25:54 PM by clflyguy »