VAWT backyard experiements

[MattM]

May consider hanging it on hinges to allow them to twist without destroying the arms.  Gravity will keep them vertical until enough wind tilts them on the hinge.  There will still be some twisting going on but shouldn't be nearly as much torque applied to the arm.  This would be similar to how horizontals have furling to limit forces captured by the device for safety reasons.  Your buckets will need to connect somehow, though, to prevent them from asynchronous oscillations.  If one tilts they all need to be able to tilt simultaneously.

[brandnewb]

Yes Matt!! this is proving harder than expected. Both without a doubt showing that eddy currents are not at play and going oversized.

I will admit that I am not qualified yet going this large of feathers!!

So I will be taking things down a notch just to get a feel for things before I start pushing envelopes again.

As for the eddy currents. Would it be ok if I spin this dual (actually quadrupal) magnet disk for like 1 minute using a hand held drill and then assess the temperature? If no real change then good?

[brandnewb]

But please never let it be said that trail and error is not one of the best ways of advancing.

Here is a sign of what is to come.



Although not really cheap these panels are easy to work with. Can take a beating and also do not care about weather conditions.

The way I installed them they also have a natural self destruct moment that I have no idea yet on how to determine that. But they can just pop out when things get tooo rough.

But maybe i need them to pop out far earlier than in their current configuration. I am thinking yes!

A 4x1 blade is just insanity at this stage of my capabilities.

Even though I am not one to shy away from a challenge I might not take this particular one  if going more containable will also render usable power.

[brandnewb]

I really hope I do not have to be reminding everyone that this project is in dire need of constructive criticism.

If the intend is good then I will not snap. In fact I am known for letting things slide
Let us leave the snapping to cheap cable tensioners that have clearly not been quality controlled

This is not to say that I am without temperament. But only when feeling threatened, or in a more romantic setting, it can become obvious that I am

Luckily I am mostly amongst adults so am not usually exposed to juveniles that can trigger me like that.

So please feel free to give any and all advice one might have and maybe then this bird will take flight in a controlled manner

[MattM]

May want to let her spin around awhile to test her strength.  That way when everything comes together she has been battle-tested like the true Apache spirit.

[Mary B]

Mary did really inspire me when she said "oversize"

I am going to try 4m heigh 1m wide cups.

Just to see things go horribly wrong

Where did I put that kevlar body armour again?

(Attachment Link)

Over BUILD lol aka make things twice as strong as they need to be!

[brandnewb]

13.3 kg for the 4x1m frame alone. I might strap 13 of 1 liter milk cartons on the other end to keep things balanced.

Yes you have guessed it correctly. I am not going down without a fight I am keeping the frames for now yet will not install the wind catching panels yet.

Let it spin for a few days and then slowly I can keep adding panels and see what happens while keeping a birds eye on signs of stress.

Mary did really inspire me when she said "oversize"

I am going to try 4m heigh 1m wide cups.

Just to see things go horribly wrong

Where did I put that kevlar body armour again?

(Attachment Link)

[Bruce S]

"Let it spin for a few days and then slowly I can keep adding panels and see what happens while keeping a birds eye on signs of stress."

With this in mind , and using the 3-blade set up that you posted back on the 15th. Unless you add counter weights, the whole thing will be off balance.

Might be a good idea to put all 3 on and check them often.

In as far as the criticize, I cannot speak for others. I am watching the different changes and waiting for the blades to be attached so we can see how well it operates.
We are rooting for you!!   

Bruce S

[brandnewb]

The bird has spoken.

She does not like to be grounded (tied down). Doing so will result in vibrations only helicopter pilots can tolerate (this is just an assumption I make as I know nothing of helicopters. I certainly never been in one let alone also actually flown one. I just keep the entertainment of the reader in mind when I write. Only keeping it to dry facts tends to make for, albeit important and valuable, less engaging reading material).

Anyway I have noticed after a few experiments with alu arms on or off / filled or not, and variations on that concept that birds do not like to be grounded. Especially The Phoenix (or is it Pheonix?) does not like that. And she will make it known with intimidating warning signs mind you!!!!!

