A century ago, the Kettering Aerial Torpedo—a cruise missile prototype—was tested southeast of Arcadia at Carlstrom Field. It was one of two aviation training camps that the U.S. Army built during World War I to train pilots, and so Arcadia proudly called itself “The Aviation City of Florida.”
On April 6, 1917, the U.S. had declared war on Germany. Major Gen. George Owen Squier (1865-1934) in November accepted an invitation to observe the flight of an unmanned airplane at the U.S. Navy’s Amityville, Long Island, test site, according to Twenty-five Years Ahead of Its Time: The American Aerial Torpedo in World War I by Michael H. Taint, Lt. Colonel, USAF (Ret.).
Squier was the first Army officer to earn a doctorate—electrical engineering from Johns Hopkins University—and he wrote the specifications for the “Heavier-Than-Air-Flying Machine” in 1907, to procure the first aircraft for the military from Orville and Wilbur Wright. However, a combat air fleet was not funded until the National Defense Act of 1916 appropriated $17 million to build 375 new military aircraft and created an Aviation Division in the U.S. Army Signal Corps.
Inspired by his observation of the Navy machine, Squier proposed the development of an aerial torpedo—smaller and cheaper to build than airplanes. To lead the design team for the secret project dubbed “Liberty Eagle,” he chose Charles F. Kettering (1876-1958), who had invented the electric ignition.
The team met in Dayton, Ohio, on Christmas Eve 1917 to design not an explosive that “would fly a one-way mission and simply crash into the desired target, detonating its bomb with the metal components of the airframe and engine serving as shrapnel during the explosion. The payload would be a 200 lb. high explosive bomb, with a maximum range of 50 miles and an allowable target error of 1/4 percent in degrees.” The team called it the “Kettering Bug.”
Launched from a track as with the first Wright aircraft, the Bug flew “with a standard National Cash Register counter which ‘measured’ the distance and, after a designated number of turns, cut the ignition and folded the wings,” as described by Kenneth P. Werrel in The Evolution of the Cruise Missile.
On Jan. 25, 1918, contracts were awarded to the Dayton-Wright Airplane Co. and also to the Dayton Metal Products Co.—both partly owned by Kettering. He divided the development into three subsystems.
The aircraft called “the kite” was a miniature biplane fashioned of wood, cardboard, and paper mache with a 12-foot length and 15-foot wingspan. It consisted of several modules easily shipped and assembled with hand tools in the field.
The DePalma Manufacturing Co. built the low-cost, air-cooled, two-stroke, four-cylinder engine. The company was founded by C. Harold Wills (1878-1940), former chief engineer at Ford, and Ralph De Palma (1882-1956), American race-car driver who won the Indianapolis 500 in 1915.
The flight control system included Elmer Ambrose Sperry’s gyroscope and an aneroid barometer/altimeter sensitive to changes of a few feet in altitude. Mechanical Engineer Thomas Midgley Jr. (1891-1944) and Kettering designed a pneumatic control system with parts produced by the Aeolian Co. of New York, manufacturer of keyboard instruments.
As the project struggled to find and hone components, the Army pressured Kettering to move to testing. The first test flight on Sept. 14, 1918, failed because of a faulty engine carburetor and a misadjusted control system. After improvements and additional test flights on Oct. 4, 1918, the Bug flew large circles for 20 minutes at 10,000 feet ... and was lost to sight.
The police in Xenia, Ohio—a small town 25 miles from the launch—notified what is today the Wright-Patterson Air Force Base—that a military airplane had crashed about four miles outside of town, 1,000 feet from a farmhouse, and the pilot was missing. The local newspaper was covering the event.
Lt. Col. Bion Joseph Arnold (1861-1942) and Col. Henry Harley “Hap” Arnold (1886-1956) drove to the scene, and Bion Arnold identified Hap Arnold—sporting his flying jacket—as the missing pilot (even though the Air Service did not issue parachutes at that time). They told the police and newspaper that the flight was a secret project, and all publicity ceased. The remains of the fuselage were burned and pieces of the engine and control system were collected. Later the wings and tail that had dropped off prior to crash—as designed—were recovered.
Refinements and tests continued. Bion Arnold toured the southern U.S. searching for a more remote test site to avoid the security compromise, and he selected Carlstrom Field near Arcadia. The Armistice, Nov. 11, 1918, stopped the project. Both Kettering and Arnold requested and were granted release from the project.
In January 1919 a three-officer board recommended “further development of the ‘flying bomb’ by the Air Service.” A former coast artillery officer, Lt. Col. Guy L. Gearhart (1883-1922), took on the project and 12 aerial torpedoes were shipped to Carlstrom Field. In September and October 14 test flights were conducted. Four were successful, including the last of 16 miles. An U.S. Army Air Service film of the test flights is available at https://www.youtube.com/watch? v=LQAi0_lN4FQ.
The summary report from Carlstrom Field recommended that a catapult rather than the wheeled track be developed, the engine improved, and a larger gyro installed. In 1927, when Kettering applied for a patent, the final test report was written by the first officer awarded a doctorate in aeronautical engineering in America, Lt. James “Jimmy” Doolittle (1896-1993). He recommended radio control.
In World War II, Col. Arnold recommended a “new and improved Bug” called the A-1—a radio-controlled 500-pound bomb with a 400-mile range. Tests revealed flight control issues. And because Germany was out its range, development of the A-1 was abandoned.
Sidebar: Oct. 2, 2018, was the 100th anniversary of the Kettering Bug’s first successful flight and the founding of the Engineers Club of Dayton, Ohio, by Charles F. Kettering, Orville Wright, and Edward Deeds, president of the National Cash Register Co. That year was also the centennial anniversary of their building’s construction. In honor of these anniversaries, the club presented the Charles F. Kettering Aerial Torpedo Bug Award to the Ohio State University College of Engineering, Aerospace Research Center, for setting world records of speed and distances flown by an autonomous unmanned aerial system.