Dahlgren: A Bubbling Cauldron of Technical Curiosity, Segment 2 of 7
By Alan J. Dean
Lighting the Fire Under the Cauldron
Eleven years after the Wright Brothers demonstrated powered flight was possible on the beaches of North Carolina, the Army was pursing 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 potential of the Army’s remote piloting efforts 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, were used in the latter part of testing by the Army because of their increased stability and load carrying capabilities. Other N-9H aircraft were being housed at the Navy Proving Ground in Dahlgren in support of range observation. The Army Float plane was sent to Dahlgren.
Dated Sept. 16, 1924. NP Radio-controlled Plane, single prop-open cockpit, amphibious landing biplane. A starboard bow view of an NP radio controlled aircraft on the ramp at the NPG, Dahlgren. This is believed to be one of the five N-9 airplanes from Copaigue, Long Island, that were sent to Dahlgren and formed the original Naval Air Detail overseen by C. C. Middlebrook. This particular aircraft is supposedly the first flown under remote control without a pilot. Photo courtesy of NSWC-Dahlgren Division.
After approval to proceed was given by 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, 1924, 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.
1924. This N-9 was the first Navy plane to take off and land successfully by radio control. Lt. John J. Ballentine, USN, (later Admiral John J. Ballentine, USN, Ret.), directly under the propeller, was the gentleman doing the flying. Fifth from left is L. R. Daniel, and sixth from right is Charlie Middlebrook, who died in 1965 and who worked on the Norden Bombsight at Dahlgren. Names of all in the picture (L-R): Caldwell, Arnold, Bryant, Spear, Daniel, Pepper, Stone, Mirick, Ballentine, Luke, Middlebrook, Armstrong, Vile, Stansbury, Griffin, and Beasley. Photo courtesy of NSWC-Dahlgren Division.
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.
Carl Norden’s association with Dahlgren only began with the radio-controlled piloting experiment. In 1924, he and his partner Theodore H. Barth delivered three prototype Mk XI bombsights to Dahlgren for testing. In 1931 Carl Norden, working under Navy contract, began the research, development, and flight testing of the Mark XV Norden Bombsight. Initial research into bombsight technology began during World War I, when the Navy became interested in arming its seaplanes with a device that could successfully drop bombs on moving ships. The problem of accurately calculating both a falling bomb’s trajectory, particularly at high altitudes, and its impact point presented even greater complexities than those associated with naval gunnery. As a weapons platform, a bomber in motion was anything but steady. Often buffeted by turbulence, it rotated about three axes and flew at relatively high but inconstant velocities in three dimensions. The bombardier’s challenge was to determine the exact point at which to release a bomb in order to achieve the greatest probability of a hit. The Mark XV was in all essence a mechanical computer allowing the bombardier to adjust (program the bomb) for the aircraft altitude, speed, and angular orientation, bomb ballistics, and wind. From 1932 to 1945, Dahlgren again filled the air with airplanes testing 7506 Norden Mark XV bombsites for both the Navy and the Army.
Carl Norden at Dahlgren with his Bombsite (U.S. Navy Photo)
Norden Bombsite Similar to One at Dahlgren Museum (Dean Photo)