What a blast!

[Peppyy]

Ok, I'm excited! Silly but this is the first mill I have had produce

power and fly.

I started with a tape drive motor from an old VCR. 6vdc and a 3 volt

super red LED with a 490 ohm 1/4 watt resistor just in-case it hit 12 volts.

I added an old piece of trim from the mobile home, a hunk of cardboard

and some masking tape for the tail. A lid from a serlite food storage container

with 8 - L shaped slots to serve as a prop or rotor of sorts. A #8 galvanized

nail and several 3/16" flat washers for bushings hammered into the end

of an 8 foot piece of pine trim.

I tried several other motors first with no luck. I could spin the shaft

and get the LED to light but I could not get high enough RPM with the rotor

to get the led to light. Didn't try to take photos of my tests, (me, driving

down the road holding it out the window with my left hand, trying to watch

the voltmeter, speedometer and road all at once). Thought it might not

be a great idea to try and hold the camera in my other hand.

By the time it got dark I had it pretty well worked out and of course

the wind had all but quit, here at least. I drove up the mountain to the

dam our local pond with the mill and my camera not even giving a thought

to how I was going to take a photo of it while I was holding it in the

wind. I lashed it off to a post with some audio patch cords that were in

my trunk and grabbed my camera.

I was almost beside myself when the led started glowing brighter and

brighter I was actully giddy. This is definatly better than beer! It's

hard to tell in the photo how bright the led was since it was pointed away

from me but I am sure it was full brightness.


 

The LED is hanging in the wind below from the test clips.

Here is a better view of the Serlite Turbo Rotor.

Well, That is my first wind power experiment and I can't wait to start

the next one

[wpowokal]

Offically adicted!

[Old F]

Yes and there is no know cure :  )

thank God

Old F

[Galagedara]

Dear Peppyy,

Its a wonderfull achevment, keep going and you will see lights! Wish every thing will be a positive result for you.

Kind Regards!

Leonard.

[hiker]

 thats what its all about[power made from scratch]...

dam ive got a itch--time to hit the shop.............................later.

[wooferhound]

Interesting prop idea there ,  Lets scale it Up.

[Peppyy]

Yep! I too have the itch, just not the shop. But that may change soon. I have a garage that is more like a avalanche waiting to happen. I would certainly have enough cloth if I wanted to male a sail type prop but I can't even find my soldering gun. I should have a 14 yard dumpster coming today or tommorow. Hoping to be able to see a good part of the floor by this weekend. Might even have to pipe my Wood Doctor into there for heat.

Woof, I was amazed at the speed of that so called prop. In further testing it lit the led around 4mph in the vehicle test. It has several unique characteristics that might not be too great for a larger version tho. With all the weight around the outer edge, it has a lot of flywheel effect so when the machine yaws the prop flexes in the center like a gyroscope. I'll try to get a video sometime.

When the wind is gusty it speeds up quickly and tends to keep spinning for a long time if the wind stops. Definatly wouldn't be good for an area with turbulance, or would it? It tends to keep the machine pointed in the direction of the prevailing wind. Anyone ever heard of a furling blade? Perhaps with a rubberized u-joint mount it might take some of the pressure off the bearing but I would think it would limit the power.

It also has a lot of wind resistance, especially with the cupped ring around the outer edge. This may improve the power by forceing the wind into the blades. Would be fun to do a wind tunnel test on it and see just what is happening there. Overall it seems to produce quite a bit of power. Maybe I should see just what else I can drive with it. It's only 9 inches in diameter.



I see testing in my future!



Questions, questions, questions. Can't wait to answer them.

[BruceDownunder]

Great Peppy.  but don't give away your beer yet, you WILL need it ,promise

bushboy

[ghurd]

Looks good.

Have you considered a lid from a large detergent, or drywall mud bucket?

About 14" or so. It would really increase the swept area.

I agree with Bruce. You are going to need your beer.  Even whiskey if you try to get it up to 12v.

[tecker]

  55 gal dum lid

[Peppyy]

Thanks for all the encouragement everyone. I have been seriously concidering a larger version of this prop though it may be rather un-conventional. We have a nice program here in VT called the Vermont Buisiness Material exchange and while I was looking through the listings I found a listing for 4.5 gallon plastic container lids. Said they had an ongoing supply and currently had 75 available. I thought about it for a minute and skipped it.

I think the inherient centrifugal force of the design would restrict the yaw too much at larger diameter and cause too much stress between the prop and genny. From what I have observed at my site, there is a lot of turbulance. Although the wind is primarily from the North or South in my valley location it does tend to get a bit gusty whenever the wind starts to change direction.

Next time the wind decides to coopreate I will try to get a short video so you can see how the prop tends to stay in one plane while the machine yaws back and forth in the shifting wind currents. That said, I plan on finding a larger motor, generator for further testing. I need to pick up an amp-meter and some supplys for a small tower, Test stand).

