brakes are shut by the airstream. This action is
brake control switch to the IN position. This
necessary only if the speed brake relay does not
de-energizes solenoid A by removing the power
energize when the speed brake control switch is
to the solenoid and energizes the speed brake
in the IN position. If an electrical failure (such
relay. The action of the speed brake relay removes
as a popped circuit breaker) occurs with the speed
the power from solenoid B.
With both selector valve solenoids de-
brakes extended, retraction is the same as
actuation of the emergency retract switch.
energized, the selector valve permits pressure flow
to the retract side of the speed brake. It also allows
Canopy System
return flow from the extend side to the hydraulic
ret urn. The speed brake warning light goes out
As you already know, solenoid valves have
when both speed brakes are in the fully retracted
many applications in naval aircraft. The canopy
position.
hydraulic system shown in figure 4-20 is an
electrohydraulic system using a solenoid selector
EMERGENCY RETRACTION. --To accom-
valve. The canopy selector valve is a four-way,
plish emergency speed brake retraction, place the
emergency speed brake switch in the EMER-
two-position spool valve, which actuates either
RETRACT position. This switch de-energizes
electrically or manually.
The canopy system consists of a sliding canopy
solenoids A and B of the selector valve (normal
mounted over the cockpit area and the com-
solenoid positions for retracting the speed brakes),
which connects both the extend and retract sides
ponents required for normal operation and
emergency jettison of the canopy. The entire
of the speed brake actuators to the system return.
With the removal of hydraulic pressure, the speed
system is hydraulically operated except for the
Figure 4-20.-Canopy system.
