----- Original Message -----
Sent: Thursday, April 30, 2009
18:55
Subject: [LML] LNC2 gear
Here's an interesting quirk
of the retract system, I think....
Yesterday, spurred by a
helpful LML suggestion to increase the preload in my nose strut, I chocked the
mains, weighted the tail, and supported the nose with the nosewheel an inch
off the ground, in order to rotate the nosegear up a little in order to get an
air chuck on the schroeder valve less than an inch behnd #3 exhaust
tube.
So I pushed up the over-
-center brace and pushed back the strut which moved back a little... which
reisted .... still locked up. So I opened the free-fall valve. Pushed back the
nose strut, chucked my new $22. / 300 psi made-in-china strut pump, on, and
put in the max.
Then lowered the nosewheel
to over-center lock, lowered the nose, removed the weight on the tail, and
observed 3 inches of strut!
So I pulled the plane out to
run an engine idle check, and glanced at the right wing, was shocked to see
the gear leaning inward about 10 degrees. !
I managed to get the jack in
place and raise the wing enough to push the gear in place and pull the
over-center strut to lock.
Checked the left gear... and
found its over-center strut pushed up, unlocked, too!
Jacked and pulled it down,
and then put the plane back in the hangar and ran a retract-extend check
-- after putting the free-fall valve back in closed
position.
My guess is that with
the hydraulic system closed/normal, in pushing the nosegear over-center
lock up and pushing back on the nosewheel I also hydraulic-pressured the main
cylinders to pull their over-center locks up.
So, if this is true,
then here's a scenario to consider:
Gear down, no nose green
light.
System pump or
solenoid CB pops.
SO, pull the pump CB, gear
switch in Down, valve to free-fall.
Still can't get a nose green
light. Just the mains.
To land, should the free-fall
valve be left open, or moved to closed?
If it is moved to
closed, and the nosegear is not locked over-center... will aft pressure
on touchdown unlock the mains too, damaging not only the prop/engine but also
the gear and fuselage?
Terrence
L235/320
N211AL
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