Originally posted by hobbsy
I just don't see how this is possible, if one balde has an imbalance of .25 of an ounce on the blade tip and another has an imbalance of .25 of an ounce at the root but the two weigh the same, the extra .25 ounce at the tip is going to be influenced by far more force than that at the root.
Your example would change the CG of the prop. Any object always rotates exactly aroung its CG. This is true at ANY RPM. An apple floating in the space station, when spun slow, has NO DIFFERENT vibrational node than if spun fast. It will spin around the same CG, slow or fast. So does a propeller. It doesn't matter HOW you set that CG. A small mass far out, or a big mass close in. One side can have a big mass close in, and the other a small mass far out and the CG will be right in the middle. The prop will still want to spin at the CG, period. Once you are mounted off the CG, the prop will still want to spin around the CG. The difference between mounting position and CG and the forces trying to spin the prop on the CG we know as vibration.