fiberglass blade availability [Archive]

Stewart Corman

18th February 2007, 13:17

All of a sudden on eBay there are two dealers selling quantities of molded fiberglass blade sets which may be under the brand label of "WindMax"

http://i6.ebayimg.com/03/i/000/83/20/272d_1.JPG

3 blade sets in 81.5" ( 6.8ft/300watt?), 102" (8.5ft/600watt?), 110" (9'2"/600w@17.9mph) and 157" (13ft/2KW?) BTW all modestly priced
here is a link to his pics:
http://i20.ebayimg.com/02/i/000/79/b2/50b6_1.JPG
http://i23.ebayimg.com/02/i/07/c3/fc/83_1.JPG
http://i8.ebayimg.com/02/i/000/79/b2/5132_1.JPG

he has multiple offerings of these sets and claims thay are "mass produced" from a commercial source.
Has anyone had experience with these specific blades.
Can anyone identify which manufacture of turbines they would have been manufactured for?

"WindMax"???? I can't find any references to such a commercial turbine nor any advertised specs

This seller is severly lacking in any specs whatsoever other than TSR of 6, but his prices are attractive and he has the matching hubs. I am NOT promoting their auctions, so I am NOT posting the specific link ...easily found by doing an ebay search on "Wind Turbine Generator Blade "

Stew Corman from sunny Endicott

Rob Beckers

18th February 2007, 14:15

Good find!
What's presumably the same EBay add, has this info for the 13.1 feet blade set:

Blade Diameter: 13.1 Feet.
Rated Capacity: 2000w
Rated Wind Speed: 10 m/s
Start-up Wind Speed: 3 m/s.

They also mention a Cp of 0.49. It's kind of foolish to publish this for a set of blades, as you can't really say what it's going to be until you have an entire combo of blades, bearings, alternator etc. (and especially how you're loading that alternator). Still, if they are well made, it could be a good deal. I guess they took some commercial blade, made a mold from it, and used that to reproduce these. If the original was good then these could be good too...

-Rob-

Stewart Corman

18th February 2007, 18:20

Rob,
when all of a sudden, you see a gob of something on eBay, then it is usually when a company went out of business and someone got a warehouse full at an auction ...I'd bet these were made in China ...I posted on AWEA and we'll see if someone recognizes the blade specifications by lengths ...somewhere there is/was a company manufacturing a whole line of turbines ...13 ft is out of the "toy" dept!

My buddy Jack is talking about bidding on one of the mid sizes

Stew Corman from sunny Endicott

Stewart Corman

26th February 2007, 09:17

This is a compilation of comments received by emails/ebay in addition
to those posted on the AWEA thread:

Overall consensus is that they are made in China. There is no known
turbine product line that incorporates these sizes, they are raw and
need significant finishing/final coat.

Speculation is that these are seconds from a production run?
Profile does not have any twist and they are designed for high TSR ie
6->9+.
BUT contradicting above: " pitch at the tip is too steep" would
indicate to me that it is NOT high TSR?
The blade structure is solid and appear durable with proper finish
coat ie epoxy or polyurethane paint since raw fiberglass deteriorates
under sun/UV exposure.
The weight of three blades in 7 foot size is about 15 pounds w/o hub.
The hubs are probably metric or some oddball dimension and are crudely
cast, not machined from plate stock.

There are two sellers (both in TX) selling similar items under
different packages/pricing...some are BIN w/option to "make offer"
(check auction history) ..others are plain auctions with fixed
starting price

response from seller #1:
"Right now you need to make your hub by yourself since the hub is not
available currently and also it's not fit to most of the existing
motors. The blades are pretty good and smooth. No need to do sanding.
On the contrary, sanding may hurt the blades. Thanks Jeff"

BUT, Randy B (endorsement on his auction) contradicts above seller:
"I bought the smaller fiberglass blades to replace the nylon filled
ones I had that broke in a windstorm. These Chinese ones are well
made but definitely not close to being a finished product. The
leading and trailing edges had large mold marks that took a lot of
belt sanding to remove. That along with some auto body filler and
many hours of hand sanding and primer have the blades ready."

seller #2 ...no response after three days when asked about surface
finish and hub dimensions.
pic shows a finished mill but that pic shows diff mounting assm than
shown in avail parts.
Detail pic within auction shows 5 diff length blades raw w/ diff
mounting holes, poor pic of hub
Are blades installed backwards in pic?

Overall consensus is that at the prices offered (IMHO except the
13ft), they are fairly inexpensive, lightweight, stiff, strong,
durable, and cost effective compared to carving from wood from scratch
(material + time).
You need car body "Bondo" experience to complete (not rocket
science!). Recommend flat "flap" wheel on 6000rpm hand grinder to do
speedy sanding/shaping.
Performance is a big ? since nobody has done a power curve ...auction
indicates peak power around 28->30 mph, but questionable source of info

Stew Corman from sunny Endicott

Stewart Corman

26th February 2007, 09:35

for those wanting to build a real hub for these blades, or need steel plates for an axial generator, I have a limited source for 1/4x11" and/or 1/4x12" flat steel plates that were laser cut and these can fit (2 or 3?) in a USPS flat rate box for $8.10 shipping + $1.30 insurance within the US ..

Make me an offer I can't refuse, or offer something to barter. Those in Canada might find the shipping prohibitive?
I also have 1/2x13" plates that won't fit in a flat rate box, so shipping would have to be calculated after I weigh one of them.

If you want the precision holes drilled like the pattern in this pic, it can also be arranged

http://i145.photobucket.com/albums/r203/scorman1/Turbine%20project/4146.jpg
note how easily a surplus sprocket gear can be mounted to be used as a precision taper-lock hub adapter

Stew Corman from sunny Endicott

Ted Sanford

28th February 2007, 09:12

I ordered a set of the 13.1' blades to try to adapt them to my Dakota, which I view as a relatively inexpensive gamble. I'll keep updating this as the project moves along. At the least tho, I would apply leading edge protection (the aircraft wing tape) because rain, ice, hail eats everything.

Stewart Corman

6th March 2007, 17:56

I posted some of this on another thread, but thought it might be of benefit here as well:

BTW, for those considering carving HAWT blades, I updated my Excel calculator to include twist. It adds twist degrees to the tip (considered zero) and proportions it uniformly to the root

I saved it with two scenarios ...20mph, 15P fixed pitch, TSR=3.5 and twisted 15 degrees starting at 4 degrees blade pitch, TSR=7

noted that high TSR = high RE# = turbulence = drag dominated, low TSR = low RE# = laminar flow = lift dominated

this is the link to the Excel file:
[/URL][url]http://www.greenpowertalk.org/attachment.php?attachmentid=85&d=1173284306 (http://www.greenpowertalk.org/attachment.php?attachmentid=84&d=1173212139)

Stew Corman from sunny Endicott

Stewart Corman

6th March 2007, 20:57

Just found this chart which shows how much twist you need to have a constant 4 degree AOA at TSR =4.5:

http://www.thebackshed.com/Windmill/Articles/images/table1.gif

Also note that the minimum tip blade angle is 8 1/2 degrees and yet I have seen many claim that their tips are only 4 degrees ??

Another observation: these numbers seems off the wall with huge root twist angle, however, we do NOT know what the others specs on this design are ie what is the tip to root cord ratio and the 5% station is very close to the shaft ...my calculator shows only a minimum 25% station which is 41.6 degrees apparent wind angle on the above chart

Stew Corman from sunny Endicott

Stewart Corman

9th March 2007, 11:43

I have had some conversations with the fellow on Otherpower who was offering molded high tech fiberglass blades.

