Rapidly Engineering a Vertical Unmanned Aerial System

Northrop Grumman’s (northropgrumman.com) Fire-X vertical unmanned aerial system (VUAS) doesn’t have a lot in common with the majority of today’s autonomous aircraft developed for military purposes. For instance:

•    Most are fixed-wing aircraft. Fire-X is a vertical system (i.e., helicopter).
•    Most are small, generally only a few feet long because they’re used for stealth surveillance. Fire-X measures 41.4 x 8.1 x 10.2 ft because it is designed for transporting military cargo.
•    Most are developed in three to four years. Fire-X took its first flight 11 months after project launch.

“Our real expertise is knowledge of flying aircraft, whether they are helicopters or fixed wing,” says Bob Davis, Northrop Grumman Director of Business Development, Unmanned Systems. “Sometimes we build our own aircraft, sometimes we leverage the aircraft built by others.” Fire-X is a bit of both. Because its purpose is transporting cargo, engineers knew the aircraft platform was going to have to be large. But instead of developing that platform from a clean-sheet, they chose to take an existing helicopter and make it autonomous. They chose Bell Helicopter’s 407 airframe, which has been in commercial service since 1996. “They are used in a piloted context worldwide in a variety of different flight environments ranging from sea level to high altitude, from hot environments to very cold environments,” Davis says. He describes the 407 as a “non-complex aircraft” that offers adequate room to integrate the autonomous system. And while it is a simple platform, the single-engine chopper is capable of flying at a 20,000-ft ceiling at speeds up to 133 knots. What’s more, it features a 3,200-lb maximum payload capacity, which is ideal for getting supplies, fuel, etc. out to troops in dangerous areas. Explains Davis: “It doesn’t obligate putting together a convoy of trucks and driving at comparatively slow speeds over roads that are known to be littered with IEDs [Improvised Explosive Devices], subject to attack by the enemy. If you can get that cargo out to those folks expediently and reliably, it alleviates the necessity to send that convoy out and put people at risk on the ground.”

The real challenge for Northrop Grumman engineers was making the 407 aircraft autonomous. To do it, they relied on a previous VUAS platform, Fire Scout, which was developed by Northrop Grumman in the early 2000s to provide situational awareness and precision targeting support for the military. As engineers learned during Fire Scout’s development, and as the Navy learned after its deploy-
ment, the vertical platform offers several tactical advantages compared to fixed-wing aircraft. For instance, it has the ability to easily land and take off aboard naval ships and in other confined areas. Fire-X engineers deployed the autonomous software technology used in Fire Scout, integrating it into a platform twice its size.

Fire-X is engineered so that it could be flown by a pilot, but Davis says this feature could be eliminated to boost payload capacity. “If it’s a purely unmanned aircraft, you would not necessarily need an instrument panel,” he explains. “You would not need flight controls. You would not need a seat. The fact that you might retain those in the aircraft so that it can be optionally piloted all equate to mass. The question, invariably will be, what is the con-
sequence in having optionally piloted capability in terms of mass and maintenance?”

On Dec. 10, 2010, less than one year after project launch, Fire-X took its first test flight at the Yuma Proving Ground in Arizona, demonstrating a fast-track solution for a growing military need.