TM 1-1520-238-T-5
Change 1
7–31
7–7.
SYSTEM DESCRIPTION (cont)
7–7
(d) The longitudinal, collective, lateral and directional servocylinders (fig. 7–14) are of tandem design
and utilize primary and utility hydraulic system pressure. The servocylinder has two modes of operation, normal
and BUCS (refer to TM 1-1520-238-T-7 for BUCS operation). During normal (mechanical input) operation,
pressurized fluid from the utility hydraulic manifold enters the servocylinder through port P2. Fluid is routed
through a one–way check valve to the stability augmentation actuator. The check valve prevents pressurized fluid
from being forced back through the pressure port. The manual servo valve and stability augmentation actuator
control both the primary and utility system fluids in the servocylinder. The position of the manual servo valve and
stability augmentation actuator determines if fluid pressure is equalized or routed to the piston or primary barrel.
When one side of the piston is pressurized, the other side is routed through return port R2 to the primary hydraulic
reservoir.
M68-110
ACTUATOR
STABILITY AUGMENTATION
RETURN UTILITY R2
PRESSURE UTILITY P2
POWER PISTON
CHECK VALVE
MANUAL VALVE
UTILITY BARREL
Figure 7–14.
Servocylinder Functional Diagram