He is building a scaled down version of SG6050 (very similar to NACA4415) twisted and TSR=7

I have had a few conversations with him and he referenced the following very detailed NREL report as to where he got his design:
http://www.otherpower.com/images/scimages/4937/Resin_Transfer_Molding.pdf

this is very detailed and it took me 20 minutes just to "skim"

I posted some airfoil charts on the other thread which are relevant here:
http://www.greenpowertalk.org/showpost.php?p=1431&postcount=25

Stew Corman from sunny Endicott

Ted Sanford

12th March 2007, 17:32

I got the blades I ordered, and I think I can understand why they are on the market. I have never seen an airfoil shape like this one. The high pressure side of the blade that is supposed to be flat has almost as much convex curve as the other side. I don't think they will work without a lot of fiberglass added to the leading edge and shaping. The 13.1' blades are 7" shorter than advertised, and they turn right when viewed from the front, as opposed to my old Dakota (Jacobs) blades that turn left. Have fun, guys

Stewart Corman

12th March 2007, 18:52

Ted,
Why not post some pics and closeups at a few diff angles so we can see what you are talking about?

It is possible that these Chinese blades for which there is no commercial turbine line known to any of us, might in fact be blades produced for commercial water tower coolers as used for plant airconditioning systems. Then someone decided to throw together a completed tubine from parts that were available?? just guessing here.

I have three of such blades in my possession which are cast alloy aluminum and are 7 1/2 feet long and weigh 55 pounds each: here is a pic:

http://i145.photobucket.com/albums/r203/scorman1/buffer/4000.jpg

I just did a quick search of my reference links and I will admit that I couldn't find a single concave blade ...in fact the more advanced designs are much more teardrop shaped than a NACA44 series

Did you get the hub included in the package? ...the pic of the completed turbine shows the blades mounted outboard on a flange ie possibly bigger diameter than the circular hub shown in the auction

Stew Corman from sunny Endicott

Stewart Corman

13th March 2007, 12:21

Was looking on OtherPower and noted this thread where indeed they are currently making concave profiles "Gottingen 222 " :
http://www.fieldlines.com/story/2007/2/21/3919/03252

http://www.ae.uiuc.edu/m-selig/ads/afplots/goe222.gif

http://www.otherpower.com/images/scimages/2717/Windcharger1.JPG

Stewart Corman

25th March 2007, 07:01

Ted Sanford : I got the blades I ordered

any update on these 13 footers? How are you mounting them? ..when will they be up and flying ?

Buddy Jack did order a set of the 9.2 footers off eBay w/o hub and has them flying.
I have not seen them personally but will have some pics from him later or a link to his site
He claims they are quite well made , required no bondo and only the most minimal fine sanding.

They have twist and are slightly concave on "flat" side with slight tail "lift'.
At 4.5:1 he has them geared too high for the Ametek "boss", which puts out 32 amps at 39 volts at 1050 rpm..which results in hard starting, but will run very fast in stiff wind.. He is going to replace pulley to get down to 3:1 ratio.

More details as I get them,
Stew Corman from sunny Endicott

Mark Parsons

25th March 2007, 08:23

Just a quick potential re-direction.

Ted said:I have never seen an airfoil shape like this one. The high pressure side of the blade that is supposed to be flat has almost as much convex curve as the other side.

Keyword point - convex - resembling a more symetrical airfoil?

Stew said: They have twist and are slightly concave on "flat" side with slight tail "lift'.

Keyword point - concave - resembling your GOE 222 example.

Probably just semantics and Stew has Ted's intended meaning well understood. Another example of 'a picture is worth a thousand words.'
I too am quite interested in unbiased experience with these Chinese blades. If decent, sure takes a lot of work out of a DIY project.

Mark

Stewart Corman

25th March 2007, 11:15

Just did some scanning and ran that GOE222 on Javafoil:

file:///G:/DOCUME%7E1/Dad/LOCALS%7E1/Temp/moz-screenshot-7.jpgfile:///G:/DOCUME%7E1/Dad/LOCALS%7E1/Temp/moz-screenshot-8.jpg
AOA Cl Cd (Cm 0.25) Cp M
0.0 0.523 0.04449 -0.129 -1.069 0.642
2.0 0.742 0.04632 -0.139 -1.269 0.613
4.0 0.971 0.05029 -0.143 -1.489 0.585
6.0 1.190 0.05173 -0.147 -1.827 0.549
8.0 1.400 0.05582 -0.150 -2.178 0.518
10.0 1.615 0.06353 -0.155 -2.583 0.488
12.0 1.804 0.07147 -0.157 -3.126 0.455
14.0 1.977 0.08747 -0.160 -3.963 0.415
16.0 2.083 0.10250 -0.163 -5.679 0.357
18.0 2.121 0.11839 -0.166 -7.751 0.311
20.0 2.064 0.14871 -0.165 -10.079 0.276
the listing of 1550 profiles is here:
http://www.ae.uiuc.edu/m-selig/ads/coord_database.html

the gifs give a quick pic ..the data gives txt file for importing into Javafoil

I did a search for "low RE#" and most airfoil shapes found are in fact concave and are high lift designs/high drag like above chart, even tho the eBay info states high TSR >6 (opposite of low RE#)

Be interesting to thumb thru profiles to find one more similar to Chinese blades and then run Javafoil

Stew Corman from sunny Endicott

Ted Sanford

27th March 2007, 14:47

Well, folks, I finally figured out how to get photos on this, I hope. The blades are sold as a 13.1' rotor, but they measure 6', and with the hub, make a 12'6" rotor. They weigh 11 lbs, making them too heavy for my Dakota, as my sole remaining blade at 6'8" weighs 9 lbs w/o hardware. At the widest, they are 8", and 5 1/4" at the tip. The hub end is 4 5/8" wide and 1 11/16" thick.
To give you an idea of their twist, and airfoil shape, I leveled the hub end, and then set the level in the center of the blade, both top and bottom. I don't see a lot of difference between the shapes of the two sides, after accounting for twist.
I hope this is useful to you.
If anyone wants them...... It was a worthy gamble anyway. We are going to try to make a mold from the remaining jDakota blade, and cast up 3. More later,
Ted

Stewart Corman

27th March 2007, 15:38

Ted, thanks for the pics and that shape is high tech!
you are concerned with adding a few pounds??? like 20% ?
And you don't even think about bondo ...these were DESIGNED
looks like the following to me but maybe a little "fatter"
(I'll get some Javafoil performance plots later):

Stew Corman from sunny Endicott

http://www.ae.uiuc.edu/m-selig/ads/afplots/fxs03182.gif

Ted Sanford

27th March 2007, 16:41

Well, that info sure gives me something to think about. Thanks. Do you have any idea how much more power these would produce compared to the original, and how the start-up windspeed would compare?
I will still have a few problems, though. The rotation on these is backwards, so I will have to take the generator down and change the brush-holders to turn in the other direction, and these blades are 8" shorter than mine. Because the Dakota (Jacobs 3kw copy) uses a centrifugal flyball governor, (the blades slide out on rods and feather as they overspeed) the extra weight means that I either have to get beefier springs or be satisfied with lower performance.
I could probably add a little length to these without too much trouble, and probabaly a little thickness at the hub end to take the 11" long, 1 1/8" od pipe that the rod slides in. Another possibility would be to grind off some extra thickness to reduce the weight.
Any suggestions?
Ted

Stewart Corman

27th March 2007, 20:43

Ted,
All seems doable, but I really don't have much info on your basic Dakota turbine ...give us some details on design or a good link and perhaps we can help out.

Is this the mechanical diagram of the variable pitch assembly?

http://www.otherpower.com/images/scimages/284/jacobs10.jpg

you stated:
to take the 11" long, 1 1/8" od pipe that the rod slides in.this is a 14 footer and the blades are on a 1 1/8" OD pipe ie that is the support spar or is that pipe just the rotating mechanism and the blades are on heftier hardware?

