Lu
The blades would only 'hang back due to inertia' while the blades were accelerating. After they had reached a constant rotational velocity, the tangential effect of inertia would be nil. They may well hang back due to air resistance, and indeed, they are pivoted at the base to allow them to do that.
I don't thing the reference to the moon really helps, because the motion and forces experienced in the plane of rotation, assuming this is horizontal, are entirely independent of gravity. This is really the answer to the original question about 'weight'. Out-of-plane accelerations open up a whole new can of gyroscopically precessing worms.
Pie