Graham Warwick/FORT WORTH
Lockheed Martin has begun installing an all-electric flight control system in an F-16 testbed under a programme to mature the technology for use in the Joint Strike Fighter (JSF). Ground tests are to start in August, leading to a first flight next January.
The Advanced Fighter Technology Integration (AFTI) F-16 testbed is being modified for the JSF Integrated Subsystem Technology (J/IST) demonstration. The hydraulic primary flight controls have been removed and is set to be replaced by a 270V DC electric power generation and actuation system.
An all-electric JSF is expected to be smaller, lighter, cheaper and more reliable.
The demonstration system comprises an 80kW, two-channel, switched reluctance generator mounted on the engine accessory- drive gearbox, replacing the main hydraulic pump. Electrical power is supplied via two buses to five electrohydrostatic actuators on the rudder, flaperons and stabilators.
Generated power is conditioned by two inverter/converter/controllers mounted in the ammunition bay behind the cockpit. Five power drive electronics units - one for each actuator - are mounted in the AFTI/F-16's dorsal spine, and convert commands from the digital flight-control computer into control-surface movements by modulating the power supplied to the dual motors on each actuator.
There is no back-up flight control system, hence the extended ground testing before the first flight. To provide redundancy, there is a 15kW generator on the emergency power unit and an emergency battery in the nose to provide fill-in and get-home power.
A 10kW AC generator has been added to power "legacy" systems, and hydraulic pumps are retained to drive the leading-edge flaps, speedbrakes and landing gear.
Lockheed Martin will receive its first actuator from Parker Aerospace in August. Sundstrand is supplying the generator. Equipment will be integrated in the simulation laboratory before installation.
Source: Flight International
