Are there differences between each of the blades - yes. I noticed that by the time that I got the 3rd blade done that I tended to leave a larger radius on the leading edge, in the end I believe that the 3rd blade came out the best (of course...)

Here is a picture showing the blade tips:

And here is one with the blades side-to-side showing the trailing edges:

Paul had suggested that I glass up the blades in two phases, wrap the trailing edge up the body of the blade, and then wrap the leading edge of the blade putting the dynel fabric *underneath* the glass cloth. The reason for putting it underneath is that dynel does not sand very well.

Here is a picture showing the completed blades, I stood them up outside one of my garage doors to add some perspective:

While the paint was drying I moved onto the 30" diameter plates. I made a wood template the same size as the hub portion of my blades and traced out the pattern onto the 1/4" steel plates. I also drew a circle which represents the 20" rotors, took out my plasma cutter and removed the excess steel from between where the blades will sit. Removing this excess material cut the weight of each hub from 30 lbs down to 25 lbs each.

I made both hubs identical and drilled out the pattern for the center studs that connect to the hub. Later on I will drill additional bolt holes to hold the plates to the blades:

I will also need to make up a couple of spacers, one spacer that goes between the rotors, and another to go between the front rotor and the back hub. The reason for the second spacer is to allow me to use additional bolts to hold the blades to the hub plates and allow clearance for the bolt heads between these plates.

The other main job that I wanted to finish up today were the rotors. I have been putting them off till just about last.

First thing that I did was to drill and tap 4 holes for the jack screws in the most forward rotor plate, I made them for 1/2"-13 NC thread. I then completely cleaned them up using some acetone to remove any oil from the surface. I used a felt pen and drew some lines from magnet pins to the corresponding one on the other side, this will help me to get them straight. I also used the felt pen and marked on each rotor the pole for each magnet location.

I got one magnet out and hung it from a string to determine which face was the North pole, I then wrapped it in some tape and clearly marked it, I used this as my reference magnet.

For the first rotor I decided to pre-sort the magnets and mark them for polarity. I put a long piece of angle iron out, separated and marked 1/2 the magnets. This turned out to be a not so good idea and for the second rotor simply 'peeled' off the magnet, determined the polarity and placed it into position on the rotor.

The amount of force from these magnets is amazing! To separate them out of the stack at times was like a sumo wrestling match, and it took about all my strength to separate them. What worked easiest was to take the magnet and rotate it 90 degrees, then turn it lengthwise so that there was not so much surface area to deal with.

I decided that I needed to make up two wood wedges that the combined thickness is 3/4". I will be using these wedges to position the magnets over the pin and to lower them down to the plate surface. It worked out fantastically!

Here are a couple of pictures showing the wedges in place, the magnet put into place to engage the pin and finally the wedges pulled out:

And finally the rotor with all the magnets in place:

Before I put on the last magnet that I had been using as my reference magnet, I used it and went around to all the magnets on both the rotors to double check and ensure that I had indeed marked and placed them correctly. Once done I mounted the last magnet. I then checked that the alignment of all the magnets were correct and then went around all the edges of the magnets with some super-glue to keep them from moving.

Finally I made up two 9" diameter 'islands' out of 3/4" thick plywood. Once I rough cut them out with the jig saw I put them onto my lathe and brought them down to the exact size desired, I also was very careful to make the outside diameter slightly angled for relief to ease in removing them (I had this problem casting the rotor).

With the wood islands caulked and positioned correctly I started chopping up some fiberglass matt into fibers to help give the resin some strength. I first made up 10 oz of straight resin and wetted out the entire interior area and all along each of the sides of the magnets. The next two 10oz cups of resin I put in the chopped fibers, with the final two 10oz cups of resin I again used it straight so that it would level out nicely. So in all I used about 50oz of resin total for both of the rotors.

Here is a picture of the resin poured also notice that I put tape on the magnet surfaces and around the perimeter:

I ended up buying a can of Krylon spray paint with a color that was close to the urethane enamel paint for minor touch ups and kept me from having to break out all of my paint equipment for these minor modifications, the color is close.

I cleaned up the resin edges around the rotors and spray painted them black. Here is the outside rotor with the four jacking screws installed and awaiting assembly, you can clearly see the pins in the center of each magnet:

Assembly started with the alternator finally, got the center hub, with the attached brake rotor in place first using some 12" lengths of stainless steel all-thread. Important note: all nuts use lock-tite as well as lock washers! For the stator I used 8" lengths of all thread. Here is next picture with the back rotor mounted as well as the stator. In the center you can see the aluminum spacer that I made up to space the rotors.

I had a little trouble finding exactly the amount of aluminum that I needed to space the rotors apart and ended up using some stainless nuts and steel washers to establish the final distance the rotors were apart.

