A Brief History of Unmanned Aircraft

The Union and Confederate armies both used balloons for spying on the enemy during the U.S. Civil War, with pilot-observers onboard. At least one person—Charles Perley of New York City—imagined that they could also be used to deliver weapons. His patent dated February 24, 1863 calls for a “divided basket” which would open like a clamshell when a timed fuse expired, thereby releasing a bomb. “A balloon can be made to pass over any object, and…any-sized bomb or missile of destruction can be carried up over the place to be destroyed,” he wrote.

The Kettering Aerial Torpedo, later called the “Kettering Bug,” was a small biplane powered by a De Palma 4-cylinder engine and guided by gyroscopes, a barometer, and a mechanical “computer.” It flew in 1918 and had a range of up to 75 miles. The onboard computer counted engine revolutions (to gauge distance), then powered down the engine and jettisoned the torpedo’s wings at a pre-determined distance (calculated before launch based on prevailing wind speed and direction). At that point the fuselage would crash into its intended target with an explosive payload onboard. The Bug was never used in actual combat.

British-born actor Reginald Denny, who had served in the Royal Flying Corps during World War I, developed a fascination with radio-controlled aircraft in the 1930s. He and his partners formed the Radioplane Company and created the “Radioplane OQ-2,” the first mass-produced UAV, at their southern California-based facility. Eventually the company rolled out nearly 15,000 airplanes for the U.S. Army and Navy, who used the Radioplanes as targets for antiaircraft training.

While Denny enjoyed a long Hollywood career, appearing in films like Alfred Hitchcock’s Rebecca, one of Radioplane’s humble employees went on to greater stardom. An actor friend of Denny’s, U.S. Army Air Forces Captain Ronald Reagan, sent a photographer to Radioplane in June 1945 to shoot female assembly workers for Yank, the Army Weekly magazine. The photographer, David Conover, focused on one worker in particular, Norma Jeane Dougherty, and asked her to pose for other shoots, which led to a modeling contract, a film career, and a name change—to Marilyn Monroe.

The first truly intercontinental weapon system, Japan's “Fu-Go” balloons were designed to cause widespread forest fires and damage to North American cities, civilians, and croplands during World War II. The hydrogen-filled balloons measured 30 feet in diameter. Each carried a payload of 32 paper sandbags, two incendiary devices, one small bomb, and an altitude regulation mechanism.

Launched from Japan, the balloons would rise to roughly 30,000 feet, where they would hitch a ride on the jet stream and travel at speeds of up to 120 miles per hour eastward. As hydrogen leaked out slowly, the balloon descended. At 25,000 feet, the altitude regulation system would drop one of the sand bags, causing the balloon to rise back to 35,000 feet. This continued until just the incendiary devices and bomb remained; then they too were dropped on the last dips to 25,000 feet. The Japanese launched up to 9,300 of these balloons, but only 300 actually reached North America. They caused six deaths: a woman and five students who happened upon one of the unexploded bombs during a church picnic in Oregon.

The United States attempted to weaponize unpiloted bombers during World War II, using specially modified B-17 Flying Fortresses and other airplanes loaded with explosives. In Operation Aphrodite, the U.S. Army Air Forces installed radio-controlled actuators to each aircraft’s flight controls, along with two television cameras (one looking out the nose of the craft, and one aimed at its instrument panel). Two pilots set out in the drone B-17s. At an altitude of 10,000 feet, they armed the explosives, passed radio control to another B-17 (the “mothership”), then bailed out using parachutes. Personnel on the mothership (which was fitted with television receivers and radio control equipment) would then guide the drone to German V-2 launch sites. That was the plan, anyway. None of the B-17s (or B-24s or PB4Y-1s also used as makeshift UAVs) ever made it to their intended targets, and a number of crew—including Joseph Kennedy Jr. (pictured)—died during these attempts.

