Author Topic: H-Darreius wind turbines ( VAWT ) ! (Read 78111 times)

electrondady1 · « **Reply #132 on:** April 19, 2021, 09:26:10 AM »

harnessing the wind .
oh yea, that's so easy .
ha ha ha
$:-\$

topspeed · « **Reply #133 on:** April 21, 2021, 02:45:56 AM »

What is intriguing is the fact that if I increase the rpms and make better aerodynamics that allow higher rpms....the g-forces become stupendous...especially if the generator fails or is not on. Stress loads on the wings are beyond any chart where they ought to withstand them stresses.

I guess this is the risk I have to take.

SparWeb · « **Reply #134 on:** April 22, 2021, 12:22:09 AM »

Stress goes up with RPM squared. Gotta love it!

topspeed · « **Reply #135 on:** April 22, 2021, 10:24:39 AM »

Quote from: electrondady1 on September 04, 2020, 07:53:08 AM

you can do a lot with a table saw.

Makes a helluva noise.

topspeed · « **Reply #136 on:** May 14, 2021, 07:01:38 AM »

This is the way I lengthen the legs by ½ a meter.

E1000 · « **Reply #137 on:** May 17, 2021, 04:33:52 PM »

Quote from: topspeed on April 21, 2021, 02:45:56 AM

What is intriguing is the fact that if I increase the rpms and make better aerodynamics that allow higher rpms....the g-forces become stupendous...especially if the generator fails or is not on. Stress loads on the wings are beyond any chart where they ought to withstand them stresses.

I guess this is the risk I have to take.

I remember reading you had this VAWT up to 900RPMs or something like that? Why are you trying to get such high RPM? More RPM = less efficient, more drag, more friction, etc. You want RPM to be as low as possible to extract maximum energy from the wind.

For instance the Department of Energy tested VAWTs in the 80s and their systems ran between 15 and 35 RPM maximum. 35 RPM not 900+!

You VAWT can only light up a halogen lightbulb at these high RPMs. Have you actually tried to pull a real load from this VAWT and try to charge a battery or something? Very cool project you know, just....don't understand the point.

topspeed · « **Reply #138 on:** May 18, 2021, 09:16:28 AM »

Yes hello E1000 !

My vawt is a really small unit with just 300 watt capability.

I am not aiming at 900 rpm...it just happened with the smaller system displaying different proportions.

I am still learning...solidity was wrong on SN3...thus I need to make SN4.

There went really many things hayward on SN3 at high winds. I needed to digest all the info over the winter.

There are many features in this VAWT which could make it a winner....if I get the proportions and manufacturing quality in to par.

I just cleaned the work shop....and prepared new generator to be ready to assemble in the system.

I had 2 wisdom tooth removed and had to take penicillium....and now getting my vitality back.

I just have to pray that no new nasty phenomena would appear while testing.....I am starting to be pretty broke by then......if not already.

Absolute low has been to get stuck in the sand in the Island where there are good winds always.

topspeed · « **Reply #139 on:** May 20, 2021, 12:10:17 PM »

Quote from: Mary B on April 18, 2021, 01:25:38 PM

"Failure is the mother of all invention!"

Have to fail before you fly!

Yes yes yes !

I just don't wanna fail very many times.

Someone here said my foil is a failure...I think I agree now.

I did some work with XFLR-5 to mend it.

Usually only foil you see in VAWT is NACA 0012.

Fire away and tell is it still better than this displayed in polars.

I see it has an advantage still in some areas.

electrondady1 · « **Reply #140 on:** May 21, 2021, 08:38:16 AM »

you can do a lot with a table saw

GOE222_2X6.pdf (24.74 kB - downloaded 224 times.)

topspeed · « **Reply #141 on:** May 21, 2021, 10:42:59 AM »

Quote from: electrondady1 on May 21, 2021, 08:38:16 AM

you can do a lot with a table saw
(Attachment Link)

I HAVE HAULED 3 THICKNESS OF PLYWOOD AND 650 GRAMS OF BOLTS AND NUTS and HALF A CUBIC METER OF STYROFOAM TO MY WORK SHOP.