Outside rotor installed:

I could have made the spacing between the rotors and stator pretty tight, but opted out for about .100". This will give me slightly less output but hopefully less maintenance issues. Here is another picture with the outside rotor installed as well as the final spacer between the rotor and the blade hub:

Once I got to this point I decided to do some quick output tests. Not very scientific but spinning the rotor by hand I was able to measure about 50volts between each of the 3-phase posts, no load. Don't know if this is good or not as a very rough test I checked across each of the posts I measured the same, so output across each phase looks roughly the same. At least this tells me that I think that the coils are connected correctly in each phase and that the magnets have proper alignment/polarity.

In between a couple of runs to a local hardware store for some needed bolts and supplies I began doing a lot of last minute completion of my work including putting grease zerk fittings anywhere that would periodically need greasing, electrical wire, assembling all of the tower modifications that I did and mounting them onto the tower.

So after about 1/2 hour on the phone I located some #8 S/O cable and got it back home and soldered on some lugs for connecting to the alternator as well as a length of flexible cable to connect to the linear actuator.

The crew finished up running all the conduit, putting on the electrical boxes, running all the cable to the garage which is about 80' away from the tower, and making all the electrical connections to that point.

I got the blades mounted onto the hubs, ran all 15 bolts through and torqued them down. I also made up a lifting bracket that I bolted on temporarily:

Finally got around to some last minute modifications to the mounting of the linear actuator as well as making up the connecting linkage between it and the brake caliper. The linkage had to be made so that it could be taken apart in case of maintenance. Here are a couple of it (first is a little fuzzy):

Crane showed up on time and he lifted the tower into place along with all tower mods. Once positioned the crew did the final assembly of mating the tower to the foundation, completed running the 'life-line', then it was time to climb the tower and release it from the crane.

Once done the crew checked things out around the top and came back down so that we could get a strategy for how to proceed. The weather was turning a bit, some wind had kicked up and there was an ominous threat of rain, so it was decided that we would not completely assemble the turbine on top of the tower today. Instead we would use the big crane to hoist up the alternator and yaw bearing to the top stub and leave off the blades and tail assemblies.

So the next thing that we did was to use the big crane to lift the alternator so that we could mount the blade and hub assembly onto it so that we could balance the blades. Since the blades were not going to be mounted permanently yet, we simply duct-taped some steel weights onto the blades to determine where and how much weight that was needed to balance it out. Once done we removed the blades and the alternator/yaw bearing was lifted up to the top of the tower and installed along with the thrust bearing.

This turned out to be a good decision (in spite of my initial disappointment) as small droplets of rain came and went a couple of times. With the wind kicking up and the occasional rain I was not able to make the climb with the crew - another day.

It turned out that the cost of the crane was a bit more than estimated, in all the total bill for the crane/operator and travel was just over $1900. I think that it was a wise decision that I fabricated up my own davit-crane for any future maintenance! We will be using my crane for the final assembly of the wind turbine.

I put up some pictures on the tower raising page.

Those of you that have seen my Vortex project know that I used this method to fiberglass on mounting plates onto the chassis. The principal is simple you take a steel plate fill it with holes, next you mount it with glass matt between the plate and the surface. Then you put one (or more) layers of matt over the surface, pushing the matt down where the holes are and then finally put a cover of 6oz glass cloth. The pushed down matt in all of the holes bond to the matt that is below the plate and give you a super strong hold!

The total weight needed to be added was 1 lb 3 oz to the remaining two blades. So I took a couple of pieces of 1/8" thick steel plate and approximated the size and cut it out in the basic shape of the blade, slightly tapered on one edge. I did a pretty good job of approximating it as it came out to be 1.5 lbs, right on target! I filled both of them with a series of 1/2" holes and tapered all of the outside edges.

Once all the holes were in I put a slight bend in along the length just after the first set of holes as they were positioned to start up to the leading edge of the blade. Here is a picture of the final plates, they came in at a hair under 1lb:

The reason that I made them slightly lighter is that I was going to add between 3-4oz of resin and I wanted the total weight added to be my target weight. The entire surface of the blade needed to be sanded to remove the epoxy paint where I was adding the patch, you have to get down to the subsurface layer of glass cloth for best adhesion.

(Post Note: Do not do this - read below as to why)

Here is what the plate looks like where I will be mounting it:

I added some white pigment to the resin so that I did not have to paint when done, in addition I added some milled fibers to help thicken the resin so that it would not run off and create voids.

