Maybe if we built our rotor blades flexible enough we could do without hinges (or teetering). But actually blades do flex quite a bit - well I`m sure mine do as I have had a blade strike the fuselage although seemingly having plenty of clearance when still on the ground.
Stabilty - OK, the blade advancing into the airflow lefts to neutralise lift, still seems amazing that this happens automatically to just the required amount. Part of the magic of autogyro flight! But why does the blade lifting kill off lift? This puzzled me until I realised that it is to do with `angle of attack`. This angle is all important as it on this that the degree of lift of a rotor blade (or a wing) depends. When moving upwards the angle of attack on this blade is not the same as the retreating blade, because there is an upward movement, as well as a forward one, the airflow has a degree of downwards flow (because the blade is moving upwards a little). Therefore the angle of attack is less, meaning less lift, balancing out the more lift generated by the faster airflow. Phew!!!!!!
Colin