BTW ..on Javafoil, the design I posted has great performance at 4 degree AOA, but great stall after 10 degrees
In order to compare to Jacobs, I'd have to know the profile they use

I have attached the txt file you can import profile data into JavaFoil (very simple to do)

Stew Corman from sunny Endicott

Ted Sanford

28th March 2007, 07:00

Stew:
I believe this is the mechanical diagram from a 10kw Jake, because it has 2 springs and the worm gear, but the governing mechanism is similar. My 3kw unit has one spring and the 120vdc generator is mounted horizontally on the same shaft as the blades.
The hub you see is called the spider, because it has 3 1" rods pressed into it. The blades have 1"id, 1 1/8"od pipes in their centers, and they slide on the rods, held on with the springs. The piece on the rotor shaft behind the hub has a ball joint that bolts to the angle iron on the end of each blade, and slides on the shaft, feathering the blades as centrifugal force pushes the blade out against the spring tension. As you can see, extra weight will change the required spring tension. My current ones are 3/8" wire wound to 2"od. Perhaps a call to a spring winder can get me some info on forces required to open different springs. Going to double springs like the picture is not out of the question, either.
Regarding the airfoil on my current blades, I have a template I made, but I don't know how to get it into your program. (I am only marginally computer literate) Is there anywhere I could fax it?
Also, it appears that there is enough stock in these blades that they could be ground into something close to the GOE222 airfoil, while getting lighter. I will probably drill a hole through one to see if it is solid or it has a foam core before I do any of that.
Ted from windy RI

Stewart Corman

29th March 2007, 08:22

Ted,
first w/r to the blades you have just gotten ...why even consider changing them until you see how they perform? (sand trailing edge to get it smooth and remove any molding marks, but don't reshape anything)

It is quite possible (unless you have an induction motor/generator) that you can get rid of all the pitch stuff and use the twist design for what it was designed (BTW easy to vary the fixed pitch angle when mounted on a spar when you determine the best output for typical WS)

The complications of the pitch design/springs/weight etc, plus the diff in profile and twist vs no twist on originals, plus the diameter being slightly diff ..all contribute to a BIG ?????? ...KISS ...ream out a hole for the tubing, epoxy them in, get some self tapping hardened flat head screws ( the ones for cement board are great!) to lock them on ( never trust glue only) ..RUN IT!

attached is a pic of reaming out spar holes using "spade bit"
I went in 6 inches and used three screws
BTW, I would use a heavier tubing made for the top rail of chain link fence which is galvanized 1 3/8" OD and 0.065" wall thickness (1 1/4" ID) and slip the smaller diameter tubing inside it to fit the "stub" ..this costs about $20USD /20 ft
Especially if you want to extend the blades to get the same turbine diameter you had (or bigger?)

Regarding the airfoil on my current blades, I have a template I made, but I don't know how to get it into your program.easiest way is to go to that link which has 1550 profiles and pick the closest ..I thought that Jacobs used NACA44xx?
If you have a file in any format, send it to me in email and we'll try

scorman@stny.rr.com

Ted,
OT - Please take some closeup pics of the hub from diff angles and the steering mechanism as well and post here with description.

thx,
Stew

Ted Sanford

29th March 2007, 12:20

Hi, Stew:
Thanks for pushing me to try the new blades. I was reticent because of the labor required to take the generator, gin pole, tail, etc up and down the 110' tower to change the brush holder, but I can do a test with the brush holder the way it is, and if they work, then change it.
I got a reference from another blog on the old blade design: and he says they are the Clarke-Y, close to NACA 4412. The Clarke design is not flat enough on the bottom, and NACA 4412 is empty in that list of foils. The one that is closest is the USNPS4.dat\jacobs, down at the bottom of the list.
On the new blades, the thickest points are at .3 top and bottom. At the tip, where the width is 5.5", the top is 1/2" above the midline at .3, and the bottom is 3/8" below the midline at .3. I would love to see a computer comparison if that could be done.
These blades are very smooth, and will only need to have the mold line around the blade feathered off.
I don't think I need to change the design of the inserted pipe, because as you can see, both the angle iron at the root of the blade, and the one that holds the eyebolt for the tension spring, bolt through the blade over the pipe, effectively clamping it in place, backed up by the spring tension.
The only other thing I will need to do to perform a test is to weld a small piece of angle to the end of the angle at the blade root, so that the flyball can bolt to the other side of the blade, and that will be taken care of at the machine shop while repairing the hub.
If you want to reach me directly for more pics or other info, my e-mail is tedsanford@verizon.net.
Thanks for the help
Ted

Stewart Corman

30th March 2007, 12:59

Laurie Forbes

31st March 2007, 20:42

Dewayne Vaughn

10th October 2007, 06:39

Hi, first post.

For a better look at those blades go to http://www.magnet4sale.com/xcart4/home.php?cat=302

He's been selling these blades for a few years now ( that I know of )

I buy neo magnets and magnet wire from him, but I like VAWT's so the blades don't interest me.

His prices are ok, and as he's only 7 miles from my house I like going there.

You can get the phone numbers and address from his site. His name is Jeff and he and his staff (3 or 4 people) are from China. ( speaks clear good english )

Laurie Forbes

12th November 2007, 20:42

Just ordered a set of 10.1s from CMS Magnetics (Plano, Texas) for $108 plus shipping. These blades appear to be similar to what has been discussed previously on this thread.

Since my two blade, pitch controled, turbine seems to work properly, I am now converting it to three blades (everything else the same; one more blade is the only difference).

I noticed mention of one or two others having similar blades but nothing yet posted on how well they perform. Has anyone had any success as of yet??

Laurie Forbes

17th November 2007, 16:32

Just received my blades from CMS Magnetics (hello? - is anyone still out there?).

Anyhow, they look pretty good with a smooth translucent surface (for the most part) and a few small blems which can probably be sanded out easily. Kind of typical made in China stuff. The curve looks pretty conventional with an almost flat leading face and curved back with a good sharp trailing edge. There is a bit of twist, particularly towards the root and the blades are tapered but not quite as wide at the root as my old blades. All in all I'd say a good buy but will have to see how they perform.

I'm wondering if they should ideally be painted, esp if some sanding is required? The website claims a UV resistant surface but maybe I will call them and ask.

Rob Beckers

18th November 2007, 07:16

Hi Laurie,

Could you post a few pics of the blades? That's a very good price for a set of that size. If I remember right, epoxy is not completely UV resistant (they are epoxy-fiberglass blades right?). If they added a gel-coat on top then that may do the trick though. Ask them. If not, then a pigmented paint should do the job (for example aircraft enamel rated for epoxy-fiberglass).

I get the blades for the Scirocco wind turbine that we sell painted in black, it's a good color for shedding ice. A little sun after an ice-storm will warm the blades enough to stop its adhesion.

-RoB-

Your asking if anyone is still out there; Actually we have more members than ever but people have stopped telling us about their projects. As you can see from the forum index page all the 'regulars' are still regularly checking back. Just not much posting going on...

Laurie Forbes

18th November 2007, 22:24

Here's some pics of my CMS Magnetics blades. These are mainly closeups - for full length shots, go to the CMS web site:

http://www.magnet4sale.com/xcart4/home.php?cat=302

They appear to be pretty much identical to what Stewart posted earlier.

1st is front root
2nd is front tip
3rd is front root
4th is back root
5th is partial front

It's not visible but the trailing edge has what appears to be mold marks and a little sanding would help. Trouble is, the blades are supposed to be coated with a UV resistant material which I suppose would come off if sanded. It may be necessary to paint afterwards but that would also improve the appearance as they are kind of blotchy in appearance now (which is not all that evident in the pics).

I'm going to call them tomorrow to see if they recommend painting.

All in all not a bad buy I guess (at least so far) but I wish the root portion was a little longer (to provide a more secure mounting).

Stewart Corman

19th November 2007, 08:30

Laurie,
They look quite good from your pics ...not nearly as "crudely finished" as some had claimed

could you please ad a pic taken from the tip end "head on" so we could see the profile?

As far as finishes, I wouldn't trust anything they claim from China and Rob made an excellent point about black paint ...I wouldn't even ask them the question!

A polyurethane is a also a good choice as it sticks to anything, especially plastic.
I just got some 15oz Krylon gloss black from the $ store ...made to go directly on metal w/o primer ...using it on my new tower project ...dries in 15 minutes and gets very scuff resistant ..reminds me of gloss one part epoxy that I used to get.

Back to your project ...have you built the new head assembly that is designed for three blades?? would like to see closeups of the hardware

keep up the good work
Stew Corman from sunny Endicott

Laurie Forbes

19th November 2007, 14:31

Stewart:

Yes, they appear to be usable, with a little sanding. I've also noticed the training edges could be a bit sharper.

