I built one of these 2 days ago and was doing some testing. I got one of my planes that I've been flying for a while and I was getting weird readings. Then I realized something that I don't recall reading in any of the Vanessa CG info out there. If the dowel is not parallel to the wings, and your plumb bob is hanging from one of the dowel legs, then you get a wrong reading. By how much, it depends on the angle that you have between the dowel and the wings.

It was late last night and I was trying to figure it out why sometimes my dowel is not parallel with the wings. I think it's due to the fact that I'm using a single loop on the fuselage. Every time I hoisted the plane and had to rotated the dowel to get the horizontal stab at 0, the plane would tilt to one side. I had to grab the plane and adjust side to side, when I did that, that's when the dowel started showing an angle to the wings. I tried to manually twist the whole thing and try to eliminate the angle, but it doesn't seem to work and it's not reliable, so I ended up putting the plumb bob hanging from the center of the T. The bad part is that now I have the plumb bob right on top of the fuselage and not on top of the wing, but at least should be a lot more reliable. The other thing I might try, is the 2 loops and hang from the wing, instead of fuselage.

Any thoughts?