VAWT Prototypes

[Crockel]

Here's a couple VAWT prototypes I built a few months back. One is a pure drag model with flapping panels for blades while the other is a Savonius style turbine. I was quite impressed by how much better the Savonius turbine performed.

And, yes, that is duct tape.

[MagnetJuice]

  SAVONIUS WINS!!!

And, yes, that is duct tape.

I thought there was no duct tape left in Canada.

Didn't Red Green use it all up? 

Ed

[SparWeb]

Ah, there's no better prototyping tool than duct tape.  Other common items like hot-glue and WD40 just don't stand a chance.

Agree: the Savonius will win when it comes to "excess" energy among VAWT's.  There's the energy needed to keep the machine spinning, and then an "excess" that will accelerate it, if there is any. 
If not, well it just wallows along.  If it wallows, don't bother putting a generator on it because it doesn't have any power to spare.


MJ:  Red Green has been off the air for many years, and supplies of duct tape have (slowly) recovered since then.

[Crockel]

My intention with the Savonius turbine was to move it around the property looking for the best wind exposure. Eventually I just set it up and let it run.
Although I have the outmost respect and admiration for Red Green, the duct tape did not last long. It didn't help that the turbine had been previously damaged after being blown over a couple times.

[Crockel]

[MattM]

I think drywall screws in little sheet metal tabs would have held better.

[electrondady1]

welcome Cockel.
pretty much how i started.
being in the Painting business i had a lot of 20 litre pails hanging a round
started building 3 bladed drag mills out of them,
 stacking them up 5 high.
used a 5/8" cold rolled steel for an axel
if you have a Princess Auto  near by you can get a lot of what you can use there
 

[Crockel]

I have a pond on my property that my son wants to stock with trout. My next wind prototype (first practical project) will be a wind powered aerator. The blades for my first savonius turbine were made from a 20 litre pail, but I've recently brought home a large plastic barrel to make larger blades. There will be no duct tape on this one though. The blades will be attached to the endplates using either wooden blocks or sheet metal tabs as MattM suggested.

I'll have to pay a visit to my local Princess Auto for bearings and other bits. Lot's of good stuff there.

[topspeed]

My first prototype also sort a broke a bit ( though repaired ) but teached me a lot.

[SparWeb]

... The blades will be attached to the endplates using either wooden blocks or sheet metal tabs as MattM suggested.

Or cut curved slots in the endplates, slide the arcs through them.

I'll have to pay a visit to my local Princess Auto for bearings and other bits. Lot's of good stuff there.

It's like they have this hobby in mind!

[MagnetJuice]

This is what I do to hold the blades in place and to shape them to the way that I want them.

I draw the line on the end pieces , then I use screws as shown and place the blades between the screws.



Another advantage of doing it like this is that I can try different profiles by just moving the screws to hold a different shape.

Large stove pipes makes good blades.



For the center shaft, I use a piece of all-thread rod inside a pipe with large washers and nuts at the ends.

Ed

[Crockel]

It's like they have this hobby in mind!

Considering all the weird stuff I've found at Princess Auto, I'm afraid to think of what other hobbies they have in mind.

It looks you came come up with some pretty radical blade designs by shaping sheet metal like that, MagnetJuice.

I had some time to tinker this afternoon, so I made the blades for Savonius #2 from the 50 gallon drum. Now I just need to cut the endplates and set it up. I used blocks and woodscrews on this one. No duct tape.

[topspeed]

A bit like this 100 mm type...cool.

[MattM]

Crockel, keep up the fine work.  How are you mounting these to an axle?

Topspeed, those scoops look like they would concentrate drag towards the center.  My intuition says lever arms are best made long, not short.  I've seen a lot of videos on Savonius and the best are the simplest.  That 3D print probably does scale well.

[topspeed]

Crockel, keep up the fine work.  How are you mounting these to an axle?

Topspeed, those scoops look like they would concentrate drag towards the center.  My intuition says lever arms are best made long, not short.  I've seen a lot of videos on Savonius and the best are the simplest.  That 3D print probably does scale well.

CFD of that would be cool to see.

[Crockel]

A bit like this 100 mm type...cool.

(Attachment Link)

I thought that for a Savonius turbine, the blades would have to be overlapped in the middle for air to pass through the center.

MattM,
My blades are mounted using endplates.

[Crockel]

Here's my finished turbine mounted on a steel rod for testing. The static torque seems pretty low, around 2 inlbs in a 20 km/hr wind. As it starts to turn, the acceleration increases. The next challenge will be to mount it higher and turn it into a pond aerator.

[MattM]

Its looking like it functions.  It may be just the video playing tricks on me, but do I see a wobble?  Most people doing these types run a brace across the top to stabilize them because once you get better wind the forces are going to be crazy high on that shaft.

[Crockel]

I'm not sure if it's a wobble in the mounting shaft or my unsteady camera hand. The hole in bottom plate is a bit large for the shaft due to my limited collection of hole saws, so there is a wobble in the turbine.

