My first complete set of Wood Blades

[valterra]

Here are some process and final pictures of my last project.

http://picasaweb.google.com/jehmobile/WindGeneratorWoodBladesV02beta

There are captions under each picture.  Feel free to ask me questions.

I started out wanting to make the blades from a single piece of wood.  Mostly because I do not trust my carpentry skills enough to try to build 3 identical pieces, and THEN mount them at 120 degrees from each other.

I am NOT a wood-worker, and I was very intimidated by the project.  I got the plans from someone in a PDF file, and I seriously looked over them for a YEAR trying to figure out what I was looking at.  I used a hand-saw, chisel, and belt sander (with 50 grit sandpaper) to do this project.  I made LOTS of mistakes - chiseling too deep, cutting over the lines, sanding too much, but they STILL WORK GREAT.  And they only cost me 4 feet of a 2x6, which I bought for $5.  So that's $2.50 for these, with another, uncut 4 foot section for my next project.

Well, folks, if you are intimidated like I was about working with wood, the best advice I can give is to go out, buy a 2x6, and start marking and cutting away.  It all makes sense once you start doing it.  And it's CHEAP.  

I also had a lot of help from Windstuffnow Ed, who I'd wholeheartedly recommend as both an adviser and a vendor.  

As I mentioned, I made a few mistakes.  But, as I found out, this is NOT an exact science.  If you are a new person, don't be intimidated by all the talk of angles, airfoils, air gaps, etc.  

Those people have legitimate points - they are trying to extract every possible bit of energy out of their systems.  But in practice, these wind generators are very forgiving.  As long as your blades are balances and slanted, they'll work.  It's only a matter of HOW WELL they'll work.  And that will get better as you make more of them.

I mounted this bladeset to my 40v Ametek motor, which I figured out need approx 400 rpm to get to 12 volts.  I held it in my hand and saw my voltmeter peak at 15 or 16 volts in a nice, hardy wind.  This was just standing in my driveway!  PLEASE be careful if you hand-hold these things.  If they are off-balance, the amount of shaking at 400+ RPM will literally throw them out of your hand.  And the blades can seriously injure you.

Any questions, just ask!  And hopefully my next project (there's always just one more) will look better than this one!  But for now, these are going to be put to work.

[Flux]

Well done, you are right it's not that difficult when you overcome the fear.

I would strongly advise never hand holding any form of wind generator however small.

Vibration is only a tiny issue, the big problem is that you have no reasonable way to stop runaway blades. The immediate instinct is to turn the thing away from the wind. That is the day that you learn about gyroscopic forces and chop your legs or head off depending which way you try to turn it.

Very tempting but please DONT do it.

Flux

[Capt Slog]

Nice work.

I keep saying I'm going to have a go, but as you point out, it is intimidating.

Can you tell me how much that set weighs?  This is another point that has always bothered me.  The ones you have there look nice and thin, and most likely weigh less than the PVC brutes I've favoured so far.

[TheCasualTraveler]

     Thanks for that post. Time I got off my arse and carved blades. I've had the wood for a month, and like you, spent about a year looking at these things from all angles till I finnally "get it". Again, thanks for taking the time for that very encouraging post.

[mbeland]

Nice job on those blades. What is most intimidating to me is the space to put that tower on. We live on a 2 acres lot with a few trees and I can't figure out where it could fit with all the guy wires. Where and how high will those blades fly? I am starting to think about finding a friend who has plenty of space and a nice shop to share the project (coil winder, molds, and knowhow) and experiment.

Martin

Eau, soleil le vent!

[SparWeb]

Your first set of blades are always an adventure!  Thanks for sharing that with us.

I cut my first 2x6 only a couple of years ago.  Carrying it to a fence-post, it got away from me, and suddenly there was a serious gyroscope on my shoulder!

You learn quickly once you start.  Try getting a draw-knife (or "spoke-shave") to finish up the chisel work.  It doesn't have to be a very expensive one for your occasional projects.

[valterra]

That's good advice.  My Plastic 40 Gallon Drum blades ( http://picasaweb.google.com/jehmobile/Wind/photo?authkey=40RK_KqbAU8#5169085925157103890 ) had some VERY sharp edges.  I cut my finger just turning them by hand one time.

And the triangular base ( http://www.jeharper.com/windmill/ ) had sharp screws sticking out all over the place.  

YES - I would turn it out of the wind, but it was VERY scary!!!

[valterra]

They are VERY light.  Maybe 1 to 2 lbs.  And they are surprisingly strong.  

The first time I tried it (with a 1x4), I sanded the trailing edge too thin, and it started bending and breaking.

This set is very sturdy, and seems to weigh nothing.  In fact, when I stand on my digital bathroom scale with and without them, it displays the same weight both times.

[valterra]

For this kind of project (Ametek Motor, 12 volt system, low amperage), you can just mount them on your roof.  

I know that's a controversial idea here, but this isn't a kW system with giant blades.  Have a look at http://www.jeharper.com/windmill for how I mounted it before.  There's plenty of wind up there - and I didn't have to buy a tower.  

In fact, you could argue that I would never make up the cost of a tower by the increase in energy farther up in the sky.

The tripods on my roof are available as Television Antenna tripods at your local hardware store.

Like I said - I wouldn't try this with a big system.  And I had to take it off of my roof because those big plastic blades were terribly off-balance, and sent a pounding sound through the entire house.  That's another reason I went for the dual-blade design this time.

[valterra]

Yes, from someone who is NOT a woodworker or a purist in any way, I can tell you that cutting BY HAND is the way to go.

The softwood ("SPF") boards are so easy to work with.  I had to pay $7 for chisels at Harbor Freight, $6 for sandpaper, and about $12 for a saw set.  The belt sander was borrowed.  Sure, I wish I had a band saw (anyone reading this in the Omaha, NE Area??) but like I said - this wood is so soft that a hand held pull saw just cuts right through it.

[valterra]

oh, and those plastic blades spun like crazy.  You can make them in literally 20 minutes with a jigsaw or sawzall, so I DO highly recommend them.  But they are VERY HEAVY and therefore much more dangerous.