I've included three pics of the tip head on - not quite flat on the leading surface but pretty close. You can't see from the pics but the blade is bent slightly forwards (slightly concave along the radial axis facing forwards). I don't know if this is on purpose but it might be a good thing as the wind load would tend to straighten it.

Thanks for the suggestions on the paint. I like the appearance of white but as Rob points out, black has advantages. I would guess it would be more prone to bird strikes however(?).

Haven't yet assembled the three blade head but it will be the same as the two blade with one "arm" added to the spider. I had intended to try bevel gears, which would be a better solution, but couldn't find anything decently priced (plastic would likely work OK and would be cheap but could not find anything large enough; I would want the "sun" gear to be 3 or 4" diameter at least for strength). I'll post pics when I get it put together but work will have to wait for warm days now (I wish I could weld & cut in the basement :)

Stewart Corman

19th November 2007, 17:14

I've also noticed the training edges could be a bit sharper.I agree from the photo ..trailing edge could be a "knife", but then would be too hard to hold the paint ...I'd try for 1/8" thickness and smooth off any sharp edges.

looks similar to a NACA 4412 except for the leading edge not quite as rounded ...the Jacobs has a similar leading edge profile as yours and they have been working for 50+ years

The pics Ted Sanford had posted showed a totally diff contour ..far from flat on one side

Stew

Stewart Corman

20th January 2008, 12:01

"The mills of the gods grind slowly, yet they grind exceedingly small"

My buddy Jack finally has his mill up and running:

337

338

These were the 9+ foot Chinese blades off eBay, painted, mounted on a 13x 1/4" inch mounting disk ...so final diameter slightly over 10 feet.
The generator is the 24v/194rpm PM DC motor that I had been using.
Using a vbelt with about 1.1:1 ratio.
Load is a single 230v/4500watt/12 ohms calrod in a water tank.
A second element is available to hook in parallel to increase load.
Simplest control is a 24v relay using a resistance bridge to trip in at 70volts.

Was running this morning is stiff breeze at 68v/6amps = 400watts
Working numbers backwards rpm = 550rpm at generator = 500rpm at rotor
Thinking of reversing the pulleys to reduce rpm and increase starting torque and accomodate higher top end WS

Observation: ran QUIETLY!!!!

The motor internal windings are about 7 ohms.
Bench tested in a lathe at up to 90v ..stayed cool
Unfortuneately, to increase load with lower total load resistor brings total load to 6 ohms , so 1/2+ of all power is heating the atmosphere up on the tower. Ideal design is to have as high a voltage as possible with as low an internal winding resistance ..not the other way around. Jack has a 90v Ametek which will go up next. We can probably run that up to 200v. Need to measure the internal winding resistance.

Bottom line ..nothing wrong with these Chinese blades which are currently going for under $100 shipped for a set of three (advertised now for lower TSR but I'd bet they are same blades as year ago!)

I have a short mpg video of turbine in motion, but haven't found a good site to upload to ...can email to anyone interested

Looking for updates from Laurie and Ted Sanford on their projects????

Stew Corman from sunny Endicott

Laurie Forbes

20th January 2008, 12:27

Thanks much for posting that Stew - v interesting.

Particularly glad to hear the QUIET part. By strange coincidence, I have just about finished the three blade hub (with pitch control) - will post pics in a few days (if we get warm enough welding weather here again soon that is).

Was also interested in the 500 RPM rotation speed of the blades. I wonder how high one can go while retaining reliable service? My mill, which will have the 10' blades, and an effective diameter of about 12', will turn about 300 max.

Dan Lenox

21st January 2008, 11:36

Stew,

snip...
The blade structure is solid and appear durable with proper finish
coat ie epoxy or polyurethane paint since raw fiberglass deteriorates
under sun/UV exposure.

Stew Corman from sunny Endicott

Typically in the fiberglass composites construction of parts the outside finish is simply a gel-coat, and not a paint. It is a pretty durable finish and provides UV protection as well, typically when making the parts pigment can be added to obtain about any color you can think of, or graphics can be applied as well.

When laying up the parts in the mold the gel-coat is applied first and then the layers of whatever composite material(s) are being used.

If the resin used is polyester, vinylester or epoxy then the gel-coat used is compatible with the resin.

I am pretty familiar with the process as my good friend Paul Schreiner owns and runs PS Composites http://www.pscomposites.com, he has assisted me in a number of my projects. Currently Paul and I have been making a mold for a battery tray that can hold up to 6 #31 batteries, first trays should come out of the mold this week. (shamless plug) If any one is interested they should contact PS Composites for pricing and availability. I have no affiliation with them - other than him being a very good friend.

From all of the pictures shown about these blades the surface finish, while workable is actuall sub-standard. A good molding/finishing process actually produces very smooth, slippery and glossy surfaces. My guess is that the "finish" is actually the polyester resin, and that they do not even use a gel-coat finish.

Dan Lenox

Dan Lenox

21st January 2008, 11:56

Laurie,

snip...

I had intended to try bevel gears, which would be a better solution, but couldn't find anything decently priced (plastic would likely work OK and would be cheap but could not find anything large enough; I would want the "sun" gear to be 3 or 4" diameter at least for strength).

You should look into automatic transmissions! The older ones typically contain at least *2* complete planetary gear systems! Very easily to modify for your specific use. On one of my pages I show one sun gear from a transmission that I am using for a reverse operation. Just go to http://www.briery.com/vortex/log/2007-03.html and look near the bottom of the page to see some pictures of them.

Of course if you want bevel gears then a manual transmission is the way to go.

Dan Lenox

Laurie Forbes

21st January 2008, 13:57

Dan, thanks for the interesting comments on blade finishing and gears.

I'm not sure how a sun gear could function in my application but bevel gears from an old transmission just might work (come to think of it though, I'm not sure why a manual transmission would have bevel gears in it unless it's from a vehicle with front wheel drive and a longitudinally mounted engine). Another issue is that I would need only a single sun gear (if that's the right terminology) but three "planetary" gears (maybe that means I would have to dismantle three transmissions in all)!

Any clarification you could offer would be appreciated.

Oh, wait, maybe the "differential" in the transmission (assuming front wheel drive) would have bevel gears (?).

Dan Lenox

21st January 2008, 14:11

Stewart Corman

22nd January 2008, 16:01

Dan,
Just a quick reply to:

Typically in the fiberglass composites construction of parts the outside finish is simply a gel-coat, and not a paint. It is a pretty durable finish and provides UV protection as well, typically when making the parts pigment can be added to obtain about any color you can think of, or graphics can be applied as well.

no argument that a gel-coat needs no paint, but all accounts for these Chinese blades is that they are raw (see pics posted further up), with some fibers that need sanding off, or mold flashing that needs to be removed at trailing edge ..these are NOT made by the fancy molding techniques you describe, but rather cheaply mass produced ...so painting is in order unless one want to apply gel-coat, which is certainly doable and will be the hardest finish ...spray can of poly is cheapest and quickest

Stew

Laurie Forbes

22nd January 2008, 19:34

Laurie,

A planetary gear set is about the ultimate in simplicity, it is essentially an extremely compact gear reduction/increase system (depending on how you drive it).

The set is comprised of 3 components, a sun gear, ring gear and planet gears (aka carrier). Here is a link that describes their usage http://www.transmissiondenver.com/facts.html.

I don't want to hijack this thread so if you have more questions, contact me directly or start another thread.

Dan Lenox

Thanks Dan. I do know how planetery gears function and, as I recall I mentioned before, I don't see an application of such gears to my pitch control project. I was more interested in what kind of bevel gears might be obtainable from a transmission.

Laurie Forbes

22nd January 2008, 19:52

Dan,

no argument that a gel-coat needs no paint, but all accounts for these Chinese blades is that they are raw (see pics posted further up), with some fibers that need sanding off, or mold flashing that needs to be removed at trailing edge ..these are NOT made by the fancy molding techniques you describe, but rather cheaply mass produced ...so painting is in order unless one want to apply gel-coat, which is certainly doable and will be the hardest finish ...spray can of poly is cheapest and quickest

Stew

It appears there is some sort of clear coating on the front and back of the blades as the surface there is smoother and shinier than the sides and end of the butt. I don't really know though as I've never examined anything else for comparison.

