UAVs Step Into Combat Arena

The growing need for long-range/endurance reconnaissance and surveillance, coupled with defense planners' strategic shift away from manned combat aircraft, has opened the door for a new category of weapon: the unmanned combat aerial vehicle.

For UCAV designers, putting weapons on unmanned aerial vehicles is a natural progression. From precision-guided weapons to directed energy weapons such as lasers and high-power microwaves now under development, unmanned aerial vehicles could be the platform of choice for many combat requirements.

Interestingly enough, the first UCAV might be one of the oldest operational UAVs-specifically General Atomics' Predator long-endurance, medium altitude surveillance craft. In April, the U.S. Air Force successfully hit three stationary tanks with three Hellfire anti-armor missiles fired by Predator. The Hellfire missile is normally fired from AH-64 attack helicopters.

In the first shot, Predator hit a tank from an altitude of 2,000 feet, a speed of 70 knots and a range of about three miles. The target beam came from a ground-mounted laser. In the second test, a laser mounted on the aircraft designated the target. The third shot was a direct hit with a live warhead.

"We'll be challenged with how to employ the UCAV," said Gen. John Jumper, chief of Air Combat Command, after witnessing the third successful Predator test. He added that the most likely roles for UCAVs are in the suppression of air defense, "perhaps in connection with directed energy."

The next step for Predator is to raise the Hellfire launch altitude from 2,000 feet to 15,000 feet, where the UAV stands little chance of being shot down. Another program under discussion is giving Predator the ability to fire short-range, heat-seeking AIM-9 Sidewinder missiles against such targets as helicopters and low-flying aircraft

But such a program is only a stopgap until the first generation of purposely designed UCAVs take flight. These include UCAVs from Boeing, Northrop Grumman, Dassault and others, all being designed with a variety of new technologies never before available in an autonomous craft.

Technological advances in 13 specific research areas are the goals of the high-profile, U.S. government UCAV program-the X-45A UCAV being developed as part of a $131 million, 42-month cost-sharing agreement between the USAF, Defense Advanced Research Projects Agency (DARPA) and Boeing's Phantom Works. Boeing is funding $21 million of the program.

Those technologies include information collection and fusion; information assessment and presentation; autonomous targeting identification and recognition; miniature munitions systems; fluidless power, actuation and cooling; low-observable antennas; miniaturized modular training environment; mission management and planning; higher-thrust, limited-life, storable engines; and low-cost structures and manufacturing.

The X-45A is a stealthy, tail-less, 27-foot-long aircraft with a 34-foot wingspan, and is powered by a Honeywell F124 turbofan sitting centerline in the fuselage. It weighs 8,000 pounds empty and can carry a 3,000-pound payload. The reconfigurable mission control station has robust and secure satellite-relay and line-of-sight communications links for distributed control in all air combat situations.

It can be stored unassembled in small containers for up to ten years, and be reassembled in about one hour. Up to six UCAVs can fit inside a C-17 transport. Estimated cost for a single operational UCAV is about $10 million.

The Boeing UCAV is being developed as an affordable weapon system that expands tactical missions for the military, while providing new revolutionary air power for two lethal roles: suppression of enemy air defense and precision strike.

Flight testing of the number-one X-45A is scheduled to begin this summer at NASA's Dryden Flight Test Center in California. Testing with a second X-45A to perform simulated suppression of air defenses missions is scheduled to begin in mid-2002.

Pegasus is Northrop Grumman's UCAV demonstrator, which the company is building as the foundation for its work in a DARPA/U.S. Navy program. Pegasus is under development at Northrop Grumman's Advanced Systems Development Center in El Segundo, California.

The unique kite- or diamond-shaped Pegasus UCAV is the first aircraft to be developed by Northrop Grumman in many years. The company is funding the UCAV itself because of technological advances it expects to make that can be transferred to other military aircraft programs. One such technology is a modular vehicle management system, as well as weapons and sensors integration.

The Pegasus air vehicle features a 55-degree swept leading edge and a 35-degree forward-swept trailing edge, with the single engine inlet on the top-front of the upper fuselage.

Northrop Grumman has said it plans to build a second flight demonstrator under the DARPA program. That UCAV demonstrator, however, would not necessarily look like the kite-wing design of the first air vehicle-primarily because the U.S. Navy has recently expressed greater interest in a long-endurance surveillance vehicle rather than a strike and suppression UAV.

Because the kite design is not the best shape for long endurance, the company has not yet determined whether the second vehicle would be a modification or redesign of the original Pegasus. Northrop Grumman is contemplating a "cranked kite" planform modification, adding rectangular wing extensions at the port and starboard points to provide additional lift.

Lockheed Martin's Skunk Works is also working on a UCAV program with the USAF and DARPA under a classified program. Under the black program, Lockheed Martin is believed to be developing an armed, stealthy UCAV that could be wing-launched from a manned aircraft.

EADS Military Aircraft is working on designs for a stealthy UCAV that would be 39 feet long with a 29.5-foot wingspan-somewhat longer and heavier than Boeing's X-45A UCAV. The vehicle would be capable of carrying internal weapons, and have an empty weight of about 9,900 pounds and takeoff weight of about 18,000 pounds. The UCAV could be built under the European Technology Acquisition program, which may be signed by European nations by the end of the year.

Working independently of EADS, as always, is Dassault Aviation, which has conducted flight tests of a scale model UCAV being designed under the AVE program (Aeronef de Validation Experimentale). Besides a UCAV, the AVE program plans for a tactical UAV, a medium-altitude, long-endurance UAV, and high-altitude, long-endurance UAV.

Nicknamed "Petit Duc," the small demonstrator has a blended wing design with twin vertical stabilizers and an internal weapons bay. The all-composite aircraft measures 2.4 meters in both length and wingspan. It first flew about 11 months ago, and is being used to validate computer modeling and stealth technology for what a Dassault spokesman called the "Grand Duc."

A model of Petit Duc is on display at the Dassault Aviation stand at Le Bourget.

By Barry Rosenberg