Under the metallic and composite skin of Gulfstream’s new G500 and G600 lie several new innovations that came to light in supplier announcements and interviews at the NBAA convention.
A key theme from Gulfstream in the 14 October unveiling of the two jet designs is a goal to migrate the Mach 0.935 maximum speed, cabin comfort and fly-by-wire technology of the G650 to a slightly smaller, shorter-range class of aircraft.
Thales designed the flight control computer for the fly-by-wire system on the G650, which translate inputs from the flightcrew’s control columns into commands to Parker Aerospace’s actuators on the flight control surfaces, replacing the mechanical linkages with digital signals.
Operational limitations embedded in the computer’s control logic improve safety by preventing the pilot from flying too fast or too slow. It can also improve performance indirectly by softening loads on structures, allowing designers to slightly reduce structural margins and weight.
The fly-by-wire system for the G500 and G600 adds another feature to the G650’s fly-by-wire architecture, says Michel Grenier, vice-president and general manager of avionics for Thales. Embraer is already introducing BAE Systems active control sticks on the KC-390, a military tanker/transport. Gulfstream is now applying the same technology in the commercial market for the first time. These back-driven sticks digitally emulate the forces of mechanically-linked controls, requiring the pilot to use more force, for example, as aerodynamic loads increase.
Integrating such a system requires developing and installing new software into the flight control computer, Grenier says. The software has to be continually refined through the development process, until the feedback forces are accurately modeled.
The flight control computer itself is another innovation in the G500 and G600 jets, Grenier says. On Gulfstream’s newest jets, including the G650, Thales repackaged the system into two computers running four channels, along with a backup computer in case all four systems fail.
Another unique system revealed at NBAA is the design of the electrical power system by GE Aviation. Other jets distribute electrical power from central hubs, requiring wiring to run the length of the aircraft, says Brad Mottier, GE Aviation’s president and chief executive of business and general aviation and integrated systems. In the G500 and G600, GE aviation is unveiling “power tiles” that segregate electrical loads in each fuselage section, which reduces the overall weight by 136kg (300lb).