So with feathers (the blades) or not I will just keep her free to rotate for now until I have more experience to help develop intuitions.

{1}So with only alu c channels things will vibrate like crazy even when free to rotate. With the spruce wood vibrations are soo much less! Yet even with spruce wood when grounding the bird again things are getting scary again. Most likely due to the ties (those bright orange ones) used are catching too much wind. In fact I think I can see them oscillate either at the same frequency or at an harmonic to that of the arms. It all so early to be able to know for sure. But resonance seems for real the birds greatest enemy.

* Kghh Come in Apache I
* Kghh Apache I reporting for duty.
* Kghh Set your full arsenal to eliminate "resonance" fire at will
* Kghh Roger!
--


-

-* Kghh Target acquired!! Going at it!!

{1}

[brandnewb]

One thing I already to think I need to change is the central column.

I just do not know with what yet.

As per usual please shoot if one has a suggestion.

To help one help me the problem is that the steel column is just too flexible. I believe it to be an American dimensioned tube. 48.3mm diam by 2.8mm wall thickness. I guess that translates to 1 1/2 inch diam?

Other than the dimensions not being fit for purpose I am not subliminally suggesting that there is anything wrong with American steel!! Steel is steel after all. Sure with many variations in composition but those variations are available anywhere.

[brandnewb]

strike that please.

I just have gotten a far  better idea. Also looking to how the final version of this majestic bird should look like.

Why don't I kill 2 lesser birds with 1 stone

Rather than replacing the central column Why do not I build some body armour on it. Something similar I use now for the guy wires but then directly attached as it is free to rotate and far taller. from the center up and down wards.

I am thinking of wood like I have now. But which type I do not know. Please advice.

It will also motivate me like never before to finally get this cnc machine and start upgrading my abilities.
With the cnc machine I would like to carfe drawings like a tatoo artist of related images. Of course The Pheonix will be one of them.

I have in my sphere of acquaintances an actual tattoo artist that I can make an offer he can't refuse

So please all advice. Which type of wood and how to orient it ?

[Mary B]

Plywood gussets halfway up the column. Cut a half sheet of plywood diagonally then attach to the center with steel angles(attach angles then the plywood) You have to make flex where it joins the base. The arms should have been rectangular aluminum not C channel that twists really easy!

[MattM]

To help one help me the problem is that the steel column is just too flexible. I believe it to be an American dimensioned tube. 48.3mm diam by 2.8mm wall thickness. I guess that translates to 1 1/2 inch diam?.

Perhaps your inner diamer is 37-38mm.  That would be the correct diameter for 1.5" pipe.  Tube and pipe measure differently.

[brandnewb]

Plywood gussets halfway up the column. Cut a half sheet of plywood diagonally then attach to the center with steel angles(attach angles then the plywood) You have to make flex where it joins the base. The arms should have been rectangular aluminum not C channel that twists really easy!

I am actually rather serious about a giant cnc router table.

I was thinking to buy a few huge special extremely fit for purpose wooden logs and machine them into a work of art that also serves as a retainer.

Or if we are still talking practicality then I am also still interested to learn what you meant. But then I am just not sure how you meant the implementation. perhaps a rough scetch might help?

[Mary B]

Attach angle iron to central column and legs with bolts, cut right triangle pieces of 1" plywood and bolt to those pieces of angle iron. Angle iron will add stiffness, plywood will add a LOT more!

[brandnewb]

Perhaps your inner diamer is 37-38mm.  That would be the correct diameter for 1.5" pipe.  Tube and pipe measure differently.

Here I go again making blunders.

I found the official definition of the column

1 1/2" (48.3 x 2.9 MM)

But because of the corrosion on it I can no longer make accurate measurements.

When doing my own translation between imperial and metric I find there to be a mismatch between how the column was sold and how my best attempt at making accurate measurements seem to be.

Yet please let us please not spend more than 2 days of interwoven thought about it. After all this is just a road bumb, not a road block.

