I have to go back a few years to give you an answer. If I remember correctly on the CH-37 the centrifugal loading exerted by an individual blade on the attachment cuff and then to the head was somewhere around 72,000 pounds. On a smaller helicopter (S-58) it was around 24,000 pounds.
As an aside, I once sat in on a maintenance course for the H-37 and the instructor was asked what would happen if one of the blades came off. His reply was that the other blades would move accordingly and take up for the missing blade. These blades as massive as they were are balanced to ¼ inch ounce.
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The Cat