In any case, I've bought a can of Sico "alkyd-expoy" paint. Sanded and cleaned the blade surface with paint thinner, then applied the first coat by brush. It seems to go on pretty well but there are a number of small spots that the paint has flowed away from as the paint drys as if that particular surface was not wetted by the paint sufficiently well. I'm hoping that a second coat will take care of that (maybe a primer should have been used?). Apart from the spots, the dried paint surface looks pretty good - smooth and glossy and a lot better in appearance than the unpainted surface.

Ralph Day

23rd January 2008, 08:50

LF,
In my experience with epoxies, paints and such, if you have "fish eyes" happening, it's contamination underneath. Sometimes sanding isn't emough, epoxies sometimes leave an amine blush which can be washed off with amonia, or wet sand instead of dry sanding.

Only remedy, wet sand the spoiled area and re-apply paint.

ralph

Laurie Forbes

23rd January 2008, 13:27

OK, thanks for the advice Ralph - I'll try that.

Laurie Forbes

24th January 2008, 23:01

Rube Goldberg strikes again! Have finished assembly of the three arm hub & spider with pics attached (also blades in various stages of painting).

The hub is pretty heavy duty for a 12' turbine (it weighs close to 50 Kg) but I hope to add longer blades in future. I should have it flying when the snow melts....

Dan Lenox

25th January 2008, 08:43

Laurie Forbes

25th January 2008, 11:15

Laurie,

You also might try to clean the blade surfaces with some acetone before applying paint. Unfortunately since you already painted them the acetone might remove the paint to a degree as well...

Dan

Hi Dan:

I've gone to a coarser grade of sandpaper and cleaning thoroughly with paint thinner which seems to be working pretty well (much less fisheye). I hope the paint sticks - still wondering if a primer of some sort would have been beneficial.

I'm also thinking in terms now of a taller tower. What I have now is only 20' of 4" pipe with a single set of guys. I'd like to try 40' at least but an unsure about the design. Can anyone recommend a source of design info for guyed pipe towers with a gin pole hoister?

I'm also going to need a better source of grunt to lift the thing (my little 15HP diesel tractor won't be able to handle much more than I have now).

Stewart Corman

25th January 2008, 11:38

Rob, decide with Laurie whether further talk on Laurie's newest design should be in a new thread? I think it is warranted considering he plans on flying it soon ....I can easily cut and paste the following there:

Laurie,
Things look great.

I'd like you to clarify a few specifics on your design:

Is your counterbalance mechanism to feather not furl?
If feather, how do you furl?

Is it dynamic variable pitch vs old Jacobs design which is "in" or "out"?

You start with high pitch angle to aid in starting, and then shallow the pitch to get higher rpm and efficiency?

At very high WS/rpm, is the forward stop set so that you can feather to slight negative pitch to keep it from overdrive?

I see that a chain spocket is part of the subassembly, which I remember you using before...then you use an idler shaft to gear it up further?

What is your rotor design max rpm and how much sprocket ratio are you using?
Using the xls calculator I posted:
At TSR = 6, at 20mph you'll be cranking 1KW output (for Cp=0.33) at 336rpm

Do you have any comments/advice/negative experiences on using roller chain?
Do you use fixed shaft distance and leave some slack, or crank it tight?
I found some motorcyle chain lube by Fuchs: "Silkolene" ..advertised as non-fling and ant-rust ??? It goes on thin and then gets "sticky"

like the "sockets" you made for the blade stubs

can't tell from your photos but are the three counterbalances synchronized yet? I know there was a discussion with Mark a ways ago about using a ring gear.

Yes, you need to consider the tower situation ...I am planning on 57ft similar to Mario's:
http://www.greenpowertalk.org/attachment.php?attachmentid=69&d=1171585065

forget a tractor ....my wife could crank it up in three minutes!

Overall, what is your performance expectation when it is finally running?

Stew Corman from very sunny Endicott (but brass monkeys outside)

Ric Murphy

25th January 2008, 13:53

Hi Laurie,
I'm using a 70', 3 section tilt up tower. Pipe is 4". I designed the couplers and hinge base and built the unit myself (hired a welder though). I've raised and lowered it a dozen times over the last 2-1/2 years and have had no problems. I use a 8000lb 12v winch although I could use a tractor if I wanted to. The winch does grunt abit when the weight is the greatest. Once the gin pole and winch are in place it takes me less than 5 minutes to move the 3 guy wires to the gin pole and lower it. What is your guy wire anchor spacing? I was taught that the distance from tower base to each anchor should be 1/2 of tower height. I've seriously considered adding another 21' section to mine but am concerned that the anchor spacing would be insufficient based on the above rule. I don't have a lot of close up pictures of the tower components but here's few. I found the OD of 3-1/2" pipe to be very close to the ID of the 4". My couplers are actually inserts that connect each tower section and include the guy wire flanges. The flanges were made out of 1/2"x3" flat stock. I cut 2" rings out of 4" pipe and welded them above and below the flanges. They carry the weight of the tower. Each insert extends approx 1' into the tower section above and below each coupler. The weight of the tower and the guy wires hold everything together. There is no other means of clamping. The hinge mechanism is basically the same. The gin pole is 4" also and simply slides over the horizontal segment. I used a large drawbolt for the hinge pin.
Ric
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Laurie Forbes

25th January 2008, 17:54

Thanks Stew. The blades are designed to stall - they start at a higher than normal pitch to aid starting and rotate towards the "normal" operating position as RPM increases and continue rotation with increasing RPM towards stall which slows it down. The rotation force is provided by the flyweights that tend to move forward via centrifugal force and therefore rotate the blade shaft(s) as they move. Restorative force is provide by the torsion springs (modified safety pins). The "spider mechanism keeps the blade shaft rotation synchronized and collectively negates the additive or subtractive force of gravity on the flyweights as the prop rotates. I would like sometime to replace the "spider" with a central bevel gear meshed with a smaller bevel on each of the blade shafts (less friction and easier to build I think but, probably more costly depending on the gear source).

Yes, I employ a two stage roller chain drive with an overall ration of about 5.5 to 1. In future I may replace the ceramic mags in my motor conversion to neos and hopefully reduce the required alternator RPM such that only a single stage gear-up will be required.

Your calculation of 1 KW o/p at 336 RPM is just about spot on (this however with my old setup of four blades and tilt-back speed control). I expect this setup to be similar but with better overall performance as it should keep on chugging even in strong winds instead of starting/stopping as with a tiltback mechanism. No tilting should furthermore reduce blade stress as I imagine there is considerable additional gyroscopic force on the blades when they tilt at high RPM.

I haven't had a lot of actual running experience with the roller chain drive as this is an experimental device only. However to date I have seen no particular problems. There is a degree of noise generation though (a kind of whirring which sounds like roller chain noise) but it is really not too noticable. I would like to devise some sort of automatic lube mechanism but I don't know if it's really required if a decent lube is applied (motorcycles use chain drive v successfully and don't seem to require a whole lot of maintenance). My thinking is that they could be lubed every month or two (or three), maybe with the "silkolene" you mention and perhaps replace the chain and driven sprocket every year or so(?).

Thanks for the info on the tower - I will definately look at it - my current 20 footer is far too short, especially since it is close to trees.

One other thing - it's not present in the pics but my original two arm spider had a centralizer rod connected to it (the rod slid back and forth in a hole ithrough the centre of the main shaft and served to keep the spider mechanism aligned without binding). I have found however that the three arm spider is inherantly much more rigid with respect to side motion or rotation relative to the main shaft so I think I will leave the centralizer rod unconnected.

Laurie Forbes

25th January 2008, 20:21

Ric, thanks for your tower detail. Good idea for joining the pipe sections - I was thinking of butt joint welding with 4 pieces of angle iron bracketing each joint for extra strength (the guy wire could also be connected to the angle pieces) but I like your idea better as it affords disassembly if necessary. What schedule for the 3 1/2 and 4" pipe are you using?

