Everyone that know much about wind power typically says that the higher up you put the turbine the better the outcome, primarily due to turbulence and ground drag, putting up higher puts it into a more laminar/smoother flow of air. Initially I was interested in putting up a 50' (even knowing that I would loose some output) or so tower but in the end went with the decision that an 80' tower would be best.

So I went back to the 20' and 17' websites to do comparisons. The framework for the 20' was beefed up considerably over the 17' turbine that they made and it weighs in at about 400lbs, while the 17' one weighs in at 160lbs.

In addition I saw some notes that mentioned that they had to do a couple of repair jobs on the 17' after it was put up.

In the mean time I have been researching towers and recently I was referred to a tower company that manufactures and installs towers AN Wireless. Typically the towers that they sell are for communications equipment and not for wind turbines. They are fairly close and just over the border in Somerset county PA.

After talking to Dan Simmonds for a while and filling him in on the details of my project he decided that to ensure that there would not be any problems that I would need to pay $550 for an engineering study. For this their engineers will decide if their current series of towers were suitable, if not then they would propose a design for my application.

At first I balked at the cost, then realized that it would be money well spent so I agreed and sent them out a check.

He stated recently that they did mount a Skystream 3.7 generator (12' blade diameter) on top of a 100' HD series tower that they make, however the 17' diameter might exceed the capacity. The price for a 70' freestanding HD series tower seemed quite reasonable at just over $3100. One side note is that none of their towers are tiltable, meaning that either a crane is used for raising/lowering the tower or a davit be constructed for raising/lowering the wind turbine.

Dan had also mentioned that there was a 3 month wait for towers, as this is their busy period. I figure that the timing would be just about right for me to build the turbine and make the tower base which puts the installation into September, so I had him put my name in the queue.

Here are a list of my requirements:

• 70' tall tower
• freestanding, no guy wires
• 10' stub extension on the top (I will be building the 10' stub as it should be simple enough to do)
• 17' diameter, 3 bladed rotor
• 350lbs total turbine weight

In addition they specified using their A style pad/pier foundation (which they show here), so it would appear that their towers are plenty strong enough and the weak link would be the foundation. In the drawing it is not really clear how the rebar structure should be built, however there are pictures of an actual foundation construction which clarifies this issue.

Their location is less than an hour from my house so I will be picking it up myself and saving a bunch of money instead of having the tower shipped to me by truck! During this week they preassembled each individual section so that I do not have to assemble them (nice). I will be using my car trailer to haul it back home.

The combined weight of the seven tower sections weigh about 1,600 lbs and my trailer has a capacity of 7,000 lbs so weight should not be a problem.

Here is the breakdown of the tower costs:

• $3152 - HD-70 tower
• $280 - step bolts for 7 tower sections ($40/section)
• $450 - 3/8" complete steel life-line system for 70' tower
• $240 - life-line steel safety sleeve with carabineer
• $80 - dual base grounding kit
• $48 - 6 mounting brackets with bolts/nuts/washers to connect (2) mounting plates for stub

Some of the sections are small enough that they could go inside other sections making it stack better. In the plastic tubs are an assortment of nuts/bolts/etc for assembling the tower sections, including the 3/8" diameter life-line, dual grounding kit and the mounting brackets for the top stub.

Out here there is very little 'flat' land, it is all mountain or hill side so the top side of the hole was almost a foot deeper than the bottom.

Here is a picture of my prize tractor, it's not real big but just about the right size. I don't know what I would do without it now days, I have a bunch of attachments for it, brush hog, post pounder, back hoe and front end 60" snow blower for the winters.

I did not have to weld up the rebar, but I feel that it makes installation a whole lot easier than trying to hold everything together with wire. The final assembly will be done using wire however as it would be too difficult to completely weld up all the rebar the assembly would be too heavy and awkward to move - easily that is.

I was able to get all the rebar into the pit and wired up, this took a while as I was working alone and the large 8' 6" sections of welded up rebar turned out to be quite a handful. I cut up about 12 lengths of 12" long rebar to separate out the two large rebar layers.

By the end of the day I got the 4 sections of the center pedestal rebar in place, along with the 5' long tower section all in, wired up and basically sitting on top of the large bottom layer of rebar. I forgot to take a picture of the rebar, but here is an image from the AN Wireless website that shows the large rebar pad on the bottom with the columnar pier rebar and the tower base in the center section of the pit. One thing that is missing is additional diagonal braces on the tower base that tends to get in the way of the rebar:

Again working alone I cut up the 3/4" plywood into 4 pieces of 42" x 70" long sections and put three lengths of 2x4's horizontally, one across the top, bottom and middle. Two of the sections had the 2x4's cut 3" longer so that they overlapped the other section and could tie them together.

I lowered all four of the sections into the pit and temporarily rested it on top of the bottom rebar platform, the wire ties held up fine (this was a concern.) Once in place I screwed all four sections of the plywood together with essentially about 2# of 2" long screws.

Along the top outside lengths of two of the sections I screwed 2 lengths of 2x6's which extended out from the form by about 5'. The ends of these lengths were used to lift the entire plywood form assembly up off the rebar by about 4" and leveled off on the ground using cinder blocks, wood blocks, whatever so that the entire top of the form was level in all directions. It was also centered around the central rebar so that each inside of the form was about 4-5" away from the rebar.

