The Top 10 Unmanned Aerial Vehicles

Based on the Schweizer Model 330SP manned light helicopter, the RQ-8A Fire Scout operated by the U.S. Navy can remain on station providing reconnaissance and targeting capability for more than four hours at a distance of some 120 miles from its launch site. The vertical-takeoff-and-landing (VTOL) Fire Scout is equipped with a GPS-based navigation system for autonomous operations and the system's ground control station can control three UAVs simultaneously. An improved version called the Sea Scout is able to carry precision-guided air-to-surface missiles. The U.S. Army has selected an even-more-upgraded version known as the MQ-8B for its Future Combat System Unmanned Aerial System requirement. The combined Army/Navy MQ-8B buy will be for up to 192 aircraft.

Produced by Pioneer UAV (a joint venture between AAI of the United States and Israel Aircraft Industries), the tried-and-trusted RQ-2B Pioneer has been in service with the U.S. Marine Corps, U.S. Navy and U.S. Army since 1986. Pioneer provides reconnaissance, surveillance, target acquisition, naval gunfire support and battle damage assessment, day and night. It is launched from ships by rocket assist, or launched by catapult or from a runway on land, and recovered into a shipboard net or (on land) by using arresting gear. Pioneer, which is 14 feet long and has a wingspan of 17 feet, can reach an altitude of 15,000 feet and can fly for five hours. Its gross takeoff weight is 452 pounds and Pioneer can carry a 75-pound payload of optical or infrared sensors, or chemical- and mine-detection equipment.

Based on Insitu's Insight UAV, the 40-pound Scan Eagle can loiter over a designated area for more than 15 hours, cruising at speeds just below 60 mph at an altitude of more than 16,000 feet. It carries a 13-pound payload and can be launched or retrieved in any terrain, including ships at sea. Scan Eagle, which has a 10-foot wingspan, is invisible to radar and barely audible more than 50 feet away, according to the U.S. Marine Corps. This GPS-guided UAV has a maximum level speed of nearly 80 mph and its gimbaled, nose-mounted camera turret carries either a zoom charge-coupled device optical or an infra-red sensor.

The world's biggest and most sophisticated unmanned aerial vehicle, the RQ-4 Global Hawk was the first UAV to be certified by the FAA to file its own flight plans and use civilian air corridors in the United States with no advance notice. This potentially paves the way for automatically piloted passenger airliners in the future. Famously, a Global Hawk was flown from the U.S. to Australia, where it carried out a reconnaissance exercise, and back across the Pacific in one long-duration test flight. Including development costs, each Global Hawk costs more than $123 million. The aircraft cruises at 65,000 feet and gives U.S. battlefield commanders high-resolution, near-real-time intelligence, surveillance and reconnaissance imagery.

Designated by the U.S. Air Force as an 'MQ'-class UAV -- the 'M' standing for multi-role and the 'Q' for an unmanned aircraft -- the Reaper was developed from General Atomics' earlier and highly successful Predator. In fact, the Reaper was originally known as the 'Predator B.' Now in U.S. Air Force service in Afghanistan and Iraq, the MQ-9 is primarily used as a hunter-killer and can carry AGM-114 Hellfire missiles and two types of Joint Direct Attack Munitions. With a maximum takeoff weight of nearly 5 tons, the two-crew (pilot and sensor operator) Reaper cruises at around 230 mph at altitudes up to 50,000 feet and can fly 3,682 miles. It has a 3,750-pound payload and can carry a sophisticated video and IR targeting sensor package, a laser rangefinder and designator, and a synthetic aperture radar. The MQ-9 can be disassembled and loaded into a container for air deployment to any standard U.S. airfield worldwide. Each Reaper system -- which includes four aircraft with sensors -- costs $53.5 million.

The RQ-11A Raven, developed in 2002-2003, is essentially a half-size version of the 1999-vintage AeroVironment Pointer, but thanks to technological improvement in the intervening years it carries the same GPS navigation system, control equipment and payload. Made of Kevlar composite material, each 4-pound Raven costs about $25,000 to $35,000, has an effective operational radius of more than 6 miles and can stay airborne for 80 minutes at speeds of 28 to 60 mph. The Raven B weighs a little more, has better performance characteristics and better sensors and can carry a laser target designator. The Raven and Raven B often break into pieces when they land but are recovered, repaired and readied for new missions.

For obvious reasons often called "the flying peanut," the Bombardier CL-327 VTOL unmanned surveillance system is powered by a Williams International WTS-125 turboshaft engine that produces a flat-rated 100 shaft horsepower. Weighing 770 pounds maximum on takeoff, the CL-327 can act as a communications relay, perform environmental inspections, patrol borders, or can be used in drug-enforcement or military reconnaissance operations. It can stay on station for nearly five hours at a distance of more than 60 miles from its launch site. The CL-327 has a payload capacity of 220 pounds and an operational ceiling of 18,000 feet. It can carry a variety of sensors and datalink systems and has both GPS and inertial navigation systems.

By far the world's most widely operated civilian unmanned aerial vehicle, with as many as 2,000 now in service, the Yamaha RMAX mini-helicopter performs a variety of missions ranging from agricultural spraying jobs to research tasks. Powered by a two-stroke Yamaha piston engine, the RMAX's flight control software restricts its maximum altitude to just under 500 feet. It can be fitted with video and still cameras for research missions, but is best known for its precision pest-control spraying work on rice paddies and other fields on Japanese farms. The use of a GPS-equipped Yamaha RMAX in April 2000 for close observation of the erupting Mt. Usu in Hokkaido represented the first-ever autonomous operation of a remote-control helicopter beyond visual range.

Originally produced to meet the U.S. Air Force's Force Protection Airborne Surveillance System (FPASS) requirement, the Desert Hawk entered production in 2002. Made of durable mold-injected polypropylene foam, Desert Hawk is powered by an electric motor that drives a pusher propeller. GPS-equipped, the Desert Hawk is launched by two people using a 100-meter bungee cord that is attached to the UAV and then simply let go. Normally it operates at around 500 feet but Desert Hawk can fly at 1,000 feet. Operating autonomously using an onboard GPS receiver and pre-programmed waypoints, it is being used for perimeter surveillance of U.S. Air Force installations in Iraq. The Desert Hawk's flight path can be re-programmed in flight by means of data link from its ground control station, which controls up to six UAVs at a time. The small UAV can cruise for an hour at up to 57 mph and it offers an operational radius of some 7 miles.

A medium-altitude, long-endurance interdiction and armed-reconnaissance aircraft, the Predator cruises at around 84 mph, though it can fly at up to 135 mph. Its range is more than 450 miles and the MQ-1 can reach 25,000 feet in altitude. It carries two laser-guided AGM-114 Hellfire missiles and was the first U.S. Air Force unmanned aerial vehicle to attack and destroy hostile forces, in Afghanistan. A fully operational Predator system consists of four aircraft and their sensors, a ground control station, a Predator primary satellite link (PPSL) and approximately 55 personnel to operate the UAV system round the clock on active deployment. Powered by a 115-horsepower Rotax 914F piston engine, the Predator can operate from 5,000-by-75-foot hard-surface runways. It needs line-of-sight communications for takeoff and landing, though the PPSL provides over-the-horizon control and communications.