The ability to strike at an enemy without exposing oneself to retaliation is one of eternal value in war. The spear, slings, bows and crossbows and eventually firearms were all invented to fulfill this purpose. The two world wars took the approach to new heights.
It can be argued that the first “drone weapon” was built as early as the 1870s, shortly after the American Civil War. U.S. inventor John Louis Lay developed an anti-ship torpedo that was powered by compressed CO2 gas and controlled from the shore by two cables transmitting electric signals.
During World War I, both the French and the British experimented with small, explosive-laden vehicles in an attempt to break through enemy trenches. Either wire-controlled or simply moving straight forward, they could cross no man’s land and explode. Overshadowed by the invention of the tank, they failed to achieve much but they inspired French military engineer Adolphe Kégresse (who also invented the half-track) to design a similar remote-controlled mobile bomb in the 1930s.
When Germany attacked France, Kégresse hid his prototype, but it was found by the Nazis and the Wehrmacht decided to develop a similar device. The result was the Goliath, officially named Sd.Kfz. 302 (Sonderkraftfahrzeug “special purpose vehicle”) and Leichter Ladungsträger (“light charge carrier”). Different versions could carry either 130 or 220lbs of explosives: enough to destroy a tank, cause heavy casualties in a tight infantry formation or demolish a house or a bridge. The tracked bomb was controlled by an operator through a 2,130ft long three-strand electric cable which controlled its movement, detonated the explosives and powered the electric motor. The latter component turned out to be both expensive and hard to maintain and was eventually replaced by a more reliable but louder (and more conspicuous) gasoline engine.
Goliaths saw use in numerous theaters, including the Allied landings at Anzio, the Warsaw Uprising, the Operation Dragoon landings in Southern France and a few were deployed on the beaches of Normandy on D-Day. While the 7,564 Goliaths produced caused tremendous damage when used successfully, they were easily foiled and generally considered a failure. Their light armor could be penetrated by small arms fire, their control cable could be cut and their low speed of 6 mph meant they could be spotted and taken out from a long way away. In Normandy, the naval bombardment preceding the landings severed the control cables but one Goliath still killed over a dozen men after the beach was taken: a soldier, unaware that it held explosives inside, tried to destroy it by dropping a grenade in its cargo hold.
The Goliath also had bigger brothers. The Springer medium charge carrier could be controlled with wires or wirelessly and held 730lbs of explosives but only 50 were made. The biggest version, the Borgward IV heavy charge carrier, 1,181 of which were built, was radio-operated and had a 990lbs payload. Unlike the smaller versions, it wasn’t disposable: it dropped the explosives at the target and retreated before those were detonated.
The British also had their own Goliath-equivalent, the Beetle (later renamed mobile land mine). It had two electric motors and some specimens were amphibious but it was deemed unsuccessful. They also experimented with a remote-controlled version of the Matilda II tank called the Black Prince, which was intended to spring enemy ambushes.
The Soviets also converted various types of tanks for remote control during the Winter War against Finland. The Teletank was controlled by radio signals from another tank following it at 500-1,500yards with the control vehicle also providing fire support. Besides dropping bombs next to enemy fortifications, it could also fire machine guns, flamethrowers and smoke canisters.
On the American side, one of the numerous, though ultimately unused, versions of the M4 Sherman was the T10 Mine Exploder, a wheeled version going ahead of its controlling tank and hopefully detonating landmines with its massive wheels.
“Drones” were also developed for water and aerial use. In the First World War the Imperial German Navy built 17 FL-boats (Fernlenkboot, “remote controlled boat”). Controlled over a 12-mile long wire, they could ram enemy ships while carrying 1,800lbs payloads.
Experiments with remotely controlled planes have started during World War One but usually with the aim of facilitating realistic gunnery training against drones, rather than to develop offensive weapons. One such target drone, the American Radioplane OQ-2, was responsible for the rise of a celebrity. An Army photographer visiting the manufacturing plant noticed a pretty assembly worker and took her picture. This photo got her a screen test, catapulting Norma Jeane Baker to worldwide fame as Marilyn Monroe.
Some of the few offensive remote controlled planes were the American TDR-1 Edna and the TDN-1. Both were envisioned as carrier-based weapons that could be radio-controlled from the ground or a following chase plane up to 7-8 miles away and could drop a torpedo or a bomb. The TDN-1 never saw service but 21 of the 50 deployed Ednas hit their targets.
Another type of offensive drone plane was jerry-rigged rather than built for the purpose. Operations Aphrodite and Anvil involved old B-17 Flying Fortresses and Consolidated PB4Y-2 Privateers converted to radio control, loaded with explosives and remotely flown into heavily armored German targets. They were equipped with television cameras pointed at the cockpit controls and the ground, transmitting live footage back to the control plane. During takeoff, the planes were flown by live pilots who then transferred the plane to radio control and parachuted. It was during one of these missions that Joseph P. Kennedy, older brother of future President John F. Kennedy died when his plane exploded due to unknown reasons.