The shaft is only temporary though. Eventually, once the turbine design is worked out, I'll mount it on a more solid rotating shaft to drive an aerator or pump.

Even though the wind was light, I was expecting more torque. I'm thinking I don't have enough space in the middle for the air to pass through. It will only get worse if I mount it on a larger diameter axle, so I might have to rearrange my blades.

[gsw999]

What a terrible design why are you even wasting your time, just cut a metal oil barrel in half with a plasma cutter and use that , awful plastic and wooden lark will be blown apart in ten seconds.

[DamonHD]

Come on, let's not be attacking.  There are many ways to make things work, including experimenting with new ones, and ones based on materials and tools that we have to hand and are comfortable with.

Rgds

Damon

[Bruce S]

BEGIN----Moderator MODE----

gws999

Please do not post telling someone their idea is awful!

We the Owners/admins/moderators will not put up with this.

We're guessing you either had a bad day, bad moment, or ,,,
Next one will have you put in the read only mode for a period of time

END----Moderator MODE----

Bruce S

[electrondady1]

seems like a big improvement on the first unit .
carry one .

[Mary B]

I know someone using cut in half 55 gallon plastic barrels... less rotating weight so the central shaft sees less stress. They have survived my nasty winds up to 90mph(once a summer usually).

[Adriaan Kragten]

A bit like this 100 mm type...cool.

(Attachment Link)

I thought that for a Savonius turbine, the blades would have to be overlapped in the middle for air to pass through the center.

MattM,
My blades are mounted using endplates.

For a Savonius rotor with two buckets, there must be an overlap en between the buckets in the centre to make that there is a flow through the rotor. This flow makes that the rotor works as a lift machine during a part of the revolution and therefore a Savonious rotor can have a higher maximum Cp than a pure drag machine (for drag machines, see public report KD 416). However, only two buckets make that the starting torque is fluctuating very strongly. For Savonius rotors with three buckets, there is almost no flow through the rotor and therefore such rotors are much worse than Savonius rotors with two buckets.

The strong fluctuation of the starting torque can be flattened by using a Savonius rotor with four buckets and by shaping the buckets such that there are no buckets in the centre of the rotor. So a flow through the rotor is possible. This idea is described in my public report KD 703. I have tested a small prototype and there is no strong fluctuation of the starting torque but I have not proven that such a rotor has an acceptable maximum Cp. Four buckets are also logic if you use square end plates.

Savonius rotors have some very important disadvantages. One is that a lot of material is needed for a certain swept rotor area. Another is that it isn't possible to use a safety system which limits the rotational speed and thrust at high wind speeds. So these rotors are very dangerous during storms.

[topspeed]

Here is my H-Darrieus prototype no 2 with an old 2 MW Winwind turbine.

It has now only got 12 % efficiency, but can withstand 800 Gs.

[JW]

I recommend we remove that guys post and the admin warnings. As long as you are doing something its good, that's how we learn things.

[Crockel]

I know someone using cut in half 55 gallon plastic barrels... less rotating weight so the central shaft sees less stress. They have survived my nasty winds up to 90mph(once a summer usually).

That's what I was using for mine. My local dump has an ample supply, but most had been used for oil (the last thing I want near my pond).

Hi Adriaan,

Your VIRYA 1.45 has a lot more space in the middle than my model. With the low torque I'm seeing, I think I might be mostly seeing drag.

This must be your Darrieus here, Topspeed.

[Crockel]

I recommend we remove that guys post and the admin warnings. As long as you are doing something its good, that's how we learn things.

I suggest we keep it. It saves me from having to scroll through Twitter.

[JW]

https://www.fieldlines.com/index.php?action=dlattach;topic=150633.0;attach=14931;image

I like the workmanship of this image

[SparWeb]

LOL
Very well, let's keep it.  But if there's any more nastiness, Elon Musk might come and try to buy Fieldlines!

There's no use letting it happen again, so I want to remind everyone, nasty comments are not welcome and normally removed.

[topspeed]

I know someone using cut in half 55 gallon plastic barrels... less rotating weight so the central shaft sees less stress. They have survived my nasty winds up to 90mph(once a summer usually).

That's what I was using for mine. My local dump has an ample supply, but most had been used for oil (the last thing I want near my pond).

Hi Adriaan,

Your VIRYA 1.45 has a lot more space in the middle than my model. With the low torque I'm seeing, I think I might be mostly seeing drag.

This must be your Darrieus here, Topspeed.
(Attachment Link)

Yes Crockel..it is a small one..I also have 6 x bigger in swept area, but it has not runned yet.

[Crockel]

I like the workmanship of this image

Cutting the 2x4 to shape for attaching the blade was a bit much for my little jig saw. However, I picked up this little guy from my neighbor's acreage sale yesterday that should make things much easier next time.