There are two hydraulic-lock-valve panels, one for
the launch valve (fig. 4-15) and one for the exhaust
valve (fig. 4-16). The launch-valve hydraulic-
lock-valve panel consists of two air-solenoid valves, a
hydraulic lock valve with lock positioner, the launch
pilot latch solenoid, and piping connections. The
launch-valve hydraulic lock valve (fig. 4-17) provides a
hydraulic lock to hold the launch-valve control valve in
the FIRED position until launch is completed or until
the launch-valve emergency cutout valve is placed in
the EMERGENCY position, by controlling the flow of
fluid to the launch-valve control valve.
The launch pilot latch solenoid controls a plunger
that prevents the lock valve from being shifted to the
FIRED position unless the catapult control system is in
the FINAL READY phase of operation. (A manual lock
screw [fig. 4-17] is provided to secure the valve during
nonoperational periods.) When the catapult FIRE
circuit is energized, the fire air-solenoid valve directs
air pressure to shift the lock valve to the fired position.
This causes pressurized fluid to be directed from port A
through port B to the launching-valve control valve, the
keeper valve, and port D via the launch-valve
emergency cutout valve. Fluid pressure in port D
hydraulically locks the valve in the fired position.
When the catapult LAUNCH COMPLETE circuit is
energized, the close launch valve air-solenoid directs
air pressure to again shift the lock valve, venting port D
to gravity and directing pressurized fluid from port A
through port C to the launch-valve control valve and
closing the launch valves. (During a HANGFIRE
condition, port D is vented and port C is pressurized
when the launch-valve emergency cutout valve is
placed in its EMERGENCY position, ensuring that the
launch valves remain closed.)
The exhaust-valve hydraulic-lock-valve panel (see
fig. 4-16) consists of the exhaust-valve hydraulic lock
valve, two air-solenoid valves, and piping connections.
SOLENOID VALVE (FIRE SOLENOID FS)
Figure 4-15.Launch-valve hydraulic-lock-valve panel.