Wear in cone/flap hinges
Lu, you had a concern about wear in the cone/flap hinges of the R-22 head. The following bit of information should be of interest, and may be of interest to others.
I was talking to the director of maintenance for a large authorized Robinson maintenance company and I asked him about wear in the rotor head. He said that they maintained sixty R-22's. Many are used as logging company pickup trucks, and spend much time hovering, where the rotor torque is constantly changing. These helicopter have their teetering bearings changed every 300-500 hours, where as the regularly used ones have this bearing changed every 1000-1200 hours.
He said that they had never replaced a cone/flap bearing and that they appear to be good for the life of the helicopter.