I'd also be interested in how you constructed the tower base and the guy wire ground tie points. I live on top of a glacier till pile (clay mixed with a lot of rocks) which is v hard to dig a straight sided hole in. I'm therefore considering pounding in 6' lengths of heavy duty T-bar fence posts and pouring a cement pad (maybe a foot thick and 3' square), with some extra horizontal rebar welded on, over the protruding T-bars (sort of like pilings with a base cap).

What size cable did you use? I'd like to see a pic of your winch install if possible. Also, what is your top-side weight?

I guess I'm going to have to get a winch or borrow the neighbour's tractor to raise & lower. I wonder if a hand winch would be worth considering but I imagine you may need arms like Rambo to use the thing.

BTW, I envy all the flat land you appear to have. I live on 20 acres and I doubt there's two sq feet of level surface on the whole place. This of course makes selection of a mounting site harder as the the base and the ground support points for the two side guys have to be m/l the same elevation.

Ric Murphy

26th January 2008, 09:56

Hi Laurie,
The pipe is all S40. My chart shows the 4" ID as 4.026" and the 3-1/2" OD as 4.000". They fit together very nicely. I was trying to design something simple and modular. Whether you want a 2, 3, or 4 section tower you just keep adding identical components. The commercial couplers I've seen are all compression type (picture below). With this design there's no way it could ever come apart. The weight of the pipe above each coupler in conjunction with the guy wires prevents that. I can't think of any weather condition that would create enough lift to cause a failure. The sections are standard 21' in length. I don't know what the actual lift weight that the winch sees is. The 21' sections of 4" weigh 283lbs each (x3). I'd estimate each coupler weighs around 50lb (x2) plus the stub pole at the top for another 50lbs (transitions from 4" down to 2" and is 3' long) and the turbine at 37lbs. If my calcualtor is correct thats a total of 1036 lbs. Total height is approx 70'. I used 1/4" for the wires and fully admit I did no calculations to determine if that was sufficient (tend to fly by the seat of my pants too often....have to admit that might not be a good idea when your last name is Murphy!!). My main concern were the 3 guy wires that carry the weight during raising and lowering the tower. Once up there's not that much side thrust even during high winds (that depends based on the size of turbine I guess). The base is fairly simple. The mounting plate is 1/2" x 16" x 16". Welded to that are 2 pcs of 4" x 1-1/2" channel iron 8" long. These are the uprights that support the tower weight. I drilled a 1" hole thru each upright about half way up (approx 4" from the base plate). Welded over these holes are 2 - 1"ID bushings to help distribute the weight on the pin. The tower/gin pole connections are 3-1/2" pipe about 20" long. One end of each is cut on a 45 degree angle and welded to each other. I drilled a hole thru the 45 degree welded joint at the half way point large enough to accept the OD of 2 more bushings and welded them in the holes. A gusset of 1/2" plate is welded between the 2 - 3-1/2" pipe sections for strength. Lastly a 2" ring of 4" is welded over the 3-1/2" sections for the tower and gin pole to butt against.

My anchor piers are 4' deep and 18"dia, concrete filled. The tower base is 24" dia and also 4' deep. The guy anchors are 1/2" round rod (I think). I took a pc about 10' long and bent it in half forming about a 3" radius. These were pounded into the bottom of the hole before the concrete was poured. They stick into the earth about 3"-6". I figured this way they would act as a ground for the tower (but not the only ground). Yes our land here is very flat. My soil type is black, light sand down about 12" and then clay. I hired a guy to dig all my footing. He was in and out of here in no time. I think he charged me $120.00 to do 18 holes that day. You're location certainly complicates things. There is a company making a "screw" post specifically for guy wire anchors. They resemble the ones that you can buy to leash a dog to but much larger. Also might look into what the hydro company uses to anchor the cables they attach to their poles for side support. I believe they drive them into the ground with some type of impact hammer. Maybe there's an attachment for jack hammers??? My turbine is down right now for repairs and hope to get it back in a week or so. I'll take some pictures of the winch/gin pole assy for you as it's going back up. I don't think the hand winch idea is an option but a set of heavy duty chain falls should work as long as there's enough travel. If you didn't have enough travel you could stop half way, anchor with a chain and then re attach and finish. It would be slow but should work.
Later,
Ric
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Laurie Forbes

26th January 2008, 14:34

Ric, thanks much for the detailed and helpful information. Your way is the way I'd do it for tower base and guy anchor points but I'm afraid the ground conditions preclude it (That little auger machine in your pics wouldn't make it far for sure - the local power company digs pole holes with a similar sized auger and it's quite interesting to watch as they try to punch through the rocks, sometimes not successfully and they have the auger mounted on one of those big tandem axle trucks commonly employed for such jobs. I'm not sure if one could hire such a unit - might be worth looking into). At this point I'm still leaning towards pounding in fence T-bars. My current setup (20 ft tower) uses only one T-bar at each guy anchor point and I've had no problems so far. I've pounded in a couple dozen of those posts for fencing purposes and one can usually bang them through any rocks encountered - only had one which would not go in all the way. I would guess the difficulty in pounding them in also results in their apparent high resistance to being pulled out. Anyhow, I would think that maybe three posts at each anchor with a concrete top would be ample and I could do all that myself.

When you slide the 3 1/2" sched 40 into the 4" does it bind at all on the 4"ers weld seam??

You definately have a very nice tower there and I'm even more envious now of your ground conditions :) I'm a bit surprised though that your 8,000 lb winch grunts when lifting your tower. I calculate a force of only about 2,500lbs should be enough to lift the 1,000+ lbs tower weight (assuming a 20' gin pole and the winch anchored one tower height away from the base).

BTW, I would guess that you would still be OK with the present guy anchors if adding another pipe length height (considering the light weight of the turbine and the heavy construction used for the tower itself).

Ric Murphy

26th January 2008, 14:58

Laurie,
You're quite welcome! The 3-1/2" & 4" pipe I'm using have no seam welds so the fit is about as nice as one could ask for short of turning on a lathe. Actually I usually have to use a sledge hammer to pound the gin pole on but thats mainly due to rust. Last time I greased the stub and that helped but the grease has now gummed up. A squirt of oil is likely in order next time. The 8000lb rating on my winch is somewhat misleading. It only has that much pull on the first wrap of cable thats directly on the drum. Once it get's into the 2nd and 3rd wrap it's rating decreases significantly (I can't find the manual at the moment). I don't know how many layers of cable there are (I think there might be 4) but I'm only using the outer one and half of the second. If I eliminated all but just the cable I need for the tower I'm sure it wouldn't work near as hard. If I was to add another 21' section (bringing the total tower weight to 1369 lbs) what would that make the lift weight on the winch? I think I'd see a decent increase in output if I got up near 100'. The turbine manufacturer only called for a 2" tower but I went with 4" just incase I decide to go with a larger turbine someday. No sense building a second tower!!
Ric

Laurie Forbes

27th January 2008, 17:37

Ric, I calculate about 4,000 lb winch load for your 1369 lbs & 90' tower but again assuming a 20' gin pole (maybe a 30'er would be better(?)). A 30' gin pole would reduce winch load to about 3100 lbs (assuming the winch at ground level & one tower height from the base). You could reduce that somewhat by moving the winch further away.

Agreed that an overkill tower is desirable esp if you plan on a bigger turbine.

BTW, your 1/4" cable is looking a bit light for hositing the larger tower with a 20' gin pole (Princess Auto 1/4" rates at 7,000 lb breaking strength). I would like to see a safety factor of at least 2 which would mean 5/16" (breaking at 9,800) for a 4,000 lb winch load.

I have attached some more pics of my hub/blades (balancing the assembly) - looks like only a few ounces on one arm will be required.

BTW, are you the guy with the shovel? :) Looks like you have a beautiful location there - do you grow or raise stuff??
Also, are you tying your turbine O/P into batteries etc. etc.?

I'm looking forward to pics of your completed turbine including the top-end assembly!

