Doing everything wrong the first time around "My Wind Turbine"

[00MrNotWrong00]

I've been wanting to build a wind turbine for a long time and I finally got some time ( here and there ) to put something together.  I've made an instructable of what I've done and I'd love to get some feed back from the community.

So here is a link to my instructable http://www.instructables.com/id/Wind-Turbine-1/

and here is some nice video <a href="http://www.youtube.com/watch?v=QJfsst5xnOE" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://www.youtube.com/watch?v=QJfsst5xnOE</a>(man I hope that worked)

And here is a nice photo

Let me know what you think and I will post more fun stuff here when I change my gear ratio and put the new nose cone on.

[Beaufort]

Very nice.  I ran across this on Instructables a few weeks ago and took note of it.  One thing that jumps out is the 45 degree blade angle out to the tip.  This will limit your RPM due to the drag of the cross sectional area, however this may have been on purpose to have a high blade count/high torque machine.  I would expect a large increase in RPM and overall power increase (Torque X Speed) by going with a much smaller blade angle.  There are others here who have experience with PVC pipe blades and could suggest a good compromise angle.  Find some pictures of the old windmill pumpers with dozens of blades; they have a slight curve like PVC pipe but an overall shallow angle of attack. 

[ghurd]

I am a bit worried about it.

The blade angle is far too steep.  And the angle at the tip should be a lot less than at the root.
That's why they are turning so slow.

No reason to have 10' diameter for a treadmill motor.
They typically top out around 100W for a normal direct drive, maybe 150W.  Not sure I have heard of any US-type treadmill motors making 200W (UK-type treadmill motors seem better built).

If you get the blades effectively catching wind:
- the forces will tear that bike stuff off the tower, if the bike stuff is strong enough to hold together that long.
- the forces will snap the tower slightly above where it is 3 pieces together, which I am guessing will take about a 32MPH wind to be in a bad situation.
- the thin wall PVC that long will break.

Make the blades of heavy pipe, make the angle better, the diameter smaller, then worry about the gear ratio.
I doubt it needs to be even 6' diameter.

Keep an eye on that little tensioner sprocket.
They are usually replaced between 4000 and 8000 miles, even with top quality parts.  They are not as hard as the others because they have no high stress in the application they were designed for (many are nylon).
With a smalller faster set of blades, the sprocket on the motor will be a lot larger anyway.
G-

[00MrNotWrong00]

When I cut the angles on the blades I was left with very thin strips that would bend like rubber,  I was a little scared at first that they would break,  but after playing with these strips for a while I know that they can't be broken.  Flexing is my biggest fear attributed to the material now and it's a small one.

The winds were around 30 mph the other day and she held together,  but she didn't go around as fast as my first mock up.  So when I bring her down to change the gearing and replace the nose cone,  I will be cutting 9 new blades at a much more shallow angle.

I'm not afraid of the 6x6's snapping or the 3/4 ply wood .   The winds are pretty good today and she is going around real nice,  but much to slow (to date I have not seen more than 0.99 volts,  and that's with the two to one gear ratio).

So she needs a lot of love.  I will at some point be wrapping my own coils,  the treadmill motor is not going to make the final cut.  This is my first real attempt and I would like to see parts break.  I need to see first hand how and where this happens. 

I'm going to be spending a lot of time here from now on,  learning as much as I can and sharing ideas,  please check out my other posts and my other instructables.  I'm very interested in becoming completely self sufficient.

[ghurd]

I know that they can't be broken. 

They will break.
It is only a question of When they will break.
18 to 24 months seems common, even if UV protected.
I expect thin wall, and that long, would be less.

I am not so worried about the tower, because the swept area will end up a lot less by the time you get it all worked out.

The winds were 30MPH up 100'.
Way to many trees for the wind to get down to 20'.
I'd be surprised if it got 15MPH where it is.
G-

[klsmurf]

As Mr. G stated, They Will Break! Schedule 40 8" PVC. Two coats of enamel paint. Only 4 months on the job. Guess it's time to break out the carving tools. I really liked the curvature of the 8" PVC as shown in the second photo. They are 3' long, spun my geared up genny nicely, were very quiet, just not strong enough over time. 35-40 mph gusts did them in. By the way, G, The genny made a new high watt output that day of 132 Watts.
http://i889.photobucket.com/albums/ac93/klmurf/Geared%20Up%20Gennie/IMG0245A.jpg[/img]]
http://i889.photobucket.com/albums/ac93/klmurf/Geared%20Up%20Gennie/IMG0246A.jpg[/img]]

[Hilltopgrange]

I totally agree with G. not if but when is good advice!

 when they do part company be prepared to have to pick them out of a neighbours  garden, car,window or kids head!
 I had a 6ft rotor throw a blade after it flexed and struck the tower. It was found by a local farmer 3 fields away sticking out of the ground.

