Author Topic: An unusual VAWT (Read 7722 times)

powerbuoy · « **on:** March 31, 2006, 01:39:50 AM »

Hi group:

We had built this "beauty" (or better "beast???) last summer. It is a VAWT, therefore turning vertically around its axis. It is important to note that one blade is always facing the wind, the opposite one is flat, and the remaining two blades are at a 45 deg angle head on to the wind. The wind vane is connected to a transmission. The trans will always put always one blade 90 degree to the wind up and the opposing one flat.

A true drag device. Unfortunately, even a storm did not produce more then 12 RPM. Power output -> Thumb test -> was below 10 Watts ... what shall I say.

Editors Note:

Due to the very large photos you posted, I made them links so folks on slow connections can see the story without waiting for huge files to download.

Please consider reducing the picture file sizes considerably before including them next time

Editor

Massive Photo1

I cannot claim this idea for myself. Truth is that I found somebody on the internet a couple years ago who had built one and provided some valuable input. I do not have his mailing address/name anymore, otherwise I would have given him the credit.

Massive photo 2

I hope everyone enjoys the pics, the transmission with the constant adjustment to the wind was almost a piece of art.

Massive Photo 3

Massive Photo 4

Powerbuoy

wdyasq · « **Reply #1 on:** March 30, 2006, 07:46:57 PM »

wdyasq · « **Reply #2 on:** March 30, 2006, 08:03:03 PM »

Countryboy · « **Reply #3 on:** March 30, 2006, 09:43:37 PM »

"A true drag device."

You can't make a more accurate statement. The designer's #1 goal was to create maximum wind drag, while actually being able to turn.

IMHO, this looks like something built by 'college educated idiots' - folks with zero common sense.

One blade standing vertical into the wind catches the wind.

The horizontal blade opposite, creates drag.

The 45 degree angled blades try to act like a fan - one blade tries to cut into the air above the blade, while its opposite tries to cut into air beneath the blade. That's gotta play heck on the vertical shaft, as the 45 degree angled blades are trying to flip the rotor.

Since the 45 degree blades each have 1/2 the swept area of the one blade catching the wind, they are trying to cancel each other out. The energy gained by the vertical blade is applied to the wind that hits the 45 degree angled blades.

Factor in the drag of the horizontal blade, and it's a wonder this thing actually turned.

I'd estimate the blades to be about 18 inches by 5 feet. That gives this machine a whole whopping 7.5 sq feet of swept area. That's roughly equivalent to the swept area of a 3 foot diameter HAWT.

I sure hope none of my taxpayer dollars went into this.

powerbuoy · « **Reply #4 on:** March 31, 2006, 08:06:34 AM »

Countryboy ... thank you for these nice comments ... your input is truly appreciated.

Of course it honors me that you assume that this device was worthy of tax dollars, unfortunately this was build with zero funds. You are looking at a heap of scratch metal and shelving units, the wind vane by the way was made of card board.

We built this unit mainly for two reasons:

A) People said that this unit would never turn (people like yourself) -> We proved them wrong

B) Because we were enjoying a fun project related to wind power.

The unit had one other side effect: We placed it on top a hill right next to our facility in an industrial park where it turned for three days with a paddeling motion. We had every day people stopping by, inquiring about it and pulling us into discussions about wind power. You see ... we even managed to get you going .... only good things can come out of it.

whatsnext · « **Reply #5 on:** March 31, 2006, 11:57:47 AM »

This device would be more apropiate for a Rube Goldberg forum than here but you did get it to turn so tally ho. Is the base tied down? I ask because it looks more likely to flip over than to actually produce any power.

John..

/class naysayer

whatsnext · « **Reply #6 on:** March 31, 2006, 12:00:51 PM »

sorry for the mizspellin.

cyplesma · « **Reply #7 on:** March 31, 2006, 01:19:58 PM »

If I had to give it a name it would be:

VAWTHL

Vertical Axis Wind Turbine Horizontal Lentz

where the typical lentz VAWT have their blades mounted vertically. with this one the blades are just horizontal.

Bruce S · « **Reply #8 on:** March 31, 2006, 01:28:16 PM »

After looking at the pictures, both full and abridged. I have a few questions.

Let me know if my observations are correct and I am not trying to make fun of it at all as it does look quite interesting.

