Figure 7–9. Servocylinder Functional Diagram

TM 1-1520-238-T-5 7–24 Change 1 7–7. SYSTEM DESCRIPTION (cont) 7–7 (e) The longitudinal, collective, lateral and directional servocylinders (fig. 7–9) are of tandem design which 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 mode of operation). During normal (mechanical input) mode of operation, pressurized fluid from the primary hydraulic manifold enters the servocylinder through port P1. Fluid is filtered by a 25 micron filter and 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 determine if fluid pressure is equalized or routed to the power piston and primary barrel. When one side of the piston is pressurized, the other side is routed through return port R1 to the primary hydraulic reservoir. M68-107 RETURN PRI R1 ACTUATOR STABILITY AUGMENTATION POWER PISTON SERVO VALVE MANUAL CHECK VALVE PRIMARY PI PRESSURE FILTER PRIMARY BARREL Figure 7–9. Servocylinder Functional Diagram