History of flight
by Chris Woodford. Last updated: January 26, 2023.
Socrates had the right idea. Way back in ancient Greece, he insisted that: "Man must rise above the Earth—to the top of the atmosphere and beyond—for only thus will he fully understand the world in which he lives." Intrepid inventors would spend the next 2000 years making that insistent dream a bold reality. How about the Italian polymath Leonardo da Vinci, for example, who sketched a design for a wooden "ornithopter" around 1485, over 400 years before the first powered flight? Or Otto Lillienthal, fragile wings strapped to his body and flapping furiously, quite convinced he could fly like a bird—until a fateful date with gravity ended his experiments, and his life, in 1896.
Photo: Supersonic—faster than sound—flight is the norm for military jets in the 21st century, but it took thousands of years of innovation to get to that stage. Photo by JT Heineck, with Schlieren data processed by Neal Smith, courtesy of NASA Ames Research Center.
Scientists weren't always convinced that human flight was a possibility. William Thomson (Lord Kelvin), one of the most eminent physicists of the 19th century, confidently asserted that "Heavier-than-air flying machines are impossible," while another eminent scientist, Sir George Cayley, thought the opposite: "I am well convinced that Aerial Navigation will form a most prominent feature in the progress of civilization." Two science-minded brothers, Wilbur and Orville Wright, eventually settled the dispite, proving that Kelvin was absolutely wrong, when they made the first, stuttering, engine-powered flight in 1903. Today, we can see that Socrates was a visionary and we're taking him absolutely at his word with rockets and probes that venture well beyond Earth's atmosphere into deep space. But in between dreams of the air and the reality of flying, where exactly did this great adventure—the story of human flight—properly begin? Let's take a closer look!
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Contents
Dreaming of the sky
Humans first soared to the sky in bold adventures of the imagination. The wondrous eastern tales of the Thousand and One Nights (Arabian Nights), for example, feature a magic carpet, while another ancient Persian epic, the tale of Kay Kāvus, includes a flying throne carried by specially trained eagles. Something like 5000 years ago, an ancient Sumerian shepherd-king named Etana is reputed to have hitched a ride to heaven on the back of an eagle. Several thousand years later, while Socrates was busy imploring people to take to the skies, fellow ancient Greeks were all too aware of the perils, real or metaphorical, of over-reaching themselves: the famous Greek legend tells how Icarus fell to Earth after flying too close to the Sun with hasty wings made of feathers and wax. The Greeks also had a flying horse called Pegasus, while the Romans, following in their ancient footsteps, had Mercury, their own winged messenger from the heavens.
Photo: A statue of the winged messenger Mercury at Saltram House in Devon. Look closely and you'll see the wings under his hat!
Stories like these, which we're still recycling to this day, must have played an inspiring part in the first real attempts to take to the sky along, of course, with practical observations of birds, insects, and other flying creatures. No-one knows who made the very first human flight—or when—but one strong candidate is Abbas Ibn Firnas (810–897CE), an Andalusian version of Leonardo da Vinci, who jumped from a tower in Cordoba (now Spain) around 850 with flapping wings strapped to his body and reputedly flew quite some distance. Over in Malmesbury, England about a century later, a young monk named Eilmer attempted a similar flight, proudly commemorated in a piece of stained glass in the town's abbey. Using a pair of crude homemade wings, he reputedly glided a distance of about 200m (650ft) from the Abbey tower before crash landing and breaking both legs, rendering him lame for the rest of his life.
Photo: A boy sets off on a flying carpet in adventures of the imagination. Photographs in Carol M. Highsmith's America Project in the Carol M. Highsmith Archive, Library of Congress, Prints and Photographs Division.
Floating free
There's more than one way to fly—and the first real flights might be better described as "floats," since they involved buoyant (floating) balloons rather than winged aircraft. The science of floating, as we understand it today, was clearly understood by Greek mathematician Archimedes (287–212BCE) around 2200 years ago. Famously, he figured out how objects displace (push aside) their own weight of fluid, which is the first step toward understanding why ships can float on the sea. Though Archimedes floated these thoughts c.200BCE, the first balloonists are thought to have taken to the air long before then. Some believe that the Nazca people of southern Peru built balloons hundreds of years earlier, perhaps c.500BCE, from which they planned the famous, vast, incredible artworks in their dusty desert landscape (popularly known as Nazca Lines) that are still visible from the air to this day (though this explanation is controversial and disputed).
Photo: Hot-air balloons fly by floating.
It takes a flight of insight to understand that the same science floating boats on the sea allows balloons to rise and float in the air. The person who figured this out was English polymath Roger Bacon (c.1214–1294); taking Archimedes' ideas a step further, he understood that air pressure could support a balloon in the same way that water pressure supports a ship. All very well in theory, but how could you achieve it in practice? Modern balloons have hot air inside them that's less dense (lighter) than the air around them, so they feel a force called lift that makes them rise into the sky. The basic science—hot air is less dense than cool air—was first properly worked out by a brilliant 17th-century chemist named Robert Boyle (1627–1691), but people had an intuitive grasp of the idea long before then. Over 2000 years ago, Chinese children are believed to have played with toy flying "machines" made from eggshells with burning twigs inside them. As the twigs burn, they heat up the air inside, making the shell into a miniature hot-air "balloon" that (supposedly, if it's not too heavy) rises into the sky. Sweet wrappers (Amaretto papers) that fly into the air when they burn look like mini hot-air balloons but work on different principle (the burning paper creates an invisible draft of rising hot air that eventually sucks the paper up with it).
Though the theory and practice of using hot air to make lift seems to have been known for thousands of years, it wasn't until 1783 that the first proper hot air balloon was created, by French brothers J. Étienne and Joseph M. Montgolfier (1745–1799 and 1740–1810). With an "envelope" (gas-containing bag) fashioned out of cloth and paper, blown high by a straw and wood fire burning beneath, their pioneering aircraft achieved an amazing height of 900m (3000ft). Later that year, they safely sent a sheep, rooster, and duck into the air, before Étienne Montgolfier became the first human balloonist (albeit safely tethered to Earth by rope) shortly afterward. A few weeks later, the first free-floating balloon flight carried Jean-François Pilàtre de Rozier and Marquis François Laurent le Vieux d'Arlandes high over Paris in a Montgolfier balloon.
Illustration: A later flight by the Montgolfier brothers and their passengers over Lyon, France, on January 19, 1784. Hand-colored etching: Enaut et Rapilly, rüe St. Jacques à la ville de Coutances, 1784, courtesy of US Library of Congress.
Hot air balloons evolved into steerable, engine-powered airships called dirigibles, which were pioneered by another Frenchman, Henri Giffard (1825–1882), in the first part of the 19th century. By the end of the 1900s, they'd evolved once more, into huge passenger-carrying balloons called Zeppelins, named for German army officer Count Ferdinand Graf von Zeppelin (1838–1917). Unlike the Montgolfier's balloon (and modern hot-air balloons), airships like this were rigid-framed rubber balloons containing a number of individual cells filled with hydrogen, a very light gas. In the early decades of the 20th century, when wing-powered airplanes were still a very new thing, airships seemed to be the stately future of intercontinental travel. But hydrogen has a huge drawback—it's highly flammable—and a series of spectacular disasters soon put paid to that idea. The worst of these happened in May 1937 when an enormous German airship called the Hindenberg (about 245m or 800ft long) crashed as it landed in New Jersey killing 36 people.
Maybe there were better ways to fly?
Finding our wings
Airships and balloons are vast, clumsy, and cumbersome things: they need a huge volume of lighter-than-air gas to make enough lift to overcome their weight. The giant, fateful Hindenberg, for example, needed something like 200,000 cubic meters (7 million cubic feet) of hydrogen, while even a more modest Zeppelin needed about 14,000 cubic meters (500,000 cubic feet). Modern airplanes carry much bigger loads than these airships without any help from floating gas bags at all—and they do it using wings. Broadly speaking, the larger the plane (or the heavier the load it has to carry) the bigger the wings it needs.
Exactly how wings help a plane to fly is quite a complex thing (you'll find it explained in detail in my article about how planes fly). A plane doesn't necessarily need an engine, but it does need wings: it's the wings that make the upward lift when the engines push the plane forward through the air. If you make a plane go forward without an engine, its wings will still generate lift. That's the idea behind gliders, which are simply planes without engines. As we've seen already, one of the first pioneering historic flights, by Eilmer the Monk in Malmesbury, was essentially a glider flight by a man with wings strapped to his body.
Gliders—and the science of flight—made huge strides forward in the 18th and 19th centuries thanks to a brilliant English aristocrat named Sir George Cayley (1773–1857). Unlike so-called "birdmen" aviators, who tried to fly by flapping wings attached to their bodies, Cayley concentrated most of his efforts on the design of fixed-wing aircraft and figured out how to optimize the wings to maximize lift. He made his first model glider in 1804 and spent the rest of his life refining the design until, in 1853, he was ready to launch a full-sized glider with a human inside it.
Photo: "Birdman" Otto Lilienthal flying one of his gliders in 1895, the year before his death. Photograph attributed to the Wright brothers (a glass negative from the papers of Wilbur and Orville Wright) courtesy of US Library of Congress.
Cayley's work took flight in two different directions, practical and theoretical. From the practical side, it helped to inspire glider makers like Jean-Marie Le Bris (1817–1872) and Otto Lilienthal (1848–1896), who made 2000 daring glider flights before finally crash-landing and killing himself in 1896. Cayley's work also marked the real beginnings of the science of aerodynamics, later extended by Lilienthal's experiments with airfoil design and 20th-century pioneers such as Ernst Mach (1838–1916, who researched supersonic flight, and for whom Mach numbers are named) and Frederick Lanchester (1868–1946, another pioneer of modern airfoil theory). Cayley was the first person to figure out that a plane moves through the air in a balance of four forces: thrust (moving it forward), drag (air resistance, pulling it back), lift (the upward force on the wings), and weight (the force of gravity pulling the plane back down).
Illustration: Getting in a flap: One of Sir George Cayley's human-powered flying machines, c.1853. Courtesy of US Library of Congress.
People still fly gliders to this day, but they're typically just small, one- or two-person craft that take great skill to pilot. Though it's just about possible to imagine a glider that could carry more, no glider could ever do what modern jet planes do—ferrying hundreds of people at high speed over deserts, mountains, and oceans, day after day, year in and year out. For that kind of dependable, steady flight, you need more than just a plane with wings; you need a plane with powerful engines.
“I can state flatly that heavier than air flying machines are impossible... I have not the smallest molecule of faith in aerial navigation other than ballooning, or of the expectation of good results from any of the trials we heard of.”
Lord Kelvin, 1895/1896
Powered flight
Where would those engines come from? Since the early 18th century, most of the world's mechanical power had come from coal-powered steam engines, the first practical example of which was built by Thomas Newcomen, in England, in 1712. Steam engines were huge dirty beasts, originally much too big and bulky even to drive things like railroad engines, so there was no prospect of using them to power a plane. Even so, that tantalising possibility opened up with the development of smaller, lighter, high-pressure railroad steam engines, by such people as Richard Trevithick (1773–1833) in Britain and Oliver Evans (1773–1833) in the United States.
Ultimately, a number of engineers believed it was perfectly worthwhile to experiment with putting steam engines in planes. It seems a remarkable idea now—using a heavy, coal-powered engine to lift itself off the ground—but there was still no serious, credible alternative to steam at the time. That's why a number of intrepid inventors in different parts of the world seriously experimented with steam airplanes, including Englishman William Henson, Frenchman Clément Ader, and Americans Samuel P. Langley, Hiram Maxim (inventor of the automatic machine gun), and Horatio Phillips. None of these attempts got beyond models and prototypes and, though several made promising flights, none led to the development of a practical, steam-powered airplane.
Illustration: William Henson's Aerial Steam Carriage, optimistically sketched making a bold voyage over the Thames River in London c.1843. Although Henson and his partner John Stringfellow were granted a patent in 1842, in reality, even a model of this stupendous steam plane never got off the ground. Courtesy of US Library of Congress.
