Lesson 7: A History of Aerodynamics - Part I
In this session, we will learn about some of the great contributors to the field of aerodynamics tracing from Leonardo da Vinci, Issac Newton, George Cayley, and the Wright Brothers. This lesson will also provide background on the invention of the airplane.
Section 1 - Before There was Flight
EARLY BEGINNINGS
It was not that long ago when people could only dream of being able to fly. The dream of flight was the subject of great myths and stories such as that of Icarus and his father Daedalus, and their escape from King Minos’ prison on Crete. They attempted to build a flying machine to free them from prison. However, legend has it that they had difficulty with structural materials in building their escape, as opposed to the actual aerodynamics.
In subsequent years, there were many legends of people attempting flight. It would appear that people have been experimenting with aerodynamics for thousands of years.
In quoting from an 1880’s book, La Navigation Aerienne, Octave Chanute describes how Simon the Magician in about 67 A.D. undertook to rise toward heaven like a bird. “The people assembled to view so extraordinary a phenomenon and Simon rose into the air through the assistance of the demons in the presence of an enormous crowd. But that St. Peter, having offered up a prayer, the action of demons ceased…”
Human flight was affected by several theories and arguments on its impossibility. This research topic was not taken seriously until the very late 1800’s. It was regarded as an important paradox that birds could so easily accomplish this feat that had eluded people’s understanding.
In 1891, Octave Chanute wrote, “Science has been awaiting the great physicist, who, like Galileo or Newton, should bring order out of chaos in aerodynamics, and reduce its many anomalies to the rule of harmonius law.”
Research papers suggested that perhaps birds and insects used some “vital force” which enabled them to fly and which could not be duplicated by an inanimate object.
Technical meetings were conducted on the problem in the 1890’s. The natural ability of birds to guide without noticeable motion of the wings and with little or negative altitude remained a mystery for some time.
Then, the theory of aspiration was developed. This stated that birds were in some way able to convert the energy in small scale turbulence into useful work. Later, this theory fell out of favor. The birds’ ability was attributed more to proficient seeking of updrafts.
LEONARDO DA VINCI
Designs of aircraft were made long before people had the slightest idea how they flew. Leonardo Da Vinci designed ornithopers in the late 1400’s which were modeled on his observations of birds.
Da Vinci was an inventor, engineer, architect, artists, and mathematician who was way ahead of his time. Born in 1452, Da Vinci is best known as a great Florentine painter who created the famous masterpiece, the Mona Lisa. But he excelled in many fields ranging from physiology to engineering, providing the first sketches of parachutes and helicopters.
His amazing work in aerodynamics only came to light with his many scientific manuscripts at the end of the last century. It is believed that in these manuscripts were a total of 35,000 words and more than five hundred sketches dealing with flying machines, the nature of air, and bird flight.
Leonardo had studied the anatomy of both birth and man. He believed that the goal of flight might rouse the extra strength in man to rise in an ornithopter even though he was aware of the fact “that the sinews and muscles of a bird are incomparably more powerful than those of man.”
He designed ornithopters for pilots in a prone or upright position, who flapped the wings via pulleys, employing both hands and feet, an advance beyond strapping wings to arms only.
A JESUIT PRIEST
In the late 17th century, the Italian Jesuit priest Francesco Lanaterzi, a professor of mathematics and philosophy, realized that a lighter gas than air was needed to lift a balloon or an airship, as opposed to a heavier-than-air machine such as Leonardo’s ornithopter.
Lana-Terzi designed an airship to be carried by four evacuated spheres, each with a diameter of 20 ft (6 m).
A sail was mistakenly added to keep the contraption on course. Lana-Terzi also realized that the vacuum sphere’s paper-thin walls could not withstand the external atmospheric pressure and would collapse.
He was to have said that in any case God would not permit the success of such an invention, since it would open up immense possibilities for destruction. Later, Lana-Terzi’s prophecy was proved wrong, with the successful development of military aviation.
Giovanni Borelli, was the first to point out the physiological differences between humans and birds. In his De Motu Animalium, he stated that man could not hope to support his weight in air “without mechanical assistance.”
A full understanding of the physiology of humans in relation to flight would come about 120 years later through Sir George Cayley, who is considered to be the father of modern aviation.
Cayley showed how a powerful airplane would be possible by discarding the ornithopter.
We will discuss more on Cayley later, but first let us backtrack to the myth, legend and early adventures of flight.
