Hey Bruce, looks like i missed replying to this one. Yes. The old #2 set of blades kept us in power until yesterday.
Yesterday, the tail unfurling spring broke, and the turbine shut down. I thought it was a good excuse to put the new blades (4th version) up. They have been hanging on the shop wall for months.
They are up spinning now and making power. They are better balanced, and start up a touch better than the version #2 that were up there. They might even be better than the version #3 that broke.
I haven't really got good numbers from them yet. They were making 250w in some pretty light winds yesterday.
As always, I didn't take as many pictures as i thought i should
As you can see it took a fair bit of weight to get them balanced.
The hub got extended ears made out of 3/8" steel plate.
I also have the power furling project on the go, but I'll save that for another time.
Specs on these blades.
13' /4m diameter
2x8 spruce lumber so 1-1/2" x 7-1/4" at the root
4" wide at the tips
They are about a 20% thickness flat bottom airfoil.
3deg pitch at the tips
11 deg at the root.
The pitches were set much more carefully than before. I think this helps balance.