H-Darreius wind turbines ( VAWT ) !

[topspeed]

If the drill is 500 watts output....and I use my box to measure out put of the generator ...is this useless ?

[Adriaan Kragten]

Ahh! Makes sense now, I can see the reason for the square cutout in the ribs. Was wondering why they were there.

Yes...this cuts down the tower drag about 95%.

(Attachment Link)

One has to be alert what area is used if drag coefficients are compared for different geometries. For a real drag body like a sphere, an angle iron or a car, one takes the area of the body perpendicular to the wind. For an airfoil, one takes the product of the airfoil chord times the airfoil width. This product is much larger than area of the airfoil perpendicular to the wind because the airfoil chord is much larger than the airfoil thickness. Airfoils therefore have very low drag coefficients if compared to drag coefficients of real drag bodies but this is partly because for an airfoil, a much larger area is used when the drag coefficient is calculated from the measured drag. The drag coefficient for an airfoil is defined in formula 3.2 of my public report KD 35.

[topspeed]

Ahh! Makes sense now, I can see the reason for the square cutout in the ribs. Was wondering why they were there.

Yes...this cuts down the tower drag about 95%.

(Attachment Link)

One has to be alert what area is used if drag coefficients are compared for different geometries. For a real drag body like a sphere, an angle iron or a car, one takes the area of the body perpendicular to the wind. For an airfoil, one takes the product of the airfoil chord times the airfoil width. This product is much larger than area of the airfoil perpendicular to the wind because the airfoil chord is much larger than the airfoil thickness. Airfoils therefore have very low drag coefficients if compared to drag coefficients of real drag bodies but this is partly because for an airfoil, a much larger area is used when the drag coefficient is calculated from the measured drag. The drag coefficient for an airfoil is defined in formula 3.2 of my public report KD 35.

I have perfect proportions on this according to Hoerner...1:3.7 ( 27% thick ).

[SparWeb]

according to Hoerner...1:3.7 ( 27% thick ).

Now THAT'S an excellent reference for your work!
https://hoernerfluiddynamics.com/

[Adriaan Kragten]

Ahh! Makes sense now, I can see the reason for the square cutout in the ribs. Was wondering why they were there.

Yes...this cuts down the tower drag about 95%.

(Attachment Link)

I have perfect proportions on this according to Hoerner...1:3.7 ( 27% thick ).

(Attachment Link)

A thickness of 27 % of the chord is very large. The drag coefficient of an airfoil normally increases with the airfoil thickness but it also depends very much on the Reynolds number. If you have used this airfoil to cover the tower pipe, the drag will certainly be lower than that of a pipe and there will be much less turbulence which destroys the flow around the blade when it is at the back side. But if you use such a thick airfoil for the rotor blades, you have to calculate the Reynolds number at moderate wind speeds and check the Cd/Cl curve of the airfoil for this Reynolds number to see if the Cd/Cl ratio is low enough.

[bwprototyping]

You mentioned a while that you are being secretive about location because you haven't patented it yet? What is there to patent? Doesn't really seem like anything that is that novel

I would definitely advise against patenting.. For private inventors it just doesn't seem worth it. And at the end of the day, if you get your patent, are you prepared to defend it? The money needed to make a patent is nothing compared to what you'll dish out trying to chase down anyone who infringes! (If it really is that amazing    )

Nice build though! I have always been so intrigued by VAWT's!!

[topspeed]

There are about 12 new innovations in this.

That tower fairing is one....here is another one.

[topspeed]

These wheels are for being able to mount the moment arm that connects the wings inside for testing...without damaging the links !

[topspeed]

Additional 3 lamp console for this H-Darrieus.

[topspeed]

Possible fire hazard has been avoided like this !



Situation on the leg will provide light reflections from the rotating wings.

[topspeed]

I am using XFLR-5 CAD program to see some situations in my VAWT wing....are these generally trustworthy ?

http://www.xflr5.tech/xflr5.htm

[SparWeb]

Meh:
http://www.xflr5.tech/docs/Part%20IV:%20Limitations.pdf

If you enjoy experimenting with it, and learning as you go, then great. 
It's not a real answer for any calculation you give it, though.
It's most accurate if your wing is a perfectly flat plane.  If you have an airfoil, it's only an approximation.  The more thickness and camber, the poorer the approximation.

Yes, that "5.436" would give me pause, too.

The advantages to perfect airfoil selection will be very difficult to measure.  Won't be obvious unless you build two complete sets of blades and measure performance from them both.  With fluctuating wind, the difference will vanish in the scatter of the data you collect. 