Sorry caps lock !

My foils is not like GOE displayed. But I do dare to say it rocks ( if XFLR-5 is not broken ) !

E1000 · « **Reply #142 on:** May 21, 2021, 12:16:00 PM »

Quote from: topspeed on May 20, 2021, 12:10:17 PM

Usually only foil you see in VAWT is NACA 0012.

Fire away and tell is it still better than this displayed in polars.

I see it has an advantage still in some areas.

(Attachment Link)

Actually, the US National Renewable Energy Laboratory did extensive testing and found the Somers S824 was the most efficient airfoil to use on their multiple different VAWTs.

topspeed · « **Reply #143 on:** May 21, 2021, 01:10:05 PM »

Quote from: E1000 on May 21, 2021, 12:16:00 PM

Quote from: topspeed on May 20, 2021, 12:10:17 PM
Usually only foil you see in VAWT is NACA 0012.

Fire away and tell is it still better than this displayed in polars.

I see it has an advantage still in some areas.

(Attachment Link)
Actually, the US National Renewable Energy Laboratory did extensive testing and found the Somers S824 was the most efficient airfoil to use on their multiple different VAWTs.

Cool...I have to check it out. Thanks ! :

-----

Interesting thing: https://www.researchgate.net/profile/W-Sheng/publication/29816886_Applications_of_Low-Speed_Dynamic-Stall_Model_to_the_NREL_Airfoils/links/00b495363babd11a75000000/Applications-of-Low-Speed-Dynamic-Stall-Model-to-the-NREL-Airfoils.pdf

E1000 · « **Reply #144 on:** May 21, 2021, 01:44:09 PM »

If you want to build a good VAWT the attached document is required reading: energy.sandia.gov/wp-content/gallery/uploads/SAND2012-0304.pdf

Dyamic stall is how you keep your VAWT from tearing itself apart

topspeed · « **Reply #145 on:** May 22, 2021, 01:58:08 AM »

Quote from: E1000 on May 21, 2021, 01:44:09 PM

If you want to build a good VAWT the attached document is required reading: energy.sandia.gov/wp-content/gallery/uploads/SAND2012-0304.pdf

Dyamic stall is how you keep your VAWT from tearing itself apart

Yes stall is very viciuos if not treated right in a VAWT.

My VAWT is more related to the McDonnell Aircraft design (of 1980) than Sandia types of non-articulating VAWTs.

E1000 · « **Reply #146 on:** May 23, 2021, 10:37:31 AM »

Quote from: topspeed on May 22, 2021, 01:58:08 AM

Yes stall is very viciuos if not treated right in a VAWT.

My VAWT is more related to the McDonnell Aircraft design (of 1980) than Sandia types of non-articulating VAWTs.

Yep and the McDonnell Douglas VAWT was a commercial failure and the Sandia designs are not. The document explains that straight blade VAWTs like yours need to be excessively heavy because of the forces. A VAWT like the Sandia types can be made exceptionally lightweight because the blades can be loaded in tension and they naturally stall before ripping themselves to shreads.

Your VAWT is not making much power and it keeps shredding itself to pieces. I thought maybe you'd be interested in solving those problems...

topspeed · « **Reply #147 on:** May 23, 2021, 11:40:34 AM »

Quote from: E1000 on May 23, 2021, 10:37:31 AM

Quote from: topspeed on May 22, 2021, 01:58:08 AM
Yes stall is very viciuos if not treated right in a VAWT.

My VAWT is more related to the McDonnell Aircraft design (of 1980) than Sandia types of non-articulating VAWTs.
Yep and the McDonnell Douglas VAWT was a commercial failure and the Sandia designs are not. The document explains that straight blade VAWTs like yours need to be excessively heavy because of the forces. A VAWT like the Sandia types can be made exceptionally lightweight because the blades can be loaded in tension and they naturally stall before ripping themselves to shreads.

