Yet another Pinwheel.

[TomW]

Thats a 6 foot diameter blade on a 40 volt tape drive motor. It spins in very light breezes but seems lame at any high speed but no real wind to test it either. Rule #1

These 2 are shots of our high tech, mobile test facility.

Bottom line is it starts easy runs slow and is too flimsy. We had a good time and it was a learning experience and we have ideas on a 3 foot or so 2 blade pinwheel.

Heres an mpeg file of it actually ripping along at 3 or 4 rpm:

http://www.otherpower.com/images/scimages/4/MOV01653.MPG

Cheers.

TomW

[windstuffnow]

    I never took the pinwheel to such heights.  The main reason they slow turning is because of the bulky leading edge.  This causes lots of drag.  If this could be worked down a bit it might make a reasonably efficient prop.  One idea that came to mind ( never tried it ) was to install an aluminum tube for the main structure of the wing and wrap the aluminum sheet around the tube forming a less bulky leading edge and adding structure to the wing.   Sort of forming a "," shape(comma shape- you know what it looks like if you write it).  They would be vulnerable to stress cracking which there are a few of those on mine.  I get antsy to build another one so if it made a couple years use without any problems there would be another in it's place shortly after.  I like to see new idea's good bad or indifferent... I especially like to see the really strange ones... I have a few of those

Lots of Fun!

Ed

[TomW]

Ed;

Reck n Destroy.

Well, that 2 blade one did not survive the night with the awesome 8 or 9 mph gusts we had.

Way too much flex and it actually folded forward on itself and had developed several stress cracks around rivets. A couple of spots had problems from being against a square edge a known problem I think.

I'm looking at several other options including an actual formed wing shape with foam injected but im kinda slow with limited ability and none in metal working. Plus that gets away from "pinwheel" and into "formed metal blade" territory.

The most successful version so far is the standard 4 blade pinwheel shape. I'm thinking on a way to do 3 blades. Its mostly the fun and anything learned is icing on the cake.

Cheers.

TomW

[windstuffnow]

  Foam injection sounds interesting, I've cut a few sections of foam with a homemade cutter ( basicly an "E" string off a guitar stretched between a couple dowels and a battery).  Cuts some nice airfoils.  Keep us posted on the foam injection stuff... sounds fun!

Withdrawl's... getting weak... need... windpower..

Have Fun!

Ed

[Norm]

   A couple of weeks ago I was thinking about the aerodynamics of a pinwheel and the feasibility of using it to drive a generator and here it is ...I should have known it's probably just a coincidence...but still seems weird, well anyhow, I'm thinking with reinforcing along the edges some epoxy and a lot of pop rivets it would really fly! Great job ! Real neat!
Norm.