Editing Leonardo da Vinci (section)

=== Engineering and inventions ===
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| caption1 = A design for a flying machine ({{circa|1488}}), first presented in the ''[[Codex on the Flight of Birds]]''
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| caption2 = An ''[[Leonardo's aerial screw|aerial screw]]'' ({{circa|1489}}), suggestive of a helicopter, from the ''[[Codex Atlanticus]]''
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During his lifetime, Leonardo was also valued as an engineer. With the same rational and analytical approach that moved him to represent the human body and to investigate anatomy, Leonardo studied and designed many machines and devices. He drew their "anatomy" with unparalleled mastery, producing the first form of the modern technical drawing, including a perfected "exploded view" technique, to represent internal components. Those studies and projects collected in his codices fill more than 5,000 pages.<ref name="guarnieri1">{{Cite journal |last=Guarnieri |first=M. |s2cid=202729396 |year=2019 |title=Reconsidering Leonardo |journal=IEEE Industrial Electronics Magazine |volume=13 |issue=3 |pages=35–38 |doi=10.1109/MIE.2019.2929366 |hdl=11577/3310853 |hdl-access=free}}</ref> In a letter of 1482 to the lord of Milan [[Ludovico il Moro]], he wrote that he could create all sorts of machines both for the protection of a city and for siege. When he fled from Milan to Venice in 1499, he found employment as an engineer and devised a system of moveable barricades to protect the city from attack. In 1502, he created a scheme for diverting the flow of the Arno river, a project on which [[Niccolò Machiavelli]] also worked.<ref>{{cite book |last=Masters |first=Roger |author-link=Roger Masters |title=Machiavelli, Leonardo and the Science of Power |year=1996}}</ref><ref>{{cite book |last=Masters |first=Roger |title=Fortune is a River: Leonardo Da Vinci and Niccolò Machiavelli's Magnificent Dream to Change the Course of Florentine History |publisher=Simon & Schuster |year=1998 |isbn=978-0-452-28090-8}}</ref> He continued to contemplate the canalisation of [[Lombardy#Soils|Lombardy's plains]] while in Louis XII's company{{sfn|Wallace|1972|p=145}} and of the [[Loire]] and its tributaries in the company of Francis I.{{sfn|Wallace|1972|p=164}} Leonardo's journals include a vast number of inventions, both practical and impractical. They include [[Viola organista|musical instruments]], [[Leonardo's robot|a mechanical knight]], hydraulic pumps, reversible crank mechanisms, finned mortar shells, and a [[steam cannon]].{{sfn|Bortolon|1967}}{{sfn|Arasse|1998}}

[[File:Leonardo da Vinci - 1860,0616.99, Studies of military tank-like machines (cropped).jpg|thumb|left|Leonardo's drawings of a scythed chariot and a [[Leonardo's fighting vehicle|fighting vehicle]]]]

Leonardo was fascinated by the phenomenon of [[History of aviation|flight]] for much of his life, producing many studies, including ''[[Codex on the Flight of Birds]]'' ({{circa|1505}}), as well as plans for several flying machines, such as a flapping [[ornithopter]] and a machine with a helical [[Helicopter rotor|rotor]].{{sfn|Arasse|1998}} In a 2003 documentary by British television station [[Channel Four]], titled ''Leonardo's Dream Machines'', various designs by Leonardo, such as a [[Parachute#Early Renaissance|parachute]] and [[Leonardo's crossbow|a giant crossbow]], were interpreted and constructed.<ref>{{cite web |url=https://www.imdb.com/title/tt0365434/ |title=Leonardo's Dream Machines (TV Movie 2003) |website=IMDb|access-date=30 June 2018|archive-date=8 February 2017|archive-url=https://web.archive.org/web/20170208160755/http://www.imdb.com/title/tt0365434/|url-status=live}}</ref><ref>[http://www.bl.uk/onlinegallery/features/leonardo/parachute.html British Library online gallery] {{Webarchive|url=https://web.archive.org/web/20191121011521/http://www.bl.uk/onlinegallery/features/leonardo/parachute.html |date=21 November 2019 }} (retrieved 10 October 2013)</ref> Some of those designs proved successful, whilst others fared less well when tested. Similarly, a team of engineers built ten machines designed by Leonardo in the 2009 American television series ''[[Doing DaVinci]]'', including a [[Leonardo's fighting vehicle|fighting vehicle]] and a [[Leonardo's self-propelled cart|self-propelled cart]].

Research performed by [[Marc van den Broek]] revealed older prototypes for more than 100 inventions that are ascribed to Leonardo. Similarities between Leonardo's illustrations and drawings from the Middle Ages and from Ancient Greece and Rome, the Chinese and Persian Empires, and Egypt suggest that a large portion of Leonardo's inventions had been conceived before his lifetime. Leonardo's innovation was to combine different functions from existing drafts and set them into scenes that illustrated their utility. By reconstituting technical inventions he created something new.<ref>{{citation |mode=cs1 |surname1=[[Marc van den Broek]] |title=Leonardo da Vinci Spirits of Invention. A Search for Traces |publisher=A.TE.M. |location=Hamburg |isbn=978-3-00-063700-1 |date=2019 |language=en}}</ref>

In his notebooks, Leonardo first stated the 'laws' of sliding [[friction]] in 1493.<ref name=Hutchings>{{Cite journal |last=Hutchings |first=Ian M. |date=15 August 2016 |title=Leonardo da Vinci׳s studies of friction |url=http://www.sciencedirect.com/science/article/pii/S0043164816300588 |journal=Wear |language=en |volume=360–361 |pages=51–66 |doi=10.1016/j.wear.2016.04.019 |issn=0043-1648|access-date=22 January 2021|archive-date=12 February 2017|archive-url=https://web.archive.org/web/20170212083723/http://www.sciencedirect.com/science/article/pii/S0043164816300588|url-status=live}}</ref> His inspiration for investigating friction came about in part from his study of [[perpetual motion]], which he correctly concluded was not possible.{{sfn|Isaacson|2017|pp=194–197}} His results were never published and the friction laws were not rediscovered until 1699 by [[Guillaume Amontons]], with whose name they are now usually associated.<ref group="‡" name=":0" /> For this contribution, Leonardo was named as the first of the 23 "Men of Tribology" by [[Duncan Dowson]].<ref>{{Cite journal |last=Dowson |first=Duncan |date=1 October 1977 |title=Men of Tribology: Leonardo da Vinci (1452–1519) |url=https://asmedigitalcollection.asme.org/tribology/article/99/4/382/429918/Men-of-Tribology-Leonardo-da-Vinci-1452-1519 |journal=Journal of Lubrication Technology |language=en |volume=99 |issue=4 |pages=382–386 |doi=10.1115/1.3453230 |issn=0022-2305|doi-access=free|access-date=22 January 2021|archive-date=23 February 2023|archive-url=https://web.archive.org/web/20230223055154/https://asmedigitalcollection.asme.org/tribology/article/99/4/382/429918/Men-of-Tribology-Leonardo-da-Vinci-1452-1519|url-status=live}}</ref>