Friday the 13th - my version

[SmoggyTurnip]

Well if you have been following my project you will know that my blades struck my tail on the first night because the tail boom lifted on the hinge.  This shows the scratch left by the tail boom stop and that is how I was able to tell what happened.

I built a complete new set of blades for the machine.

I can now carve a blade in 4.5 hours.

This is how I balanced them:

I painted my tower:

I put the machine on the tower on Friday the 13th!

It was a dark and gloomy day:

And lifted it up:

I put it up in the morning while the wind was calm and the wind gradually increased in speed all day long.  It did not turn!  What is wrong now??  It was too windy to take it down until Monday.  I took it down and while it was still on the tower I gave the blades a little push and heard a terible grinding noise.  I turns out that a nail was lodged between the stator and rotor.  It was a finish nail so the head was just the right size to jam in there and scratch the stator to pieces.

I made a new stator. And put it back in the air.  It has been up for a week now and there has been lots of wind and no serious problems yet.

It does need at least one change.  It turns out of the wind in very light winds before it starts to furl.  Maybe the tail is too small.  I am not sure if I will

make a bigger tail or reduce the offset.  It also furls a bit too early - but that is what I wanted until I get bit more comfortable with it.  

I want to get an anamometer to put on my tower.  I think I will put it at 75 ft. the trees are 50ft and the turbine is at 100' so I think that might be a good place. Any suggestions.  I want something that I can just hook up to my PC and get both wind speed and direction in the $500 CDN price range.

Anyway - it sure is fun to watch it now - I am getting a sore neck.

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[Flux]

If you reduce the offset, make sure you don't go below the 4% rotor diameter or you will have trouble.

You can offset the tail away from the furling direction, this saves having a monster tail. looks a bit odd but works fine. If it only turns about 30deg away from the wind you will probably see no obvious reduction in output.

flux

[WXYZCIENCE]

Smoggy, how are you holding the tail on this time so it won't come off again? They sell those neck brace thingies lol.
Joseph.

[asheets]

I got one of these for my tower:  http://scientificsonline.com/product.asp?pn=3081809&sid=merfroogle&mr:referralID=a22183a0-15
2f-43a7-9674-cbcd5926545a&bhcd2=1161977234

although you can probably find them much cheaper than this.  I paid $70 for my set, used.

[SmoggyTurnip]

I drilled and tapped a 1/2 inch hole through the top of the hinge (which has 1/2 inch steel disk welded to it).  I cut out another circular disk the same and threaded a 1/2 inch hole through it.  A threaded rod was passed through the top hole down through the hinge pipe and then the other steel disk was added at the bottom. Jam nuts were then added to the top and bottom.  I think it will work very well but I am keeping a close eye on things.

The first night that I had it up this last time we had the same type of winds that gave me the tail crash.  I was too worried to let it go so I left it shorted out all night.  The next night was also very high winds and I left it shorted out again.

It will be a while before I have the guts to let it go in high winds at night.  We have been having good winds in the daytime since I put it up and I am getting more comfortable with it each day.

I was surprised that it did not furl at all during the high winds when it was shorted out in the high winds - gusts to 60 mph.  I went as high a 10 rpm but never furled - is this normal?

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[jmk]

 Nice set up, and congratulations Smoggy. The tower looks nice painted. I am glad to see you painted it. It will last a lot longer now. I used to get burning pins and needles in my neck and back when I ran the crane at work. I couldn't figure out for the longest time what was causing it. I always noticed the pain starting by the time I was driving home from work. Are you seeing any good power before it turns out of the wind? I was waiting for you to post that you got it back up. Your getting a lot done. It's a lot of work isn't it? Are you doing it all by yourself or do you have help? Is there a special name for your winch? I was looking for one, but all I can find are the ones that hold about thirty feet of line. I am using my van. It's been tearing up the lawn, plus getting stuck when lowering the tower, and raising it. I have to drive up hill to lower it so it is actually harder to lower it than raise. I see Harbor freight has one that holds 90' of cable. That would work with one pulley. As it is now I am using four with a fifth one to the base so I can change to an area where I can drive my van. It eats up 180' of cable, but at the most it's only about a 500 lb pull. I could hand crank it real easy if I kept four pulleys. I was even thinking of making one from a hand crank winch.    

[jmk]

 My machine does the same thing. I don't think it will ever furl when shorted. The blades wont catch enough wind to lift the tail when shorted. The wind will cut right through, wich is what you want.  

[harrie]

Very nice set up, it looks like you didnt want your stator to move, with all the bolts? After balancing the blades the way you did, do they run smooth without shaking the tower now that you have it up? I would beleve it would be a good start, but still think one would need to balance it as a unit also. Thanks for all the good pictures.

