To: Dave Jackson
I honestly can’t say how much the blades flap but they flap sufficiently to induce leading and lagging. If you remember in another thread an individual indicated that they used a training aid in one of his classes in a Robinson school. He indicated strange wear patterns on the cone hinges. His instructor told him the wear pattern was caused by excessive power application. In actuality the elliptical wear pattern was caused by a tendency to lead and lag with this lead and lag being reacted by the cone bushings. The rotorhead was removed from an Australian R-22 that was used in cattle mustering where they are constantly maneuvering the helicopter. I saw the same pattern on a rotorhead that came off of an R-22 used to train Japanese pilots at a flight school in Everett, Washington.
Because of the wear pattern I would venture to say that there is a lot of flapping going on.
Regarding the amount of pitch change Vs flap angle I am looking at a very detailed drawing of an R-22 rotorhead. In the picture the pitch change rod is coincident with the cone hinge. Looking at the drawing and visualizing the upward movement of the pitch link and then trying to visualize the flapping angle it appears that there is some degree of pitch change with flapping but I can’t say how much.
[ 05 December 2001: Message edited by: Lu Zuckerman ]