TM 55-4920-428-13
1-9. Hydraulic Unit Description.
(See fig. 1-3.) The hydraulic unit provides control of fluid pressures at the pressure and return sides of
the ILCA or link under test. Hydraulic fluid MIL-H-83282 is supplied to the unit from an external test
stand and controlled by the hydraulic unit. Pressure requirements range from 300 to 2250 psig on the
pressure side and 60 to 190 psig on the return side. The unit includes a 5-micron filter with a contami-
nation indicator in the pressure supply line.
a. Cycling Motor. (See fig. 1-3.)
(1) The cycling motor on the panel is controlled by the electrical unit. It is used to cycle the ILCA
under test, simulating mechanical input from the flight control system.
(2) The cycling motor consists of a gear motor, a crank arm, and a driver crank. The crank arm is
5.03 in. nominal length.
(3) The crank arm is attached to the driver crank by a shear bolt. The crank arm is secured in
stowed position by a quick-release pin and a spring.
b. PIN 1. (See fig. 1-3.)
(1) PIN 1 is stored in a hole in the panel and attached to the panel by a flexible cable. The pin is a
quick-release type, 1.1 in. long.
(2) PIN 1 is used to connect the cycle motor crank arm to the ILCA input arm.
c. PIN 2. (See fig. 1-3.)
(1) PIN 2 is stored in a hole in the panel and attached to the panel by a flexible cable. The pin is a
quick-release type, 2 in. long.
(2) PIN 2 is used to lock the ilca input arm at neutral position.
d. PIN 3. (See fig. 1-3.)
(1) PIN 3 is stored in a hole in the panel and attached to the panel by a flexible cable. The pin is a
quick-release type, 1.3 in. long.
(2) PIN 3 is used for neutral rig checks and to secure the bearing to the ILCA output arm for
the travel checks. The pin also secures bearing 145GS278-15 to the panel in stowed position.
e. Rigging Fixture. (See fig. 1-3. )
(1) The rigging fixture is an aluminum angle secured to the
ILCA input arm in neutral, using PIN 2.
(2) The fixture is 3 in. high and 4 in. long with a 1/4 in. slot
in. from the top.
f. ILCA Manifold. (See fig. 1-3.)
panel. A slot in the fixture locks the
n the center. The slot extends down 1
(1) The manifold is aligned on the unit panel by two pins and secured by screws.
(2) The manifold provides fluid connections and a mounting for the ILCA to be tested. The alu-
minum manifold contains four ILCA mounting bolts and six check valves arranged to match the ILCA
to be tested. There are three pairs of ports: ILCA pressure, extensible link pressure, and return pressure
ports. The manifold on unit No. 2 and subq includes a rigging handle and improved rigging fixtures.
g. SOLENOID Shutoff Valve. (77, fig. 6-5.)
(1) The valve is near the right side of the hydraulic unit, below the panel. The SOLENOID
manual lens (knob) is accessible from the top. The valve body is accessible from beneath the panel.
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