BLADES ?

[2windy]

Has anyone built a set of blades out of 2"x6" lumber and put a wedge under the root mount to increase the pitch? I would like to know if anyone has any success or is it a bad way of doing it. I need to mount to a 1" shaft so I am going to make a backing plate out of 1/4" plate then put a angle shim on each side of the blade then another plate on the front. The pitch that I would get out of just 1 1/2" lumber is just not quite enough. I was going to laminate 2 together then this thought came up. I have read about angle shims at the root before, but thought I would ask here before I waste my time. My rotor dia. is going to be 12'  Thanks for the comments.

[wpowokal]

From my experience in my location, I would not get hung up on starting torque unless I had cogging issues.

If there is enough wind to produce power the blades will spin, I believe too many aim for a cut in speed that is too low believing they will get power from low winds, and stalls the turbine. If one studies hard enough one will realise that large blade diamiters are necessary for useful power in very low winds. But then I'm a lone woolf likeley to be howled down.

Should you go with angle shims, provided you bolt all parts up tight I don't see why it would not work.

allan down under

[coldspot]

"put a angle shim on each side of the blade"

I've tried this on one side only on much smaller

than 2"x6" lumber.

Just shims on the leading edge only helps my "trim blades" but using trim for blades and little DC motors way to large for trim and needing many RPM's

dousn't give me a lot of room to talk! lol

But,

"thought I would ask here before I waste my time"

Thats something I've been getting better at!

Asking and researching before I go off on a wild idea!

 But I'm sure I'll do a few more anyway.

"going to laminate 2 together",

Thats also my plan on when I actually do get around to carving some, 2x6's with just about first 1/3

having a extra 2x6 laminated to the bottom and not

just clamped together but bottom one offset a bit towards the trailing edge.

darn it! "I go off on a wild idea"

There, thats how easy it is for me to get started!

lol

[SamoaPower]

If you're interested in decent efficiency from your blades, please don't design them to fit a given piece of lumber. That's almost as bad as carving an arbitrary airfoil instead of a documented one.

Do whatever is necessary to come up with wood to fit the correct design. Don't be overly concerned with what goes on aerodynamically in the first 20% of the blade's radius. Just make it strong enough.

Make sure the angles and chords are right in the outer 50% for the design TSR.

[picmacmillan]

i think that 2x? lumber is thick enough for the machines up to say 12' diameter(6' per blade)..i would use 2x8 though, and not 2x6(i have made these), unless you are in a windy location like hugh piggots place(imho), i feel there will be too much drag if you wedge the blades, and it will hurt your overall tip speed, and i would think would create more noise from the extra air being pushed by the blade???here is another option as per hugh piggot that might help?? hugh has some great plans and are available here? forgive me if you have already seen them, just an idea that came to me, but the wedge on these blades is on the front, just not the back..hope this helps ..good luck on your project...pickster

[2windy]

Thanks for the info, will use 2x8's instead. I was also thinking about the added drag, but needed someone to tell me.