Also BTW, I notice my "Rep Power" has increased to 2. Does this mean I am becoming famous :):)

Ric Murphy

28th January 2008, 07:03

Hi Laurie,
The guy with the shovel is my dad....I'm the photographer. My wind and solar both feed into a battery. The system is grid connected but I cannot backfeed into the grid. See this post for more info on my system. http://www.greenpowertalk.org/showthread.php?t=1369
I've now installed the last 300w of solar (1200w total) and have seen close to 7kwh on good days (not many of them though lately). I suspected the 1/4" guys wires were marginal but with the tower weight being carried by 3 cables during raising and lowering I guess I'm ok for now. Would certainly increase the size if I add another section. I'm anxious to see your bird in the air. Based on the problems I've had with my purchased turbine in the last 2 years I'm beginning to think I could have built a better one myself!!
Ric

Laurie Forbes

28th January 2008, 11:33

Ric, thanks for pointing out your previous post - I had not seen it and had not realized you have a working system. What make of turbine do you have - it sounds like you are having problems with it?

All in all an impressive installation!

Re your guy wires, I'm sure the 1/4" guys would be OK even with a taller tower but do you have 1/4" on the winch itself? - that's where the problem might lie.

It also occured to me that the long U rods you have embedded in the guy anchors (& acting as ground rods) would be similar to the T-bars I'm considering pounding into the ground. Maybe I'll strip off the paint to get better conduction and, it might also be worthwhile to run copper jumpers from the guy wires and tower pipe to the T-bar assembly(s).

Ric Murphy

28th January 2008, 13:25

Laurie,
The winch cable is 3/8" I believe. My turbine is a Lakota by Aeromag. Used to be made in the US. Now manufactured in China. Rated at 900w @ 28mph. I've seen as high as 1500w in high winds before furling. Furl method is tilt up. 3 failures in less than 2 years of actual flying time but almost 3 years since actual purchase. First 2 were covered by warranty. Current failure is worst one yet and now warranty has expired. I'm working with the Canadian distributer on this issue. We'll see what happens.
Ric
P.S. I swear the blades at the beginning of this thread are identical to the ones on this turbine
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Laurie Forbes

28th January 2008, 22:12

Ugh - not a welcome sight. I would consider salvaging the alternator (assuming it's still operable), getting some replacement blades similar to others on this thread and rebuilding everything else only this time in heavy duty. My mill may not be elegant but I'm pretty sure it would not befall a fate such as yours. I figure my total top weight will push 300 lbs and, although weight does not necessarily equate to strength and durability, there is a pretty good corollation assuming the design is not too wonky. All you need are a drill press, cutoff saw and buzzbox along with some modest welding skills (that's all I have but, then, my mill has not seen a lot of service yet so who knows?).

Dan Lenox

8th February 2008, 14:06

Dan Lenox

8th February 2008, 14:08

Laurie,

forgot to mention: the external finish of both sets are quite rough and will have to be worked, they also did not provide any protective packaging and both sets were just thrown into a box and shipped...

Dan Lenox

Laurie Forbes

8th February 2008, 16:14

Laurie,

I recently purchased a set each of the Magnet4Less 10' and 13' blades off eBay.

The prices were so reasonable ($80 & $140) that I could not resist. Now I will have to start another project... But most likely save them for future use.

The 13' blades do have a convex airfoil, quite different from the 10' blades.

Dan Lenox

Not bad prices! The 13 footer is $209 on the CMS web site (assuming they are the same blade). Even if they need a little finishing, $140 seems a bargan. I wonder though why the different airfoil?

My next project would likely be in the 16' range. They do have a set of that size but the price of $953 seems pretty wonky compared to the smaller sizes. The new turbine would likely be accompanied by a motor/alternator conversion with neos in the 3 hp range - it's scary though contemplating handling and inserting a rotor of that size covered with neo magnets!

My 12 footer is just about ready to go - will launch it when it warms up. May switch to a one stage roller chain (two stage now). For the required 4.5/1 ratio a 60 tooth sprocket (1/2" chain) and a 13 tooth would do it (both available at the local Princess Auto for not much $). I'm trying to recall why I did not do it that way in the first place(?).

Dan Lenox

8th February 2008, 16:47

Laurie,

It looks like the 2 sellers of the glass blades (CMS and Magnet4Less) are having a bit of a price war, and on eBay if our judgement doesn't get impared, then the buyers win.

More than likely I will use my purchased blade sets for turbines if my friends want to try their hand at power generation.

I made the blades for my 17' out of sassafras, it was the first time I did so and was surprized that it actually was not that hard to do. The most efficient tool that I used was an electric power planer! It removes the wood FAST! My blades will go up also when it gets warm.

My rotors were 20" diameter, each with 16 1-1/2" x 3" x 3/4" N42. Lots of attraction there, just be sure to use 3 jack screws and keep your fingers out of the way.

Dan

Laurie Forbes

9th February 2008, 11:40

Dan, sassafras? As in 'Sufferin' sassafras"? Seriously though, Wiki says "The wood is light, soft, weak, and brittle." Can you actually make blades with it?

I've seen pics of assembling a radial alternator using threaded screws but I'm referring to a motor conversion with the neos in slots on the rotor. I'm not sure how threaded screws could be employed there although I suppose something could be rigged up. I was thinking more of a winch connected to one end of the rotor with the motor case securly fastened down by some means and something rigged up to guide the rotor in. I do have visions though of the lams/field windings being sucked out of the case as I would guess the attractive force would be hundreds of pounds (for a 3 hp motor or thereabouts size).

I would sure be interested in seeing some design & performance specs & pics for you 20"er - have you posted anywhere about it? It sounds like something I might like to consider.

Dan Lenox

9th February 2008, 15:57

Laurie,

Don't believe it! I have over 1000 board feet of sassafras, it is quite strong and flexible. It works and cuts like black walnut, but I actually prefer to work with the sassafras over just about any other wood.

I also laminated it through the thickness of the blade and then used a layer of fiberglass cloth on the outside surface. Since the surface is covered I have left the tips un-glassed. The reason for this is that if/when any moisture gets to the inside of the blades that centrifugal force will drive it out the tips - otherwise it could get trapped.

In my spare time I use the sassafras to make spinning wheels.

The three jack screws are put into drilled/tapped holes in the outermost rotor plate, the jack screws that I used were simply 1/2-13 threaded rod, about 7-8" long with a nut welded onto one end.

They are used to safely put on the 2nd rotor onto the hub assembly. On my 20" rotors there are a 16 magnets on each, the specs say that each one has approx 150# holding capacity. The combined force of attraction between the plates is easily 4800 lbs - nothing to fool with.

I have a website dedicated to the wind turbine build : http://www.briery.com/wind_turbine

I also have a website for a scratch built 3-wheeler that I made: http://www.briery.com/vortex

Dan

Laurie Forbes

9th February 2008, 20:03

Laurie,

Don't believe it! I have over 1000 board feet of sassafras, it is quite strong and flexible. It works and cuts like black walnut, but I actually prefer to work with the sassafras over just about any other wood.
........

Dan, great mooga booga, that's some turbine!

I'm v impressed with the appearance of the sassafras - around here it's like pulling teeth getting suitable clear lumber for blade construction (you can't even buy #1 grade construction SPF here - it's _all_ sent to the USA). That's the main reason I decided to buy the fibreglass blades.

Was wondering where you got the drawings for construction of the mount/furl assembly (I perused the Otherpower 17' turbine writeup and while they have lots of pics, I saw no detail dimensions).

BTW, one small hint I might offer in regards to coil winding is applying epoxy or resin while the turns are added to the coil (kind of layer by layer). When the winding form is removed, the coils stay nice and tight and, they are probably better secured internally than what would happen by only pouring the resin around them later. I've tried a few experimental coils this way and it works well.

I'm looking forward to see your turbine fly Dan - please keep us up-to-date.

Dan Lenox

10th February 2008, 11:45

Laurie,

Yea the sassafras that I have is about 99.9% completely free from *any* knots it typically sells for about $4-$5 per board foot, but I got it at an auction for only $.50 per board foot! It sat drying out for about 7 years I'm told, and when you work with it, it smells fantastic!

For the 17' dimensions, you have to read very carefully in their article describing the build, hidden in there are almost all the dimensions. Then if you read their article about the 20' turbine they give *all* the dimensions for it, for the missing dimensions just scale it back a bit.

I knew about using epoxy on the coils when winding, but I am a bit of an impatient guy at times...

