Editing History of aviation (section)

=== Renaissance ===
{{See also|Early flying machines#The Renaissance}}
[[File:Leonardo Design for a Flying Machine, c. 1488.jpg|thumb|left|One of Leonardo's sketches]]

Eventually, some investigators began to discover and define some of the basics of rational aircraft design. Most notable of these was [[Leonardo da Vinci]], although his work remained unknown until 1797, and so had no influence on developments over the next three hundred years. While his designs are rational, they are not scientific.{{sfn|Wragg|1974|p=11}} He particularly underestimated the amount of power that would be needed to propel a flying object,<ref name=time/> basing his designs on the flapping wings of a bird rather than an engine-powered propeller.<ref name=":0">{{Cite book|last=Durant|first=Will|url=https://www.worldcat.org/oclc/869434122|title=Heroes of History: A Brief History of Civilization from Ancient Times to the Dawn of the Modern Age|publisher=Simon & Schuster|year=2001|isbn=978-0-7432-2612-7|location=New York|pages=209|oclc=869434122|author-link=Will Durant|access-date=18 January 2021|archive-date=7 March 2024|archive-url=https://web.archive.org/web/20240307231132/https://search.worldcat.org/title/869434122|url-status=live}}</ref>

Leonardo studied bird and bat flight,<ref name=time/> claiming the superiority of the latter owing to its unperforated wing.<ref>{{cite book |last=Da Vinci|first=Leonardo |editor-last=Taylor |editor-first=Pamela |title=The Notebooks of Leonardo da Vinci |publisher=New American eLibrary|year=1971 |page=107}}</ref> He analyzed these and anticipated many principles of aerodynamics. He understood that "An object offers as much resistance to the air as the air does to the object."{{sfn|Fairlie|Cayley|1965|p=163}} [[Isaac Newton]] later defined this as the [[Newton's third law|third law of motion]] in 1687.

From the last years of the 15th century until 1505,<ref name=time>{{cite book |last=Wallace |first=Robert |title=The World of Leonardo: 1452–1519 |publisher=Time-Life Books |location=New York |year=1972|orig-year=1966 |page=102}}</ref> Leonardo wrote about and sketched many designs for flying machines and mechanisms, including ornithopters, fixed-wing gliders, rotorcraft (perhaps inspired by [[whirligig]] toys), parachutes (in the form of a wooden-framed pyramidal tent) and a wind speed gauge.<ref name=time/> His early designs were man-powered and included 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.<ref name="popham">{{cite book |last=Popham |first=A.E. |title=The drawings of Leonardo da Vinci |publisher=Jonathan Cape |edition=2nd |year=1947}}</ref>

In an essay titled ''Sul volo'' (''On flight''), Leonardo describes a flying machine called "the bird" which he built from starched linen, leather joints, and raw silk thongs. In the ''[[Codex Atlanticus]]'', he wrote, "Tomorrow morning, on the second day of January 1496, I will make the thong and the attempt."<ref name=":0" /> According to one commonly repeated, albeit presumably fictional story, in 1505 Leonardo or one of his pupils attempted to fly from the summit of [[Monte Ceceri]].<ref name=time/>