Just get the angle of attack right, and a smooth surface, a fair rounding to the leading edge, and a sharp trailing edge.

My HAWT blades are pulling in a CP of about 50% +/- 10% with an approximate NACA airfoil.  I really don't care about the remaining 9% enough to make another set with another airfoil on the speculation that it will improve anything within my ability to measure.

[topspeed]

Meh:
http://www.xflr5.tech/docs/Part%20IV:%20Limitations.pdf

If you enjoy experimenting with it, and learning as you go, then great. 
It's not a real answer for any calculation you give it, though.
It's most accurate if your wing is a perfectly flat plane.  If you have an airfoil, it's only an approximation.  The more thickness and camber, the poorer the approximation.

Yes, that "5.436" would give me pause, too.

The advantages to perfect airfoil selection will be very difficult to measure.  Won't be obvious unless you build two complete sets of blades and measure performance from them both.  With fluctuating wind, the difference will vanish in the scatter of the data you collect. 

Just get the angle of attack right, and a smooth surface, a fair rounding to the leading edge, and a sharp trailing edge.

My HAWT blades are pulling in a CP of about 50% +/- 10% with an approximate NACA airfoil.  I really don't care about the remaining 9% enough to make another set with another airfoil on the speculation that it will improve anything within my ability to measure.

Yes.....two sets of blades would do it.

Someone told me the number above counts only if the wing kept on going at M 0,2 at that high AOA. That never happens.

[topspeed]

Interesting small turbine electrical data: https://www.youtube.com/watch?v=r-cmCHEhN3k

Fuses are in the AC cables...neat !

[topspeed]

Wings are taking shape.   

[topspeed]

Merry Christmas everyone !

I am slightly farther now...as for the first time I attacheded the wing on the lever arm yesterday with my daughter.





New winglets took 4 days to make and finish. I had to invent a new tool for them.

[topspeed]

What do you think of these winglets/endplates ?

[MattM]

Everything you've done looks like high quality.

[topspeed]

Merci beaucoup Matt ! 

[topspeed]

Here is a pitch control mechanism like Pinson and Roman Buhler had on theirs.

Vane based timing: https://iopscience.iop.org/article/10.1088/1742-6596/524/1/012055/pdf

How many have tried that ?

[SparWeb]

The US DOE has:  https://www.osti.gov/biblio/6046045
https://wind.nrel.gov/public/library/SERI_TP-35-263.pdf

[topspeed]

Loks like the McDonnell Aircraft Giromill fronm 1978.

[bigrockcandymountain]

Are you an aircraft homebuilder by chance? All of your worksmanship looks very high quality and homebuilt aircraft influenced. 

[topspeed]

Are you an aircraft homebuilder by chance? All of your worksmanship looks very high quality and homebuilt aircraft influenced.

I have decided to build a homebuilt after this. So that is what you might see here...a 20 years dedication to build an aeroplane.

My first prototype or proof of concept was made of the root wing panels of my intented homebuilt planes 1/3 scale model.

I have build many radio controlled models. Kent Walters, Chad Veich and those dudes are my friends...like Paulo Iscold.

[topspeed]

Here are the wings/blades....as wood ready state.

I am slightly worried as while Re-number is fine the AR (aspect ratio) is not that great...but I might make another set of wings.

Those both weigh 2118 gramms each...and 5 lbs when painted.

[topspeed]

What do you think of this VAWT ?

Looks very interesting in general.

https://www.youtube.com/watch?v=_hnrOn-pTHQ

[electrondady1]

i like the squirrel cage type.

[Bruce S]

I like the fact they show the gen part too.
I'd like to see the output numbers.
It was nice to watch :-)

Thanks for the post!

Bruce S

[MattM]

What do you think of this VAWT ?

Looks very interesting in general.

https://www.youtube.com/watch?v=_hnrOn-pTHQ

How do you stop such a monster when one arm breaks??

[topspeed]

I like the fact they show the gen part too.
I'd like to see the output numbers.
It was nice to watch :-)

Thanks for the post!

Bruce S

Be my guest !

How about this Vertogen ?

https://www.youtube.com/watch?v=a-Kv5AB3RH0

[topspeed]

What do you think of this VAWT ?

Looks very interesting in general.

https://www.youtube.com/watch?v=_hnrOn-pTHQ

How do you stop such a monster when one arm breaks??

You wait until it stops blowing outdoors.

[topspeed]

Colour been added to the blades.

[topspeed]

I have been gas welding to make final pieces on my test turbine.

Portable actuator rods were the last item to be forged.

These steel rods keep the thing on the ground.