I too am looking forward to seeing how the turbine performs. I am located at the top of a mountain with 270 degrees of 50 mile panoramic view and we *always* have wind here! To boot the wind typically comes through the valley below us and accellerates up the hill side - we live at the topmost portion of the ridge.

When climbing my tower I have noticed that 1/2 way up when I get above the tree line that the wind wacks you pretty good and it gets stiffer the farther up I go. Just need to wait for a fairly calm/warm day and I can haul the blades and tail up - hoping for first part of April.

Dan Lenox

Laurie Forbes

10th February 2008, 13:58

50 cents/BF for clear lumber is like free! I don't know why it's so hard to obtain clear lumber here in quantity. I was in Seattle once and was amazed at the quantity and quality of clear fir, cedar, red wood etc - this stuff was so good I had to look carefully to see it wasn't artificial.

I did notice the 20' turbine article did contain dimensions - I would like to know however how they came up with it. All in all v impressuve but I'm a bit surprised at how they joined the tower pipe sections - I would have thought short lengths of 10" pipe would have made better joints (assuming the 10" tubing would give a snug fit) - maybe they just used what was on hand.

Anyhow, I hope the Wiki sassafras article is incorrect :) BTW, do you really have to wait until April? - even up here in the GWN, April is usually pretty warm.

Dan Lenox

10th February 2008, 17:37

BTW, do you really have to wait until April? - even up here in the GWN, April is usually pretty warm.

Where I live it is not the warm but relatively *calm* day that I need. I have a crane on the tower top to haul large items up and with the blades, well they tend to catch the wind a bit...

Dan

Laurie Forbes

10th February 2008, 21:00

Just ordered, from eBay, a new AO Smith 3hp 3ph 1760 RPM motor for $90 plus $40 shipping to Canada (less than half what it would cost to buy something similar here). Next to buy some neos and do the conversion :D

Maybe I'm missing the point somewhere but this method still appeals to me vs building an axial alternator from scratch.

BTW, the motor amperage at 230VAC is listed at 8.8 amps. Can someone kindly point out how to convert that to total KWs (for a 3ph motor that is).

Rob Beckers

11th February 2008, 06:54

Hi Laurie,

For 3-phase and a resistive load power is:

P = Sqrt(3) * I * V

where I and V are the phase current and phase-to-phase voltage. In your case that makes

P = 1.73 * 230 * 8.8 = 3.5 kW

That's for a resistive load, which a motor is not. So the actual power depends on the phase angle between current and voltage and is somewhat less than that (to be exact, it adds a cos(angle) term to the above). In terms of horsepower, it's 746 Watt per hp, so that makes 4.7 hp.

-RoB-

Stewart Corman

11th February 2008, 10:21

Laurie,

Just ordered, from eBay, a new AO Smith 3hp 3ph 1760 RPM motor for $90 plus $40 shipping to Canada (less than half what it would cost to buy something similar here). Next to buy some neos and do the conversionYou will be machining the armature to affix the magnets, or replacing it?
Why don't you start a new thread on your motor conversion project as soon as you get the magnets??

Maybe I'm missing the point somewhere but this method still appeals to me vs building an axial alternator from scratch.
I am in some agreement about not building an axial, having seen Jerry Ball's 50hp conversion at Mario's, but not necessarily do I understand why you would want to build from scratch, buy magnets which are not cheap, vs procuring a 3 phase/460v/PM servo motor similar to the one posted in my pics and what Mark is also implementing??

OT ..I found an old Otherpower post circa 2001, where you had asked Hugh P about building a resistance load relay controller ...did it ever get built??

Stew

Laurie Forbes

11th February 2008, 14:20

Laurie,
You will be machining the armature to affix the magnets, or replacing it?
Why don't you start a new thread on your motor conversion project as soon as you get the magnets??

I am in some agreement about not building an axial, having seen Jerry Ball's 50hp conversion at Mario's, but not necessarily do I understand why you would want to build from scratch, buy magnets which are not cheap, vs procuring a 3 phase/460v/PM servo motor similar to the one posted in my pics and what Mark is also implementing??

OT ..I found an old Otherpower post circa 2001, where you had asked Hugh P about building a resistance load relay controller ...did it ever get built??

Stew

Stew, I will be "machining" the armature but not actually machining - will likely cut rectangular slots using an abrasive wheel on a radial arm saw (did my last one like that and it worked well however it is pretty time consuming).

I will start a new thread, now as I have another question re neos.

Where does one procure a 3ph servo motor you mention (at reasonable cost that is)? I'm not sure I want to have 460V o/p but maybe they work OK at lower output levels(?). One thing to keep in mind re cost for a motor conversion is that fewer neos are needed (for a given o/p) vs an axial machine. I guess the reasons would be presence of laminations and higher RPM.

Re the load controller, Hugh has a circuit but I never did try it (couldn't find the equivalent components here , couldn't figure out exactly how it worked and, stumbled upon another much simpler solution using only a couple of triacs & pots). The triac circuit cuts in the load gradually after the voltage reaches a certain (adjustable) level. Makes non-intended use of the triacs however so liability is a question - hasn't failed yet though. With my forthcoming motor conversion will have to use higher voltage triacs however (220VAC).

Chris Martin

24th March 2008, 22:19

I ordered a set of the windmax blades (10.6' dia) from e-bay (magnet4less). they came quickly.

Their fabrication is ok, some voids in the fiberglass and some "flash" at the edges.

To risk sounding like an idiot, I couldn't tell at first which side should face the wind as the air foil seems upside down to me on this one with the "flat side" placed into the wind.

They have very low starting torque and take forever to "ramp" up even in 10+ mile an hour winds. They are fairly quite and ran well on my shaky test rig even unbalanced with out the spacing checked.

Rad Jon

17th April 2008, 10:56

I too just got my fibreglass blades and magnets from magnet4less (Applied Magnets).
Mine are the new version they just got in this month and the edges and finish on the blades are both perfect. Couldn't be happier.
If interested here are their links:

ebay store: http://stores.ebay.com/Neodymium-Magnet-For-Less

main website: http://www.magnet4less.com/index.php?cPath=8

Cheers!

Bruce Downunder

17th April 2008, 16:38

Hi,, I'm brand new here today ...

Been reading about "those" blades ,,I have a set around 3 feet . A friend gave them to me ,,he was shocked to see how rough they were. He sent them to me ,because I reckon I can do something with them .. To be honest,, they are "shockers" the workmanship is really terrible,very rough leading and trailing edges,really need ,if possible, some serious sanding and filling to get a nice finish. Trouble is ,,I may have to get down to the glass matt or further ,,so who knows what I 'll expect if I do this,,huge hollows ???.

Anyhow,, thats my honest opinion,I'm not a novice ,,made a few lovely blade sets , and have some good gear at the "IRC Photo Album " Brucedownunder.

Nice forum ,lots of interesting people and I've many weeks of reading to do ..

Thanks to the admin for letting me join

Bruce

Mark Ebert

18th April 2008, 12:29

Welcome aboard Mr Downunder :v)
Mark

Chris Martin

23rd September 2008, 21:07

the latest eBay offerings are going down in price.
He shows a new pic of the 10'3" blade:
http://i6.ebayimg.com/01/i/000/93/d5/59d2_1.JPG

This is totally different than what Ted got in the 13 footers which were convex both sides.
Jack got the 9+ footers and has them flying now ..waiting for a report, but he claims that they looked very well made and are quiet in high wind

Stew Corman from sunny Endicott

I got a set of the 13.1 windmax blades after i wrecked a 9.2 set. They are up on my super low tower amongst the trees in my yard. They were quite difficult to balance as one blade was a bit heavier ( CG wrong too) than the others.

They are very quiet and very slow. Its only been a couple of days, but they do not seem to have the TSR anywhere near 8:1. They have much better starting torque than the 9.2's though.

They rotate clockwise as viewed from the front ( I hope). The blades are difficult for beginners like me to determine direction.

I think they are the same type of construction as the 9.2 which are actually hollow ( I broke them when my test rig tipped )

Anybody have any flight time experience with these blades to share?

I hope to post a few photos and videos soon.

added crappy video

BR,
Chris