Flight test experience with an electromechanical actuator on the F-18 Systems Research Aircraft

TLDR

Development of reliable power‑by‑wire actuation systems has been pursued to replace hydraulic systems in aircraft and spacecraft, and the EPAD program—an Air Force, Navy, and NASA joint effort—validated this technology on a primary flight control surface of a tactical aircraft. This paper investigates the integration and testing of the EPAD electromechanical actuator (EMA) on the NASA F/A‑18B Systems Research Aircraft. The EMA was installed in place of the standard hydraulic actuator on the left aileron, its architecture and integration with the flight‑control system were evaluated during a flight‑test program that recorded numerous parameters and compared its performance to the standard hydraulic actuator on the opposite wing. The flight‑test program showed that the EMA’s performance was very close to that of the standard hydraulic actuator, and lessons learned along with recommendations for future research were identified.

Abstract

Development of reliable power-by-wire actuation systems for both aeronautical and space applications has been sought to eliminate hydraulic systems from aircraft and spacecraft and thus improve safety, efficiency, reliability, and maintainability. The Electrically Powered Actuation Design (EPAD) program was a joint effort between the Air Force, Navy, and NASA to develop and fly a series of actuators validating power-by-wire actuation technology on a primary flight control surface of a tactical aircraft. To achieve this goal, each of the EPAD actuators was installed in place of the standard hydraulic actuator on the left aileron of the NASA F/A-18B Systems Research Aircraft (SRA) and flown throughout the SRA flight envelope. Numerous parameters were recorded, and overall actuator performance was compared with the performance of the standard hydraulic actuator on the opposite wing. This paper discusses the integration and testing of the EPAD electromechanical actuator (EMA) on the SRA. The architecture of the EMA system is discussed, as well as its integration with the F/A-18 flight control system. The flight test program is described, and actuator performance is shown to be very close to that of the standard hydraulic actuator it replaced. Lessons learned during this program are presented and discussed, as well as suggestions for future research.