A vehicle driven through the air by a self-carried power source, supported by air pressure against the wings or rotors, and controlled in flight path and destination by the pilot.
In religion, mythology, legend, and imagination, human levitation and flight are old and familiar concepts. Birds, bats, and insects were visible proof that flying through the air with wings was possible in nature, and for centuries humans imitated birds by attempting to fly with flapping, birdlike wings carried by human arms. These “ornithopters,” frequently launched from hillsides, towers, or barns, formed a long and frequently farcical or fatal tradition in humankind’s attempt to fly.
Some early Greek physicists appreciated that a compressed jet of air could be a motive force, but saw no practical way to achieve this. During the Renaissance, Leonardo da Vinci sketched out a few ideas regarding helicopters and propellers, but with no suggestion for a power source. Still, the evidence that moving air could exert a tangible and useable force on sails, kites, and windmills was plain enough. In the eighteenth century, some “whirling arm” experimenters, such as John Smeaton, began to quantify the lift and drag forces exerted by moving air upon flat surfaces. In France, Launoy and Bienvenu devised a model helicopter in 1784. Late eighteenth century technology developed steam as a power source, but by 1783 Jacques-Étienne Montgolfier’s balloons had captured public interest and also had given the French the premier place in aeronautics development.
Significant heavier-than-air research was done in early nineteenth century England by Sir George Cayley, an inventor, scholar, and publicist whom many authors describe as “the father of modern aviation.” Cayley’s studies and experiments confirmed that a curved-wing, or cambered, surface supplied more lift than did a flat one, that low pressure on the upper surface exerted considerable lift, and that air pressure on an adjustable plane surface in an airstream varied in extent and location. He drew attention to the problem of stability, and also built model helicopters and gliders. One glider was capable of supporting his coachman in a short airborne hop. The pioneer pilot’s verdict was “Please, Sir George, I wish to give notice. I was hired to drive, not to fly.” Cayley’s extensive publications were not widely known in his lifetime, but they had later influence. Cayley’s English followers, such as William Samuel Henson and John Stringfellow, attempted an aerial steam carriage, but of greater importance was the first wind tunnel, built in 1871 by Francis Herbert Wenham and John Browning.
Frenchmen dominated aeronautical study and experimentation in the nineteenth century, but their more elaborate machines were less successful than a device of great simplicity. In 1871, Alphonse Pénaud employed twisted rubber as a power source for a model aircraft. His “planophore” was a stick fuselage holding curved and angled monoplane wings with their extremities tipped up, a vertical rudder, and a pusher propeller at the rear, powered by a twisted rubber band directly under the fuselage. In an apparently simple toy, Pénaud incorporated the essentials of airplane structure, including lift, inherent stability, and elementary vertical and horizontal control. The major challenge remained to find a better power source. One key to the progress of aviation was the development of the internal combustion engine by Nikolaus August Otto, Gottlieb Daimler, and Carl Benz.
In the 1890’s, hang gliding was greatly developed and popularized by the exploits of Germany’s Otto Lilienthal. The author of Des Vogelflug als Grundlage der Fliegekunst (1889; Bird Flight as the Basis of Aviation, 1911), Lilienthal believed that gliders copying bird wings would lead to successful powered flight. From 1891 to 1896, he built five monoplane gliders and two biplane gliders and made two thousand flights with them, measuring lift and drag. These glides of up to 750 feet in distance drew spectators, reporters, and photographers. The “German bird-man” was a hero to the air-minded, especially in the United States, and remained an inspiration even after his August 9, 1896, fatal crash.
Other European aviation pioneers were concentrating on powered flying machines. Alexander Feodorovich Mozhaiski attempted a steam-powered hop in 1884. In the 1890’s, Victor Tatin and Charles Rivet built a steam-powered model plane, which in one test flew about 460 feet. Clément Ader claimed to have flown about 50 meters in 1890 in his steam-powered Eole and to have surpassed this distance on October 14, 1897, with a flight of 300 meters in his government-financed Avion III. Whether this was a continuous flight or the total length of a series of hops in unclear, but the French army observers were less impressed than Ader was, and the project was dropped.
In the 1890’s considerable press attention was given to the construction and testing of a £30,000 steam airplane by Sir Hiram Maxim. It had a lifting area of 4,000 square feet, two 180-horsepower steam engines, twin propellers of 17.8 feet, a 1,800-foot launching track, and a total weight of 8,000 pounds. On July 31, 1894, with a steam pressure of 320 pounds per square inch, this monster barely left the ground, colliding with the guard rails. Maxim’s craft had ample power, but lacked all the other requirements for flight. This experiment was not pursued further and made no advance in aviation technology, but it did keep attempts to fly in the public mind.
At the turn of the century, European aviation interests were turning to semirigid powered airships of increasing size, culminating in the German zeppelin. Hang gliding was continued, however, by Percy Pilcher, a Lilienthal disciple and English engineer. Pilcher was briefly joined by Lawrence Hargrave of Australia for testing some of the latter’s box-kite designs. Pilcher’s career was ended by a fatal crash in 1899. The next major experiment in heavier-than-air flight was made in America.
