Northrop Grumman steps up ISR challenge as piloted UAV enters flight test
New shapes in the sky are no strangers to the denizens of Mojave, where developmental and test aircraft frequent the clear desert air. Yet even the most seasoned of observers could be forgiven for taking more than a casual glance at the twin-boomed Firebird, which began flight tests there on Nov. 11.
The unconventional aircraft is unusual, not simply because it is designed to fly with or without crew, but also because it represents a potential new evolutionary stage in the quest for more affordable persistent surveillance. While requirements for intelligence, surveillance and reconnaissance (ISR) have hardly changed since observer balloons floated over the World War I battlefields of France, the ability to serve these needs has driven constant innovation.
Now, 19 months after unveiling its secretly developed Firebird medium-altitude unmanned aerial vehicle (UAV) demonstrator,believes a new two-seat derivative of its optionally piloted vehicle (OPV) concept is one such development. Aimed originally at enabling a medium-altitude UAV to transit freely through controlled airspace by having a pilot on-board, the growth of Firebird to a new two-seater enables the penetration of a broader section of the heavily contested ISR market including the buoyant one for special-missions aircraft.
To underscore the fact this is more than a marketing pipe dream, the company has quietly clinched its first contract from an unidentified customer and is beginning developmental flight tests of the first production-ready model at Mojave. It was here, like the demonstrator variant before it, that the newest Firebird was built and developed by Northrop Grumman's Scaled Composites (AW&ST May 9, 2011, p. 52). As with the first version, which took around one year from start to flight, the two-seater enters flight slightly more than 14 months after the program started.
“We're trying to think of when we last did a winged aircraft aimed at civil certification in that timeframe,” says Firebird program manager Jerry Madigan, who adds: “We set ourselves a tough goal. We are looking at completing development testing at the end of the first quarter of 2013 with delivery after that. We do anticipate sensor upgrades and improvements over the systems life cycle because of its versatility and open architecture.”
The second pilot position was added at the request of the customer, offering a new dimension to the concept of a purpose-designed UAV with the option of a pilot on board. Madigan says the second seat now gives users the option of a position for a co-pilot and/or sensor systems operator, while retaining the original goal of providing a low-cost ISR platform.
The two-seat Firebird is therefore also being positioned as a “replacement for the aging, inefficient and unsustainable fleet of special-mission aircraft,” says Northrop. “Some of them are looking at asymmetric warfare situations where aircraft like the  King Air or Caravan do not have the endurance, or the versatility,” says Madigan.
“We'd like to hit all parts of the life cycle, and make it very reasonable to operate this capability. We're aiming at $10 million per aircraft with flight avionics and a basic sensor,” he adds.
The price target is exclusive of the ground station that has been developed to operate with the Firebird. In addition to the basic capability of a maximum unpiloted endurance of 24-40 hr., depending on payload and engine, the Firebird offers a “versatile display and a big payload bay.” The booms and wings offer “a lot of surface to do things with,” says Madigan. Without naming the first user, he adds that the initial production rate is pegged at two per year during the next five years.
In early 2009, less than two years after Northrop bought out all the remaining shares in Scaled Composites, the company asked: “What if we designed it as a UAV from the start but then made it optionally piloted?
“It was drawn on a napkin and 12 months to that day later, they flew it on Feb 9, 2010,” recalls Madigan.
Although the obvious target was the virtually uncontested medium-altitude, long-endurance (MALE) market enjoyed bywith the Predator and its follow-on Reaper and Gray Eagle, the Firebird is now evolving to compete across a variety of fronts.
The concept received key exposure at the 2011 Empire Challenge, the final interoperability and intelligence-sharing exercise run before the U.S. Joint Forces Command was disbanded.
“At Empire Challenge everybody saw us out there. Before that we kind of kept it quiet,” says Madigan. “In all, we have flown 12 different payloads and at Empire Challenge we flew four payloads that we never tested before. These included electro-optic/infra- red (EO/IR) sensors, radar and a communications relay. One of the things people were amazed with was we set up an impromptu Droid cell phone network from the air,” he adds.
Although Firebird's presence at the exercise was sponsored by the U.S. Army, other potentially more immediate customers at the event included U.S. Special Operations Command. Northrop previously said the command was interested in Firebird, but Madigan says only: “We competed for an undisclosed customer and we won, and they have certain requirements, including a two-seat production-standard vehicle.
“There are maybe applications where it could replace vertical-lift or other intelligence MALE vehicles, and the price point will come down,” says Madigan. “The Army has a number of plans they've pushed out a little bit, but we're working with them on LEMV (long endurance multi-intelligence vehicle) and we can probably fit with their road map in a couple of areas.” Northrop is scheduled to demonstrate Firebird to the Army “in a couple of weeks and do a couple of unmanned landings,” he adds.
A final round of tweaks to the software for landing the vehicle in its unmanned configuration is scheduled to be released in late November as, to date, the Firebird has flown with a pilot in the cockpit.
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.
|Production-Ready Firebird||Demonstrator Firebird|
|Gross Takeoff Weight:||6,650 lb.||5,000 lb. (maximum)|
|Wingspan:||72.2 ft. (53 ft. folded)||65 ft.|
|Length:||35.5 ft.||34 ft.|
|Height:||9.8 ft.||9.71 ft.|
|Altitude:||up to 32,000 ft.||up to 30,000 ft.|
|Maximum Endurance:||24-40 hr. (payload- and engine-specific)||up to 40 hr.|
|Payload Capacity||1,240 lb.||1,240 lb.|
|Top Speed:||200 kt*||200 kt*|
|Powerplant:||Lycoming TEO-540E or optional heavy-fuel engine||Lycoming TEO-540E|
|Source: Northrop Grumman|