Have you ever seen those toy radio controlled helicopters where the rotor blades are connected by a ring? Do you ever wonder why real helicopters are not that way? Well one reason is because helicopter blades flex quite a bit. Yes a scary thought indeed, but they are suppose to be that way and actually safer because of it. But what if a ring around the rotor blades also flexed or controlled the flexing moving outward or inward?

Of course one obvious question that any student of aeronautics would immediately explain that there are indeed aerodynamic issues to consider as the ring will block airflows at certain angles and become dangerous to the rotor blade