Aviation

I

Introduction

Aviation, the science and practice of flight. Heavier-than-air craft include aeroplanes, gliders, helicopters, ornithopters, convertiplanes, and VTOL (vertical take-off and landing) and STOL (short take-off and landing) craft. These are distinguished from lighter-than-air craft, which include balloons (free, usually spherical; and captive, usually elongated), and dirigible airships. This article deals with heavier-than-air flight.

Operational aviation is grouped broadly into three classes: military aviation, commercial aviation, and general aviation. Military aviation includes all forms of flying by the armed forces—strategic, tactical, and logistical. Commercial aviation embraces primarily the operation of scheduled and charter airlines. General aviation embraces all other forms of flying, such as instructional flying, crop dusting by air, flying for sport, private flying, and transport in business-owned aeroplanes, usually known as executive aircraft.

II

Early History

Centuries of dreaming, study, speculation, and experiment preceded the first successful flight. The ancient legends contain numerous references to the possibility of movement through the air. Philosophers believed that it could be accomplished by imitating the wing motions of birds, and by using smoke or other lighter-than-air media.

The first form of aircraft made was the kite, about the 5th century bc. In the 13th century, an English monk, Roger Bacon, conducted studies that led him to the conclusion that air could support a craft in the same manner in which water supports boats. At the beginning of the 16th century, Leonardo da Vinci gathered data on the flight of birds and anticipated developments that subsequently became practical. As well as inventing the airscrew, or propeller, and the parachute, he conceived three different types of heavier-than-air craft: an ornithopter, a machine with mechanical wings designed to flap like those of a bird; a helicopter, designed to rise by the revolving of a rotor on a vertical axis; and a glider, consisting of a wing fixed to a frame on which a person might coast on the air. Leonardo’s concepts also involved the use of human muscular power. Although many of his concepts were quite inadequate to produce flight, Leonardo made an important contribution to aviation because he was the first to make scientific proposals.

III

The 19th Century

The practical development of aviation took various paths during the 19th century. The aeronautical engineer and inventor George Cayley was a far-sighted theorist who tested his ideas with experiments involving kites and controlled and man-carrying gliders. He designed a combined helicopter and horizontally propelled aircraft and deserves to be called the father of aviation. Francis Herbert Wenham, a founding member of the Royal Aeronautical Society, in Britain, used a wind tunnel in his research and foresaw the use of multiple wings placed one above the other.

Makers and fliers of models in Britain included the inventors John Stringfellow and William Samuel Henson, who collaborated in the early 1840s to produce a model of an airliner. Stringfellow’s improved 1848 model, powered with a steam engine and launched from a wire, demonstrated lift but failed to climb. The French inventor Alphonse Penaud produced a hand-launched model powered with rubber bands that flew about 35 m (115 ft) in 1871. Another French inventor, Victor Tatin, powered his model plane with compressed air. Tethered to a central pole, it was pulled by two traction propellers; rising with its four-wheeled chassis, it made short, low-altitude flights. The Australian inventor Lawrence Hargrave produced a rigid-winged model, propelled by flapping blades that were operated by a compressed-air motor. It flew 95 m (312 ft) in 1891. The American astronomer Samuel Pierpont Langley produced (1896) steam-powered, tandem-monoplane models with wingspans of 4.6 m (15 ft). They repeatedly flew 900 to 1,200 m (3,000 to 4,000 ft) for about 1y minutes, climbing in large circles. Then, with power exhausted, they descended slowly to alight on the waters of the Potomac River, near Washington, D.C.

Numerous efforts to imitate the flight of birds were also made with experiments involving muscle-powered paddles or flappers, but none proved successful. These included the early attempts of the Austrian Jacob Degen, who carried out various experiments from 1806 to 1813; the Belgian Vincent DeGroof, who crashed to his death in 1874; and the American R. J. Spaulding, who actually received a patent for his idea of muscle-powered flight in 1889.

More successful were the attempts of aeronauts who advanced the art through their study of gliding and contributed extensively to the design of wings. They included the Frenchman Jean Marie Le Bris, who tested a glider with movable wings, the American John Joseph Montgomery, and the renowned Otto Lilienthal, of Germany. Lilienthal’s experiments with aircraft, including kites and ornithopters, attained greatest success with his glider flights in 1894-1896. In 1896, however, he met his death when his glider went out of control and crashed. The Scot Percy S. Pilcher, who had attained remarkable success with his gliders, had a fatal fall in 1899. The American engineer Octave Chanute had a limited success with multi-plane gliders, in 1896-1902. Chanute’s most notable contribution to flight was his compilation of developments, Progress in Flying Machines (1894).

Additional information on aerodynamics and on flight stability was gained by a number of experiments with kites. The American inventor James Means published his results in the Aeronautical Annuals of 1895, 1896, and 1897. Lawrence Hargrave invented the box kite in 1893 and Alexander Graham Bell developed huge man-carrying tetrahedral-celled kites between 1895 and 1910.

