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Didn't view the video until
yesterday, and would like to recount an experience that I had. I have been
building my plane for a long time, with some long breaks between getting back to
it. So at a time when I was going to swing the gear to check wheel well
clearances, I jacked the plane up, released hydraulic pressure so that I could
manually push the gear into position. Felt the resistance of the
mechanical lock. Had forgotten about the tool that I needed to release the
pin, and was thinking that it was a type of 'lock' that just required pressure
to overcome a spring loaded pin, and that the 'extra' pressure would pop out the
lock. There was a couple of inches of wheel swing, so I just gave it a
good quick push, heard a releasing snap and the gear and wheel went up into
position.
When I let the wheel down, I
expected to hear the 'clink' of the pin resetting into and indent. Didn't
happen. Also noticed that the gear didn't want to swing quite
all the way back to its original position. Then remembered a long time
previous having to make up a tool to pull the down lock.
I pulled the assembly apart and
found that I had snapped off the down lock pin. Also saw the porting that
is built into the system whereby hydraulic pressure releases the pin under
normal operation. The material used in the pin appeared to be extremely
hard and non-ductile in nature when viewing the fractured faces of the
pin. The replacement pin that Lancair provided appeared to be not so
brittle.
Point I would like to make here
is that from my experience of breaking the pin by manually pushing on the gear,
I think it is very be possible to block the mains, apply tremendous
power as in the turbine or high powered V8's, and break the mechanical
lock. Think a lot of care needs to be taken if full power static run-ups
are done.
GaryR
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