Irlandes:
You are correct in that teetering can also be a form of flapping, but the point I was making is that flapping can, and does, occur without any teeter, and occurs offset from the teeter point even in some two bladed systems. The point you make about conning hinges is well made, however the Heuy has a preset cone in the hub and no hinges for this purpose.
Dave:
I think you are continuing to ignore the flapping issue. As above, the blade can flap independantly of teeter, thus when one blade goes up, the other doesn't just go down the same amount as per your discussion. This means that the centre of lift, etc, will not as you theorise, stay aligned. An easy way to see this is the conning angle increase , which is not flapping but it shows that both blades can come up at the same time and demonstrates that the blades can move up and down independantly of teeter. Thus you enter the lead lag issues mentioned by Nick courtesy of Hooke's, etc. I did not know that the rotor mast absorbs lead lag, and when I think of that small Huey mast absorbing all that, I shudder. Luckily on the Huey they do have drag braces to help absorb the forces.