[brandnewb]

hahhah the western storm is staring to kick in.

I have gotten 11.3 m/s so far.

Please do not worry. I have taken down the bones (arms) because I saw this storm coming.

I just went out and touched the central column and the guy wire that is most responsible for keeping the column up based on the direction of the wind and which guy wire will do most of the retaining.

Sure there are vibrations but sooo little that I still can not believe that with proper design (I certainly can NOT do it yet/if ever) there can be a structure that one can place on roofs.

[MattM]

48.3mm matches Schedule 80 pipe.  It should be easy to find the engineered limits of those pipes because its so well specific and defined.

https://riggit.com/wp-content/uploads/2019/12/RGT-PipeLoadTable_80Steel_2019.pdf

[Bruce S]

Perhaps your inner diamer is 37-38mm.  That would be the correct diameter for 1.5" pipe.  Tube and pipe measure differently.

Here I go again making blunders.

I found the official definition of the column

1 1/2" (48.3 x 2.9 MM)

But because of the corrosion on it I can no longer make accurate measurements.

When doing my own translation between imperial and metric I find there to be a mismatch between how the column was sold and how my best attempt at making accurate measurements seem to be.

Yet please let us please not spend more than 2 days of interwoven thought about it. After all this is just a road bumb, not a road block.

I wouldn't worry too much about translating from Metric to imperial.
We can easily google it 

Cheers
Bruce S

[brandnewb]

yes!!!!!!!!!!
back on track!!!!!!!!!!

I am killing so many (lesser ) birds with one stone hopefully.

You see there is nothing wrong with this pipe column I have. In fact it is a blessing in disguise.

Because of the flex it had it started a whirlwind in my mind of what to do. Earlier we have been talking about the body armor doubling as art work.

But what if we just cut 1m of the pipe. {1}because then the bending will be much less{1} (already did that but no photo yet). And simply remove the wooden feet beams as the structure is technically no longer free standing anyway.

Sure one could argue "Well that is a waste of money" But i would counter that that is the nature of prototyping. And think of the cost savings it will have on the Bill Of Materials on the final version! hmm that is assuming there will ever be a final version ;(

The guy wires will be staked to the ground for now. But believe you me that I will hopefully find some neutron star material that I can put as a base for the guy wires. Then technically it will be free standing again

And think of all the less issues with the arms when they are closer to the ground!! {2}I just remembered that turbulence is the greatest enemy of the arms, not wind speed which was my reasoning{3}amongst others{3} to go for lowering them{2}

More to follow because a picture says a thousand words.

[brandnewb]

The c channels have a 100mm height, a 50mm width and a thickness of 5mm. On paper this looked sturdy to me but in the field these less than fit for purpose channels like to vibrate.

They are sold as U profiles but that is like potatoes and potatoes!

Aluminium U-profiel 50 x 100 x 50 x 5 MM 6060 T6


So I will no longer be using them as wind catchers. They are now upgraded  (or reduced depending on ones angle of perception) to rectangles. {1}By means of taping duct tape around them{1}

I really do not believe we are going to need any additional wind catching abilities when things start spinning for real. {2}If for one thing only then bringing down the weather station down from the roof to the yard did make me less nervous as I have not seen any 19+ m/s yet. But 11+m/s is also not something I am looking forward to to be honest. So sooner or later a self destruct moment, that is planned for and therefor safe, needs to be build in. I will make sure I do{2}

But we will cross that bridge when we get there.

My mistake on the picture.  I could have sworn the weather station flipped sides.  It may be your pictures taken from different angles disoriented my perspective.  I will whip up a picture soon.  Really its simpler than it sounds.

[brandnewb]

Yesss, I think you have cracked the code!!

Now tell me how many more data breaches are you responsible for hahhahh

48.3mm matches Schedule 80 pipe.  It should be easy to find the engineered limits of those pipes because its so well specific and defined.

https://riggit.com/wp-content/uploads/2019/12/RGT-PipeLoadTable_80Steel_2019.pdf

[MattM]

If you need the wooden arms longer then you can shift the pivot hole over.  Just have to make sure all three have balance.

