So, today we spent all day on fixing the balance of the machine, and while it is a lot better now than yesterday it is still not perfect.
Balancing on the machine is really really hard. We built a test rig that allows us to spin the machine close to the ground (either by hand or let the wind take it).
That gives us all kinds of ways to check things that would be a lot harder when it's 60 feet up in the air.
First thing we fixed was the tip of the governor. The allthread simply wasn't rigid enough to support all that weight dangling of it, and I suspect once it got upset a bit it started to make the problem worse in a hurry. So, I made a quick fix, a ring that I still had with a nut welded to the center of it and a bunch of threaded rod to the baseplate to stiffen it up.
Then we improved the tracking a lot, all blades now track within about 5 mm, and we corrected the angle of one blade by about a degree or so.
Last change was the balancing itself, this took the rest of the day, whenever there was a lull in the wind and we could see what we were doing.
We almost managed to get ourselves to the hospital, I figured the neos we used for temp weight attachement would hold the nuts on just fine, and seconds after I told Johannes I couldn't possibly see how they could fly off one did and hit the ginpole with a loud PING.
Famous last words...
We brought it back down again and taped all the nuts with some duct tape and took it back up.
It's been running for the last 8 hours or so and making a bit of power (about 200 to 500 watts). So far so good !
Tomorrow more balancing, then when we know the required weights we'll machine them from one piece, bolt that on and trim to the exact weight (machine them a little overweight).
pictures follow:
The test rig we built, basically a way to spin the machine about 10' off the ground. Pretty scary to be up close to that thing when it's doing 150 rpm or so, and being on a hill it'll easily pick up that much wind even this close to the ground.
A clsoeup of the changes:
