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Early flying machines include all forms of aircraft studied or constructed before the development of the modern aeroplane by 1910. The story of modern flight begins more than a century before the first successful manned aeroplane, and the earliest aircraft thousands of years before that.
The origin of mankind's desire to fly is lost in the distant past. From the earliest legends there have been stories of men strapping birdlike wings, stiffened cloaks or other devices to themselves and attempting to fly, typically by jumping off a tower. During this early period the issues of lift, stability and control were not understood, and most attempts ended in serious injury or death. Designs often lacked an effective horizontal tail, or the wings were simply too small.
The Greek legend of Daedalus and Icarus is one of the earliest to come down to us. According to Ovid, Daedalus tied feathers together, from smallest to largest so as to form an increasing surface. He secured the feathers at their midpoints with string and at their bases with wax, and gave the whole a gentle curvature like the wings of a bird. Other ancient legends include the Indian Vimanas and the British King Bladud. In the 1st century AD, when Wang Mang tried to recruit a specialist scout, a man binding himself with bird feathers is claimed to have glided about 100 meters. On another occasion, in 559 AD, Yuan Huangtou is said to have landed safely following an enforced tower jump
In medieval Europe, the earliest recorded tower jump dates from 852 AD, when Armen Firman made a jump in Cordoba, Spain, reportedly covering his body with vulture feathers and attaching two wings to his arms. On landing he is said to have crashed and sustained a back injury which some critics attributed to a lack of a tail. In 1010 AD Eilmer of Malmesbury, an English monk, flew from the tower of Malmesbury Abbey in a primitive glider. Eilmer was said to have flown over 200 yards (180 m) before landing, breaking both his legs. Eilmer later remarked that the only reason he did not fly further was that he forgot to give his machine a tail. This burst of activity was followed by a lull of several centuries.
Jumping revived in 1496 with Seccio breaking both arms in Nuremberg and continued unabated at least until the early 19th century, with never more than partial success. Francis Willughby's suggestion, published in 1676, that human legs were more comparable to birds' wings in strength than arms, had only occasional influence. As late as 1811, Albrecht Berblinger constructed an ornithopter and jumped into the Danube at Ulm.
The kite was invented in China, possibly as far back as the 5th century BC by Mozi (also Mo Di) and Lu Ban (also Gongshu Ban). These kites were used as leaf kites and were constructed by stretching silk over a split bamboo framework. The earliest known Chinese kites were flat (not bowed) and often rectangular. Later, tailless kites incorporated a stabilizing bowline. Designs often emulated flying insects, birds, and other beasts, both real and mythical. Some were fitted with strings and whistles to make musical sounds while flying.
By at least 549 AD paper kites were being flown, as it was recorded in that year a paper kite was used as a message for a rescue mission. Ancient and medieval Chinese sources list other uses of kites for measuring distances, testing the wind, lifting men, signaling, and communication for military operations.
After its introduction into India, the kite further evolved into the fighter kite. Traditionally these are small, unstable single line flat kites where line tension alone is used for control, and an abrasive line is used to cut down other kites.
By 1634 kites had reached the West, with an illustration of a diamond kite with a tail appearing in Bate's Mysteries of nature and art.
Man-carrying kites are believed to have been used extensively in ancient China, for both civil and military purposes and sometimes enforced as a punishment.
Stories of man-carrying kites also occur in Japan, following the introduction of the kite from China around the seventh century AD. It is said that at one time there was a Japanese law against man-carrying kites.
In 1282 the European explorer Marco Polo described the Chinese techniques then current and commented on the hazards and cruelty involved. To foretell whether a ship should sail, a man would be strapped to a kite having a rectangular grid framework and the subsequent flight pattern used to divine the outlook.
The use of a rotor for vertical flight has existed since 400 BC in the form of the bamboo-copter, an ancient Chinese toy. The bamboo-copter is spun by rolling a stick attached to a rotor. The spinning creates lift, and the toy flies when released. The philosopher Ge Hong's book the Baopuzi (Master Who Embraces Simplicity), written around 317, describes the apocryphal use of a possible rotor in aircraft: "Some have made flying cars [feiche 飛車] with wood from the inner part of the jujube tree, using ox-leather (straps) fastened to returning blades so as to set the machine in motion."
The similar "moulinet à noix" (rotor on a nut) did not appear in Europe until the 14th century AD.
From ancient times the Chinese have understood that hot air rises and have applied the principle to a type of small hot air balloon called a sky lantern. A sky lantern consists of a paper balloon under or just inside which a small lamp is placed. Sky lanterns are traditionally launched for pleasure and during festivals. According to Joseph Needham, such lanterns were known in China from the 3rd century BC. Their military use is attributed to the general Zhuge Liang (180–234 AD, honorific title Kongming), who is said to have used them to scare the enemy troops:
There is evidence that the Chinese also "solved the problem of aerial navigation" using balloons, hundreds of years before the 18th century.
Eventually some investigators began to discover and define some of the basics of scientific aircraft design. Powered designs were either still driven by man-power or used a metal spring. The Englishman Roger Bacon predicted future designs for a balloon filled with an unspecified aether and a man-powered ornithopter in his book De mirabili potestate carto et naturae (Secrets of Art and Nature), 1250.
Leonardo da Vinci studied bird flight for many years, analyzing it rationally and anticipating many principles of aerodynamics. He understood that "An object offers as much resistance to the air as the air does to the object." Newton would not publish the Third law of motion until 1687.
From the last years of the 15th century on he wrote about and sketched many designs for flying machines and mechanisms, including ornithopters, fixed-wing gliders, rotorcraft and parachutes. His early designs were man-powered types including ornithopters and rotorcraft, however he came to realise the impracticality of this and later turned to controlled gliding flight, also sketching some designs powered by a spring.
In 1488 he drew a hang glider design in which the inner parts of the wings are fixed, and some control surfaces are provided towards the tips (as in the gliding flight in birds). While his drawings exist and are deemed flightworthy in principle, he himself never flew in it. A model he built for a test flight in 1496 did not fly, and some other designs, such as the four-person screw-type helicopter, have severe flaws. He drew and wrote about a design for an ornithopter in c. 1490.
Da Vinci's work remained unknown until 1797, and so had no influence on developments over the next three hundred years. Nor were his designs based on particularly good science.
The modern era of lighter-than-air flight began early in the 17th century with Galileo's experiments in which he showed that air has weight. Around 1650 Cyrano de Bergerac wrote some fantasy novels in which he described the principle of ascent using a substance (dew) he supposed to be lighter than air, and descending by releasing a controlled amount of the substance. Francesco Lana de Terzi measured the pressure of air at sea level and in 1670 proposed the first scientifically credible lifting medium in the form of hollow metal spheres from which all the air had been pumped out. These would be lighter than the displaced air and able to lift an airship. His proposed methods of controlling height are still in use today; by carrying ballast which may be dropped overboard to gain height, and by venting the lifting containers to lose height. In practice de Terzi's spheres would have collapsed under air pressure, and further developments had to wait for more practicable lifting gases.
The first documented balloon flight in Europe was of a model made by the Portuguese priest Bartolomeu de Gusmão. On August 8, 1709, in Lisbon, he made a small hot-air balloon of paper with a fire burning beneath it, lifting it about four meters (13 ft) in front of king John V and the Portuguese court.
From the mid-18th century the Montgolfier brothers in France began experimenting with parachutes and balloons. Their balloons were made of paper, and early experiments using steam as the lifting gas were short-lived due to its effect on the paper as it condensed. Mistaking smoke for a kind of steam, they began filling their balloons with hot smoky air which they called "electric smoke" and, despite not fully understanding the principles at work, made some successful launches and in December 1782 flew a 20 cu.m. balloon to 300 m. The French Academie des Sciences soon invited them to Paris to give a demonstration.
Meanwhile the discovery of hydrogen led Joseph Black in c. 1780 to propose its use as a lifting gas, though practical demonstration awaited a gastight balloon material. On hearing of the Montgolfier Brothers' invitation, the French Academy member Jacques Charles offered a similar demonstration of a hydrogen balloon and this was accepted. Charles and two craftsmen, the Robert brothers, developed a gastight material of rubberised silk and set to work.
1783 was a watershed year for ballooning. Between June 4 and December 1 five separate French balloons scored notable aviation firsts:
The Montgolfier designs had several shortcomings, not least the need for dry weather and a tendency for sparks from the fire to set light to the paper balloon. The manned design had a gallery around the base of the balloon rather than the hanging basket of the first, unmanned design, which brought the paper closer to the fire. On their free flight, De Rozier and d'Arlandes took buckets of water and sponges to douse these fires as they arose. On the other hand, the manned design of Charles was essentially modern. As a result of these exploits, the hot-air ballon became known as the Montgolfière type and the hydrogen balloon the Charlière.
Charles and the Robert brothers' next balloon, La Caroline, was a Charlière that followed Jean Baptiste Meusnier's proposals for an elongated dirigible balloon, and was notable for having an outer envelope with the gas contained in a second, inner ballonet. On 19 September 1784, it completed the first flight of over 100 km, between Paris and Beuvry, despite the man-powered propulsive devices proving useless.
In January the next year, Jean Pierre Blanchard and John Jeffries crossed the English Channel in a Charlière from Dover to the Bois de Felmores. But a similar attempt the other way would end in tragedy. In an attempt to provide both endurance and controllability, de Rozier developed a balloon having both hot air and hydrogen gas bags, a design which was soon named after him as the Rozière. His idea was to use the hydrogen section for constant lift and to navigate vertically by heating and allowing to cool the hot air section, in order to catch the most favourable wind at whatever altitude it was blowing. The balloon envelope was made of goldbeaters skin. Shortly after the flight began, de Rozier was seen to be venting hydrogen when it was ignited by a spark and the balloon went up in flames, killing those on board. The source of the spark is not known, but suggestions include static electricity or the brazier for the hot air section.
Ballooning quickly became a major "rage" in Europe in the late 18th century, providing the first detailed understanding of the relationship between altitude and the atmosphere. By the early 1900s ballooning was a popular sport in Britain. These privately owned balloons usually used coal gas as the lifting gas. This has half the lifting power of hydrogen, so the balloons had to be larger; however, coal gas was far more readily available, and the local gas works sometimes provided a special lightweight formula for ballooning events.
Tethered balloons were employed during the American Civil War by the Union Army Balloon Corps. In 1863 the young Ferdinand von Zeppelin, who was acting as a military observer with the Union Army of the Potomac, first flew as a balloon passenger in a balloon that had been in service with the Union army. Later that century, the British Army would make use of observation balloons during the Boer War.
Work on developing a steerable (or dirigible) balloon (now called an airship) continued sporadically throughout the 19th century.
The first powered, controlled, sustained lighter-than-air flight is believed to have taken place on 24 September 1852 when Henri Giffard flew 15 miles (24 km) in France with the Giffard dirigible, a non-rigid airship filled with hydrogen and powered by a 3 hp steam engine driving a 3 bladed propeller, travelling 27 km (17 mi) from Paris to Trappes. This was the world's first passenger-carrying airship.
A genuine advance was made on 9 August 1884, when the first fully controllable free flight was made by Charles Renard and Arthur Constantin Krebs in a French Army electric-powered airship, La France. The 170-foot (52 m) long, 66,000-cubic-foot (1,900 m3) airship covered 8 km (5.0 mi) in 23 minutes with the aid of an 8½ horsepower electric motor, returning to its starting point. This was the first flight over a closed circuit.
However, these aircraft were generally extremely frail and short-lived. Routine, controlled flights would not occur until the advent of the internal combustion engine.
Count Ferdinand von Zeppelin founded the Zeppelin firm, whose Luftschiff Zeppelin 1 (LZ 1) first flew from the Bodensee on the Swiss border on July 2, 1900, to become the world's first successful rigid airship. The flight lasted 18 minutes. The second and third flights were in October 1900 and October 24, 1900 respectively, beating the 6 m/s velocity record of the French airship La France by 3 m/s.
The Brazilian Alberto Santos-Dumont became famous by designing, building, and flying dirigibles. He designed, built, and flew the first fully practical dirigible, demonstrating that routine, controlled flight was possible. With his dirigible No.6 he won the Deutsch de la Meurthe prize on 19 October 1901 with a flight that took off from Saint-Cloud, rounded the Eiffel Tower and returned to the starting point.
By now, the airship was firmly established as the first practicable form of air travel.
Da Vinci's design for a pyramid-shaped parachute remained unpublished for centuries. The first published design was the Italian Fausto Veranzio's homo volans (flying man) which appeared in his book Machinae novae (New machines) in 1595. Based on a ship's sail, it comprised a square of material stretched across a square frame and retained by ropes. The parachutist was suspended by ropes from each of the four corners.
Between 1853 and 1854, Louis Charles Letur developed a parachute-glider comprising an umbrella-like parachute with smaller, triangular wings and vertical tail beneath. This achieved what may have been the first controlled, heavier-than-air flight. Letur died when it crashed in 1854.
Kites are most notable in the recent history of aviation primarily for their man-carrying or man-lifting capabilities, although they have also been important in other areas such as meteorology.
The Frenchman Gaston Biot developed a man-lifting kite in 1868. Later, in 1880, Biot demonstrated to the French Society for Aerial Navigation a kite based on an open-ended cone, similar to a windsock but attached to a flat surface. The man-carrying kite was developed a stage further in 1894 by Captain Baden Baden-Powell, brother of Lord Baden-Powell, who strung a chain of hexagonal kites on a single line. A significant development came in 1893 when the Australian Lawrence Hargrave invented the box kite and some man-carrying experiments were carried out both in Australia and in the United States. In 1905 Neil MacDermid was carried aloft in Canada by a large box kite named The Siamese Twins designed by Alexander Graham Bell.
Balloons were by then in use for both meteorology and military observation. Balloons can only be used in light winds, while kites can only be used in stronger winds. The American Samuel Franklin Cody, working in England, realised that the two types of craft between them allowed operation over a wide range of weather conditions. He developed Hargrave's basic design, adding additional lifting surfaces to create powerful man-lifting systems using multiple kites on a single line. Cody made many demonstrations of his system and would later sell four of his "war kite" systems to the Royal Navy. His kites also found use in carrying meteorological instruments aloft and he was made a fellow of the Royal Meteorological Society. In 1905, Sapper Moreton of the British Army's balloon section was lifted 2,600 ft (792 m) by a kite at Aldershot under Cody's supervision. In 1906 Cody was appointed Chief Instructor in Kiting at the Army School of Ballooning in Aldershot. He soon also joined the newly established Army Balloon Factory at Farnborough and continued developing his war kites for the British Army. In his own time he developed a manned "glider-kite" which was launched on a tether like a kite and then released to glide freely. In 1907 Cody next fitted an aircraft engine to a modified unmanned "power-kite", the precursor to his later aeroplanes, and flew it inside the Balloon Shed, along a wire suspended from poles, before the Prince and Princess of Wales. The British Army officially adopted his war kites for their Balloon Companies in 1908.
Leonardo da Vinci's realisation that man-power alone was not sufficient for sustained flight was rediscovered independently in the 17th century by Giovanni Alfonso Borelli and Robert Hooke. Hooke realised that some form of engine would be necessary and in 1655 made a spring-powered ornithopter model which was apparently able to fly.
Attempts to design or construct a true flying machine began, typically comprising a gondola with a supporting canopy and spring- or man-powered flappers for propulsion. Among the first were Hautsch and Burattini (1648). Others included de Gusmao's "Passarola" (1709 on), Swedenborg (1716), Desforges (1772), Bauer (1764), Meerwein (1781) and Blanchard (1781) who would later have more success with balloons. Rotary-winged helicopters likewise appeared, notably from Lomonosov (1754) and Paucton. A few model gliders flew successfully although some claims are contested, but in any event no full-size craft succeeded.
Italian inventor, Tito Livio Burattini, invited by the Polish King Władysław IV to his court in Warsaw, built a model aircraft with four fixed glider wings in 1647. Described as "four pairs of wings attached to an elaborate 'dragon'", it was said to have successfully lifted a cat in 1648 but not Burattini himself. He promised that "only the most minor injuries" would result from landing the craft. His "Dragon Volant" is considered "the most elaborate and sophisticated aeroplane to be built before the 19th Century".
Bartolomeu de Gusmão's "Passarola" was a hollow, vaguely bird-shaped glider of similar concept but with two wings. In 1709 he presented a petition to King John V of Portugal, begging for support for his invention of an "airship", in which he expressed the greatest confidence. The public test of the machine, which was set for June 24, 1709, did not take place. According to contemporary reports, however, Gusmão appears to have made several less ambitious experiments with this machine, descending from eminences. It is certain that Gusmão was working on this principle at the public exhibition he gave before the Court on August 8, 1709, in the hall of the Casa da Índia in Lisbon, when he propelled a ball to the roof by combustion.[clarification needed] He also demonstrated a small airship model before the Portuguese court, but never succeeded with a full-scale model.
However, both understanding and a power source were still lacking. This was recognised by Emanuel Swedenborg in his "Sketch of a Machine for Flying in the Air" published in 1716. His flying machine consisted of a light frame covered with strong canvas and provided with two large oars or wings moving on a horizontal axis, arranged so that the upstroke met with no resistance while the downstroke provided lifting power. Swedenborg knew that the machine would not fly, but suggested it as a start and was confident that the problem would be solved. He wrote: "It seems easier to talk of such a machine than to put it into actuality, for it requires greater force and less weight than exists in a human body. The science of mechanics might perhaps suggest a means, namely, a strong spiral spring. If these advantages and requisites are observed, perhaps in time to come some one might know how better to utilize our sketch and cause some addition to be made so as to accomplish that which we can only suggest." The Editor of the Royal Aeronautical Society journal wrote in 1910 that Swedenborg's design was "…the first rational proposal for a flying machine of the aeroplance [heavier-than-air] type…"
Meanwhile rotorcraft were not wholly forgotten. In July 1754, Mikhail Lomonosov demonstrated a small coaxial twin-rotor system, powered by a spring, to the Russian Academy of Sciences. The rotors were arranged one above the other and spun in opposite directions, principles still used in modern twin-rotor designs. In his 1768 Théorie de la vis d'Archimède, Alexis-Jean-Pierre Paucton suggested the use of one airscrew for lift and a second for propulsion, nowadays called a gyrodyne. In 1784 Launoy and Bienvenu demonstrated a flying model with coaxial, contra-rotating rotors powered by a simple spring similar to a bow saw, now accepted as the first powered helicopter.
Attempts at man-powered flight still persisted. Paucton's rotorcraft was man-powered, while another approach, also originally studied by da Vinci, was the use of flap valves. The flap valve is a simple hinged flap over a hole in the wing. In one direction it opens to allow air through and in the other it closes to allow an increased pressure difference. An early example was designed by Bauer in 1764. later in 1808 Jacob Degen built an ornithopter with flap valves, in which the pilot stood on a rigid frame and worked the wings with a movable horizontal bar. His 1809 attempt at flight failed, so he then added a small hydrogen balloon and the combination achieved some short hops. Popular illustrations of the day depicted his machine without the balloon, leading to confusion as to what had actually flown. In 1811 Albrecht Berblinger built an ornithopter based on Degen's design but omitted the balloon, plunging instead into the Danube. The fiasco did have an upside: George Cayley, also taken in by the illustrations, was spurred to publish his findings to date "for the sake of giving a little more dignity to a subject bordering upon the ludicrous in public estimation," and the modern era of aviation was born.
Throughout the 19th century, tower jumping was replaced by the equally fatal but equally popular balloon jumping as a way to demonstrate the continued uselessness of man-power and flapping wings. Meanwhile the scientific study of heavier-than-air flight began in earnest.
Sir George Cayley was first called the "father of the aeroplane" in 1846. During the last years of the previous century he had begun the first rigorous study of the physics of flight and would later design the first modern heavier-than-air craft. Among his many achievements, his most important contributions to aeronautics include:
From the age of ten Cayley began studying the physics of bird flight and his school notebooks contained sketches in which he was developing his ideas on the theories of flight. It has been claimed that these sketches show that Cayley modeled the principles of a lift-generating inclined plane as early as 1792 or 1793.
In 1796 Cayley made a model helicopter of the form commonly known as a Chinese flying top, unaware of Launoy and Bienvenu's model of similar design. He regarded the helicopter as the best design for simple vertical flight, and later in his life in 1854 he made an improved model. He gave a Mr. Cooper credit for being the first person to improve on "the clumsy structure of the toy" and reports Cooper's model as ascending twenty or thirty feet. Cayley made one and a Mr. Coulson made a copy, described by Cayley as "a very beautiful specimen of the screw propellor in the air" and capable of flying over ninety feet high.
Cayley's next innovations were twofold: the adoption of the whirling arm test rig, invented in the previous century by Benjamin Robbins to investigate aerodynamic drag and used soon after by John Smeaton to measure the forces on rotating windmill blades, for use in aircraft research together with the use of aerodynamic models on the arm, rather than attempting to fly a model of a complete design. He initially used a simple flat plane fixed to the arm and inclined at an angle to the airflow.
In 1799 he set down the concept of the modern aeroplane as a fixed-wing flying machine with separate systems for lift, propulsion, and control. On a small silver disc dated that year, he engraved on one side the forces acting on an aircraft and on the other a sketch of an aircraft design incorporating such modern features as a cambered wing, separate tail comprising a horizontal tailplane and vertical fin, and fuselage for the pilot suspended below the center of gravity to provide stability. The design is not yet wholly modern, incorporating as it does two pilot-operated paddles or oars which appear to work as flap valves.
He continued his researches and in 1804 constructed a model glider which was the first modern heavier-than-air flying machine, having the layout of a conventional modern aircraft with an inclined wing towards the front and adjustable tail at the back with both tailplane and fin. The wing was just a toy paper kite, flat and uncambered. A movable weight allowed adjustment of the model's centre of gravity. It was "very pretty to see" when flying down a hillside, and sensitive to small adjustments of the tail.
By the end of 1809 he had constructed the world's first full-size glider and flown it as an unmanned tethered kite. In the same year, goaded by the farcical antics of his contemporaries (see above), he began the publication of a landmark three-part treatise titled "On Aerial Navigation" (1809–1810). In it he wrote the first scientific statement of the problem, "The whole problem is confined within these limits, viz. to make a surface support a given weight by the application of power to the resistance of air." He identified the four vector forces that influence an aircraft: thrust, lift, drag and weight and distinguished stability and control in his designs. He argued that manpower alone was insufficient, and while no suitable power source was yet available he discussed the possibilities and even described the operating principle of the internal combustion engine using a gas and air mixture. However he was never able to make a working engine and confined his actual flying experiments to gliding flight. He also identified and described the importance of the cambered aerofoil, dihedral, diagonal bracing and drag reduction, and contributed to the understanding and design of ornithopters and parachutes.
He went on to publish in 1852 the design for a full-size manned glider or "governable parachute" to be launched from a balloon and then to construct a version capable of launching from the top of a hill, which carried the first adult aviator across Brompton Dale in 1853. The identity of the aviator is not known. It has been suggested variously as Cayley's coachman, footman or butler, John Appleby who may have been the coachman or another employee, or even Cayley's grandson George John Cayley. What is known is that he was the first to fly in a glider with distinct wings, fuselage and tail, and featuring inherent stability and pilot-operated controls: the first fully modern and functional heavier-than-air craft.
Minor inventions included the rubber-powered motor, which provided a reliable power source for research models. By 1808 he had even re-invented the wheel, devising the tension-spoked wheel in which all compression loads are carried by the rim, allowing a lightweight undercarriage.
Drawing directly from Cayley's work, Henson's 1842 design for an aerial steam carriage broke new ground. Henson proposed a 150 feet (46 m) span high-winged monoplane, with a steam engine driving two pusher configuration propellers. Although only a design, (scale models were built but they appear not to have achieved sustained flight) it was the first in history for a propeller-driven fixed-wing aircraft. Henson and his collaborator John Stringfellow even dreamed of the first Aerial Transit Company. 1866 saw the founding of the Aeronautical Society of Great Britain and two years later the world's first aeronautical exhibition was held at the Crystal Palace, London, where Stringfellow was awarded a £100 prize for the steam engine with the best power-to-weight ratio.
Francis Herbert Wenham presented the first paper to the newly formed Aeronautical Society (later the Royal Aeronautical Society), On Aerial Locomotion. He had taken Cayley's work on cambered wings further, making important findings about both the wing aerofoil section and lift distribution. To test his ideas, from 1858 he had constructed several gliders, both manned and unmanned, and with up to five stacked wings. He concluded correctly that long, thin wings would be better than the bat-like ones suggested by many, because they would have more leading edge for their area. Today this relationship is known as the aspect ratio of a wing.
The latter part of the 19th century became a period of intense study, characterized by the "gentleman scientists" who represented most research efforts until the 20th century. Among them was the British scientist-philosopher and inventor Matthew Piers Watt Boulton, who wrote an important paper in 1864, On Aërial Locomotion, which also described lateral flight control. He was the first to patent an aileron control system in 1868.
In 1871 Wenham and Browning made the first wind tunnel. Members of the Society used the tunnel and learned that cambered wings generated considerably more lift than expected by Cayley's Newtonian reasoning, with lift-to-drag ratios of about 5:1 at 15 degrees. This clearly demonstrated the possibility of building practical heavier-than-air flying machines: what remained were the problems of controlling and powering the craft.
By the 1870s, lightweight steam engines had developed sufficiently for their experimental use in aircraft. The first aircraft known to have taken off under its own power and flown at a sustained height (of six inches under its own power was a large 216 lb (98 kg) model tandem-wing monoplane, the "Aerial Steamer," made by Thomas Moy in 1875. Moy's steam engine produced just 3 hp to drive twin propellers mounted in between the fore and aft wings.
Meanwhile the British advances had galvanised French researchers. In 1857 Félix du Temple proposed a monoplane having swept forward wings with slight dihedral, a tail plane and retractable undercarriage. It was to be powered by steam. Developing his ideas with a model powered first by clockwork and later by steam, he eventually achieved a short hop with a full-size manned craft in 1874. His "Monoplane" was a large aircraft made of aluminium, with a wingspan of 42 ft 8 in (13 m) and a weight of only 176 lb (80 kg) without the pilot. Several trials were made with the aircraft, and it achieved lift-off under its own power after launching from a ramp, glided for a short time and returned safely to the ground, making it the first successful powered hop in history, a year ahead of Moy's flight.
In 1864 Le Comte Ferdinand Charles Honore Phillipe d'Esterno published a study On The Flight Of Birds (Du Vol des Oiseaux, and the next year Louis Pierre Mouillard published an influential book The Empire Of The Air (l'Empire de l'Air).
In 1856, Frenchman Jean-Marie Le Bris made the first flight higher than his point of departure, by having his glider "L'Albatros artificiel" pulled by a horse on a beach. He reportedly achieved a height of 100 meters, over a distance of 200 meters.
Alphonse Pénaud, a Frenchman living from 1850 to 1880, made significant contributions to aeronautics. He advanced the theory of wing contours and aerodynamics and constructed successful models of aeroplanes, helicopters and ornithopters. In 1871 he flew the first aerodynamically stable fixed-wing aeroplane, a model monoplane he called the "Planophore", a distance of 40 m (131 ft). Pénaud's model incorporated several of Cayley's discoveries, including the use of a tail, wing dihedral for inherent stability, and rubber power. The planophore also had longitudinal stability, being trimmed such that the tailplane was set at a smaller angle of incidence than the wings, an original and important contribution to the theory of aeronautics. Pénaud's later project for an amphibian aeroplane, although never built, incorporated other modern features. A tailless monoplane with a single vertical fin and twin tractor propellers, it also featured hinged rear elevator and rudder surfaces, retractable undercarriage and a fully enclosed, instrumented cockpit.
Equally authoritative as a theorist was Pénaud's fellow countryman Victor Tatin. In 1879 he flew a model which, like Pénaud's project, was a monoplane with twin tractor propellers but also had a separate horizontal tail. It was powered by compressed air, with the air tank forming the fuselage.
In Russia, Alexander Mozhaiski constructed a steam-powered monoplane driven by one large tractor and two smaller pusher propellers. In 1884 it was launched from a ramp and remained airborne for 98 ft.
That same year in France, Alexandre Goupil published his work La Locomotion Aérienne (Aerial Locomotion), although the flying machine he later constructed failed to fly.
Sir Hiram Maxim was an American who moved to England and changed his nationality. He chose to largely ignore his contemporaries and built his own whirling arm rig and wind tunnel. From the late 1890s he made many experiments and developed a biplane design which he patented in 1891 and completed as a test rig three years later. It was an enormous machine for its day with a wingspan of 105 feet (32 m), a length of 145 feet (44 m), fore and aft horizontal surfaces and a crew of three. Twin propellers were powered by two lightweight compound steam engines each delivering 180 hp (134 kW). Overall weight was 7,000 pounds (3,200 kg). Later modifications would add more wing surfaces as shown in the illustration. Its purpose was for research and it was neither aerodynamically stable nor controllable, so it ran on a 1,800 feet (550 m) track with a second set of restraining rails to prevent it from lifting off, somewhat in the manner of a roller coaster. In 1894 the machine developed enough lift to take off, breaking one of the restraining rails and being damaged in the process. Maxim then abandoned work on it, but would return to aeronautics in the 20th century to test a number of smaller designs powered by internal combustion engines.
One of the last of the steam-powered pioneers, like Maxim ignoring his contemporaries who had moved on (see next section), was Clément Ader. His Éole of 1890 was a bat-winged tractor monoplane which achieved a brief, uncontrolled hop, thus becoming the first heavier-than-air machine to take off under its own power. However his similar but larger Avion III of 1897, notable only for having twin steam engines, failed to fly at all: Ader would later claim success and was not debunked until 1910 when the French Army published its report on his attempt.
The glider constructed with the help of Massia and flown briefly by Biot in 1879 was based on the work of Mouillard and was still bird-like in form. It is preserved the Musee de l'Air, France, and is claimed to be the earliest man-carrying flying machine still in existence.
In the last decade or so of the 18th century, while Maxim and Ader were reliving the past, a number of key figures were refining and defining the modern aeroplane. The Englishman Horatio Phillips made key contributions to aerodynamics. The German Otto Lilienthal and the American Octave Chanute worked independently on gliding flight. Lillienthal published a book on bird flight and went on, from 1891 to 1896, to construct a series of gliders, of various monoplane, biplane and triplane configurations, to test his theories. He made thousands of flights and at the time of his death was working on motor-powered gliders.
Phillips conducted extensive wind tunnel research on aerofoil sections, using steam as the working fluid. He proved the principles of aerodynamic lift foreseen by Cayley and Wenham and, from 1884, took out several patents on aerofoils. His findings underpin all modern aerofoil design. Phillips would later develop theories on the design of multiplanes, which he went on to show were unfounded.
Starting in the 1880s advances were made in construction that led to the first truly practical gliders. Three people in particular were active: Otto Lilienthal, Percy Pilcher and Octave Chanute. One of the first modern gliders appears to have been built by John J. Montgomery; he claimed to have made a single flight near San Diego on August 28, 1883. Montgomery discussed his flying during the 1893 Aeronautical Conference in Chicago and Chanute published Montgomery's comments in December 1893 in the American Engineer & Railroad Journal. Another hang-glider had been constructed by Wilhelm Kress as early as 1877 near Vienna.
Otto Lilienthal was known as the "Glider King" or "Flying Man" of Germany. He duplicated Wenham's work and greatly expanded on it in 1884, publishing his research in 1889 as Birdflight as the Basis of Aviation (Der Vogelflug als Grundlage der Fliegekunst). He also produced a series of gliders of a type now known as the hang glider, including bat-wing, monoplane and biplane forms, such as the Derwitzer Glider and Normal soaring apparatus. Starting in 1891 he became the first person to make controlled untethered glides routinely, and the first to be photographed flying a heavier-than-air machine, stimulating interest around the world. He rigorously documented his work, including photographs, and for this reason is one of the best known of the early pioneers. He also promoted the idea of "jumping before you fly", suggesting that researchers should start with gliders and work their way up, instead of simply designing a powered machine on paper and hoping it would work. Lilienthal made over 2,000 glides until his death in 1896 from injuries sustained in a glider crash. Lilienthal had also been working on small engines suitable for powering his designs at the time of his death.
Picking up where Lilienthal left off, Octave Chanute took up aircraft design after an early retirement, and funded the development of several gliders. In the summer of 1896 his team flew several of their designs many times at Miller Beach, Indiana, eventually deciding that the best was a biplane design. Like Lilienthal, he documented his work and also photographed it, and was busy corresponding with like-minded researchers around the world. Chanute was particularly interested in solving the problem of aerodynamic instability of the aircraft in flight, which birds compensate for by instant corrections, but which humans would have to address either with stabilizing and control surfaces or by moving the center of gravity of the aircraft, as Lilienthal did. The most disconcerting problem was longitudinal instability (divergence), because as the angle of attack of a wing increases, the center of pressure moves forward and makes the angle increase yet more. Without immediate correction, the craft will pitch up and stall. Much more difficult to understand was the relationship between lateral and directional control.
In Britain Percy Pilcher, who had worked for Maxim and had built and successfully flown several gliders during the mid to late 1890s, constructed a prototype powered aircraft in 1899 which, recent research has shown, would have been capable of flight. However, like Lilienthal he died in a glider accident before he was able to test it.
Publications, particularly Octave Chanute's Progress in Flying Machines of 1894 and James Means' The Problem of Manflight (1894) and Aeronautical Annuals (1895–1897) helped bring current research and events to a wider audience.
The invention of the box kite during this period by the Australian Lawrence Hargrave led to the development of the practical biplane. In 1894 Hargrave linked four of his kites together, added a sling seat, and flew 16 feet (4.9 m). By demonstrating to a sceptical public that it was possible to build a safe and stable flying machine, Hargrave opened the door to other inventors and pioneers. Hargrave devoted most of his life to constructing a machine that would fly. He believed passionately in open communication within the scientific community and would not patent his inventions. Instead, he scrupulously published the results of his experiments in order that a mutual interchange of ideas may take place with other inventors working in the same field, so as to expedite joint progress. Octave Chanute became convinced that multiple wing planes were more effective than a monoplane and introduced the "strut-wire" braced wing structure which, with its combination of rigidity and lightness, would in the form of the biplane come to dominate aircraft design for decades to come. The inventor of the box kite Lawrence Hargrave also experimented in the 1880s with monoplane models and by 1889 had constructed a rotary engine driven by compressed air.
Even balloon jumping began to succeed. in 1905 Daniel Maloney was carried by balloon in a tandem-wing glider designed by John Montgomery to an altitude of 4,000 ft. before being released, gliding down and landing at a predetermined location as part of a large public demonstration of aerial flight at Santa Clara, California. However after several successful jumps Maloney's glider collided with a balloon cable and Maloney fell to his death.
Powered, controlled flight was finally achieved around the turn of the century.
Gustave Weißkopf was a German who emigrated to the U.S., where he soon changed his name to Whitehead. From 1897 to 1915 he designed and built flying machines and engines. On August 14, 1901, Whitehead claimed to have carried out a controlled, powered flight in his Number 21 monoplane at Fairfield, Connecticut. An account of the flight appeared in the Bridgeport Sunday Herald and was repeated in newspapers throughout the world. Whitehead claimed two more flights on January 17, 1902, using his Number 22 monoplane. He described it as having a 40 hp motor with twin tractor propellers and controlled by differential propeller speed and rudder. He claimed to have flown a 10 km circle.
For many years the Whitehead claims were ignored or dismissed by mainstream aviation historians. In March 2013 Jane's All the World's Aircraft published an editorial which accepted Whitehead's flight as the first manned, powered, controlled flight of a heavier-than-air craft. The Smithsonian Institution are among those who do not accept that Whitehead flew as reported.
After a distinguished career in astronomy and shortly before becoming Secretary of the Smithsonian Institution, Samuel Pierpont Langley started a serious investigation into aerodynamics at what is today the University of Pittsburgh. In 1891 he published Experiments in Aerodynamics detailing his research, and then turned to building his designs. He hoped to achieve automatic aerodynamic stability, so he gave little consideration to in-flight control. On May 6, 1896, Langley's Aerodrome No. 5 made the first successful sustained 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 metres (3,297 ft) and a second of 700 metres (2,300 ft), at a speed of approximately 25 miles per hour (40 km/h). On both occasions the Aerodrome No. 5 landed in the water as planned, because in order to save weight, it was not equipped with landing gear. On November 28, 1896, another successful flight was made with the Aerodrome No. 6. This flight, of 1,460 metres (4,790 ft), was witnessed and photographed by Alexander Graham Bell. The Aerodrome No. 6 was actually Aerodrome No. 4 greatly modified. So little remained of the original aircraft that it was given a new designation.
With the successes of the Aerodrome No. 5 and No. 6, Langley started looking for funding to build a full-scale man-carrying version of his designs. Spurred by the Spanish–American War, the U.S. government granted him $50,000 to develop a man-carrying flying machine for aerial reconnaissance. Langley planned on building a scaled-up version known as the Aerodrome A, and started with the smaller Quarter-scale Aerodrome, which flew twice on June 18, 1901, and then again with a newer and more powerful engine in 1903.
With the basic design apparently successfully tested, he then turned to the problem of a suitable engine. He contracted Stephen Balzer to build one, but was disappointed when it delivered only 8 hp (6 kW) instead of 12 hp (9 kW) he expected. Langley's assistant, Charles M. Manly, then reworked the design into a five-cylinder water-cooled radial that delivered 52 hp (39 kW) at 950 rpm, a feat that took years to duplicate. Now with both power and a design, Langley put the two together with great hopes.
To his dismay, the resulting aircraft proved to be too fragile. Simply scaling up the original small models resulted in a design that was too weak to hold itself together. Two launches in late 1903 both ended with the Aerodrome immediately crashing into the water. The pilot, Manly, was rescued each time. Also, the aircraft's control system was inadequate to allow quick pilot responses, and it had no method of lateral control, and the Aerodrome 's aerial stability was marginal.
Langley's attempts to gain further funding failed, and his efforts ended. Nine days after his second abortive launch on December 8, the Wright brothers successfully flew their Flyer. Glenn Curtiss made 93 modifications to the Aerodrome and flew this very different aircraft in 1914. Without acknowledging the modifications, the Smithsonian Institution asserted that Langley's Aerodrome was the first machine "capable of flight".
The Wrights solved both the control and power problems that confronted aeronautical pioneers. They invented roll control using wing warping and combined roll with simultaneous yaw control using a steerable rear rudder. Although wing-warping as a means of roll control was used only briefly during the early history of aviation, the innovation of combining roll and yaw control was a fundamental advance in flight control. For pitch control, the Wrights used a forward elevator (canard), another design element that later became outmoded.
The Wrights made rigorous wind-tunnel tests of airfoils and flight tests of full-size gliders. They not only built a working powered aircraft, the Wright Flyer, but also significantly advanced the science of aeronautical engineering.
They concentrated on the controllability of unpowered aircraft before attempting to fly a powered design. From 1900 to 1902, they built and flew a series of three gliders. The first two were much less efficient than the Wrights expected, based on experiments and writings of their 19th-century predecessors. Their 1900 glider had only about half the lift they anticipated, and the 1901 glider performed even more poorly, until makeshift modifications made it serviceable.
Seeking answers, the Wrights constructed their own wind tunnel and equipped it with a sophisticated measuring device to calculate lift and drag of 200 different model-size wing designs they created. As a result, the Wrights corrected earlier mistakes in calculations of lift and drag and used this knowledge to construct their 1902 glider, third in the series. It became the first manned heavier than air flying machine that was mechanically controllable in all three axes: pitch, roll and yaw. Its pioneering design also included wings with a higher aspect ratio than the previous gliders. The brothers successfully flew the 1902 glider hundreds of times, and it performed far better than their earlier two versions.
To obtain adequate power for their engine-driven Flyer, the Wrights designed and built a low-powered internal combustion engine. Using their wind tunnel data, they designed and carved wooden propellers that were more efficient than any before, enabling them to gain adequate performance from their low engine power. The Flyer's design was also influenced by the desire of the Wrights to teach themselves to fly safely without unreasonable risk to life and limb, and to make crashes survivable. The limited engine power resulted in low flying speeds and the need to take off into a headwind.
According to the Smithsonian Institution and Fédération Aéronautique Internationale (FAI), the Wrights made the first sustained, controlled, powered heavier-than-air manned flight at Kill Devil Hills, North Carolina, four miles (8 km) south of Kitty Hawk, North Carolina on December 17, 1903. The first flight by Orville Wright, of 120 feet (37 m) in 12 seconds, was recorded in a famous photograph. In the fourth flight of the same day, Wilbur Wright flew 852 feet (260 m) in 59 seconds. Modern analysis by Professor Fred E. C. Culick and Henry R. Rex (1985) has demonstrated that the 1903 Wright Flyer was so unstable as to be almost unmanageable by anyone but the Wrights, who had trained themselves in the 1902 glider.
The Wrights continued developing their flying machines and flying at Huffman Prairie near Dayton, Ohio in 1904–05. After a crash in 1905, they rebuilt the Flyer III and made important design changes. They almost doubled the size of the elevator and rudder and moved them about twice the distance from the wings. They added two fixed vertical vanes (called "blinkers") between the elevators, and gave the wings a very slight dihedral. They disconnected the rudder from the wing-warping control, and as in all future aircraft, placed it on a separate control handle. The Flyer III became the first practical aircraft (though without wheels and using a launching device), flying consistently under full control and bringing its pilot back to the starting point safely and landing without damage. On 5 October 1905, Wilbur flew 24 miles (39 km) in 39 minutes 23 seconds."
Eventually the Wrights would abandon the foreplane altogether, with the Model B of 1910 instead having a tail plane in the manner which was by then becoming conventional.
According to the April 1907 issue of the Scientific American magazine, the Wright brothers seemed to have the most advanced knowledge of heavier-than-air navigation at the time. However, the same magazine issue also claimed that no public flight had been made in the United States before its April 1907 issue. Hence, they devised the Scientific American Aeronautic Trophy in order to encourage the development of a heavier-than-air flying machine.
Once powered, controlled flight had been achieved, progress was still needed to create a practical flying machine for general use. This period leading up to World War I is sometimes called the pioneer era of aviation.
The history of early powered flight is very much the history of early engine construction. The Wrights designed their own engines. They used a single flight engine, a 12 hp water-cooled four-cylinder inline type with five main bearings and fuel injection. Whitehead's craft was powered by two engines of his design: a ground engine of 10 hp (7.5 kW) which drove the front wheels in an effort to reach takeoff speed and a 20 hp (15 kW) acetylene engine powering the propellers. Whitehead was an experienced machinist, and he is reported to have raised funds for his aircraft by making and selling engines to other aviators. Most early engines were neither powerful nor reliable enough for practical use, and the development of improved engines went hand-in-hand with improvements in the airframes themselves.
In Europe, Léon Levavasseur's Antoinette 8V pioneering example of the V-8 engine format, first patented in 1902, dominated flight for several years after it was introduced in 1906, powering many notable craft of that era. Incorporating direct fuel injection, evaporative water cooling and other advanced features, it generated around 50 hp.
The British Green C.4 of 1908 followed the Wright's pattern of a four-cylinder inline water-cooled design but produced 52 hp (38 kW). It powered many successful pioneer aircraft including those of A.V. Roe.
Horizontally opposed designs were also produced. The four-cylinder water-cooled de Havilland Iris achieved 45 hp but was little used, while the successful two-cylinder Nieuport design achieved 28 hp (21 kW) in 1910.
1909 saw radial engine forms rise to significance. The Anzani 3-cylinder semi-radial or fan engine of 1909 (also built in a true, 120º cylinder angle radial form) developed only 25 hp (16 kW) but was much lighter than the Antoinette, and was chosen by Louis Blériot for his cross-Channel flight. More radical was the Seguin brothers' series of Gnôme rotary radial engines, starring with the 50 hp Gnome Omega 50 hp air-cooled seven-cylinder rotary engine in 1906. In a rotary engine, the crankshaft is fixed to the airframe and the whole engine casing and cylinders rotate with the propeller. Although this type had been introduced as long ago as 1887 by Lawrence Hargrave, improvements made to the Gnome created a robust, relatively reliable and lightweight design which revolutionised aviation and would see continuous development over the next ten years. Fuel was introduced into each cylinder direct from the crankcase meaning that only an exhaust valve was required. The larger and more powerful nine-cylinder, 80 horsepower Le Rhône 9C rotary was introduced in 1913 and was widely adopted for military use.
Inline and vee types remained popular, with the German company Mercedes producing a series of water-cooled six-cylinder models. In 1913 they introduced the highly successful 75 kW (100 hp) D.I series.
The lightness and strength of the biplane is offset by the inefficiency inherent in placing two wings so close together. Biplane and monoplane designs vied with each other, with both still in production by the outbreak of war in 1914.
A notable development, although a failure, was the first cantilever monoplane ever built. The Antoinette Monobloc of 1911 had a fully enclosed cockpit and faired undercarriage but its V-8 engine's 50 hp output was not enough for it to fly for more than a few feet at most. More successful was the Deperdussin braced monoplane, which won the inaugural 1913 Schneider Trophy race flown by Maurice Prévost, completing 28 circuits of the 10 km (6.2 mi) course with an average speed of 73.63 km/h (45.75 mph).
Triplanes too were experimented with, notably a series built between 1909 and 1910 by the British pioneer A.V. Roe. Going one better with four wings the quadruplane too made rare appearances. The multiplane, having large numbers of very thin wings, was also experimented with, most successfully by Horatio Phillips. His final prototype confirmed the inefficiency and poor performance of the idea.
Other radical approaches to wing design were also being tried. The American inventor Alexander Graham Bell devised a cellular octahedral wing form which, like the multiplane, proved disappointingly inefficient. Other lacklustre performers included the Edwards Rhomboidal, the Lee-Richards annular wing and varying numbers of wings one after the other in tandem.
Many of these early experimental forms were in principle quite practical and have since reappeared.
Early work had focused primary on making a craft stable enough to fly but failed to offer full controllability, while the Wrights had sacrificed stability in order to make their Flyer fully controllable. A practical aircraft requires both. Although stability had been achieved by several designs, the principles were not fully understood and progress was erratic. The aileron slowly replaced wing warping for lateral control although designers sometimes, as with the Blériot XI, returned briefly to wing warping. Similarly, all-flying tail surfaces gave way to fixed stabilizers with hinged control surfaces attached. The canard pusher configuration of the early Wright Flyers was supplanted by tractor propeller aircraft designs.
In France, progress was relatively rapid.
In 1906 the Brazilian Alberto Santos-Dumont made a public flights in France with his 14-bis, also known as Oiseau de proie (French for "bird of prey"). A canard pusher biplane with pronounced wing dihedral, it had a Hargrave-style box-cell wing with a forward-mounted "boxkite" assembly which was movable to act as both elevator and rudder. He later added auxiliary surfaces between the wings as primitive ailerons to provide lateral control. His flight was the first made by a powered heavier-than-air machine to be verified by the Aéro-Club de France, and won the Deutsch-Archdeacon Prize for the first officially observed flight of more than 25 meters. It later set the first world record recognized by the Federation Aeronautique Internationale by flying 220 meters in 21.5 seconds.
The next year Louis Blériot flew the Blériot VII, a tractor monoplane with full three-axis control using the horizontal tail surfaces as combined elevators and ailerons. Where Horatio Phillips and Traian Vuia had failed, Blériot's was the first practical tractor monoplane and marked the start of a trend in French aviation. By 1909 he had developed this configuration to the point where the Blériot XI was able to cross the English Channel, among other refinements using the tail surfaces only as elevators and using wing warping for lateral control. Another design that appeared in 1907 was the Voisin biplane. This lacked any provision for lateral control, and could only make shallow turns using only rudder control, but was flown with increasing success during the year by Henri Farman, and on 13 January 1908 he won the 50,000 francs Deutsch de la Meurthe-Archdeacon Grand Prix de l'Aviation for being the first aviator to complete an officially observed 1 kilometre closed circuit flight, including taking off and landing under the aircraft's own power.
The designs of the French pioneer Léon Levavasseur are better known by the name of the Antoinette company which he fouded. His Antoinette IV of 1908 was a monoplane of what is now the conventional configuration, with tailplane and fin each bearing movable control surfaces, and ailerons on the wings. The ailerons were not sufficiently effective and on later models were replaced by wing warping.
At the end of 1908 the Voisin brothers sold an aircraft ordered by Henri Farman to J. T. C. Moore-Brabazon. Angered, Farman built his own aircraft, adapting the Voisin design by adding ailerons. Following further modifications to the tail surfaces and ailerons, the Farman III became the most popular aeroplane sold between 1909 and 1911, and was widely imitated. In Britain the American expatriate Samuel Cody flew an aircraft similar in layout to the Wright flyer in 1908, incorporating a tailplane as well as a large front elevator. In 1910 an improved model fitted with between-wing ailerons won the Michelin Cup competition, while Geoffrey de Havilland's second Farman-style aircraft had ailerons on the upper wing and became the Royal Aircraft Factory F.E.1. The Bristol Boxkite, a copy of the Farman III, was manufactured in quantity. In the USA Glenn Curtiss had flown first the AEA June Bug and then his Golden Flyer, which in 1910 achieved the first naval deck landing and takeoff. Meanwhile the Wrights themselves had also been wrestling with the problem of achieving both stability and control, experimenting further with the foreplane before first adding a second small plane at the tail and then finally removing the foreplane altogether. They announced their two-seat Model B in 1910 and licensed it for production in 1911 as the Burgess Model F.
Many other more radical layouts were tried, with only a few showing any promise. In the United Kingdom, J. W. Dunne developed a series of tailless pusher designs having swept wings with a conical upper surface. His D.5 biplane flew in 1910 and proved fully stable. Dunne deliberately avoided full three-axis control, devising instead a system which was easier to operate and which he regarded as far safer in practice. Dunne's system would not be widely adopted. His tailless design reached its peak with the D.8 which was manufactured under license in France by Nieuport and in the USA as the Burgess-Dunne, however it was rejected as a practical warplane by the British Army, in which Dunne was an officer, because it was too stable and hence not manoeuvrable enough in battle.
A problem with early seaplanes was the tendency for suction between the water and the aircraft as speed increased, holding the aircraft down and hindering takeoff. The British designer J. C. Porte invented the technique of placing a step in the bottom of the aircraft to break the suction, and this was incorporated in the 1914 Curtiss Model H.
In 1909, aeroplanes remained frail and of little practical use. The limited engine power available meant that the effective payload was extremely limited. The basic structural and materials technology of the airframes mostly consisted of hardwood materials or steel tubing, braced with steel wires) and covered in linen fabric doped with a flammable stiffener and sealant. The need to save weight meant that most aircraft were structurally fragile, and not infrequently broke up in flight especially when performing violent manoeuvres, such as pulling out of a steep dive, which would be required in combat.
However these evolving flying machines were recognised to be not just toys, but weapons in the making. In 1909, the Italian staff officer Giulio Douhet remarked;
The sky is about to become another battlefield no less important than the battlefields on land and sea....In order to conquer the air, it is necessary to deprive the enemy of all means of flying, by striking at him in the air, at his bases of operation, or at his production centers. We had better get accustomed to this idea, and prepare ourselves.
In 1911, Captain Bertram Dickson, the first British military officer to fly and the first British military officer to perform an aerial reconnaissance mission in a fixed-wing aircraft during army manoeuvres in 1910, predicted the military use of aircraft and the ensuing development and escalation of aerial combat in a submission to the UK Technical Sub-Committee for Imperial Defence.
Aeroplanes were first used in warfare during the Italo-Turkish War of 1911–1912. The first operational use took place on 23 October 1911, when Captain Carlo Piazza made a flight near Benghazi in a Blériot XI. The first aerial bombardment followed shortly afterwards on 1 November, when Second Lieutenant Giulio Gavotti dropped four bombs on two oases held by the Turks. The first photographic reconnaissance flight took place in March 1912, also flown by Captain Piazza.
Some types developed during this period would see military service into, or even throughout, World War I. These include the Etrich Taube of 1910, Fokker Spin of 1911, Royal Aircraft Factory BE.2, Sopwith Tabloid/Schneider and a variety of obsolescent types that would be used for pilot training. The Sikorsky Ilya Muromets was the first four-engined aircraft and the largest of its day, the prototype first flying in 1914 just before the outbreak of war. The type would go on to see service in both bomber and transport roles.
The early work on powered rotor lift was followed up by later investigators, independently from the development of fixed-wing aircraft.
In 1877, Enrico Forlanini developed an unmanned helicopter powered by a steam engine. It rose to a height of 13 meters, where it remained for some 20 seconds, after a vertical take-off in Milan.
In 18th Century France, an association was set up to collaborate on helicopter designs, of which there were many. In 1863 Gustave de Ponton d'Amécourt constructed a model using the established counter-rotating rotors. Initially powered by steam it failed, but a clockwork version did fly. Other designs, covering a wide variety of forms, included Pomés and De la Pauze (1871), Pénaud, Achenbach (1874), Dieuaide (1887), Melikoff (1877), Forlanini (1877), Castel (1878) and Dandrieux (1878–79). Of these, Forlanini's steam-powered contra-rotating model flew for 20 seconds and Dandrieux' rubber-powered model also flew.
Hiram Maxim's father conceived of a helicopter powered by two counter-rotating rotors, but was unable to find a powerful enough engine to build it. Hiram himself sketched out plans for a helicopter in 1872 before turning his attention to fixed-wing flight.
In 1907 the French Breguet-Richet Gyroplane No. 1 lifted off in a "tethered" test flight, becoming the first manned helicopter to rise from the ground. It rose about 60 cm (2 ft) and hovered for a minute. However, the flight proved to be extremely unsteady.