To: Gaseous
Cone hinges could be designed with 90 degree pitch horns.
72 degrees phase angle is crap. 90 degrees is not negotiable. Why on earth should the incorporation of cone hinges and 72 degree pitch horns determine the phase lag.
In response to quote 1): If you have a cone hinge upon which the blade flaps or cones the 90-degree pitch horn would have to reach across the cone hinge. The cone hinge in this case acts as a fulcrum. If the blade cones or flaps up the pitch horn would move down (first class lever). If the pitch horn moves down its' movement is restrained by the fixed pitch link. Since the pitch link is rigid the downward movement of the pitch horn would result in the increasing of the pitch in the blade. In order for pitch flap coupling to exist upward flapping should cause the extraction of pitch in order to return the blade to the tip path plane. The opposite would be true for the retreating blade. With a 90-degree pitch horn when the blade flaps up pitch would be added and when either blade flapped down pitch would be extracted. This would render the helicopter uncontrollable.
If the pilot pulled enough pitch to hover the upward coning blades would increase pitch over and above what the pilot pulled collective wise. And when the pilot pushed the cyclic the pitch input into the blades may be increased or decreased over or below what was input by the cyclic movement depending on the movement of the blades.
Regarding Quote 2): It was my contention all along that the phase angle of the R-22 was 90-degrees just like any other helicopter. Unlike other helicopters that had a built in rig phase angle of 90-degrees the R-22 did not. It was their contention that the phase angle was 72-degrees and the maximum pitch deflection took place 18-degrees ahead of the lateral axis and all downward flap took place in the following 72-degrees.
