Aluminum Sheet Pinwheel

[TomW]

The material is .008 inch thick [yes 8 thousandths] aluminum sheet that is 2 feet by 3 feet. He cut one sheet down to 2 foot square and cut and folded it into a pinwheel that he attached to the motor.

Here it is. Tha pinwheel measures about 34 inches tip to tip on the points.

Here is Lane doing duty as a tower. This thing actuall spins up pretty well and seems to zip right along.

This was simply a prototype "will it work?" excercise. The only support is a 1 & 1/8 inch diameter quarter inch plywood disc behind the center. This allows a lot of flex and the blade was tending to rub on the mounting hardware for the motor. It had a tendancy to rotate from any air movement including walking with it in the air.

As you can see one of the "wings" got pretty distorted right away but we know what the problem is and have a solution.

Maybe more another day.

Cheers.

TomW

[windstuffnow]

Hi Tom,

   Here are some tips on keeping it going.  I built one 3 years ago and found it to be quite flimbsy.  I added a square piece behind the pinwheel and riveted it together.  Added 2 large fender washers to the front mount.  Make a crease in the trailing edge of each blade ( bend it at about 3 or 4 degrees ) about 3/4 inch in.  So far mine has been up for 3 years and has been through some pretty heavy storms with 60+ mph winds.  It has a threaded rod through a piece of tubing that has been greased twice now... its still going.  I've attatched it to a couple generators and a few homemade alternaotors for testing and you'd be surprised at the power you will get from it.   Mine came out to 27 inches tip to tip.  It will make 50 watts in a 30 mph wind... not super efficient but its torky.  Mine runs at a TSR of just over 2... I'll have to get a picture of the old wreck.  Lots of Fun!!!

Ed

[TomW]

Ed;

Thanks for the feedback. I was going to try a paint can lid as a stiffener for the backside of the pinwheel mostly because I have one around.

Just curious what material and thickness yours is built from? And by "crease" you mean like the little bends they put in ductwork to stiffen the sides of a plenum? I've seen them do those with a screwdriver and "score" the piece of sheetmetal in an X shape.

Cheers.

TomW

[windstuffnow]

Here is a picture of the pinwheel

http://www.otherpower.com/images/scimages/15/front.JPG

http://www.otherpower.com/images/scimages/15/back.JPG

I couldn't figure out how to do the IMG SCR thing so hopefully you can click on the links

The back shows the aluminum plate I used as a stiffener and the front shows the crease in the trailing edge as well as the washers in the center.  It was a fun project... quick and simple

Have Fun

Ed

[TomW]

Ed;

Funny how the simplest things can actually work.

We were thinking of a 2 blade version but it has not clarified itself just how to do it.

Thanks for the pictures.

Cheers.

TomW