hydraulically lock the canopy actuator in any
position when the canopy pneumatic control
module is in the neutral position. Flow regulators
control actuator speed by permitting free flow of
hydraulic fluid to the actuator and restricted flow
from the actuator. Thermal relief valves relieve
pressure from the double-acting cylinder to the
transfer cylinders. The canopy hydraulic actuator
is accessible from the NFO station when the
canopy is opened and the NFO ejection seat is
removed.
Canopy-Lock Pneumatic Actuator
The canopy-lock pneumatic actuator locks
and unlocks the canopy. It operates with
nitrogen pressure from the canopy pneumatic
control module and the canopy pneumatic
timer. The actuator moves the canopy for-
ward or aft to the RETR (locked) or EXT
(unlocked) position, respectively. When the ac-
tuator piston reaches its full EXT (unlock) travel
limit, the timer check valve permits pneumatic
pressure flow from the canopy pneumatic control
module to the open side of the canopy hydraulic
actuator. While the canopy closes, the timer
check valve vents pneumatic pressure from the
canopy hydraulic actuator through the canopy
pneumatic control module. When the canopy-lock
pneumatic actuator piston moves toward the
RETR (locked) position, the timer check valve
reseats.
Lock Actuator Restrictors
The lock actuator restrictors regulate the speed
of the canopy-lock pneumatic actuator during
canopy locking and unlocking.
Canopy Pneumatic Timer
The canopy pneumatic timer permits pneu-
matic pressure flow from the canopy pneumatic
control module to the lock side, of the canopy-
lock pneumatic actuator and vents or pressurizes
the canopy hydraulic actuator shutoff valves. The
last closing motion of the canopy actuates the
timer.
Canopy Pneumatic Control Module
The canopy pneumatic control module
regulates pressure from the canopy pneumatic
reservoir and directs it to the canopy pneumatic
timer, timer check valve, canopy hydraulic
actuator, and canopy-lock pneumatic actuator.
The module contains a filter, restrictor, two
pressure reducers, two relief valves, low-pressure
sensor, and control valves. If canopy pneumatic
reservoir pressure drops below 225 psi, the low-
pressure sensor causes the module valves to lock
the remaining pressure in the canopy hydraulic
actuator to counterbalance the weight of the
canopy. This allows manual opening and closing
of the canopy. Canopy unlocking is accomplished
by the auxiliary unlock mode.
Canopy Pneumatic Reservoir
The reservoir stores high-pressure dry nitrogen
for operation of the canopy pneumatic system.
The reservoir is serviced to 3,000 psi; it has a
225-cubic-inch capacity. Servicing is accomplished
through the pneumatic servicing charging module,
which is remote from the reservoir.
Reservoir Check Valve
The reservoir check valve is in the servicing
line to the canopy pneumatic reservoir. The valve
prevents nitrogen flow from the reservoir to the
pneumatic servicing charging module.
Reservoir Relief Valve
The reservoir relief valve, on the canopy
pneumatic reservoir, prevents overpressurization
of the reservoir. The valve opens at 4,500 psi and
reseats at 4,100 psi.
Pneumatic Servicing
Charging Module
The pneumatic servicing charging module is
in the nosewheel well. This module contains a
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