The Man Who Invented the Predator
Before he designed the world’s most feared drone, Abraham Karem was just trying to get a robot to stay in the air.
- By Richard Whittle
- Air & Space magazine, April 2013
(Page 4 of 6)
Thus were the seeds of the drone revolution sown. The Predator, though nearly twice as large, is a direct descendant of Amber, as their near-identical configurations suggest. Amber’s thrust came from a two-blade wooden propeller at the rear of the fuselage. Its tricycle landing gear retracted into its body. The V-shaped stabilizers at its tail pointed downward. Karem chose that distinctive feature mainly for aerodynamic stability but also because, in a rough landing, the stabilizers could hit the ground and skid, keeping the propeller blades from shattering on the runway.
Like the Albatross, Amber was radio controlled and could be configured to take off and land like conventional aircraft or fold its wings and stabilizers for launch by rocket from a canister. Most ingenious of all, Amber could be recovered by putting it into a “deep stall”—a feature used in free flight glider models to escape thermal updrafts and stay within flight time limits. The stall would bring Amber to “a near-vertical landing so it could be used from small ships, submarines or trucks/trailers,” Williams explains.
By 1988, Karem was expecting to build large numbers of the UAV for the Navy. With GPS becoming available and other key technologies gaining momentum, interest in UAVs was growing. Leading Systems now occupied 200,000 square feet of industrial space in Irvine, California, and had a contract on an airfield near El Mirage Dry Lake. In June of that year, an Amber flew over El Mirage at 5,500 feet above sea level for 38 hours. Even so, the Navy dropped a plan to buy 200, and the Army rejected the aircraft when Karem offered it as a short-range UAV, a mission in which endurance was no advantage. Around the same time, piqued by the money spent on programs like Aquila and Condor, which failed to develop useful and affordable UAVs, Congress froze funding for such programs and created a joint program office to consolidate drone development. DARPA transferred Amber to the joint program office, which promptly cancelled it.
Developing a useful and affordable UAV, however, is precisely what Karem had done. His achievement, says Bob Williams, “was not a high-aspect-ratio wing, good aerodynamics, or a lightweight structure, although good designers could do those things, and Abe could do them better than most. The issue really was reliability. Manned aircraft fly for tens of thousands of hours without crashing. So how do you even get in that ballgame? The crowning success of Amber was that by the end of the program, we were able to fly 650 hours without a loss. That was a huge order of magnitude increase in reliability [over other UAVs at the time].”
When Amber’s future looked unsure, Karem shifted his focus to a lower-tech export version his team had been working on with private funding: the Gnat-750. The number refers to the chord of the wing in millimeters at its root, a dimension of the airfoil from leading to trailing edge. The Gnat was bigger, heavier, and less capable than Amber, with a two-stroke Rotax 532 engine and no canister launch capability. While Karem tried to make a foreign sale, a $5 million bank loan came due.
Alerted to the opportunity by a mutual friend, the owners of General Atomics, brothers and reputed billionaires Neal and Linden Blue, bought the assets of Leading Systems out of bankruptcy in 1990. Their company, which had been working on its own UAV with minimal success, got everything Karem had achieved with Amber and Gnat, Karem says. The Blue brothers, lifelong aviators and entrepreneurs who also saw unmanned aircraft as a beckoning frontier, hired Karem and eight of his people, getting “a team that was flying advanced UAVs like nobody else,” Karem boasts.
A few years later, when the Clinton administration was desperately looking for a way to monitor ethnic conflicts in the Balkans, CIA chief James Woolsey remembered Karem, whom he’d met and come to admire years earlier. “Abe’s an entrepreneurial engineering genius,” says Woolsey today. “He lives to create.” The CIA bought two Gnat-750s with video cameras and started flying them over Bosnia. They were launched from Albania, where their ground control station and operators were located. As that was happening, the Department of Defense held a competition for the right to demonstrate in actual missions a more advanced “medium-altitude endurance” UAV. One requirement was that the aircraft have a satellite antenna so it could be flown by operators who were much farther away than those flying the Gnat, which over Bosnia had to relay its signals to Albania through a piloted, motorized glider.
To make room for the satellite antenna, Karem gave the Gnat-750 a nose job, adding a big upward bulge. The only other major changes were a Rotax 912 engine (upgraded later to the 914), heavier landing gear, and a wing chord that measured 1,100 mm (43.25 inches) at the root. The new craft wasn’t armed, but GA-ASI’s then-president, former fighter pilot and retired rear admiral Thomas J. Cassidy, decided they should call it Predator, the name the company had used for its pre-Karem UAV.