Originally Posted by Snowflake
Pull into a vertical climb, and your prop is lifting your entire gross weight, half on each blade (for a two-bladed prop). I doubt you're pulling with that much force when you move it on the ramp.
What he is talking about is that the spinning of the prop and resulting centrifugal force changes the force vector on the blade so it is closer to parallel to the blade vs perpendicular. So that actual thrust load is low compared to the total load on the prop. Think of the tightrope example from physics class. The load of the person walking the rope is transferred to the tension of the rope. In this case, the centrifugal force replaces the anchor point at one end of the rope.
That said, unless someone is nuts, they pull from right up against the spinner near the root of the blade. The nickel is well outboard of that area so there is no bending load being applied to that part of the blade. I don't think it is a contributing factor to the cracking.