Your VAWT is not making much power and it keeps shredding itself to pieces. I thought maybe you'd be interested in solving those problems...

I am very interested solving my problems...and I have been doing it all day even today.

Sandia is not articulating.

It is true that many articulating ones have failed ( or did they ? )...Pinson, Bühler ( Roman ) ...etc, but ANEW in Poland took another road and claims are stupendous.

Why McDonnell did not carry on is a mystery..they had funding for another 4 years in 1982. Oil Crisis ended....and their system was very promising albeit not quite ready in 1980....maybe a bit too complicated.

Bruce S · « **Reply #148 on:** May 24, 2021, 08:47:45 AM »

Quote from: E1000 on May 23, 2021, 10:37:31 AM

Quote from: topspeed on May 22, 2021, 01:58:08 AM
Yes stall is very viciuos if not treated right in a VAWT.

My VAWT is more related to the McDonnell Aircraft design (of 1980) than Sandia types of non-articulating VAWTs.
Yep and the McDonnell Douglas VAWT was a commercial failure and the Sandia designs are not. The document explains that straight blade VAWTs like yours need to be excessively heavy because of the forces. A VAWT like the Sandia types can be made exceptionally lightweight because the blades can be loaded in tension and they naturally stall before ripping themselves to shreads.

Your VAWT is not making much power and it keeps shredding itself to pieces. I thought maybe you'd be interested in solving those problems...

Begin Moderator MODE

E1000:
Instead of criticizing Topspeed's efforts and each answer from Topspeed; how about you show what you've built and explain why.
I've watched this thread for a bit now and TopSpeed is both building and learning.
ALL I've seen from your posts is criticism. SO instead of constantly saying why this won't work or here's what you did wrong . Show what you've done, which would to include details.

You're not yet at the number of posts that will allow you to post pictures , BUT anyone of the Moderators or Admins can assist with them if they are relevant to this post.

I also highly suggest you go to the very beginning of his posts on this and read them so you can have a better understanding of what he's doing, learning and accomplishing. Before you send another criticizing post.

End Moderator Mode

Bruce S

topspeed · « **Reply #149 on:** May 30, 2021, 01:32:32 AM »

Yes thanks Bruce...learning curve has to be pretty steep...otherwise you'll "die" in business sense.

I checked my SOLIDITY on my recent tests seems that the hot system had .4 and this latter .49....so .49 was too much.....where as .40 was really phenomenal.

This is also verified by the literature.

https://www.sciencedirect.com/science/article/pii/S0360544218319704 .......link explains nc/d = .36 as a good in gaining high Cp.

Where as some even mention solidity of 1 to be ok ?

https://www.hindawi.com/journals/isrn/2012/528418/

Some even cannot count the solidity like others do: https://eprints.whiterose.ac.uk/95454/5/Revised_manuscript-R3_for%20Upload.pdf

But when deciphred it in indicates solidity of 0.52....which is way over the top.

All this also explains why McDonnell Aircraft Giromill failed.

https://wes.copernicus.org/preprints/wes-2019-98/wes-2019-98.pdf

It had solidity of 0,2 only.

topspeed · « **Reply #150 on:** July 29, 2021, 04:33:00 AM »

Hello everyone !

I give a brief update on the advancement of my 2 wing darreius type pitch controlled system.

The structure connecting the wings is almost ready. It is almost 1 metre wider ( longer ) than the previous had with similar generator. This has been a bit stressful since the bending was much more than I expected in the system. I had to reincorporate the wood composite that I had developed 2016 into it and some V-shaped struts from aluminium to keep the loads and stresses in a limit. The bending as such is not a problem, but the mechanism cannot work if there is too much of it. All this is learning by doing...certainly ( almost ) avoidable if you have a good enough structural engineer on it.....but the bending is also visible on aeroplane wings....before and during the flight...main thing is that it is firm in all winds and speeds....and is smooth and light(ish ?).

