Replacing spherical bearings at the wing root? (Grob Astir CS)

HI

When I owned a Astir CS some years ago I replaced those bearings. At the time I felt that they had too much free play or slop in them.
I made a device fitted into the centre of the bearing and then expanded out to grip the internal grove inside the bearing. I then had a outer cup which that had an internal bore just greater than the outer of the bearing. The system was such that by screwing up a nut on the outside it would pull the bearing out whilst pushing on the outer mounting region. I have still have the device in my shed.
Those bearings take the bending moment of the wings into each other.
In service the only time those bearings move would be during rigging and hence it should never be to large angles. Free play in the bearings would really only be noticed in load reversals. Binding in those bearings would only be a problem if they were causing difficulty during rigging.

As Papa3 mentions the secret in rigging is getting the wing angles correct. I never worried about lining up the bearings just made sure that the wing angles were correct and presto it worked for me.

johnorto at gmail dot com