The first successful, unmanned, radio-controlled seaplane takeoff-to-landing flight occurred on September 15, 1924, at Dahlgren, Virginia.
Eleven years after the Wright Brothers demonstrated that powered flight was possible on the
beaches of North Carolina, the Army was pursuing remotely-piloted aerial transports. This experimentation was inspired by an event that took place in France in 1914. Aviation entrepreneur and inventor Lawrence B. Sperry, building on the auspicious gyro-compass developed by his father, Elmer Sperry, stunned spectators at the Airplane Safety Competition (Concours de la Securité en Aéroplane) when, during a low-altitude pass, he and his assistant climbed onto the wings of the aircraft to demonstrate the safe and stable operation of what became the modern-day autopilot. The Navy recognized the remote piloting efforts of the Army and, in 1920, requisitioned a modified Curtiss N-9H floatplane from the Army project. The N-9H aircraft, a model already in use by the U.S. Navy, was used in the latter part of testing by the Army because of its increased stability and load-carrying capabilities. Other N-9H aircraft was being housed at the Navy Proving Ground in Dahlgren in support of range observation. The Army Float plane was sent to Dahlgren.
After approval to proceed was given by the Chief of Naval Operations (CNO), radio engineer
Carlos B. (C. B.) Mirick, under the supervision of the Bureau of Ordnance, was sent to Dahlgren in 1922 to begin retrofitting the acquired Curtiss aircraft for pilotless, radio-controlled flight. In addition, Carl Norden, a former partner of Elmer and Lawrence Sperry and inventor of the flywheel catapult used in the Army's experiments with Sperry's aircraft, was called upon to assist the team that assembled at Dahlgren. The skies over the Potomac became filled with airplanes.
By November 1923, 33 radio-controlled flights of the N9 had been successfully flown from a ground-based command post with naval aviator Lieutenant John J. Ballentine, aviation officer at the Proving Ground, on-board as an observing safety pilot. The last flight, performed before senior officials of the Navy's Bureau of Ordnance, successfully executed 16 radio-controlled commands during 25 minutes of radio-controlled flight. Although the flight proved mostly successful, an attempt at a fully unmanned flight was postponed for nearly a year due to the approaching winter weather.
Testing continued in the spring and summer of 1924. By September 15, all was ready for the big test. The weather was perfect. Temperatures hovered in the mid-60s, and there was little chance of precipitation. Following two flawless radio-controlled manned flights, the craft was beached, allowing Lt. Ballentine to exit. With a bag of sand for weight distribution in his place, the single engine started, and the pilotless plane taxied onto the Potomac for its maiden unmanned flight.
After a successful departure, the plane was put through its paces for the duration of the 40-minute flight. Executing radio-transmitted commands, the plane was safely returned to Dahlgren and guided to a less-than-ceremonious landing in the river due to a hole in one of its pontoons. The plane and equipment were recovered successfully. For the first time in U.S. Navy history, a pilotless aircraft had been flown from take-off through full flight maneuvers and returned for landing solely by ground-based radio control. While this project was abandoned a year or so later for many reasons, its effect lit the kindling and forever linked the foundations of the elements of proof testing to vigorous experimentation of new technologies at Dahlgren.
Text from “Dahlgren: A Bubbling Cauldron of Technical Curiosity” by Alan J. Dean.