Fluidic Backup Flight Control and Integrated Pump-Actuator for Advanced FBW Rotorcraft

Flight control system vulnerability is a significant issue in military helicopters. Future U. S. Army helicopters will have fly-by-wire (FBW) control systems, and the Army is exploring means of reducing aircraft vulnerability to known threats. This paper discusses vulnerability reduction by using 1) a fluidic backup flight control system that is inherently immune to electromagnetic effects, and 2) an independent integrated pump-actuator hydraulic system, driven by the tail rotor gearbox. The paper includes a brief description of applications for a future generic Army scout-attack helicopter and a flight demonstrator helicopter. The paper also includes a design description of the flight demonstrator aircraft: a modified Apache with experimental FBW flight controls and with yaw axis fluidic backup controls and integrated pump-actuator.