Perhaps the best-known unmanned vehicle of World War II was the German Fieseler Fi 103, also called the V-1 “Buzz Bomb” (“V-1” stood for Vergeltungswaffe Eins, or “vengeance weapon one”). Meant to kill British civilians—per Adolf Hitler’s order for a weapon to be used against “non-military targets”—the V-1 was powered by a pulsejet engine that made a distinctive buzz. It carried a 2,000-pound warhead approximately 150 miles, and had a sophisticated guidance system consisting of gyroscopes, barometers, and an anemometer, which was used to calculate distance flown. Once over the target, the guidance system put the V-1 into a steep dive. The Germans launched roughly 20,000 V-1s at Allied targets, primarily in London and Antwerp, Belgium. The Buzz Bombs proved devastating, killing more than 10,000 civilians and injuring nearly 28,000.

Reginald Denny’s Radioplane Company, which was acquired in 1952 by Northrop Aircraft Incorporated, led the way in post-World War II UAV development. While most of the drones designed and produced during this period were used for target practice, 1955 saw the U.S. Army’s first reconnaissance drone, the Northrop Radioplane RP-71 Falconer (designated the SD-1 by the Army), based on a target vehicle design. Launched by two rockets and recovered by parachute, the Falconer carried a still film camera and could transmit crude video.

A second-generation turbojet-powered Firebee, built by Ryan Aeronautical Company and developed from a target drone initially developed for the U.S. Air Force, led to the AQM-34, which ushered in modern unmanned reconnaissance aircraft. From the mid-1960s to the mid-1970s, the AQM-34 flew tens of thousands of missions over North Vietnam, parts of China, and even the Soviet Union, obviating the risk posed by manned reconnaissance flights.

In the 1970s, Israel began to modify existing UAVs and develop new designs. One of the most ingenious Israeli uses of UAVs came during the Yom Kippur War of October 1973, when a “swarm” of Northrop Chukar unmanned craft was sent toward the Golan Heights. The Syrian military was tricked into thinking a massive air attack was under way against its potent surface-to-air missile (SAM) batteries, and launched dozens of SAMs against the incoming aircraft, substantially depleting their air defenses. In subsequent years, Israel took the global lead in certain types of UAVs, particularly in the 1980s with the development of lighter, smaller unmanned aircraft like the RQ-2 Pioneer (pictured). Along with its sibling, the IAI RQ-5 Hunter, the Pioneer flew extensively in the 1991 Gulf War.

The RQ-1 Predator, probably the best-known modern UAV, made its first test flight in 1994. Produced by General Atomics Aeronautical Systems—based on a design by Abraham Karem, a former engineering officer for the Israeli Air Force—it was designed for “long loiter” reconnaissance work. The RQ-1 has evolved, and today its variants patrol the U.S.-Mexico border, collect air samples for scientific research, and unleash Hellfire air-to-ground missiles on military targets.

Soaring even higher than the Predator—which the military considers a medium altitude UAV—the Northrop Grumman RQ-4 Global Hawk is a high-altitude, long endurance aircraft with performance and sensor capabilities so impressive it’s scary. Born out of a 1995 DARPA (Defense Advanced Research Projects Agency) request, the Global Hawk can fly more than 32 hours at a stretch and loiter at altitudes as high as 65,000 feet, with a suite of sensors that can see through clouds, dense fog, haze, and dust storms. Thanks to a data transmission rate dozens of times faster than a T1 line, operators can view very high resolution imagery of wide swaths of the ground below.

Despite the historic focus on military uses, UAV designers see an ever-expanding non-military role for their vehicles as airframe designs, control systems, and onboard sensors become more reliable, smaller, lighter, longer-lasting, safer, and cheaper.

In 2007, an Aerosonde UAV took off from the NASA Wallops Flight Facility in Virginia and headed into Hurricane Noel, a Category 1 storm churning up the eastern coast of the United States. During its 17 hour, 27 minute flight into Noel, the Aerosonde flew as low as 300 feet above sea level, far lower than a piloted airplane would dare travel inside a hurricane eyewall. Last year, NASA used a Global Hawk to take this image of Tropical Storm Frank over the Pacific Ocean. Other non-military UAV uses include crop monitoring, search and rescue, fire spotting, mineral exploration, aerial photography and ground mapping. And those are only the ones we’ve thought of already.