of the engines. They each contain an input bevel-
MAIN TRANSMISSION (SH-60)
pinion and gear, and a freewheel unit. The
The main transmission gearbox drives and
freewheel unit allows engine disengagement during
supports the main rotor. See figure 7-14. Notice
autorotation. If an engine fails, the freewheeling
that the SH-60 main transmission, like the engine,
unit allows the main transmission to continue to
is of modular design. The gearbox consists of five
drive the accessory unit. The input module
modules. The modules are a main module, two
provides the first gear reduction between the
input modules, and two accessory modules. The
engine and the main module.
left- and right-hand input and accessory modules
are the same, and they are interchangeable. The
main gearbox is pressure lubricated and uses the
standard oil indicating systems.
Each accessory module provides mounting
and drive for an ac generator and a hydraulic
pump package. Accessory modules mount on the
forward section of each input module. Identical
The main module provides mounting for the
and interchangeable sensors are mounted on
two input and accessory units. It has oil pres-
them. A rotor speed sensor mounts on the right
sure, oil temperature, low oil pressure, high
module. The left module provides a mount for
temperature warning, and chip detector systems
a low oil pressure sensor.
A rotor brake mounted on the tail takeoff
provides the capability to stop the rotor system.
The rotor brake disc also provides the means to
The intermediate gearbox transmits torque
position the main rotor blades for folding.
and changes the angle of drive from the main
transmission gearbox to the tail gearbox. The
intermediate gearbox has an input housing and
gear, a spring-loaded disconnect jaw, a center
The input modules mount on the right and left
housing, and an output housing and gear. The
front of the main module and support the front
Figure 7-14.-SH-60 main transmission gearbox.