Despite its slightly larger size and a more conventional, boom-mounted tail, the production Firebird clearly displays the Scaled Composites lineage of its demonstrator predecessor. The forward-swept, high-aspect-ratio wing is designed to produce a better lift-drag ratio for loitering at altitudes up to 32,000 ft. The wingspan is extended to 72.2 ft., an increase of more than 7 ft. from the demonstrator, and passes through twin tail booms, where it is cranked up to provide greater ground clearance for the single pusher-propeller and belly-mounted sensors.
The enlarged cockpit houses two pilots who sit in automotive-style seats more suitable and comfortable for longer-duration missions than the rudimentary ones used in the demonstrator. The cockpit is dominated by a Garmin G3000 electronic flight information system (EFIS), which incorporates three large 14.1-in. multifunction displays (MFD) and two 5.7-in. touch-screen GTC 570 vehicle management systems. The system was developed as the first touch-screen, integrated EFIS for light turbines and is baseline on the HondaJet business aircraft.
Northrop Grumman selected the Garmin system because of its versatility and the ease with which it can be adapted to either the piloted or UAV mode. The pedestal-mounted GTC 570 controllers, for example, have been modified with a “third-party” option that enables the display and GTC to be responsive to inputs/outputs from a third-party computer.
For the pilots, the small touch-screen is used for navigation and communication radio management and page navigation on the MFD, as well as control of the audio/intercom system, transponder codes and identifications, electronic checklist entries, flight-plan entry and selecting custom display options. The GDU 1400 displays function as either a primary flight display (PFD) or MFD, or in reversionary mode as both. When used as the PFD, the screen displays a simulated 3-D perspective topography that uses the G3000's terrain-alerting database to create a detailed graphical landscape.
In MFD mode, the display can be split vertically to enable two separate pages to be viewed side-by-side along with an EFIS strip for engine and fuel data. As well as standard flight-planning and weather-type functionality, Northrop will flight-test more specific display options related to the ISR payload sensors. These will include as many as three high-definition EO/IR sensors, synthetic aperture radar, ground and digital moving target indicator radar, and full-motion video. Others include electronic support, signals intelligence, communications relay and even precision weapons.
Payload capacity is 1,240 lb., while maximum takeoff weight is increased by around 2,000 lb. to 7,000 lb. The large payload bay for most of these sensors is mounted in the belly, forward of the firewall segregating the Firebird's six-cylinder, turbocharged Lycoming TEO-540E engine, though hard points are located on the wings for pod-mounted sensors and weapons.
If not being operated in piloted mode, the Firebird is designed to be commanded by a ground station to operate in either line-of-sight (LOS) unmanned mode, or beyond LOS mode. “If you want to go further (beyond LOS), the canopy comes off, the Garmin system comes out of the flight panel, and an L-3 satcom antenna goes in,” says Madigan.