Building the sickest ® VAWT ever. Brilliant minds unite please!!

brandnewb

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if anyone can suggest large cup shaped objects, or off the shelf parts with a large volume that can be used as drag type scoops of sorts. I'll hook it up to the frame near the blades and see what happens.
 

brandnewb

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I am considering getting 3 of those
and cut them in half.
I either place 2 halfs next to each other where the rae 2822 blades are now, replacing the lift type blades completely.
I am leaning towards no more lift type stuff because of the speeds required by them. I am more than happy sacrificing efficiency if it means the turbine gets to spin slower while still producing work.

Or I could stack 2 halfs making the turbine +- 2m height rather than the current 1m.

or I could go mental and do both. so 2 next to each other and stacked ;) But not looking forward to the costs involved :(
 

justgary

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Why would you add a drag device to a lift device? You will kill any efficiency gained from lifting.

This paper discusses recent research on improving self starting in VAWT devices. They mention that a pitch of -10 degrees helps a lot (even though +5 degrees is best for efficiency after it starts). They also suggest stacking two three-foil devices, but at 90 degrees to each other. So rather than two meter long blades, make two sets of one meter blades and stack them with the second set rotated relative to the first.

They further go into some very novel ways to improve starting efficiency. Read the paper.

VAWT Paper
 

brandnewb

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Why would you add a drag device to a lift device? You will kill any efficiency gained from lifting.

This paper discusses recent research on improving self starting in VAWT devices. They mention that a pitch of -10 degrees helps a lot (even though +5 degrees is best for efficiency after it starts). They also suggest stacking two three-foil devices, but at 90 degrees to each other. So rather than two meter long blades, make two sets of one meter blades and stack them with the second set rotated relative to the first.

They further go into some very novel ways to improve starting efficiency. Read the paper.

VAWT Paper
I am considering no longer using lift as blade type as lift turbines, if I understood things correctly, need a high tip speed ratio (the speed of the blade in relation to the wind speed)
So I am hoping that going the drag route, like a anemometer, will slow things down considerably. I mean the alternator i have planned can be made to output the target 48V at almost any rpm ;)

In any case I will read that paper for sure. Thanks for the suggestion
 

Hedges

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A drag device will work, but isn't what you want. Large, heavy, low producing.
The wings could be allowed to rotate orthogonal to the wind while going down wind, to serve as a drag device for high starting torque. Then lock in proper place for lift. But normally VAWT don't do that.

I would guess either you have too much friction, preventing turning. Or, blade shape/angle isn't delivering enough lift. Could be with turbulence at low height, what would have been proper angle of attack in laminar flow has no lift.

If you want a drag device, split 50 gallon drums would do that. But power output would not be "sick".
 

brandnewb

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excerpt "Using a purely theoretical estimations it was noted that for the case of a lift-driven
VAWT with NACA0015 aerofoils, the rotor would be capable of self-starting if six blades
were utilized to increase solidity [19]."

It's a good thing I already made it possible to have 6 blades ;)
 

brandnewb

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ok I'll try replacing the bearings then with super low friction ones and adding 3 extra blades.

I am not sure I want to keep using this rae 2822. Perhaps just go with naca 0015. this paper gary mentioned is also about naca 0015
 

Hedges

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Manually spin what you've got to get it started. See if changing angle of blade makes it work.
Wrap a rope around a wheel and pull it. Cone shaped wheel to spin faster each turn?

You could attach a drag device, with freewheel, to give it a push until lift takes over and spins it faster.
You could measure wind speed with anemometer, then drive generator as BLDC motor to spin it up to start.

What kind of bearings? Any ball/roller bearings ought to be good enough. E.g. axle bearings.
 

justgary

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A drag device will work, but isn't what you want. Large, heavy, low producing.
The wings could be allowed to rotate orthogonal to the wind while going down wind, to serve as a drag device for high starting torque. Then lock in proper place for lift. But normally VAWT don't do that.

I would guess either you have too much friction, preventing turning. Or, blade shape/angle isn't delivering enough lift. Could be with turbulence at low height, what would have been proper angle of attack in laminar flow has no lift.

If you want a drag device, split 50 gallon drums would do that. But power output would not be "sick".
In reality, a VAWT will never be as efficient as a HAWT anyway. The upwind blades shade the downwind blades and you can't regain the lost power. HAWT blades tend to be more efficient also because the pitch is uniform for the whole rotation.
 

brandnewb

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i realize that VAWT's HAWTs are more efficient. But given my local code constraints they are simply not an option for me :(
Big ones are not allowed and small ones that are allowed have to spin wayyy too fast to output anything useful. it dangerous and loud and one will need alot of them if one aspires to one day go offgrid like I do :(

Nah VAWT it is as code wise I think much is possible and with a lower rpm and less noise better for the local wild like i.e. my wife.

I just hope using lift type blades does not require the damned thing to spin faster than I deem safe. Otherwise drag type is the only sane thing left.
 
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brandnewb

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it's time to scale things up a bit.

