Best angle for simple flat blade windmill

[Norm]

http://www.fieldlines.com/story/2004/10/4/22307/2023

and I'm putting blades about that size only flat from thin plywood, don't need speed just torque and start up in 7-10 mph.

  Eventually, I plan on having a variable speed drive for it, then it winds up a weight to a certain height...then releases it energy thru a DC generator!

  Don't have much wind but just making use of what's there.

   I can just imagine about every half hour of silence ...then click! Whir! Thump! As it puts out a few amps for maybe a minute...be fascinating to watch at any rate! Spelled Fun!

 ( Yeah one way or another I'll get those blower motors to putting out some useful power)

    Today is definitely not for HAWT....wind changes direction every minute....spends more time yawing than spinning....looks like a ballerina...

    Probably be interesting to put a string on it like it was a power cable and see if it would twist up or average out.(it's just a model)

               Fun just thinkin' about! stuff like this.....

think I'll try the string bit for now....maybe I'll learn something....

                       ( :>) Norm.

[Ungrounded Lightning Rod]

If you want an untwisted blade you might think about having paddles on the end of rods rather than blades coming clear down to the hub.  Most of the twist is near the hub, so an untwisted blade will stay efficient for much more length if it's out from it.  Also,  the farther from the hub, the more swept area per unit of blade length, and thus the more power collected ditto.  Your Midblade-speed-ratio will be roughly the cotangent of the angle from flat, and the TSR about that times the diameter at the tip over the diameter at midblade.

If you do that, you can aldo put a second set of flat blades near the hub at a higher angle, getting a piecewise approximation of a twisted blade.  (These can provide extra starting torque if you have a coggy genny.)

[hiker]

built a flat four blade prop sometime last year for my geared up alt..

worked okay --but the blade was to big for the size of tail i was using at the  time.

kept on yawning back and forth.. never did get around to making a diffrent size tail for it..every time it spun up in the wind it would get kicked out--then start the whole procces all over again...somthing to mess around with later!!!!!!

[hiker]

i made the hub from plywood scraps--then just cut the slots for the blades with a hand saw--drilled out the bottom of each slot...fast easy prop........

its a real torker if thats what your lookin for......

[westernoutlaw]

i just put up a win mill built out of blower motor from camp trailer.furnice.

tryed flat blades. just went around and around tracking into wind. (no spin on blades).

took fan blades off a indoor house fan .started spinning in very little wind.

put 1156 light bulb on it to see if  it will light it up or not wind died. still waiting for it to show back up.lol

 read alot or peaple looking for cheap inverters and stuff.i took old travel trailer apart. given to me free. it had inverter/charger.300 va output.

 some 1 is always trying to get rid of old trailers.some even have genys in them.

 ( just a idea )

[Norm]

   All good ideas ...Like yours about the best Hiker...

so now looks like about a plain 45degree angle

in the slots? I like your projects a lot plain

 and simple and they work I think I'll try it!

 Thanks for the help you guys! I appreciate it!

            ( :>) Norm.

[hiker]

that was just a test prop--i would taper the blades more as they get near the end..

leave the blades wide at the hub that is and then taper them out..

and of course put a sharpe edge on the leading edge---maybe some what of a airfoil

on the back side.........

i think that hub would work with some good hand carved blades--or some abs plastic blades like jerrys...

its what ever works for yah.................