Powered experiments with full-scale models were conducted by various investigators between 1890 and 1901. In 1890 the Frenchman Clément Ader built a machine that briefly left the ground in an uncontrolled flight. Most important were the attempts of Langley, who tested and flew an unmanned quarter-size model in 1901 and 1903 before testing a full-scale model of his machine, which he called the Aerodrome. This model was the first petrol-engine-powered heavier-than-air craft to fly. His full-scale machine was completed in 1903 and was tested twice, but each launching ended in a mishap. The German aviator Karl Jatho also tested a full-scale powered craft in 1903 and achieved a short uncontrolled flight.

Advances throughout the 19th century laid the foundation for the eventual successful flight by the Wright brothers in 1903, but the major developments were the result of the efforts of Chanute, Lilienthal, and Langley after 1885. A sound basis in experimental aerodynamics had been established, although the stability and control required for sustained flight had not been acquired. More important, successful powered flight needed the light internal-combustion engine to replace the heavy steam engine.

IV

Kitty Hawk and After

The American brothers Wilbur and Orville Wright based their work on that of Lilienthal and others, and first flew a glider with mixed success in 1900. By 1902 they had built a successful glider. On December 17, 1903, near Kitty Hawk, North Carolina, they made the world’s first successful flights in a powered and controlled heavier-than-air craft, of a type they called the Flyer. The aeroplane and engine had been designed, constructed, and flown by them, each brother making two flights that day. The longest, by Wilbur, extended to a distance of 260 m (852 ft) and lasted 59 seconds.

The next year, continuing the development of their design and improving their skill as pilots, the brothers made 105 flights, the longest lasting more than 5 minutes. The following year, their best flight was of 38.9 km (24.2 mi), in 38 minutes 3 seconds. All these flights were in open country, the longest involving numerous turns, usually returning to near the starting point.

Not until 1906 did anyone else fly in a powered aeroplane. In that year short hops were made by a Hungarian, Trajan Vuia, living in Paris, and by Jacob Christian Ellehammer, in Denmark. The first officially witnessed flight in Europe was made in France, by Alberto Santos-Dumont of Brazil. His longest flight, on November 12, 1906, covered a distance of about 220 m (722 ft) in 22.5 seconds. The aeroplane, the 14-bis, was of his own design, made by the Voisin firm in Paris, and powered with a Levavasseur 40-hp Antoinette engine. The aeroplane resembled a large box kite, with a smaller box at the front end of a long, cloth-covered frame. The engine and propeller were at the rear, and the pilot stood in a basket just forward of the rear wing. Not until near the end of 1907 did anyone in Europe fly for 1 minute; Henri Farman did so in an aeroplane built by Voisin.

In great contrast were the flights of the Wright brothers. Orville, in the United States, demonstrated a Flyer for the Army Signal Corps at Fort Myer, Virginia, beginning on September 3, 1908. On September 9 he completed the world’s first flight of more than 1 hour and, also for the first time, carried a passenger, Lieutenant Frank P. Lahm, for a flight lasting 6 minutes 24 seconds. These demonstrations were interrupted on September 17, when the aeroplane crashed, injuring Orville and his passenger, Lieutenant Thomas E. Selfridge, who died hours later, the first person to be fatally injured in a powered aeroplane.

Wilbur, meanwhile, had gone to France in August 1908, and on December 31 of that year completed a flight of over 2 hours 20 minutes, demonstrating total control of his Flyer, turning gracefully, and climbing or descending at will. Having recovered from his injuries, and with Wilbur’s assistance, Orville resumed demonstrations for the Signal Corps in the following July and met their requirements by the end of the month. The aeroplane was purchased on August 2, becoming the first successful military aeroplane. It remained in active service for about two years and was then retired to the Smithsonian Institution, Washington, D.C., at which it is displayed today.

Although Horatio Phillips made a short, uncontrolled flight in 1907, the honour of being the first to fly in a powered aeroplane in Britain belongs to Samuel Cody, who flew his “British Army Aeroplane No. 1” at Farnborough, Hampshire, on October 16, 1908.

Prominent among American designers, makers, and pilots of aeroplanes was Glenn Hammond Curtiss, of Hammondsport, New York State. In May 1908 Curtiss flew alone in an aeroplane designed and built by a group known as the Aerial Experiment Association, organized by Alexander Graham Bell. Curtiss was one of the five members. In their third aeroplane, the June Bug, Curtiss, on July 4, 1908, covered a distance of 1,552 m (5,090 ft) in 1 minute 42.5 seconds, winning the first American award, the Scientific American Trophy, given for an aeroplane flight. In January 1911 he became the first American to develop and fly a seaplane, the first successful one having been made and flown by Henri Fabre in France on March 28, 1910.

The first flight of an aeroplane designed, built, and flown in Britain was by Alliott Verdon Roe, on July 23 1909. A pioneering aeroplane flight across the English Channel, from Calais to Dover, covering a distance of about 37 km (23 mi) in 35.5 minutes, was made on July 25, 1909, by the French engineer Louis Blériot, in a monoplane that he had designed and built.

In 1911 the first transcontinental flight across the United States, from New York to Long Beach, California, was completed by the American aviator Calbraith P. Rodgers. He left Sheepshead Bay, in Brooklyn, New York, on September 17, 1911, using a Wright machine, and landed at his destination on December 10, 1911, 84 days later. His actual flying time was 3 days, 10 hours, and 14 minutes.