I made a 2.4m high x 63cm wide straight anemometer cup drag type blade proof of concept

1663838110069.png

The current column connector is probably not strong enough to deal with this weight and as my bowden tube for the 3d printer needs replacing and I don't have the parts, it will take some time before I can post results.

If I can get it to rotate with 3 blades then I'll try 6 blades as well to see if that improves things.
if so I will add another 2.4m on top and then I just hope we'll have enough torque to spin any alternator ;)

The rpm is going to be low but that is exactly what I am hoping for. The alternator needs to compensate for that and I think we'll be covered in that department.

this is all assuming the these rather large cups will do their job to begin with. fingers crossed
 

brandnewb

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whoooooot!!

It auto startes and it's spinning continuesly while we have almost no wind now at around 1m/s.
it took a force of 2.2KG to stop the rotation when measured at the end of an arm.

1663857371947.png
Damned this turbine is just waiting to collapse ;) it's crooked and another million weak spots.

I have some improvements to make and am going to like every second of it.

Do we still need to do this proney break thing or can we calculate things with this sparse info we have now? If we need prony then I have not found a good DIY source and how to translate the amount of pressure to torque.
 

brandnewb

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I don't think even routing water will work ;( just too much woble.
I realize not all thread holes are with thread and tightened but that won't reduce woble. THe issue is the stock x cariage and the whole 3 wheel system on those ender 3d printers to begin with.

I will give it a try with custard first, see if I can draw a smiley face in it ;)

1663922363848.png

if I can find a laser cutter that can do 5mm of HPL (high pressure laminate) then that would solve a lot of problems if the cutter it self does not weigh too much.
 

curiouscarbon

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... Then there is the art and science of mold flow; lines form when flow splits and rejoins. Matters aesthetically at least for finish surfaces; might affect performance in some way.
ultrasonic shaking device to agitate and encourage bubble buoyancy to float and dissipate 😀
 

justgary

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I don't think even routing water will work ;( just too much woble.
I realize not all thread holes are with thread and tightened but that won't reduce woble. THe issue is the stock x cariage and the whole 3 wheel system on those ender 3d printers to begin with.

I will give it a try with custard first, see if I can draw a smiley face in it ;)

View attachment 113131

if I can find a laser cutter that can do 5mm of HPL (high pressure laminate) then that would solve a lot of problems if the cutter it self does not weigh too much.
Reducing the vertical distance from the carriage to the cutter would help a lot. Even shortening the cutting tool would help. More distance is more lever arm for the force to try to rotate the assembly. Reducing cutting speed is your only other choice so the cutter has less force on it.
 

brandnewb

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Reducing the vertical distance from the carriage to the cutter would help a lot. Even shortening the cutting tool would help. More distance is more lever arm for the force to try to rotate the assembly. Reducing cutting speed is your only other choice so the cutter has less force on it.
Thank you Gary. I am sure to try that one my new revelation turns out not to hold up. I mean who does not like some custard?.... with a smiley face routed in it ;)

Anyway what I found is 2 fold;
*) This shore 72 resin is actually pretty stiff. I just tried again bending this horrendously poured test I did earlier and this time securing the quarter disk in many more places than I did during my first tests. It does still flex ever so slightly but now it took considerably more force while the flex was much less. So it's worth a try this shore 72 resin route
*) especially since I realized the magnets will be equally attracted by coils under load from both sides. Essentially resulting in 0 bending on the disk.

Until someone shoots a hole in this reasoning I am going to focus again on getting a good solid magnet disk. We need some numbers by now ;) Blow up some car lights even with this alternator.
 

brandnewb

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We're gonna need more bricks!
we'll need like 10^99999.... more bricks ;)

So I have an idea. Let's hold it up to scrutiny.

I ram 3 poles into the grass, really deep. 1 at the corner where the turbine stands. and the the other 2, 9 meters away in the other corners at 90 degrees from the turbine location.

something like my below asci art

|__

Connect those poles with 9 meter long beams, ones that do not like to bend.

Now I can make a platform that is not easy to topple over. Let some brutal wind come I would say if I was foolish enough to taunt mother nature.
But yeah, that would eliminate the need for bricks that were there all along as pseudo help.

The test rig with the bearings it self will also need a mayor overhaul. I mean 3 standard wooden 'sticks' with some screws holding the 2 OSB disks together is just not at all able to deal with lateral forces.
Well, that needs some nuance. It actually is to some extend. But not for the long run and with combat conditions in mind.

The issue with guy wires is that I can only connect to the turbine from my house. that makes for 2 guy wires rather than 4 ;(

As always, I am a sponge to suggestions.

BYW guys, all of the above still falls into the prototype phase. once we've settled on on something worthwhile I do not mind investing in more durable implementations. e.g. using actual steel or what ever rather than hap hazard 3d prints like we're doing now.

Yet the most important aspect will remain that it should be easy for anyone to duplicate and that we are not looking for the most efficient what ever.

Nah, just before the bombs are about to fall we need to be able to quickly build a few of those bad boy turbines. Or even stock pile now and make sure one does not need an actual store to get parts.
 
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