Rotorcraft flight-propulsion control integration: An eclectic design concept

Summary The NASA Ames and Lewis Research Centers, in conjunc- tion with the Army Research and Technology Laboratories, have initiated and partially completed a joint research program focused on improving the performance, maneuverability, and operating characteristics of rotorcraft by integrating the flight and propulsion controls. The background of the program, its supporting programs, its goals and objectives, and an approach to accomplish them are discussed in this report. Results of the modem control governor design of the General Electric T700 engine and the Rotorcraft Integrated Flight-Propulsion Control Study, which were key elements of the program, are also presented. Background Dynamic-interface problems involving the engine fuel control and the helicopter rotorhirframe have been around for a long time. They include engine torque and fuel control system oscillations, multiengine load sharing, undesirable rotor speed variations during maneuvers, and excessive helicopter vibration. The helicopter rotor and drivetrain system have lightly damped torsional dynamic modes that are within the bandwidth of the engine fuel control system as shown in figure 1. This figure is a bar chart of frequencies at which various dynamic modes commonly occur in rotorcraft.