The gliding school of aviation in America was continued, encouraged, and publicized by Octave Chanute, a French-born American civil engineer. He improved glider design, using the ideas of Lilienthal, Pilcher, Hargrave, and others. Collecting information on past and current aviation experiments in the United States, France, and England, he developed the Chanute biplane glider using the Pratt truss used in bridge building. Augustus Moore Herring acted as Chanute’s assistant and pilot for several hundred glides launched from the Indiana dunes in 1896 and flew up to 350 feet. In 1900, Chanute was contacted by the Wright brothers and gave them information and encouragement, while he was also in communication with the telephone inventor Alexander Graham Bell and the Smithsonian secretary Samuel Pierpont Langley regarding their own aviation projects. Thanks largely to Chanute, meetings and publications began to connect American aeronautical researchers into an informal group of scientific minds.
Langley, secretary of the Smithsonian Institution and respected in academic circles as America’s leading expert in aeronautic science, succeeded in the 1890’s in constructing steam-powered model airplanes. In 1898, during the Spanish-American War, he succeeded in gaining a grant from the U.S. Army for building a human-lifting, power-driven, controllable airplane. The result was the Pénaud-type aerodrome, with tandem wings, a tailpiece rudder, and twin-pusher propellers driven by a water-cooled gasoline engine of radial design, with five cylinders providing 52 horsepower.
On October 7, 1903, at Widewater on the Potomac River, witnessed by officials and the press, the 850-pound craft, with Charles Manly as pilot, was propelled from the roof of a houseboat, and in The Washington Post’s description, “simply slid into the water like a handful of mortar.” The New York Times decided that a practical flying machine “might be evolved . . . in from one to ten million years.” After a repetition of this failure on December 8, one congressman described Langley’s aerodrome as a “mud duck which will not fly fifty feet.” The U.S. Army quickly cancelled Langley’s project, and he died in 1906 a disappointed man. However, the Smithsonian Institution until 1948 prominently displayed the great aerodrome as “the first aircraft in history capable of flight with a pilot and several hundred pounds of useful load.”
Wilbur Wright and his brother Orville were bachelors, living with their father, Milton Wright, a bishop in the United Brethren Church, and their sister Kate in Dayton, Ohio. The brothers operated a shop for building, selling, maintaining, and repairing the popular safety bicycles of the 1890’s. Their joint interest in aviation may have been sparked by a childhood gift of a toy helicopter. It was certainly inspired by Otto Lilienthal, whose personal role in practical gliding they admired, and whose inductive, step-by-step approach to airplane design they followed. The Wrights were competent enough in algebra, solid geometry, trigonometry, and physics to understand the aeronautical problems involved in aviation, and as practical mechanics they were able to do most of the production themselves, saving expense and minimizing errors. They attacked the task in stages, concentrating first on the problem of wing lift, then on mastering flight control, and finally on adequate propulsion.
In May, 1899, Wilbur Wright wrote to the Smithsonian Institution requesting titles of books and articles on flying, and a current list was sent to him. The following August, the Wrights built their first aircraft, a biplane box kite 5 feet wide, with a fixed-tail plane, in order to test wing twisting, later called wing warping, as a method of controlling side roll. In May, 1900, Wilbur wrote to Chanute to exchange ideas on gliding, and the Wrights’ later gliders somewhat resembled Chanute types.
In September, 1900, the off-season in the bicycle trade, the Wrights took a camping vacation at Kitty Hawk, a sparsely inhabited stretch of sand dunes and mosquitoes on the Outer Banks of North Carolina. Here they flew their Glider I, mostly as a kite. The following year, a larger model, Glider II, failed to achieve the lift and drag results reported by earlier experimenters. The Wrights decided to check existing aeronautic tables with their homemade wind tunnel. These tests indicated that the Smeaton coefficient and the Lilienthal and Chanute tables from which they had been working were significantly inaccurate. Developing their own (confidential) tables, the Wrights built their successful 1902 Glider III. This craft included the mechanical linkage of wing warping to rear rudder control, which formed the chief basis of their 1902 patent application, granted in 1906. By a process of research, experiment, and checking for flaws, the Wrights developed an air frame which solved the problems of lift and flight control. The Wrights were then ready to attempt powered flight in 1903.
Much of their 1903 season, however, was consumed by problems and delays. Not finding a gasoline engine meeting their lightweight, high-power needs, they designed their own four-cylinder, water-cooled, in-line engine, weighing about 150 pounds, producing 12 horsepower, and linked by bicycle chains to a pair of pusher propellers. Marine propellers being entirely unsuitable, the Wrights used their wind tunnel to design propellers as “moving wings” traveling in a forward spiral. Altogether, testing the new machine, Flyer I, at Kitty Hawk was delayed until December 17, 1903. That day’s consecutive flights were Orville’s initial hop of 120 feet, Wilbur’s of 175 feet, Orville’s flight of 200 feet, and Wilbur’s flight of 852 feet into a wind of 20 to 27 miles per hour for 59 seconds. These straight-line distances at a low level were not revolutionary, but to take off and be airborne under power for nearly a minute was new in the annals of aviation. There were photographs and five witnesses, but the press generated only a few garbled reports.
