LOCKHEEDMARTIN has been cleared to proceed with modification of an F-16 to demonstrate the all-electric flight controls planned for the Joint Strike Fighter (JSF). The Advanced Fighter Technology Integration (AFTI)/ F-16 will be modified in 1998 for flight tests starting in January 1999.
The six-month, 60-flight demonstration, under the JSF/ Integrated Subsystem Technology programme, will be the first time that an aircraft has been flown with full electric flight-control actuation, with no hydraulic or mechanical back-up, says programme manager Mike Griswold.
The AFTI/F-16's hydraulic flight-controls will be removed and replaced with a flight-critical electric power and actuation system consisting of a dual-channel generator on the engine, a back-up generator on the emergency power- unit (EPU) and five electro-hydrostatic actuators (EHAs) for the flaperons, horizontal tail and rudder.
Griswold says that the Sundstrand switched-reluctance generator will supply two independent channels of 270VDC electrical power. The fault-tolerant generator is rated at 200kW, but will be limited to 80kW in the F-16. Only 2-3kW will be needed in the cruise, Griswold says. A Lucas emergency power-generation system, driven by the hydrazine-powered EPU, will provide one back-up channel, while an 85Ah battery will provide a "get-home" capability.
The Parker Bertea EHAs will be driven by the F-16's digital flight-control computers, with the same forces and rates as those of the present hydraulic system. Ground and flight testing will look at issues such as generator and actuator duty cycles, failure modes, and electromagnetic interference - particularly between the actuators and the aircraft's avionics, Griswold says.
Electric actuation is expected to reduce the size and weight of the JSF. The technology to be flight tested is "very close" to that planned for the JSF, Griswold says.
Source: Flight International