Not my style to slam someone whose built something,even if it doesn't perform as they had hoped, even a wrong turn becomes a lessen.;--)

Other than the slow turning, and resultant low output what kind of torque did this have?

What where the blades made of?

In thinking of how the unit operated without an AVI , I believe that each set of blades where setup to hindge opposite each other and that to keep the 90 degree out blades from slamming into upright during wind operation they would store so-to-speak at 45 degrees? possibly using springs to keep them there? and only during high enough wind did with the blade at full upright did the opposing blade go flat to lessen the turning resistance?

Is the unit still standing and turning where you could point to an AVI?

Cheers!

Bruce S

willib · « **Reply #9 on:** March 31, 2006, 02:45:32 PM »

i'd be interested to know how you got the blades to pivot?

powerbuoy · « **Reply #10 on:** April 01, 2006, 08:05:15 AM »

Hey, ... don't worry. I knew what I was getting into when I posted the pics. Still, it got at least some people thinking, some will now know what they should definetly not built, and even the die hard HAWT believers got s.th out of it. United they can stand, looking at this piece of poor performance with a "told you so" smile on their face. Don't misunderstand, I like HAWTs too and agree to their superior performance. But instead of placing HAWT pic No 3000 on the board and getting a pad on my back, I went for the unusual and posted underperformer No 1 ... at least its standing out ...haha.

How does that unit work? It's all done with bevel gears. The vane is connected to a rod that goes all the way through the center of the transmission. Each blade is connected to its own bevel gear (double the number of teeth, example: vane center bevel 12 teeth, blade bevels 24 teeth) The blade bevels are rotating around the center vane bevel. The motion is similar of somebody using a canoe, the blades are constantly revolving, almost flowerlike. As a showstopper I give it a 10.

Subject Torque ..., of course the nay sayers are correct. You cannot assume a decent output when one blade does the work and three are being dragged around. Not to forget the gear losses. I was able to hold onto the shaft in a storm...don't need to say more.

Thanks for asking,

Powerbuoy

powerbuoy · « **Reply #11 on:** April 01, 2006, 08:18:53 AM »

We held it down once, but it stood sturdy after the base legs were widened.

powerbuoy · « **Reply #12 on:** April 01, 2006, 08:22:57 AM »

The center vane is connected to a bevel gear 12 teeth

The blades have their own bevel gear 24 teeth

see the pic

They blades rotate around the vane gear. To make it work, the outer gears have to have double the No. of teeth than the center gear ... (the pic shows it the other way around, which is not correct)

Experimental · « **Reply #13 on:** April 01, 2006, 08:50:42 AM »

Hey, enjoyed your pictures, and looked like a fun project, dispite the performance !!

A lot of enginering went into this, and I can,t tell you, how many of my projects turned out "less" than I expected --- none the less, nothing ventured, nothing gained, and time spent building, beats watching TV !!!

It is interesting, and what is next

Happy building, Bill H.....

powerbuoy · « **Reply #14 on:** April 01, 2006, 09:14:11 AM »

Thx a lot Bill ... that's the spirit

Stonebrain · « **Reply #15 on:** April 01, 2006, 09:49:56 AM »

Hey,

Congratulations,I think you did a vetry good job,very good looking too

great craftmanship.

I don't understand why this make some worry about their money,but

you took it the right way.

I'm specially impressed by the gear.

Made me think of a machine used for putting hey on rows.The gear of

these that moves the forks would possibly be good for this kind of vawt.

I don't agree that hawts are superior,sure there will be a niche

for vawts.I think even this type of vawt has a future,even if it's only

because it's good looking and fun.

cheers,

stonebrain

windstuffnow · « **Reply #16 on:** April 01, 2006, 01:38:57 PM »

I think you did a great job on it! I've had ideas that I put time into that didn't work at all. I've seen similar versions of that same thing standing upright using a chain drive.

I think its great, weather it works good or not! I sometimes get ideas stuck in my head and have to get them out. The only way to do it is to build it... sometimes it works and sometimes... well ... it simply becomes parts for another project. Either way, you did it, its out of your head and you learned something from it.

I just spent 3 months building a motor that I'm completely discusted with ( actually several different variations ). I know failure well!

.

vawtman · « **Reply #17 on:** April 01, 2006, 03:35:56 PM »

I must say I flew devices alot worse than that.Its all a learning process and unless you build it yourself and fly it you will never know.I would try to design around the need for a tail mechanism in future designs.Thats a big advantage for vawts.Have fun and keep tinkering.

ffoegw · « **Reply #18 on:** April 01, 2006, 04:48:35 PM »

Love your vawt.

