Hi,
When checking the aircraft (without the tailplanes installed) I
discovered that the vertical trim motor sounds like it is running
without load briefly just after changing trim direction.
Further examination revealed that this is caused by the friction device
in the trim mechanism. This thing is (by design) out of the center of
the trim bellcrank, and therefore it bends/realigns a bit before it
starts pulling through the friction slot.
Looking at it when changing trim direction repeatedly, I observed that
the whole frame torques a bit due to the friction and change of angle of
the center bolt. I guess this is normal, but of course at the end it may
cause metal fatique.
There is no hint in the manual how to set this friction contraption,
neither is there an explanation why we need it. For small trim
deviations the thing is useless anyway because of the slack in the
system due to bending and torqueing of the various components.
Has anyone any insight in the purpose of this friction device and how we
are supposed to set it? Have others also observed the slack in the
system and bending/torqueing of the frame?
Frans
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