I fear that 1.5" pipe is a real liability.  Your last 150-200mm is unbraced and plenty long enough to flex under merciless wind loads.  Do you have access to any thicker pipe?  You can always weld a flat plate to the top of a bigger pipe and tack a small section of your smaller pipe to it to recycle whatever bearing system you already have.  Could even build a sleeve around the existing pipe and fill it with concrete to give it all the load bearing you could throw in it.   But you want mobility so concrete is out. Wood done right should be able to do it.  Something sturdy to keep the end from oscillating.  It needs to be much stronger to handle all the forces.  S-cracks can happen under torque loads.  What may calculate strong enough to handle in the vertical and horizontal planes can absolutely self destructs under torque loads.

[brandnewb]

I do not have any other pipes or tubes in the garage. Yeah sure. PVC sewage pipes I have laying around still but I am guessing let's not start using that hahah

But if I can wait for the delivery time then I can buy pretty much anything that is sold. Also business to business vendors only I can tap into so that means large scale construction project type of things.

But I would prefer to keep it consumer based. It brings added securities and in general less potential hassle. {3}And lets not forget the likeliness that one can also build something similar. I mean if I were to introduce highly specialized things to this build then that basically makes this project only meant to serve my power needs, yet completely forgoes on the humanitarian aspect of this project{3}

But I have been eye balling to go aluminum for some time now. And 'only' a 10 day delivery time.

Their largest size is
diam. 100 x wall 5 MM 6060 T6

the weight increase over the current pipe per meter would be around 1 kg. But since we are now only talking a length of 2m rather than the original 3 that increase is still within the limits of the taper roller bearing. (I must stress though that this assertion is gut feeling based and not on basis of actual technical listed properties)

You know what? As I am closing my thoughts and about to hit the post button I realize that I know far too little at this stage to start buying extra material again.
But I will leave the thought process above here anyway.

I think I had better repurpose the wooden feet beams first as body armor and get this top arm holder to not move anymore. I think then we have a better position to assess the weak points that are left and how to address them.
{1}hahah not all of the wooden feet beams of course are needed for the body armor. I am still looking to keep the load bearing structure and the retaining  (the parts, like guy wires, used to keep the load bearing structure upright) structure as little wind catching as possible {1}
{2} and that is an example of what keeps me from jumping straight to the 100mm alu pipe I mentioned here. I just do not know the added load it will bring on the retaining structure. Now I would be happy if Mary would give some fast and loose pointers on how to calculate that but I would also fully understand if there are just too many tiny factors at play here that field testing is the only way to know for sure{2}

[brandnewb]

hahahha Mary!!!!

Guess what I found, for purchase, in the mean time. In the process of getting the arm holder plate to not wiggle anymore.

Yes you have guessed it!!

JB Weld

I will first try a thin steel sheet though. wrapped around the pipe as to make the fit closer to the component responsible for holding the arms. See how far that aids in stability.

Otherwise I am considering filling the gaps all up with JB weld (after careful preparation of all surfaces involved)

I love it when a plan comes together "famous quotes. RIP George Peppard aka Lieutenant Colonel John "Hannibal" Smith. The A Team"

{1}One might wonder why not welding. Well I can weld sure. But the quality would be bad and I know very little about how to do it properly. Also the weld would be only on the outer perimeter. I strive for a bond that is everywhere{1}

[MattM]

So with shorter arms are you going 6 buckets then?

[brandnewb]

Sorry for the confusion I have caused. I meant to say that I have taped up the alu C channels to make them rectangles. And they are going back into place like before. But this time they are less likely to vibrate like crazy. Especially with weight on them and under tension.
So the diameter will remain 6 meter. But the height of the arms is reduced from around 325 cm to around 205cm.

I am thinking I need to make the blades go up rather than down. But this is just one iteration of a few to follow I think. I mean it is unlikely I find something I trust this early in the build cycle.