It looks like something out of a star wars movie.

HAWTs seem to work great however, there is one very big and expensive problem with all of them.

.............. The tower.

Thats why I am working with a vawt and trying very hard to perfect it. I sincerely believe that if I can get even close to the amount of power that a hawt can put out and yet keep it on the ground the smiles will quickly fade from all those hawt faces.

Especially if I can build it out of salvaged pipe, duct tape and some bungee cords from the local harware store.

Here is video from today of my latest vawt attempt;

http://www.fieldlines.com/comments/2006/3/9/202615/3265/21#21

Geoff

DanB · « **Reply #19 on:** April 01, 2006, 05:20:06 PM »

It is fun to see folks building odd things! Thankyou to powerbouy for sharing this one!

Regarding VAWTS and towers =- I really don't think the lack of a tower is an advantage with a VAWT (you have to think of some other good reason). Good clean wind is required for any type of machine. I think VAWTS tend to be on the ground because they're hard to get on towers - but they would benifit just as well from a tower as does a HAWT.

Mick Sagrillo addressed this at the last seminar we went to and I enjoyed his statement...

'you can put any windmill HAWT or VAWT on the ground - or you could just as well leave it in the box.' Wind turbines need to be in the air. Lack of towers are not an advantage for VAWTS, but the difficulty of getting many VAWT designs on a tower is actually a drawback.

powerbuoy · « **Reply #20 on:** April 02, 2006, 06:33:08 AM »

Unfortunately, this one needs a tail. That's the key to make it work. The tail (connected to the center gear) dictates which blade is facing the wind and which one is flat. You could simulated a wind change of 360 degree, by just holding the vane and walking one circle around the tower. You would then see the blades coming up one after the other and coming down again once you are passed them.

powerbuoy · « **Reply #21 on:** April 02, 2006, 06:39:25 AM »

Ed:

Thanks for the good words. I liked the Lentz turbine you worked on. I believed a while ago that this (Lentz Design) might be the way to go when it comes to VAWTs. Did you drive this design any further??

powerbuoy · « **Reply #22 on:** April 02, 2006, 06:46:03 AM »

Geoff:

I saw the clip ... looks nice. I have a similar set of blades and tried them in 2 and three blade configuration. I had them fixed, though...there was no angle mechanism like yours seem to have. I read many threads where it was claimed that one does not need the angle mechanism. However, either you'll then need to have your dimensions perfect or it only works under windtunnel conditions ... I have not figured that one out yet... my H-rotor did not turn at all ...bummer.

windstuffnow · « **Reply #23 on:** April 02, 2006, 08:54:34 AM »

Yes, The Lenz turbine is still a work in progress. I've been playing with small changes which so far still leaves it in the 41% efficient range. The test unit on the roof has definately run the range of wind speeds and has proven itself to be a good contender to the basic HAWT. I'll be building some larger ones this year to play around with along with a few odd ball tower ideas to mount them on. Eventually, not sure if it will be this year, I plan to build a 14ft diameter x 16ft tall that will slip inside my small 45ft silo. If all goes well this year the silo will be renovated for the new structure then I'll begin on the turbine... I still have a long list of things that need to be done this summer ( the electric S10 being the priority ) so we'll see where I end up.

.

zap · « **Reply #24 on:** April 02, 2006, 08:58:40 AM »

I wonder how this design would work if the blades weren't connected by a fixed means.

Replace the solid axle after the hub with a fiberglass rod or some type of elastomeric bearing to allow the blade to both flap up/down and fore/aft. Obviously you'd lose some on the downwind sail because the wind could just push the blade "out of the way" without immediately turning the center axle but it would give this loss back as soon as it was out of the wind. The other blades might gain because they could teeter up or down and "fly" the wind. Whatcha think?

ffoegw · « **Reply #25 on:** April 02, 2006, 09:02:57 AM »

powerbuoy,

It's the very same principles used on sailboats.

The sail is adjusted by a human being who determines the amount of angle on the sail Doing this can optimize the speed and energy derived from the wind.

I replace the human being with a bungee cord which lets the sail's angle be determined by the strength of the wind and the bungee cord(s).

Probably still not perfect but pretty close.

