>I have just assembled my main landing gear swinging arm for the first time,
and
>was surprised at how little the extent of overcentre was in the 'down'
>position. I had trouble in measuring the extent exactly (the line from the
>centre of LG09 shaft to the lower pivot LG04 is difficult to define), but
the
>overcentre could only be a couple of millimeters measured at the top plate
>(LG05) pivot pin centres when the LG08s are on the stops and the swinging
arm
>is unloaded. Mindful that there have been a few incidents attributed to
>failure of the latch/overcentre mechanism, I was wondering what the
'normal'
>degree of overcentre is. If anyone can remember, or is in a position to
>measure, their overcentres, I'd be grateful for any advice.
Hi Dave
Sounds about right from what I can remember. If the overcentre amount is
excessive, then extra bending loads would be put on the components, and
operation would be difficult.
The incidents relating to gear collapse I think you will find were due to
either the safety latch not being engaged or not functioning correct, and
movement in the operating leaver attachment which allowed the gear to
retract rather than collapse.
Jim Naylor
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