Now a challenge is two make the 2 wings light ( and yet strong ) enough that the bending does not become an issue.

Hope you all have had a good summer.

MattM · « **Reply #151 on:** July 29, 2021, 12:57:23 PM »

I'm excited to see a video of it!

SparWeb · « **Reply #152 on:** July 30, 2021, 12:16:34 AM »

The best part is the fun you're having. Thanks for sharing.
If bending's a problem, have you considered a diagonal brace?

topspeed · « **Reply #153 on:** August 03, 2021, 10:27:53 AM »

Quote from: SparWeb on July 30, 2021, 12:16:34 AM

The best part is the fun you're having. Thanks for sharing.
If bending's a problem, have you considered a diagonal brace?

I have used 3 innovations ( ~means ) to address the issue. Diagonal braces ( struts ) ....wood composite ( 1400 kg/m^3 ) and last but not least a pre stressed system....which allowed to get rid of the bending now once and for all.

Yellow stuff is wood composite (compreg).

At least you get use many tools in this.

SparWeb · « **Reply #154 on:** August 05, 2021, 08:45:56 PM »

I like the shine in the wood finish!

topspeed · « **Reply #155 on:** August 09, 2021, 10:47:04 AM »

Quote from: SparWeb on August 05, 2021, 08:45:56 PM

I like the shine in the wood finish!

How about the shine on "refurbished" old wings without winglets ?

They look raw...as I did not paint them again...I am getting rid of extra weight to make it happen.

New wings will take weeks to build.

I hope to get shiny glass like surface on this...so it glides effortlessly in the wind.

SparWeb · « **Reply #156 on:** August 09, 2021, 11:12:34 PM »

Haha.
Perhaps a more reasonable point of view is to get it working first, then make it pretty later.

Not all of us do it that way around...

topspeed · « **Reply #157 on:** August 10, 2021, 03:46:49 AM »

Quote from: SparWeb on August 09, 2021, 11:12:34 PM

Haha.
Perhaps a more reasonable point of view is to get it working first, then make it pretty later.

Not all of us do it that way around...

Yes...as one confronts a phenomena and tries to solve a problem within...the main facts start to appear in your head and everything you do is just to trying to make it work in reasonable time frame.

I really like the shine on this.

topspeed · « **Reply #158 on:** August 29, 2021, 11:04:24 AM »

I also started to do another set of high wind wings for it.

Instead of 12 % thick I decided to go to 14 % thick...here are the polars of it...on green color.

Also very high lift with minimal drag.

topspeed · « **Reply #159 on:** September 13, 2021, 01:04:20 AM »

Router makes neat foils.

Vestas's public speeker Rosie tells us about VAWTs.

https://www.youtube.com/watch?v=ldt405jIR0E

topspeed · « **Reply #160 on:** October 19, 2021, 02:25:58 AM »

Using a laser cutter would have speeded up this enough, but as it is....I have been using grinder with table saw blade on these...to get the spars into the right place.

topspeed · « **Reply #161 on:** October 19, 2021, 02:27:30 AM »

Quote from: topspeed on October 19, 2021, 02:25:58 AM

Using a laser cutter would have speeded up this enough, but as it is....I have been using grinder with table saw blade on these...to get the spars into the right place.

(Attachment Link)

There is also a jig redied for the wing assembly.

SparWeb · « **Reply #162 on:** October 20, 2021, 02:27:38 PM »

Looks good.
IMHO, good work and smooth surfaces get you mich more than any airfoil shape, at the WT scale - especially rhe VAWT scale.

topspeed · « **Reply #163 on:** November 12, 2021, 09:03:45 AM »

Thanks Spar Web,

Some more progress.

Here is a status of today.

Older yellow wing is visible on the background.

Monent arms are also now 50 cm ( 1 m together ) longer than before.

topspeed · « **Reply #164 on:** November 19, 2021, 10:35:23 AM »

Modest advancement.

News:

Author Topic: H-Darreius wind turbines ( VAWT ) ! (Read 78111 times)