Try the virtual reality dinghy sail boat feature which is at the bottom of the page linked here:

http://www.seed.slb.com/en/scictr/watch/sailing/index.htm

All the things you see happening there are the ones I am trying to emulate with my vawt.

Regards

Geoff

ffoegw · « **Reply #26 on:** April 02, 2006, 09:09:16 AM »

Hey zap,

that might work!

I would recommend attaching all the sails on powerbouys vawt by the leading edge on a hinge which when coming into the wind would force it to lay flat and drag through the wind while coming out of the wind it would be pushed up to 90 degrees and receive the full force of the wind.

It would probably never go above tsr 1 but should have plenty of torque.

Geoff

ffoegw · « **Reply #27 on:** April 02, 2006, 09:24:19 AM »

Hey Dan,

Everything you have said is true however, so is this statement:

"if I can get even close to the amount of power that a hawt can put out and yet keep it on the ground the smiles will quickly fade from all those hawt faces."

Regards

Geoff

TomW · « **Reply #28 on:** April 02, 2006, 09:41:55 AM »

See subject.

DanB · « **Reply #29 on:** April 02, 2006, 10:21:08 AM »

Like Tom said though - the trouble is the 'if' factor here and it seems a very unlikely thing to accomplish with machines of even nearly similar weight or swept area.

Keep in mind that the 'fuel' for our wind turbines is 'wind' it makes sense to put them where the fuel is. Some VAWT designs are more suitable for placement on towers than others. Either way - if we double windspeed you get 8x the energy.

Turbulance is an issue that is a problem but even if we ignore that all together..

Assuming flat ground - with no trees and no buildings... wind speed

At 100' windspeed is generally double what it is on the ground (8x the energy)

Even at 20' above the ground windspeed is about 1.5x that which it is on the ground which gets you between 3 anc 4 times the energy that you'd get on the ground.

There may be some applications where it makes sense (water pumping maybe... ) - but for electricity generation I think you'll wind up spending more $$ per KWH and wind up with a much heavier/larger machine and a bigger project if you intend to keep it near the groud vs having it up on a tower where the wind exists. I think this applies no matter what design of machine your talking about.

vawtman · « **Reply #30 on:** April 02, 2006, 11:52:09 AM »

Hi Dan

There were many times during the vawt design process I looked up and thought how nice it would be to have a 17ft machine like yours flying.

The problem I have and other vawt builders do has well is that the neighbors wouldnt be happy when a blade flew off or the tower would fail possibly landing on there property.They get ticked when a couple sticks from bottle rockets land in their yard during our 4th celebration.

You are lucky having a wide open area for your turbines.If they fail you just pick up the pieces and move on.

I woulnt see why it would be a problem putting a vawt on a high tower.The problem is the height you can go in residential type areas.

Maybe get alot less power but at least something and its a fun hobby.

DanB · « **Reply #31 on:** April 02, 2006, 12:18:03 PM »

Yes - I can see your point about that ;-)

I just wanted to stress that in order to get real usable power from any machine on the ground (and I dont think it matters if its a VAWT or a HAWT) it's going to have to be a huge machine and it will not be cost effective to any comperable machine on a tower.

I often run HAWT's on the ground too (on little 6' high stands I use for painting) for fun and to get a rough idea... 'do they work'. I can see where some vertical designs have some advantage when dealing with turbulance - so if it must be on the ground then perhaps a vertical machine has some advantage but on the ground is ever ideal and I question if its even safer than a smaller machine up on a tower. Vertical machines can spin quite fast too and throw 'chunks' I expect.

ffoegw · « **Reply #32 on:** April 02, 2006, 06:57:21 PM »

Dan,

I think perhaps there should be a measure by which hawts and vawts could be compared.

You said; "it seems a very unlikely thing to accomplish with machines of even nearly similar weight or swept area."

Is that what is being compared, weight and swept area?

I would like to propose that a good and fair measure by which to compare hawts to vawts should be real estate/power.

Or ......... watts per acre.

If you are agreable with that I would then like to ask you how many watts your hawt produces and how much real estate you need to own in order to keep it up on the tower?

I am presently myself looking for some cheap land on which to further pursue this vawt stuff (and maybe even hawts).

Your answer (and anyone elses) will help me a great deal.

Regards

Geoff

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Author Topic: An unusual VAWT (Read 7722 times)