I needed to lift slightly the tower section so that it would be the proper height above the finished level of the form, so I used some rebar to make up a small A-Frame. Here is the A-Frame that I quickly made up out of some rebar:

I used this A-Frame along with a come-along to lift each leg of the tower section and then using a C-clamp I clamped it onto a 2x6 that rested on the top of the form. This not only lifted the 5' tower section but also the central rebar assembly, in all probably about 200# total.

Paul Schreiner (my best friend and a former concrete guy) came by to help out with the concrete pour today and brought over his arsenal of concrete tools, most importantly a concrete vibrator! This vibrator is used to ensure that there are no air pockets trapped in the concrete and that it is a single solid mass.

Prior to the concrete truck arriving I double checked that the tower base inside the form was level and that each leg was at the proper width. I ended up making some minor tweaks as once the concrete is poured this can not be adjusted. An 1/8" error at the base for level can turn out to be a foot at the top of an 80' tower so it is best to get it as close as you can before you pour the concrete!

We ended up using almost 12 cubic yards of concrete! Initially I had ordered up 10 yards but we ended up a little short, they had to make a second trip with the final 2 yards to finish off the job.

One important side note is that with my climbing around on the top of the suspended form yesterday, it 'tweaked' the horizontal supports and one corner ended up being about 1" too high. During the short break between the first concrete delivery and the second we tacked on some boards along two sides and marked out a level top plumb line in which to finish off the concrete.

The concrete truck made *huge* divots into the pasture that I had to fill with dirt after the job was done.

Lastly, prior to the concrete setting I put down about 1 gallon of sealer onto the top of the wet concrete. We used this method on my driveway and I liked the results.

I ended up taking off about 1/4" from each side of the corners, this gives me some extra 'wiggle room' in case I have to move the plates around a little bit so that the collars are in the proper alignment. Here is a shot showing one corner modification:

Just in case anything was off I decided to mark the orientation of both of the plates so that I could put them back into the original positions. I used a drill bit and made a divot at one corner of each plate as well as a couple on the matching side of the tower upright.

I had a piece of thick wall tubing with the dimensions 4-7/16" ID and 5-1/2" OD, about a 1/2" thick wall. This material I am going to use to make up two collars that will be welded into the center of the plates and the stub pipe of 4-1/2" schedule 80 pipe will go into.

I cut two pieces about 6" long each, and using my lathe bored the inside diameter to about .060" over the outside diameter of the 4-1/2" pipe. In addition to boring the ID, I put a rabbit on one end about 1/4" long so that it would fit into the hole in the 3/8" plate, this will help keep things aligned so that I can weld them into position.

Once the collars were made up I put them onto the stub pipe and put the pipe into position inside the tower. After wrestling around with the stub pipe (it's over 200lbs! and 14' long) I got it positioned correctly and tack welded the collars onto the 3/8" plate. Then I removed the stub pipe, removed the plates and welded them up, putting welds on the top and bottom side on of the plates over on my welding bench. Here is a picture of one of the mounting plates:

So in all each coil used about 1.58 lbs of copper, and very little remained on the spools. To wire up the coils I ended up unwinding the last coil and cutting it, so each coil ended up being about 79 turns. So in all - almost 20 lbs of copper were used to make up the coils!

Next I had been wanting to build a couple of work platforms that will be near the top of the tower, this way when I am up there I am not standing on angled supports and killing my feet. I had found what I believe they call 'grip step', it is 7" deep and perfect for my application. I fabricated some angled mounts out of 1/4" steel, and they bolt onto the tower.

While at it I also welded in the two collars that keep the yaw bearing square on the stub, as well as a stop collar so that when I retract the stub it will have a positive stop.

Here is a picture of the top of the stub with the collars welded on:

Here is a picture of the completed crane, in all it extends about 60" above the supporting structure which should give me plenty of height to raise the turbine off the tower stub:

Here are some close up pictures of the pinned sections:

The picture above shows the bottom collar, which allows a 3/4" bar into it which will be used to keep the boom from retracting. In addition a long bar will be used to help rotate the boom so that anything being lowered can be swung safely away from the tower edge.

The end of the topmost bar also has a plate welded onto the end to keep the winch from wandering off, most likely I will not leave the electric hoist connected and bring it up only if needed. And yes, I intend to run 110 volt GFCI outlet up to the top of the tower to power the hoist::

I have been doing a lot of thinking about the top of the tower, eventially I will be putting some eye-bolts into the top plate to make it easier to clip safety equipment onto. Right now there just not enough points in which to clip onto and it will give me a big peace of mind.

In addition I want to move the hand winch up to the top of the boom crane, right now it is located at the bottom, I have realized that with it in it's current position that it forces me to move around on the tower more than should be necessary. Currently if alone I had to go to the lower platform and crank up the boom crane, then move to the top platform and pin the diagonal brace, then move back to the lower platform and lower the boom crane so that it rested on the bottom collar. And all that moving around had to be done all over again when I wanted to lower the boom crane - too much!