Woodward is a leader in the design, development, and manufacture of SCAS (Stability and Command Augmentation System) actuators. These actuators drive the mechanical linkage between the pilot’s cockpit controls and the swash plate actuators with their output superimposed on the pilot input command.
Output positional authority is usually limited to some small percentage (± 10% is typical) of total pilot input linkage stroke, as SCAS inputs from the FCC generally provide small amplitude input signals for functions such as autopilot and stability control. The SCAS actuator is sometimes built into the MRA or TRA as an integral assembly.
SCAS actuators are typically controlled by an Electrohydraulic Servovalve that, in turn, drives a SCAS output piston that is mechanically connected to the pilot input linkage. An SCAS position feedback sensor, such as an LVDT (Linear Variable Differential Transformer), is typically incorporated and provides SCAS position information for loop closure.
A typical example of a Woodward HRT SCAS helicopter actuator is shown above.
Woodward is at the forefront of providing reliable and affordable, advanced technology SCAS actuator solutions. For more information or assistance with your particular application, contact us at afs-actuation@woodward.com.
Application Notes