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HYDRAULIC SYSTEM
The DC-3 has a pressure accumulator
type hydraulic system. It operates normally,
between 675 and 925 psi.
The Hydraulic system operates the
landing gear, wing flaps, cowl flaps, windshield
wipers, automatic pilot and brakes on all series
of the airplane. It operates the non-ram carbu-
rettor air-filter mechanism when installed and the
blower controls when superchargers are installed.
The control panel is in the center aisle,
behind the copilot's seat. The Hydraulic Gauges
are at the right of the copilot's seat, housed in
their own panel box.
NEVER OPERATE THE SYSTEM
BELOW 500PSI
Hydraulic Fluid Sight Gauge
Hand Pump Shutoff Valve
Landing Gear Control Valve
Hydraulic Hand Pump
Two engine-driven pumps supply
pressure for the hydraulic system. One supplies
pressure for the main hydraulic system; the
other, for the automatic pilot. You can select
either engine pump by means of a selector valve
on the control panel.
There is a hydraulic hand pump between
the pilots' seats. A valve on the hydraulic control
panel controls flow of pressure from the pump.
When you open the valve, pressure is built up in
the accumulator. When you close it, the accumu-
lator is separated from the hydraulic system and
pressure is applied to the hydraulic lines.
Hydraulic Fluid Filter Neck
Hydraulic Pump Selector Valve
Wing Flap Control Valve
Landing Gear Safety Latch Control
MANUAL HYDRAULIC SYSTEM
In the event of a total engine failure with
resultant loss of hydraulics or for ground opera-
tion without engines, The DC-3 has a MANUAL
hydraulic pressure pump. This pump will charge
the pressure accumulator with sufficient hydraulic
pressure to operate flaps, brakes and cowl flaps,
along with other hydraulically driven components
(such as the Sperry Gyro Pilot) whilst on the
ground, with no engine power.
The hydraulic hand pump is situated
between the pilots' seats. A valve on the hydraulic
control panel controls flow of pressure from the
pump to the accumulator.
HYDRAULIC FLOW SELECTOR
9
To operate the system, first open the red
wheel hydraulic pressure valve on the pump wall.
Now pump the handle up and down 6 times. As
you do so you will see the pressure rise in the right
hand large pressure dial on the co-pilot wall. Also,
you will see the red marker fall in the sight glass to
the lower position, indicating that fluid has flowed
from the tank to the accumulator.
You can now operate some of the aircraft
systems like flaps and cowl flap controls. This is
often necessary when the aircraft is being
serviced or of course, in emergencies where a loss
of hydraulic pressure is suffered.
This should be the FIRST
thing you do on entering
the cockpit.
The Hydraulic Flow selector
lever allows you to select between
two settings. Pull the handle outward
and swing backward for TAKEOFF,
LANDING and GROUND. Swing
the lever forward to supply pressure to
the Sperry Giropilot in addition to all
the conventional systems.
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