I love having days off so I can play
Over the past couple days I've been winding new coils from #26 wire. Yeah, I know, it's still small. Anyway, 6 coils, 100 turns each. And a sloppy job of it, too. Couldn't get the tension right. Ended up with 1 coil too tight and 2 that were too loose. The other 3 were so-so, not good. I think it was too many turns for too small coils. Mounted them to some perfboard in the same fashion as the original coils. They are also thicker than the original so the air gap is also greater.
Performance sucks, for the most part. Using the caps doubler I only saw a max of about 2.5 volts and an occasional 80-90 mA. Most of the time around 20 ma. Barefoot was an easy 2.5 volts and 140 mA, though I did see 5 volts and 500 mA on one good gust. So, the doubler was a bust in this experiment. Bigger caps maybe?
I did flatten out the blades a little, got the twist and angle a little more even. Can't say it made an improvement, but I can't say it didn't either. The biggest improvement by far came from shortening up the blade by 2 inches. Starting seems easier oddly enough, certainly RPMs seem higher. There is less hunting, it seems to have a more stable point into the wind.
I also messed around with trying to get a good reading on RPM but no dice. The best I could get was an initial reading for about 3 seconds and then nothing but 0. I have another unit to try, we'll see if that's any better.
Ghurd, I was worried about the flex having a negative impact on AoA also, but that doesn't seem to have happened. At least not that I can point to definitively. The spar is just slightly forward of 50% chord, so perhaps I've just been lucky and I'm not getting any additional twist. An ultra high speed camera would be nice to prove it one way or the other
Yes, wood blades are definitely in the future. Not sure that I'm ready for them just now, but it will happen fairly soon. I think I want to try one more set of foam (yes, I'm stubborn).
Kevin