Here is a picture with the layers of matt and cloth added and waiting for the resin to go off:

Before the resin took a final set I used a sharp knife and trimmed off the bulk of the excess along the leading and trailing edges. Once the resin hardened I lightly sanded around the perimeter to get a smooth finish. Here is what the blade weight looks like when finished:

Forgot to mention that the blade weights were put on the 'back side' of the blades and not on the front side (where the blade pitch is). This way they should disrupt the air flow as little as possible.

Since I have about a week before the blades get mounted onto the turbine I have decided to rework the blade(s). I say blades as I have the option to take the heavy blade, rework it so that it is inline with the other two and reglass it. Or I can add fiberglass matt/cloth onto the other two blades along the length to bring them in line with the other blade. It may be a toss up as to which method will be easier or harder to do.

During the week I went out and purchased a digital scale at our local WalMart, it is a digital bathroom scale actually. While looking at the various digital bathroom scale I noticed that most of them had a resolution of .2 lbs, there was one manufactured and sold by Weight Watchers however that had a resolution of .1 lb, and at about $33 grabbed it up.

Once I got the scale back I checked it out and it took a little over 11lbs to even trigger the scale, anything below that and it did not register, luck for me my blades were in the 20lb range.

Did a quick check and easily saw that my heavy blade in face was the same weight as remaining two, but remember that I added about a pound to the others, so the first job was to remove the glassed on weights, sand them down and get an accurate value for the weight of all three blades.

Once the weights were off I weighed them and marked the weight on each of the blade. The offending blade was a little over a pound from the other two, and one of them was about 5 ounces lighter than the other. So using the middle blade as my target weight I decided on a plan of action. I would add weight to the lightest one by adding a layer of fiberglass, and the heaviest one I would bring the weight down

It took a little while to bring down the weight of the heaviest one, and every step I kept weighing it to see how I was progressing, until I finally got it to about 8oz less than the target weight. I did this as I knew that I had to basically glass the entire back side of the blade, and add in the weight of glass and resin. I knew from previous work that it takes about 8 oz of resin to glass one side of the blades.

The lightest one I added a layer of 4oz glass cloth along with the resin and basically squeegeed off as much of the resin that I could without starving the glass cloth. The heaviest one I again used 6oz cloth and made sure that I used a full cup of resin.

When it was all said and done, I was extremely impressed with the results - according to the digital scale they were all the same weight! Now with a .1 lb resolution I figured that at worst all three blades were within 1 oz of each other. Perfect!

I had seen one suggestion from one person saying that they use paint as the method of equalizing the weight of blades. On the lightest blade they would apply more paint than the other ones, building up the weight in a very slow and controlled manner until all were the same.

After final sanding one blade registered about 1 oz lighter than the other two, so I used this method to bring up the weight very slightly.

All said an done, initially I did not understand the importance of keeping as clean a blade surface as possible, and the implications of not doing this. I am glad that I had the opportunity to learn about the importance of blade surfaces as well as keeping a balanced system.

If anyone were to build their own blades I hope that they learn from my mistakes and certainly this is one job that having a digital scale is absolutely the tool that makes the outcome the best that you can obtain!

I was in need of a 12v power supply that I could use to control the linear actuator that I am using to activate/retract the disc brake caliper. I ended up using a modified ATX computer power supply. The 12v output of the supply is easily capable of 10 amps or more (dependant upon the specific power supply used), these supplies are cheap and readily available. The power supply needed to have a couple of modifications before I could use it, first of all pin #14 (green wire) on the connector needs to be grounded to enable the supply to power up.

Here is the pin-out of the ATX power supplies:

Next I put in a DPDT switch connected to the +12v (yellow wire) output, the DPDT switch is used to engage brake and retract brake. I mounted this power supply near a window in my garage so that I could monitor the turbine when activating/de-activating the brake. I simply crossed the +12v and ground so that the switch reversed polarity. The DPDT switch that I used has a center off position as well.

Once I got the blades in the hubs I torqued down all of the bolts to about 90 ft/lbs and used lock washers along with red (permanent) lock-tight as I hope never to have to remove the blades from the hub again.

Next in I had to make up a spacer so that I could use the duplicate trailer hub and mount it directly to the hub plates, I had to turn a piece of pipe on the lathe to be about 5-1/2" OD and 5" wide, I then used this between the trailer hub and my blade assembly. Made up three lengths of threaded rod and connected them to together. Next with the help of my wife we lifted the assembly up and inserted it into the end of my engine hoist, using a couple of pieces of angle and a spacer to help fill the gap clamped it down

Here is what the assembly looked like in the end of the crane:

I was able to lift the blade assembly quite easily using the hoist, it angled it slightly as it rose but in all it worked well. The whole thing is so large that I could not do the balancing inside the garage, and it was a relatively calm day outside. The area in front of my garage is pretty well protected from the wind. Once on the hoist, I put a little bit of blue paint on the tips of the blades so that when they are turning it is easier to see the tips of them.