Has anyone ever tried using a starter motor as a genny? I might be able to come up with one of those pretty easily.

[Ungrounded Lightning Rod]

I think the inherient centrifugal force of the design would restrict the yaw too much at larger diameter and cause too much stress between the prop and genny. From what I have observed at my site, there is a lot of turbulance. Although the wind is primarily from the North or South in my valley location it does tend to get a bit gusty whenever the wind starts to change direction.

So make your yaw bearing long (to fight the tipping force) and use a pivoted furling tail (which will also limit the force trying to move the rotor toward the new wind direction).  The gyroscopic action will then tend to smooth the yaw.

Downside is that furling will be slowed, so the blade will speed up in gusts.  But the disk at the outer edge also makes it strong against flying apart, and it should still furl fast enough to keep your genny from overheating in a larger design.

[Peppyy]

So make your yaw bearing long (to fight the tipping force)

Do you mean that I should keep the yaw bearing as close to the front of the machine as possible? I would think that that would help keep the stress off the genny bearing. It probably wouldn't hurt to shorten the body or reduce the tail some to overcome the flex in the prop either.

I think I found my next prop. 21" in diameter and a really solid piece. Now I need to figure out how large a genny it would drive.

>

Maybe I will find something while I am cleaning out the garage, the dumpster just arrived.

[Ungrounded Lightning Rod]

Do you mean that I should keep the yaw bearing as close to the front of the machine as possible?

No.  Your yaw bearing should be under the center of gravity.

What I mean is:  Your yaw bearing is of non-zero height.  Think of it as actually being two bearings - one higher and one lower on the pole:

 - The weight appears as a downward force on one of them or distributed between them.

 - The wind drag appears as a sideward force - centered at the height of the shaft of the prop.  If that's at the height of the top bearing, it appears as a sideward force on that bearing, if below it's split between the two, if above it appears magnified on the top bearing and with a reverse sideward force on the bottom.

 - The gyroscopic torque from yawing the spinning prop appears as a sideward force on the top bearing and an equal sideward force in the opposite side of the bottom bearing.

The top "thought bearing" represents the top of the actual bearing and the bottom one represents the bottom of it.  This would be for something like a pipe-over-pipe bearing.  (Alternatively, if your bearing is really thin, a torque on the genny assembly (along a horizontal axis, not along the pole's vertical axis) appears as an upward force on one side of the bearing and a downward force on the opposite side.)

The spacing of the "thought bearings" composing the top and bottom of the actual bearing doesn't matter for downward weight, sideward drag, or yaw's twisting around the vertical axis.  But for torque along a horizontal axis - from gyroscopic reaction, off-center wieght, or off-center drag - it's the short arm of a lever.

The longer the bearing, the longer the short end of the lever.  The longer the short end, the lower the sideward forces on the ends of the bearing for a given torque.  The less side-force, the less friction.  The less friction, the less restriction of yaw and the less wear on the bearing.

So if you expect a lot of gyroscopic torque, you want your bearing to be long.  If it's pipe-over-pipe you'd be better with a foot than with inches of overlap.  If it's some sort of physical bearing, you might want to think about adding a second one (dealing with side-forces only) a bit further down.  (The second one needen't be as fancy as the top one, since it only deals with side-force from torque and some friction is fine.)

[Peppyy]

Wow, that made it very clear, thank you. If it were pipe-over-pipe then I should do something along these lines. (Not to scale)

The top bearing would preform 2 functions.

1. - Support the weight of the mill
   
2. - Take the brunt of the turning force for yawing
   
   

The lower bearing would then protect the upper bearing from twisting torque. That could even be a bushing since it would be a balanced load right?

[Ungrounded Lightning Rod]

The top bearing would preform 2 functions.

     1.- Support the weight of the mill

     2.- Take the brunt of the turning force for yawing

         (actually:  Take the force going ONE way from the twist from the yawing)

     Also:

     3.- Resist the side force from the wind.

  The lower bearing would then protect the upper bearing from twisting torque.

     (actually: take the equal and opposite force going the OTHER way from the

      twist from the yawing.)

That could even be a bushing since it would be a balanced load right?

It could be a bushing, right.  Because it mostly only handles one of the two equal side-forces from the gyroscopic reaction, and the greater the separation of the two bearings the lower the side force.

For pipe-over-pipe it might as well be the outer pipe bearing against the inner one.  B-)  Put in some grease (and some kind of dust seal) if you really want it to turn freely.  Or maybe a ring of delrin from Tap Plastics if you're feeling fancy.  Or just let it run dry - especially if there's a long overlap.  (A little friction only while turning helps keep the mill from wig-wagging, and the gyro reaction make the friction be in proportion to the turning rate, which is just what you want to damp oscilations.)

Can somebody with more experience actually making and maintaining mills please confirm or correct this post and/or offer other suggestions?  Thanks.