Samuel Langley's successful flights of his model Aerodromes Number 5 and Number 6 in 1896 led to plans to build a full-sized, human-carrying airplane. Langley's simple approach was merely to scale up the unpiloted Aerodromes to human-carrying proportions. This would prove to be a grave error, as the aerodynamics, structural design, and control system of the smaller aircraft were not adaptable to a full-sized version. Langley's primary focus was the power plant. The completed engine, a water-cooled five-cylinder radial that generated a remarkable 52.4 horsepower, was a great achievement for the time.
Despite the excellent engine, the Aerodrome A, as it was called, met with disastrous results, crashing on takeoff on October 7, 1903, and again on December 8. Langley blamed the launch mechanism. While this was in some small measure true, there is no denying that the Aerodrome A was an overly complex, structurally weak, aerodynamically unsound aircraft. This second crash ended Langley's aeronautical work entirely.
Professor Samuel Pierpont Langley (1834-1906) was a leading scientific figure in the United States in the latter nineteenth century, well known especially for his astronomical research. He became the third Secretary of the Smithsonian Institution in 1887. Langley had begun serious investigation into heavier-than-air flight several years earlier while at the then Western University of Pennsylvania in Pittsburgh (now the University of Pittsburgh). He had erected a huge, 18.3 m (60 ft) diameter whirling arm at the university's Allegheny Observatory to perform aerodynamic research. At full speed, the tips of the whirling arm approached seventy miles per hour. Langley mostly ran tests with flat plates, but he also mounted small model airplanes he called aerostats, and even stuffed birds, on the arm. He also conducted an extensive series of experiments with rubber band-powered models.
Langley described these investigations and provided a summary of his results in Experiments in Aerodynamics, published in 1891. He then moved away from purely theoretical aerodynamic research, and began work aimed at engineering an actual flying machine. In 1891, he started to experiment with large, tandem-winged models, approximately 4 m (13 ft) in wingspan, powered by small steam and gasoline engines. Another large whirling arm, 9 m (29.5 ft) in diameter, was set up at the Smithsonian to test curved wing shapes and propellers, probably in connection with the design of these large powered models that Langley called aerodromes.
After several failures with designs that were too fragile and under-powered to sustain themselves, Langley had his first genuine success. On May 6, 1896, Langley's Aerodrome No. 5 made the first successful flight of an unpiloted, engine-driven, heavier-than-air craft of substantial size. It was launched from a spring-actuated catapult mounted on top of a houseboat on the Potomac River near Quantico, Virginia. Two flights were made that afternoon, one of 1,005 m (3,300 ft) and a second of 700 m (2,300 ft), at a speed of approximately 25 miles per hour. On November 28, another successful flight was made with a similar model, the Aerodrome No.6. It flew a distance of approximately 1,460 m (4,790 ft).
Langley's aeronautical experiments appeared to have concluded with the successful flights of Aerodromes No. 5 and 6, but privately he intended to raise funds to begin work on a full-scale, human-carrying aircraft. He believed his only real hope of securing the kind of funding necessary was from the federal government. The breakthrough came when Langley's friend and colleague, Charles D. Walcott, of the U.S. Geological Survey, offered to present the proposal to President McKinley. A panel was created to review Langley's work up to that time. The panel, which included Assistant Secretary of the Navy, Theodore Roosevelt, met at the Smithsonian in April 1898. After a week of deliberations, they approved a grant of $50,000 from the Board of Ordnance and Fortification for Langley to construct a full-sized aircraft. The outbreak of the Spanish-American War only five days earlier contributed to the panel's favorable and speedy decision.
Serious work on the airplane, referred to as the Great Aerodrome, or Aerodrome A, began in October 1898. Langley's simple approach was merely to scale up the unpiloted Aerodromes of 1896 to human-carrying proportions. This would prove to be a grave error, as the aerodynamics, structural design, and control system of the smaller aircraft were not adaptable to a full-sized version. The construction details and distribution of stresses on the Aerodrome A were based on the successful performance of a gasoline-powered model, one-fourth the size. This exact scale miniature, known as the Quarter-scale Aerodrome, flew satis-factorily twice on June 18, 1901, and again with an improved engine on August 8, 1903. But these successes masked its flaws as a design prototype for the full-sized, piloted airplane.