quote “ I know that they can't be broken” a similar statement was made about the Titanic!

quote “The winds are pretty good today and she is going around real nice,  but much to slow (to date I have not seen more than 0.99 volts,  and that's with the two to one gear ratio). “ from this I presume it is running unloaded and not connected to a battery. It has a long way to go to reach cut in speed unless your planning on charging a 1 volt battery. It is extremely dangerous letting a turbine run unloaded! the only thing that has saved it thus far is the gearing holding it back.
 Get rid of the gearing period, reduce the number of blades to three and reduce the size of the blades. Search here for working examples of your motor for blade size
The smaller the blades the faster they spin. More blades may give more torque but torque is meaningless without the rpm for cut in.
Get it up in the air as well, it will never make power on the ground the higher the better and make sure it has a load!

There is no need to go blind with a build like this, use the search on this site and you will get all the info you need and a lot more besides. There has been loads of builds of this sort over the years use them and learn from their mistakes it cheaper and more importantly its safer.

Your desire to be self sufficient with power is good target to aim for but be realistic it is going to cost you more than it will save you! it took me about 10 years to achieve it and it cost a fortune. A treadmill motor or even a dozen of them is never going to get you off grid!
Have fun but be safe!

Russell

[ghurd]

Personally, I think 4' dia is kind of pushing the limit with PVC.
Especially with the simplistic mounting commonly used any more.

Strengthening the root somehow seems like it would help a lot.  Sort of increase the strength by retaining the root shape instead of letting it twist an deform.

Years ago, it was done with metal over both sides of the root section and was called "Mike mods".  An example from Jerry,


Some of Jerry's later versions used a wood hub to hold the shape,
(from http://www.fieldlines.com/board/index.php/topic,128760.html)


Thin vs thick PVC,
http://fieldlines.com/board/index.php/topic,130147.0.html

"very thin strips that would bend like rubber"
If you manage to get them effectively catching any wind, they will bend back, and bend back slightly differently.
The air stream is screwed up, and the disturbance messes with the following blade.
Then they actually spin slower.
Plus the flutter makes them noisey...

That is assuming they don't bend back far enough to strike the tower,
and the high frequesncy repeated stressing in the same place doesn't cause them to break off before that.
G-

[00MrNotWrong00]

Ah cool ,  I like those metal pieces at the base of the blades.  I also really like that link with the five pound test,  thank you very much for posting.

I think when I bring my turbine down to replace the nose cone and switch to the four to one gearing ,  I will try just shaving off 3/4 of an inch from the leading edge of my blades before I go putting any more money into this.

I'm looking forward to colder weather maybe the chill will speed up the destruction of this silly project   

[ghurd]

It is probably not a lost cause.

Guessing it is the typical nearly useless 130VDC 5000 to 7000RPM motor.
And you already have the main parts of the gearing.
Cut the blades to 4' dia, with proper angles.
Change the gearing to about 2.25:1.
I bet that makes it work.

You can find some good info here,
http://fieldlines.com/board/index.php/topic,140404.0.html
Keep in mind he in in the UK, and his motor probably has twice the rated voltage.

G-

[snake21]

hi not wrong,just saw your video,it sounds that the pvc blades are wrongly cut.the tip should be about 4-5 degrees inclined.in wind condition like at your location,the turbine should turn like mad.try 5 blades.just google for diy pvc blades.just give some info about the motor you are using.maybe this will help us to guide you

[itsandbits]

I don't know if you know this but I will post anyway and just ignore it if you want but it gives you the difference between a "drag" and a "lift" type blade so that anyone reading your post this far will understand why you are not getting good rpm. when you plug up the airflow the blades have to rotate through with too many blades, the only power you get is from the wind pushing on the blades; drag type. If you open the spaces up between the blades by putting less blades on the rotor; 3 should do it, you give the wind a space to blow through the blade set and get renewed by more wind coming from behind it trying to push through the blades. You can only extract th Bentz limit amount of power from the wind before you start to stall thee wind itself and then it just blows around this big blockage you have put up, just like going round a big sheet of plywood. If you leave space foer the wind to blow through at full speed, the blades get the benefit of this full speed wind blowing through just like the sail on a boat and can excellerate sideways away form it in the form of rotation and their speed keeps on increasing till they reach a point of going faster than the speed the wind is blowing and you get all your power from lift here on up in rpm. this is the tsr and can go up above 7 in high performance blades and more. This is where a good set of blades will make you wonder if you are really seeing things because they will simply take off in a blur and if you are extracting power, you will be amazed what power there is in lift.
Now you don't want to leave too big of holes or load it up too much with gearing or a hardx to turn load, so it will not start, but with experimenting with blades and loads and  when to put the load on to get power, you can do a balancing act to get everything just right for your rig.
The experts can pick on certain parts of this but I am just trying to give an overview so some guidelines can be tried and the frustration levels can be kept down
Cheers
Lloyd.