In 1904, the Wrights practiced on a new Flyer II with a slightly larger engine, flying at Huffman Prairie near Dayton. These low-altitude flights culminated in successful circles and, on November 9, a flight of five minutes. The 1905 Flyer III had a wing area of 503 square feet, a 40-feet, 6-inch span, and wing camber of 1 in 20. Its wings were horizontally flat, with a built-up elevator and rudder, and with an engine of about 20 horsepower. Another series of Huffman Prairie flights included one of 24 miles in 38 minutes. The local audience and photographs increased, and as one foreign visitor put it, “Dayton knows the Wrights fly, but America isn’t sure.”
The 1905 Flyer III represented the completion of the Wrights’ project to build a human-carrying, powered flying machine capable of controlled flight. The Wrights offered the plane to the U.S. Army, then the British, French, and Germans. Their asking price of $250,000 or more was too steep for the war departments, who shrewdly suspected that the Wrights were reluctant to demonstrate their machine for fear of easy copying. Octave Chanute’s 1903 Paris lecture on the Wrights’ gliding experiments, Wilbur Wright’s U.S. lectures, and visits to the Wrights by European observers gradually spread the conviction that powered aviation was indeed at hand.
Meanwhile, powered glider hops, particularly of box-kite construction types, increased in Europe. Some models were advertised for sale as “Wright-type flyers.” The popular Brazilian sportsman Alberto Santos-Dumont was hailed for his 1906 flight at Bagatelle, France, as the “the first to fly.” The Wrights brought a flyer plane to Europe in 1907, but left it in storage, deciding that in 1908 Orville would compete for a U.S. Army contract, while Wilbur would demonstrate the model which they left in France.
In 1908, Orville won the U.S. Army contract to considerable public acclaim, while in France, Wilbur had a Cinderella experience. Ridiculed for weeks for his lengthy delays in assembling and repairing the stored plane, Wilbur’s August 8 demonstration flight at Le Mans, with circles, figure eights, and graceful landings under complete control, came as a revelation to Europeans who had not gotten beyond short, straight-line hops. Aviators, press, and public hailed Wilbur Wright as a hero and companies were quickly formed in France, Britain, and Germany to build Wright biplanes under license.
The 1908 Wright Flyer clearly outclassed its European counterparts in construction, performance, and controllability. However, at the Rheims air exhibition of 1909, there were several French types which had improved on the Wright Flyer. Henri and Maurice Farman offered stable biplanes, and Louis Blériot showed the monoplane type with which he would cross the English Channel to become the French hero of the year. Gabriel Voisin promised quick delivery and reliable construction. Leon Levavasseur’s Antoinettes were becoming popular. Glenn H. Curtiss upheld the United States’ reputation by winning the Gordon Bennet Speed Trophy. All these represented some form of advancement over the 1908 Wright machine. Several nations also established airplane sections in their armies in 1909.
The year 1910 saw a great increase in the number of airplane manufacturers, but a more modest growth in airplane sales. Clearly, even the largest firms would not survive without large government orders for military purposes, so patriotic public agitation was organized to that end. This brought about a major change in production types. Pre-1914 war departments wanted planes which excelled in range, stability, load, and altitude, solid and simple in design, built for careless handling with easy maintenance and repair under wartime conditions. From 1911 on, Europe’s war departments were deciding which plane types and which manufacturing firms would survive, and trying to find a remedy for the French predominance in the light engine market.
By 1913, airplanes had wheeled landing gear, more efficient tractor propellers were replacing pusher types, and cantilevered wings were the key to larger monoplanes. Monocoque fuselage construction made possible the airliners of the future, and ailerons were beginning to replace wing warping, which would clearly not be practical with the heavy wings of a large plane. Also, Igor Sikorsky had already built a four-engine plane and would later build a practical helicopter. None of these improvements on the Wright Flyer matched the difficulty or importance of the problems of flight which the Wright brothers had solved, but they marked modern aviation as a field of constant and rapid change.
Christienne, Charles, and Pierre Lissarague. A History of French Military Aviation. Washington, D.C.: Smithsonian Institution Press, 1986. A popular edition of a scholarly work providing a French view of military aviation. Crouch, Tom D. A Dream of Wings: Americans and the Airplane, 1875-1905. New York: W. W. Norton, 1981. A scholarly but readable text on American aviation up to the Wright brothers. Gibbs-Smith, Charles Harvard. Aviation: An Historical Survey from Its Origins to the End of World War II. London: Her Majesty’s Stationery Office, 1970. A comprehensive, readable, and scholarly history by an author who has published extensively in the field of Anglo-American aviation history. Jakab, Peter L. Visions of a Flying Machine: The Wright Brothers and the Process of Invention. Washington, D.C.: Smithsonian Institution Press, 1990. An analysis of the aeronautical problems faced by the Wright brothers and their probable methods of solving them.
Sir George Cayley
Glenn H. Curtiss
Leonardo da Vinci
Forces of flight
Hang gliding and paragliding
History of human flight
Samuel Pierpont Langley
Ferdinand von Zeppelin