Zub-woof type blades

[coldspot]

I am wondering about building a blade of this type using

old sprinkler pipe, aluminum 4" or 6" dia

Has anybody tried that?

I have built many using paper towel tubes and hooking to stepper motors.(need clear coated for strenght)

They work in the smallest of winds, I mean NO WIND even!

They will spin while walking slowly or even just breathing on them!

I am not finding any 8"+ Dia plastic for testing, yet!

So sprinkler pipe was just a thought.

[nothing to lose]

Thanks for the thought on Paper towel tubes

 Never thought of using those for blades. I save all that stuff, toilet paper tubes, wrapping paper tubes etc.. good for many things like packing sawdust into for little logs or fire starters.

As for the aluminum, you have to worry about stress related failures. It may look strong but it will flex a bit in hard winds and yawing and such. Eventually it will crack and break sending a blade flying somewhere. That would of course be more of a problem on larger rotors than smaller ones. Might be ok to use a decent thickness aluminum blade for a 2' rotor but I would not do 8' ones.

Wood and plastic will flex better, wood won't break as easy with stress, and if plastic breaks over time it is lighter weight and maybe sort of  feather out in flight. Aluminum would probably be a bit more like a spear or bullet. I see lots of aluminum hunting Arrows, not many plastic ones.

Well time to go re-invent the wheel

 Bicycle wheel with aluminum cans on the spokes, multie finned rotor, maybe some torque??

 Another wheel and more cans for a Vawt

 Bikes are every where cheap or free, perfectly good new looking bikes in scrap yards always. After Christmas I'll be finding tons of them just like new tossed out as scrap when the kids get new bikes. Lots of good parts for gennies perhaps. Thinking front forks for a mount, wheel as rotor, already has yaw bearing on forks too.

[cyplesma]

I've been collecting bikes just for this reason.

still unsure on the details of use. I was thinking about bending the rear forks to meet together to mount the genny there. use the yaw bearings from the front forks would be used on the pipe where the seat is. use the front part of bike as tail. balancing would certainly be the next trick.

I found a 10' 8" pvc sched 40 pipe along a freeway recently, I'll be keeping that for a blade.

I cut a plastic tube (used to sell needlepoint cloth) similiar to what you drew up in paint posted a few years ago. mine was not as flat as yours (I guess I'll have to draw mine up) but it seemed to spin up quickly in low wind as well. but..... it didn't have any real load on it either.

[IntegEner]

"...it didn't have any real load on it either."

Yes and so? Don't leave us all hanging. Should this idea be scrapped or can something be done to maintain torque under load? Otherwise it is just a tease.

It is my opinion on the matter that these "pipe", "PVC", "gutter", "tube", or what have you, blades are actually worth while and need some thought applied to them. The leading edges as cut out are invariably sharp with no rounding at all, like a knife edge, even just a sort of dull knife. This works for a narrow range of TSRs, requiring that the blade spin at a rotational speed that is close to a fixed ratio of the wind speed. So if an extra heavy load is applied the rotational speed is reduced below this speed and the torque stalls out. Or so it would seem.

Those who follow this line of endeavor usually go on to the "logical" conclusion that more blades are needed and then add them. Six and eight bladed rotors are the result.

Another, possibly better, answer is suggested herein. The leading edges would hold the flow attachment for a wider range of TSRs if they were made more rounded like the leading point of a comet with its radius of curvature. This can be done by maybe bending some sheet metal aluminum (or even steel) to the proper shape and fastening it on to the leading edges with some pop rivets - easy and simple to do. (I think pop riveting is a great way to fasten things together.) The result? Blades that are now thicker at the leading edge but will have better start up torque and will maintain torque under load better.

I have placed this post thread on my hot list for purposes of keeping an eye on it. I bend aluminum sheet metal to within close tolerances of curvature by means of wood dowels as a template and get the folded edge to close back quite well with with some padding applied to the surfaces that is struck with a rubber mallet. See the images on my website.

Anthony Chessick

www.integener.com

[cyplesma]

Here's the way I cut my test blade.

My "theroy" is instead of making a blade to spin faster in high winds, the blade should have some type of drag.

but.. should collect/grab a lot of wind in low wind.  So instead of trying to get the blade to spin as fast as it can in all wind speeds, don't worry so much about it spining upteen hundred rpms in winds of 45mph+. Just worry about trying to keep the blade spinning strongly at 200-300 rpms in 2-5 mph winds. give the blade some drag so in high winds it maybe only spins at 600 rpms.

My personal progress to date is:

-I got 16 wedge magnets

-14ga coil. I've winded my first coil several times now, keep undoing it to see what kind of consistancy I can keep.

-no workshop, doing work in 6 X 10 area of 23 x 26 living room. cut stuf in laundry room

-still need batteries, charge controller, wire from genny to whereever I decide to put battery bank

I've lurked on this board for several years and love what I see. Hugh's design is great and I believe I can make my own someday also, but I probably won't get mine flying till sometime late summer 06. I'm quite the procrastinater so we'll see.

I do think hugh's design is great for 500 watts and to get more I think it'll take more rotors/stators pairs. the lenz2 is doing great as well,

but... if someone is looking for the silver bullet to get to say 2k watts in 10mph winds it'll be awhile. I my self hope to get there someday.

[cyplesma]

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