SPECIAL OPERATIONS-LOW INTENSITY CONFLICT

U.S. Special Operations Command Weighs Deployment of Armed Drones

2/1/2009
By Matthew Rusling
After a decade of development, an experimental rotary-wing unmanned aerial vehicle may have found a customer at Special Operations Command.

The Boeing A160T Hummingbird, originally a Defense Advanced Research Projects Agency program, is undergoing a series of tests at a Boeing Co. facility in Victorville, Calif. Among the demonstrations is the use of Hummingbird as a strike weapon. For the tests, the aircraft is being equipped with air-to-ground missiles, said a SOCOM spokesman.

The command could find many uses for an armed vertical-takeoff UAV while conducting counterinsurgency operations, experts said.

Special Operations has received seven Hummingbird prototypes, three of which arrived last November, said SOCOM spokesman Capt. Wes Ticer. The aircraft’s manufacturer, the Boeing Co., confirmed that the command took delivery of the UAVs under a joint SOCOM-DARPA contract for a “Special Operations long endurance demonstration.”

Since 2002, SOCOM has awarded about $90 million in contracts related to the UAV, said Ticer. The unit cost for a Hummingbird prototype is about $3.6 million.

During the test, four dummy hellfire missiles are mounted on each side of the aircraft’s “stub wings” that hold the weapons. Initial demonstrations are testing how the addition of the missiles affects the aerodynamics, said John Groenenboom, A160T program manager at Boeing Advanced Systems.

SOCOM is also considering strengthening the skin of the Hummingbird to protect it against extreme heat and cold, since the vehicle was not designed for such environments, Ticer said. The command is also adding a redundant flight control — a backup system that is now standard in most UAVs.

The Hummingbird’s design allows it to fly higher and longer than most helicopters currently in use, said Boeing officials. The craft was initially developed by Frontier Systems Inc., which was acquired by Boeing in 2004. The company received a three-year $50 million DARPA contract in 2005 to test the aircraft. The agency remains involved in the testing of various sensor payloads aboard the A160T.

The UAV is 35 feet long with a 36-foot diameter rotor. It weighs 2,500 pounds without cargo and can hold more than 2,500 pounds of fuel. It can fly at speeds of up to 195 mph. It can carry up to 1,500 pounds, Groenenboom said.

The Hummingbird can fly 18.7 straight hours, according to Boeing. Its predecessor, a gasoline-powered drone known as the A160, made its first flight in 2002 and its longest flight was approximately 12 hours, Boeing said.

Despite the tests, SOCOM remains unsure of whether it will deploy the rotorcraft, or whether it will conduct more evaluations. There are no immediate plans to acquire more Hummingbirds, and the command has no documented requirements for the system, Ticer said. Special Operations is reviewing the platform’s capabilities to determine if it can meet future needs.

“It’s all driven by budgets,” Ticer said.   
 
Aviation analysts said the Hummingbird could be a good fit for special operations forces because of its size and ability to fly in small, tough-to-reach areas such as narrow city streets. Since it does not need a runway, it can deliver supplies to ground forces in tight urban environments, said Larry Dickerson, of Forecast International. Its size also makes it difficult for enemies to spot, he said.

The Hummingbird is also much quieter than other UAVs and can operate close to the ground, Groenenboom said. This can be a tactical advantage in a bustling city, where the UAV may not be heard amid the background noise. Stealth can help catch insurgents by surprise.

“With a helicopter, you’re going to hear it a mile away,” Dickerson said. “But a little thing like this might be able to sneak in and out of places.”

Boeing has compared the Hummingbird with the Bell 407, a four-bladed, single engine commercial helicopter. The UAV makes about 25 percent less noise than the 407, which it does by slowing the rotor to half the normal speed, Groenenboom said.

Another advantage over other UAVs is that the Hummingbird is a rotary-wing vehicle. While its fixed-wing counterparts must constantly fly in patterns, the Hummingbird can simply hover. This allows it to track ground targets more closely, Groenenboom said.

A fixed-wing UAV could lose track of a target while making a turn. Many sensors have 360-degree coverage of the ground below, but have to “reset” the video systems when certain angles are reached. If a fixed-wing drone is flying in a pattern, there is also a greater chance of losing a target behind a large building or mountain, Groenenboom said.

Users can also program the Hummingbird to fly autonomous missions. There is a Global Positioning System on the UAV, into which controllers can punch coordinates, Groenenboom said.

The drone is designed to hover at 30,000 feet, although the engine currently limits it to lower altitudes. Its commercial Pratt and Whitney 207D engine is currently certified to only fly at 20,000 feet, Groenenboom said.

Even though the altitude is limited to 20,000 feet, the Hummingbird could still be useful for delivering supplies or striking targets.

“In a mission in Afghanistan, where you’ve got mountain peaks that are at 15,000 feet, and you want to transit those, you want to stay fairly far above so you are not detected,” Groenenboom said.

Most rotorcraft cannot hover as high as the Hummingbird, Groenenboom said. Helicopter propellers require dense air to keep them aloft. The thinner the air, the more difficult it is to hover. A propeller’s diameter during flight must also be wide, relative to the vehicle’s weight.  

The Hummingbird, however, is a light craft with a wide propeller diameter that enables it to reach higher altitudes, Groenenboom said. The rotor blades also do not bend, which gives them added strength, he said.

Steve Zaloga, senior analyst at the Teal Group, said the Hummingbird’s endurance could be appealing to SOCOM.

The main disadvantage of helicopter UAVs is that they cannot remain in the air as long as fixed-wing configurations. This is mainly because they require more fuel to stay aloft for a given period of time, he said.  

But the Hummingbird is significantly more fuel-efficient than many of its competitors, and is the first of a string of experimental designs that are aimed at conserving fuel, Zaloga said. DARPA has been trying to invent a more fuel-conserving rotary UAV, he added.

The Hummingbird is equipped with a foliage penetrating radar antenna, so it can see through tree canopy. It can detect vehicles as well as people, Groenenboom said. The radar would be useful in counter-drug missions where smugglers hide in jungles.

Unlike the Predator and other fixed-wing UAVs that are remotely flown from U.S. bases, the Hummingbird must be operated locally. The vehicle is designed to be controlled from a ground station near the battlefield. Boeing is working with customers to develop a “common” ground station, out of which several different kinds of drones can fly, said Chris Haddox, spokesman for Boeing. Until then, the Hummingbird will operate from either a stationary trailer or a mobile van.

Deployable ground stations have been produced, but Boeing is looking into integrating these with other UAV stations that are already in use.

A team of two will operate the drone. One member flies the vehicle and the other individual controls the payload, Groenenboom said.

SOCOM is not the only customer for the Hummingbird. The aircraft has been evaluated by the Army for the Future Combat Systems program. The Navy also might  be in the market.

Topics: Robotics, Unmanned Air Vehicles, Special Operations-Low Intensity Conflict

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