Quote:
"I didn't quite understand the term "all the blades are in the same plane"."
Yes, it's usefull and intuitively understood by some, but isn't really accurate. Blades have thickness, so can't all be in the same plane. The term means that the planes defined by points at similar locations on the blades are perpendicular to the axis of rotation.
I'm not sure what you mean by 0-0 balancing.
Quote:
"Furthermore, there is a remaining question that comes accross my mind every now and then, looking at the turbine/ rotor from one side (at 90 degrees) the tips or even the whole blades may not seem staright, i.e. one looks leaning a bit forward and the others backward, and the tips may pass at different points i.e. one tip might cross at a point and the other may not."
You've got it! That's tracking, and it IS important. Tracking errors will also make the tail "wag", usually at moderate rotor speeds. On turbines of 3 meters diameter or so, the tolerance between blades at the tip is about 1/8", if I recall correctly. Closer is better, but unless it's done on a stationary fixture with a fixed reference point to measure from it's difficult to be more accurate than that. The tracking can be changed by shimming or removing material at the hub, or sometimes by variable tightening of the blade mounting bolts.
And while you're checking tracking, take a look at the tips to make sure that they're pitched to spec, and that they're pitched the same.
Your balancing method (A) can work well, or not. It's similar to balancing the assembled rotor on a point, ala balancing a lawnmower blade. The sensitivity of both methods depends on where the wire is attached in relation to the "vertical" Center of Gravity of the rotor, or if using the point, where the point contacts the rotor in relation to the vertical CG. The higher the contact or attachment point in relation to the CG, the less sensitive the method. So it's hard to say if you've got a balanced rotor or not from doing just A. B verifies A if the rotor was repeatedly allowed to come to a stop in varying orientations, didn't display any "heavy spots" and there was very little bearing drag. With what you've done already and making sure the tracking and the pitch are right, your rotor should be good to go.
If I've made you nervous about your balancing, it's easy enough to check your balancing by the moment method. A scale accurate to 1% of blade weight, a blunt knife edge, tape measure and a calculator are all that's required. The information gained is usefull, too. If, for instance, blade replacement is necessary, a replacement blade with the same moment (+ or - 2%) can be substituted without taking the entire rotor down for rebalancing. All because the results of the moment method are quantifiable. No other static balancing method is.
Neil