There was some problem with the Lumenlab server today that kept me from shipping and processing orders, darn. Guess I'll just have to get a start on WENDY's wings! I had entertained using a helical section of PVC pipe for the foils, but my experience with PVC is that it's kinda crappy structurally, and I don't savor the idea of a 72" rotor coming to pieces, 70' above a busy warehouse facility. We have a lot of cardboard mailing tubes which we use to mail screens.... So I decided to build a foil from a helical section of 8" cardboard tube, 30" long, then lay fiberglass on the form. I'm not an aeronautical engineer, but I know one! He was taking too long to answer my emails though (hours!), so I fell back on my sculpture background and played it "by eye". That said, I have been studying this stuff forever and a week, and I can almost say with certainty that the rotor will at least turn hehe... [Update: It turns!!!]

I snapped a few pix:

First was to hack a shape out of an 8" section of cardboard tube. My method is very scientific: I draw 500 lines trying to find the shape, then cut somewhat down the middle of this mess! I bemuse myself...I use a calculator all day long, but I'm scared to pick one up to make a foil..... Hey, my intuition is sometimes uncanny, maybe this is one of them times!

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I added some alum sheet to brace the area that attaches to the hub, as this is the most stressed area. I used alum tape to hold it all down.

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The airfoil from the bottom. Note the incision circled, very important as the root must sit flat to be bolted to the hub, and the wing is allowed to make its radius. (I sound like I know what I'm talking about, right?)

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The first layer of polyester resin and woven glass goes down easy.

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Next was to tuck under the edge: Robin is enjoying his first fiberglass experience (he's high on fumes). Myself, I've used it plenty! Nust Jay So!

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One layer on one side is finished:

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A shot from the trailing edge:

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And one from the skinny (fast) tip, before trimming glass:

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Yay that was fun! Now to build two more. I may not need the third though...we shall see! So, I'll be plodding along on this in between RoGR, micRo, raising babies and packing boxes....man ain't life great!!!

Let me just say now that I may not "ask permission" to test this on our warehouse roof at first...

I'll be following this one closely. I dream of powering my house with a wind/solar combination someday.

For a bit more explanation...

Here is an image that shows the center line of the foil. Note that there is a large portion missing on one side of the line. The missing part is the low pressure side; where air seeks the path of least resistance. This is the crux of all aero/fluid mechanics...the rest is "streamlining".

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A bit of color shows the "hot" and "cold" sides of the "piston"...high pressure/low pressure differentials are the foundation of physics...yet can be intuited by savages like me!

You might want to look at the failure mode in high wind. A small safety cable attached about 1/3 the way out from the hub to each wing would stop them from flying away in case of breakage, not that they would ever break.

When the CNC gets here I picture something like using a a Aluminum plate core of about a 3/16" thickness x6" x3' tapered along the length with high density (blue) foam glued on milled to shape and resin coated with no glass. Foam takes resin rather well and if the finish was near perfect little sanding would be needed. Add pigment on the last coat of gel and your done.

Anyone who has sanded a lot of fiberglass, like I did when replacing most of the wood and re glassing all of the front of my 21' jet boat, gets tired of the itching and mess of the glass real fast.

No glass, no itch!

This type of blade would be light strong and would be almost unbreakable.

Indeed. There's been lots of talk on foam forms for props (among other things) being RoGR'd. Carbon fiber is an option, and will certainly be used on my 1kw mill which will use something like a 20' rotor. I already have the genny for that one (obsessive-compulsive buying habit). It's a 240VDC GE motor that is 2 feet long, weighs 250lbs, produces 1kw@240v@1000RPM and has a 1 3/8 shaft diameter.

nice! me and a friend have been wanting to do this, can't wait to see how it turns out!

Phewee...Robin and I packed a lot of boxes today!

In between packing I could mix up some resin and have another coat on WENDY's lone wing, thanks to numerous internet outages...man, and biz'net is $200/mth or something; no choice being in a biz "facility". The Lumenlab shop will soon be moving to the "property" which solves these "inflicted problems" and greatly expands our core capabilities! (Buy stuff now damnit!!)

So what about this pump? I tried to get a shot looking down the "twist" to show how two++ dimensions are used to make the pump turn. The first is simply the blade angle to the wind, but a similar function is occurring from the spiral relief diminishing toward the tip. Also, there are "scoops" to grab the air off the flat hub and put it into the "system", yet the bottom "scoop" seems large (easy fix).
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I was able to hold the foil for a split second to get a shot of the length, and changing surface area.

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WOO!

This post is not going to be my biggest news for the evening...but I'm really happy to be posting on WENDY nonetheless! In between taking care of orders, and working on RoGR, and doing H2O2 degradations (hehe fun!), I'd sneak off to caress WENDY's wing some more. I took a few minutes when I got to the shop to add some more reinforcement cloth to the root of the wing, and a gel-coat to the foil on the wind-side:

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About an hour later I snuck back to add some streamlining and surface the gel flat...

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It's hard to tell from this picture, but the surface is smooth like buttah. If it were painted it would appear flawless.

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The wing is strong and flexible. I am beginning to feel confident. A test with the shop fan showed the wing could hold itself up with its lift....score 1! My friend Drew Landman at Langley Research, said my design was "inspiring"....score 2!

What are your thoughts on vertical wind generators vs horizontal?

I ask because in "Garbage Warrior" Reynolds mentions a vertical wind generator they built on an Earthship predecessor that was so powerful they had to reinforce the building it was sitting on because it kept trying to take off. (long gone at the time of filming, but they had still pics) The frame they had built around it was cube shaped, and it occurs to me that if the generator was placed in an accessible place (accessible rooftop - like and Earthship ) plywood 'walls' could be hinged to the bottom so that they would simply lay flat on the roof when not in use but in winds high enough to be damaging to the generator the walls could be hinged up, enclosing the generaetor and protecting it...

Just thinking outside the box (or rather about the box, in this case)

Perhaps something like this but with a cube of square tubing surrounding it and "walls" hinged at the bottom.

Hi Ira,

The "Savonius Rotor" is a dog for efficiency, but has loads of low-speed torque. The Savonius is an excellent choice for tasks like grinding wheat, or (wasteful) up-gearing of alternators. When a Savonius is used as such, it will produce far less power than an efficient wing, and use many times the wind-surface area, which is why they tear the roof off. (Who'd do such a dumb thing?)

I've seen instances of a small Savonius used to start a Darius rotor, AKA the eggbeater. I believe the Darius is the most efficient VAWT. A Darius would be a better choice to put on the roof, as it uses a true wing, rather than a 'wind wall'.

The lusty WENDY affair continues, thanks to my obsession with "sneaking time" to caress her wings!

Today, against odds, I got WENDY's second wing started. You can see my enthusiasm! The wing is pretty much 6' tall and the size "seems" perfect. I dunno, WENDY is sexy in a way that RoGR ain't; not that I don't like RoGR, it's just that RoGR's someone I'd play football with, pound some brews with, bottle-rocket fights etc....WENDY is a mystery you love to try to solve...she needs grace and flow, out of which a love for her form is possibly achieved.

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The "wind-screw" action is obvious in the pic:

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Hopefully Wendy will partner up with RoGR and provide you with many more "little ones" to amaze us with.

Several layers of 'glas later I was ready to do an impromptu test...

Few people know this, but I've been secretly investing the millions I've made from Lumenlab into a state-of-the-art, multi-story wind-tunnel.

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IT SPINS!!!!!!!! YAAAAYYYYYYYYY!!!!

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ok looks great but di it work to harness energy? ahd if so ehat dors the rest look likr? I am wonder vause make my hole house energy efficien to get away from rlcrv com skyrocketing privrd.

I brought it home to test and it's been dead calm since, which is rare!

Next weekend it will be erected on the back of a pick-up truck, and careful measurements taken at speed.

Those deer have nothing to worry about.

So what will you use to harness the power?

Hi LaZ,

The WENDY project has stalled temporarily due to my high work load as of late. I do have a few things in mind for this project though, and I'm anxious for "easier times" to explore these ideas further.

http://www.otherpower.com/

I recommend you visit this site, its got perhaps the best practical plans on building wind turbines. Maybe you can pick up a thing or two from it.

Thanks. OP is great, been visiting the site for years.

Bringin' this back.

The LL servo; what kind of maximum potential has it when it comes to output? In theory..

At 1200 RPM the servo should produce about 40V and 12A. My target was to shoot for 24v @ ~ 700rpm.

So that means a maximum of 480 watts at 1200 RPM? And 280 at 700. Would be very interesting to try this. My school has cnc equipment, så making a dead accurate rotor should be easy too.. Hm.

Take lots of pics!

Please do! I love pics.