Adding buckets is indeed something that crossed my mind but as far as I understand it it will only decrease the rotational speed yet not increase any efficiency. I could have misunderstood though.

{1}One thing I am also considering is integrating the c channels into the wood by using a router to cut out channels in the wood and snugly slide in the alu. Because I really am looking to keep the profile of the arms as slim as possible.

I will give a photo update tomorrow maybe more likely wednessday. As my wife does not like me in the garden or garage these holidays.

Happy xmas for those that do it
{1}

So with shorter arms are you going 6 buckets then?

[Mary B]

hahahha Mary!!!!

Guess what I found, for purchase, in the mean time. In the process of getting the arm holder plate to not wiggle anymore.

Yes you have guessed it!!

JB Weld

I will first try a thin steel sheet though. wrapped around the pipe as to make the fit closer to the component responsible for holding the arms. See how far that aids in stability.

Otherwise I am considering filling the gaps all up with JB weld (after careful preparation of all surfaces involved)

I love it when a plan comes together "famous quotes. RIP George Peppard aka Lieutenant Colonel John "Hannibal" Smith. The A Team"

{1}One might wonder why not welding. Well I can weld sure. But the quality would be bad and I know very little about how to do it properly. Also the weld would be only on the outer perimeter. I strive for a bond that is everywhere{1}

JB weld is permanent... takes a torch to soften it to get stuff apart... The 100mm(4" give or take) 1/2 inch wall(5mm give or take) AL is going to be a LOT stiffer than what you have now... to bad you aren't closer, I have an 8" diameter 1/4 inch wall 6061T6 piece of tubing in the garage. Has a couple holes from when it was a telescope pier...

[brandnewb]

Ok Before I move to 100mm alu for the central column.

I want to learn more on how to also work with what I have.

Please see, although I was unable to get there before dark, what is the intent.



So no more feet as the structure is not free standing anyway. (I will get back to this believe you me )

The column is less tall, now around 2m height.

The arm holder is closer to the column retainer (the part where the guy wires attach to)

The column retainer bearings have now a closer fit to the column.

All in all I now think I am ready to give it another try and see where things need to be improved for the next iteration.

Btw Matt, I kind of like your idea of sleeving with concrete. I mean I am probably able to move around freely objects that weight like 100 maybe 125  KG at max around.
So I am not ruling your suggestion out just yet.

On the other hand. Introducing weight is making adoption less likely.

When one has to cary by one selfs then I think 20 kg is the adviced limit is not it? I mean otherwise there would be bags of cement available far over 20 kg.

But at this stage first I want to see results before I start prioritising weight.

[brandnewb]

ugg

there is less flex indeed but not enough for me to start trusting things when the wind picks up again.

In an effort keeping the central column as slim as possible I can consider a rod rather than a pipe yet similar dimensions?

Or what about filling this pipe with concrete rather than sleeving?

I already tested 2 component foam material that turns crazy hard to see if it is a candidate for filling the column but it snaps too readily. I think for airfoils that material is still a contender but not for filling a column.

I will also reduce the blade height by 1 meter. I have tried 4m high blades but I just do not trust it. I give up (for now) on that idea yet one can't say I went down without a fight

I will share some more progress once the reduced blades are installed and things are spinning neatly.

[brandnewb]

I found this alternative in the meantime;

Aluminium round 45 MM 6082 T6

It is a solid and will weigh, even though alu, 4,33 kg/m. I almost can not believe this is a solid though. hmm whatever I am just throwing it out here so that perhaps those more experienced with alu can object now or forever hold their peace (you see how I try and sneak in little dramatic references. Perhaps {1}not perhaps, that is what I would like{1}  my true calling in life is being a writer.)

I can print with ease adapters that I trust to keep things together because of the slight dimensional change.

[brandnewb]

please see the bird ready to rotate even without feathers.



wind speed varies between 1 and 2 m/s

[brandnewb]

hahha Yes Matt

Your eyes are still good

The weather station moved again.

I will keep moving there were the wind is coming from.