TM 55-1520-240-23-5
6-1
DRIVE SYSTEM
(Continued)
6-1
FORWARD TRANSMISSION
The forward transmission receives input torque from
the combining transmission through the forward drive
shafting. It transmits it directly to the forward rotary-wing
head and blades through an integral shaft.
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A slider shaft is mounted around the integral shaft and
bolted to the top of the transmission. It provides the
bearing surface for swashplate motion.
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An integral spur gear at the bottom of the transmission
provides power to drive a pump for the flight control
hydraulic system.
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The transmission is bolted to structure directly above the
cockpit. It is part of a package that can be removed and
installed as an assembly. In addition to the transmission,
the package includes the rotary-wing head and head
controls, a weather-protective cover, and two flight
control bellcranks. Access to the top of the transmission
is through hinged work platforms at each side of the
forward transmission fairing. Access to the bottom of the
transmission is through a removable drip pan.
Lubrication System
The forward transmission is lubricated with oil from a
sump at the bottom of the transmission. Oil is circulated
by main and auxiliary pumps mounted on the bottom of
the transmission. The main pump is externally mounted.
The auxiliary pump is covered by the sump.
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The lubrication system is monitored and protected by
the following:
A combined indicating screen and chip detector and
temperature sensor on the sump.
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A pump inlet screen inside the sump.
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A main filter inside the main pump.
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Main and auxiliary pressure switches, an auxiliary
filter, and an inlet screen on the left side of the
transmission.
Hot oil from the transmission passes through a circular
oil cooler mounted on the aft end of the transmission.
The oil is cooled by air forced through the cooler by an
impeller. The impeller fit within the cooler and is splined
to the transmission input shaft.
6-5