Langley was far more concerned with producing a suitable engine for the large craft. He contracted a New York inventor named Stephen M. Balzer to design and build the powerplant. A native of Hungary, Balzer had constructed the first automobile in New York City in 1894. He designed a five-cylinder, air-cooled rotary engine for the Aerodrome A, but it produced only about 8 horsepower rather than the 12 horsepower specified by Langley. Charles M. Manly, Langley's assistant, extensively reworked the Balzer engine, turning it into a water-cooled radial that generated a remarkable 52.4 horsepower at 950 rpm with a power-to-weight ratio of 1.8 kg (4 lb) per horsepower (including the weight of the radiator and water), an amazing achievement for the time.
The airframe was an entirely different matter. It was structurally weak and unsound. Like the smaller aerodromes, it was a tandem-winged design with a cruciform tail. The control system was minimal and was also poorly conceived. The tail moved only in the vertical plane, and acted more like a modern trim tab to stabilize the flight path, rather than as an elevator for positive pitch control inputs. There was a separate rudder, but it was mounted centrally on the airplane, the position where it would be least effective. Even Langley and Manly recognized the limitations of this control arrangement, and they planned to revised it after simple straight-line flight was achieved. For propulsion, two pusher propellers, mounted between the tandem wings, were driven by shafts and gears connected to the centrally-mounted engine, again after the pattern of the smaller aerodromes. The huge aircraft spanned nearly 15 m (50 ft) and was more than 16 m (52 ft) long. It weighed 340 kg (750 lb) including the pilot, Manly.
The first test flight of the Aerodrome A was on October 7, 1903. The airplane was assembled on the rear of a catapult track mounted on a large house-boat moored near Widewater, Va., close to the site where the small aerodromes were successfully flown. Immediately after launching, the Aerodrome plunged into the river at a forty-five-degree angle. A Washington reporter on the scene remarked that it entered the water "like a handful of mortar." Langley was bitterly disappointed and rationalized the failure as a problem with the launch mechanism, not the aircraft.
After repairs, a second attempt was made on December 8, 1903. This time the houseboat launching platform was located on the Potomac River in Washington, D.C. The results were equally disastrous. Just after takeoff, the Aerodrome A reared up, collapsed upon itself, and smashed into the water, momentarily trapping Manly underneath the wreckage in the freezing Potomac before he was rescued, unhurt. Langley again blamed the launching device. While the catapult likely contributed some small part to the failure, there is no denying that the Aerodrome A was an overly complex, structurally weak, aerodynamically unsound aircraft. This second crash of the Aerodrome A ended the aeronautical work of Samuel Langley. His request to the Board of Ordnance and Fortification for further funding was refused and he suffered much public ridicule. He died in 1906.
The remains of the Aerodrome A were left with the Smithsonian Institution by the War Department. In 1914, the Smithsonian contracted Glenn Curtiss, a prominent American aviation pioneer and aircraft manufacturer, to rebuild the Langley Aerodrome A and conduct further flight tests. With significant modifications and improvements, Curtiss was able to coax the Aerodrome A into the air for a number of brief, straight-line flights at Hammondsport, N.Y. After the tests, the airplane was returned to the Smithsonian, restored to its original unsuccessful 1903 configuration, and put on public display in 1918. Smithsonian officials misleadingly identified the Aerodrome A in its label text as the world's first airplane "capable of sustained free flight." The Aerodrome A had, indeed, existed before the Wright brothers' successful 1903 Flyer, but it only flew much later and even then in heavily modified form, making the Smithsonian claim inappropriate at best. This action was, partly, what prompted Orville Wright in 1928 to lend the 1903 Flyer to the Science Museum in London as a gesture of protest regarding the Smithsonian's seeming unwillingness to give him and his brother, Wilbur, full credit for having invented the airplane. The Smithsonian finally clarified the history of the Aerodrome A and its later flight testing in its 1942 annual report, satisfying Orville, and thereby clearing the way for the return of the Wright Flyer to the United States and its donation to the Smithsonian in 1948. The Aerodrome A continued to be displayed in the Smithsonian's Arts and Industries building with a revised label until 1971, when it was removed from public exhibition and restored again by the NASM restoration staff.