Great Fun, Harrie

[Ungrounded Lightning Rod]

Downwind drag is enormously higher on a lift-type turbine when it is turning than when it is stalled - either in the "nearly stopped" sense or in the aerodynamic, "turning too slowly to keep the airflow attached to the back of the blades" sense.

When turning it's efficiently decellerating the air across the whole swept area.  When it's stalled it's inefficiently decellerating the air in the cross-section of the blades themselves and for a very small area around them.

Since the furling is the result of the slightly off-center drag on the mill fighting the tail's attempt to turn it into the wind, if you short it out and the blades stall the tail has no problem turning it into the wind.

(This effect also helps regulate the output when it's furling, so it keeps producing.  As it turns away from the wind it reduces cross-section, reducing turning force.  But when it slows down enough that it starts to stall in the aerodynamic sense, the drag reduces considerably.  So it comes back somewhat, until the air is attached for enough of the blade surface to balance the tail's righting force.  Get things adjusted right and you should be able to get it to put out most of the maximum safe current for a broad range of windspeeds above the point where furling begins.)

[Chagrin]

http://www.aagelectronica.com/aag/index.html

It's known as the "one-wire weather" station. Very popular for interfacing with a PC and possibly the least expensive. If you google for "one-wire weather" you'll find a wealth of information.

[jmk]

 Harrie I did my balance with a nail in the center. When I was done it would balance on the tip off the nail without falling. When I put it on the machine I had to balance it some more. I don't know what Smoggy did, but if he did nothing more and if he doesn't have any wobble, he got lucky. I think it's a good start to have the blades balanced first like Smoggy did. I think the hardest thing is getting the center drilled accurately. If your out by 1/16" you can throw a balanced rotor out of balance.  

[Flux]

This method works as long as the centre you balance from is exactly the same as when fitted on the alternator. If you use spigots it should be ok. If you just rely on stud holes it may need trimming afterwards.

With an air gap alternator it is easy to balance the final thing. With something that is not free enough for this you may have to balance the prop alone and make your engineering good enough.

For motor conversions Zubbly uses a dummy shaft and with the fit of the hub on the shaft being excellent there is no trouble.

Flux

[SmoggyTurnip]

I am happy that I put lots of bolts on the stator.  There are 21 coils and 21 bolts. This makes it easy to adjust the air gap all the way around the stator and I hope it will discorage warping of the stator when it gets warm (Hot).  Also I think it looks cool.

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[SmoggyTurnip]

Saturday afternoon my we were having good winds and my machine was furled most of the time.  The bearing was squeaking badly so I waited for a lull in the wind and then shorted the machine out.  That day the winds kept increasing finally reaching 60km/h gusting to 100km/h.  The fastest I have seen it turn so far was about 20 rpm.  The wind has been strong ever since 50km/h gusting to 80/kmh most of the time.

It is really worrisome to have to sit through these high winds not knowing if a strong gust is going to make it take off.  I don't want to put the external load back on because of the bearing.  I hope I am doing the right thing.  The wind is not supposed to stop until at least Friday.

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[SmoggyTurnip]

The tower looks nice painted. I am glad to see you painted it. It will last a lot longer now.

I am glad I painted it too - the pipe really rusted alot in a short time so I had it sandblasted and then painted it.  I was luky enough to have good weather to get it done in time.  I am thinking about rust checking the inside of the pipe too if I can figure out a way to do it.

Are you seeing any good power before it turns out of the wind?

The most I have seen yet is just over 3000 watts.  It is furling very early and I expect to get about 5kw after I make some changes to the furling setup.

Your getting a lot done. It's a lot of work isn't it? Are you doing it all by yourself or do you have help?

It was way way way more work than I thought it would be.  I started it last december and I thought I would be done by March 1st.  Almost everything that could go wrong did go wrong.  All of the welding was done by my brother everything was done by me.  There is still alot of work to be done yet in hooking it up to provide some heat in the house.  In the end though I can't think of any project that has been so rewarding - even better than designing and building my own house.  

Is there a special name for your winch?

I use a tractor to rais and lower the tower.  I have a small winch to hold it back when the weight of the gin pole takes over.  It is a 2000 lb winch that I got at Canadian Tire for 70 bucks.

[SmoggyTurnip]

The machine seems to run very smooth - There is no noticable vibration at all.  This is the second set of blades I have on it and they both ran pretty smooth so this method has been OK for me.

[asheets]

Yours is also a good one.  I prefer mine because the output is in 8-n-1-9600 serial, so I can use Hyperterm to cook up my own scripts and whatnot by just using a spare mouse port on my computer.