Here is a picture of the blade assembly on the hoist:

Next thing was to rotate the assembly to see where the heavy side was. I ended up using what the guys on FieldLines.com referred to as the 'pendulum method' and it works like this: "spin prop and let it settle place the "arm" at the 12 o'clock position bent inward so to be as close to the center plane of rotation as possible. Spin and let settle and add weight [nuts / washers] until it no longer settles in one spot. The arm can be adjusted left or right, also. It works very well. Once you get it dialed in, lock the nut with some shellac or nail polish so it stays on. You may need to experiment on the arm length and weights. The arm is simply a flat strap of steel with appropriate holes drilled in it and the right length."

It worked out fantastic and super easy to do, within about 15 minutes I got the weight dialed and when rotating the blades they stopped at different random points. Here is a picture of it all painted and permanently mounted:

The wind picked up slightly and I decided to let it turn freely and get a couple of pictures, in the amount of time that it took to take about 3 photos the wind gusted and the whole blade assembly was spinning pretty quickly! I was able to stop it turning eventially by using a length of 2x4 wood and applied pressure to the hub assembly from the back side - lets just say that the blades were spinning pretty quickly, probably about 200rpm and were making a nice swooshing sound, interestingly I did not notice vibration in the hoist so the whole unit must be balanced pretty well!

Once stopped I got my wife to take a picture for posterity with me and our two dogs in front of the blades to give it some perspective:

Here is the electrical panel that I made up, inside it contains 1) contactor, 2) contactor switch, 3) 3-gang 60 amp fuse block, 4) inline splice connector block, 5) 3-phase lightning arrester and 6) ground connector. The switch box is pop-rivited to the front of the panel door.

The right picture shows a better image inside the box:

POST NOTE: I have removed both the fuse block and additional connector block from this electrical box. After thinking about it there is no way that I want one or more fuses to blow, reason is that if it did then the turbine is potentially unloaded and could spin to destruction!

I put in the splicing connector block so that later on if I decide to add amp meters it gives me a convenient place for making the connections. The 3-phase lighting arrester is actually located on the left outside of the box. The switch is used to energize the contactor, when it trips it shorts out the 3 phases of the generator, essentially locking it. Note that the contactor is before the fuses. I will put a dedicated ground rod outside the wall and run a wire to the ground lug inside the box.

The heat sink for the 3-phase rectifier is just below the box, it has a couple of hinges on the left side so that it can easily be opened to get access to the rectifier and wires on the opposite side. All that is left to do is wire from the rectifier to the inverter/battery bank:

Initially this unnamed company said that they assemble and erect towers in a 2 day period, so far they spent 3 days (still not done, 1 more to complete the job). In addition they initially stated that the crane charges would typically be under $1000, 2 weeks later they said $1300 - in the end it was $1957. So far everything that they estimated was off by 100%. They seemed like nice guys and I trusted them.

But here is the worst part - It has been 4 weeks now since the tower has been erected and I could not get them to come back to finish the job! Numerous times I would contact them about coming back and finishing the job and all they could say is - well, let's see what the week looks like and we'll get back to you. If lucky they might email me on the following Friday saying - I guess that we just couldn't make it this week. For some unknow reason I felt like they abandoned me.

Now I am a patient person and over the past 4 weeks tried numerous times to get them back. Being concerned that I had no assurances from them I sent them a check but withheld about 25% of the invoice that they sent me, I tried to entice them by saying that when they come out I would pay *everything* right up front including the final day - check/cash it did not matter. All that mattered is that they finish the job that they started.

The last email that I received said "You certainly won't see us until you pay your previous bill in full. I received your incomplete payment today. You have an outstanding balance of $983.50" - like I said more concerned with their profit than customer service. Well I will pay them to complete my commitment, but they are not coming back here again.

Not to mention that I had never climbed before! I had spent plenty of time on 3-4 levels of scaffolding as well as 30' ladders and working on roof tops to know that I had the potential to climb the tower. And in preparation I had purchased all of the climbing gear that I needed. I liked heights and always suspected that I could, but I just never before had the opportunity to climb these heights. In addition Jeff had not climbed a tower since his child-hood days so he was eager to scurry up it and did so in quick fashion!

To make a long story short - once I remembered to breath while climbing it all worked out well, and got most everything done that I initially wanted with the exception of no blades and tail section. It was an amazing experience! At the base of the tower there was only about a 6mph wind, but once you got about 50-60' up there was a solid wind with what I would guess as 25mph gusts.

Here are some pictures of Jeff and I on the tower, click on them to see larger sized images:

so far so good	almost there!	made it!
fair amount of wind, check out the lanyard waving in the wind	now to get work done	flying!