HISTORY80 - The Inventions of Leonardo da Vinci

In my last two blogs (July 1, 2023 and July 13, 2023), I first introduced Leonardo da Vinci and talked about the person, his life, and his accomplishments - focusing on his paintings; and then discussed his scientific investigations.  In this third and final blog on Da Vinci, I want to focus on his inventions. 

 

I will start with a short introduction, then discuss his inventions, and end with some conclusions about his legacy with respect to inventions.  For each invention that I talk about, I’ll include a short description of how and when the invention became real.

My principal sources include: “Science and inventions of Leonardo da Vinci” and “Leonardo’s aerial screw,” Wikipedia; “Da Vinci Weapons of War,” italian-renaissancea-art.com; “10 Major Accomplishments of Leonardo da Vinci,” learnodo-newtonic.com; “What Were Leonardo da Vinci’s Top Inventions?”, waynearthurgallery.com; “Da Vinci’s Mortar and Machine Gun,” editions.covercollective.org; “Leonardo da Vinci and Flight,” airandspace.si.edu; “Leonardo da Vinci Inventions - Flight Machines and Aerial Screw,” da-vinci-inventions.com; “Leonardo da Vinci’s Life - da Vinci’s Parachute; plus, numerous other online sources.

Introduction

During his lifetime, besides the superlative paintings for which he is best known, and his scientific investigations that supported them, Leonardo da Vinci was a   prolific inventor.  He was employed several times as an advisor on military matters, having to do with innovative weapons, fortifications, and defenses.  Many of his designs, such as movable dikes to protect Venice from invasion, proved too costly or impractical.

With insatiable curiosity, Da Vinci was constantly observing, experimenting, and inventing, conceiving ideas vastly ahead of his own time.  He understood the principles governing momentum, centripetal force, the airfoil, and sliding fiction - and applied these to his inventions.

Many of his conceptual inventions couldn’t be realized in his lifetime because technology of the day wouldn’t support them.  For example, his war and flight machine concepts lacked an adequate source of power for propulsion or lift, and he lacked robust, light-weight materials.

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.  He left a large body of drawings of his engineering studies and inventions, with notes, most gathered into notebooks.

Because of the delay in publishing Leonardo da Vinci’s notebooks after his death in 1619, the full extent of his engineering studies and inventions has only become recognized in the last 150 years.   The tragedy is that much of Da Vinci’s scientific work was re-discovered at a time when the world had already embraced many of his ideas.  (For centuries after his death, Leonardo was known only as a painter.)  There is little doubt that had his work been publicized in the Renaissance era, it would have advanced the knowledge of the time. 

The scope of Leonardo’s engineering and inventions is truly mind boggling.  The list of his principal inventions spans mechanics, bridges, weapons of war, human flight, and others.

The following sections detail some of these inventions.

Mechanics

Throughout his life Leonardo was an inventive builder; he thoroughly understood the mechanical principles of his time, and contributed in many ways to advancing them.

He made designs for mills and engines that could be driven by water-power, and designed ways of cleansing harbors and using pumps to suck up water from great depths.

Da Vinci drawings of water lifting devices.

 

In addition, he made models and plans showing how to excavate and tunnel through mountains without difficulty, and he demonstrated how to lift and draw great weights by means of levers, hoists and winches.

Leonardo was a master of mechanical principles.  He utilized leverage and cantilevering, pulleys, cranks, gears (including angle gears and rack and pinion gears); parallel linkage, lubrication systems, and bearings.

Among his mechanical inventions that are credited with passing into general practical use are the automated bobbin winder (wind thread or yarn onto bobbins), the rolling mill (a machine that reduces the thickness of a metal without sacrificing any of the material), a machine for testing the tensile strength of wire, and a lens-grinding machine.  In the lens-grinding machine, the hand rotation of the grinding wheel operates an angle-gear, which rotates a shaft, turning a geared dish in which sits the glass or crystal to be ground.  A single action rotates both surfaces at a fixed speed ratio determined by the gear.

Leonardo’s drawing of a machine to grind convex lenses.

 

Leonardo's study of human anatomy, for more accurate representation of the human form in his painting, led also to his design of a “mechanical knight,” probably drawn around the year 1495, but rediscovered only in the 1950s.  According to Da Vinci’s sketches of the key components, the mechanical knight, also known as Leonardo’s robot, was to be powered by an external mechanical crank, and use cables and pulleys to sit, stand, turn its head, cross its arms and even lift up its metal visor. 

Da Vinci’s drawing of one of his concepts for a human-like robot.

  

Bridges

In a letter to the Duke of Milan in 1482, seeking employment for military matters, Leonardo told him:  “I have plans for very light, strong and easily portable bridges with which to pursue and, on some occasions, flee the enemy, and others, sturdy and indestructible either by fire or in battle, easy and convenient to lift and place in position.”  Da Vinci’s notebooks contain drawings of many such bridges.

Da Vinci worked in Milan from 1482 - 1499.   While there, Leonardo da Vinci designed a revolving wooden bridge that could be quickly collapsed, packed up, and transported for use by armies on the move to pass over bodies of water.  The bridge would swing across a stream or moat and set down on the other side so that soldiers could pass with little trouble.  The device had wheels and incorporated a rope-and-pulley system for both quick employment and easy transport.  It was also equipped with a counterweight tank for balancing purposes.  Another, similar bridge that Leonardo da Vinci designed for armies was a fast-construction bridge that made it quicker and easier for soldiers to cross multiple rivers.

Da Vinci drawing of his revolving bridge.

 

In 1502, while in Florence. Leonardo produced a drawing of a single span 720-foot bridge as part of a civil engineering project for Ottoman Sultan Beyazid II of Istanbul.  The bridge was intended to span an inlet at the mouth of the Strait of Bosporus known as the Golden Horn.  Beyazid did not pursue the project, because he believed that such a construction was impossible.  Leonardo's vision was resurrected in 2001 when a smaller bridge based on his design was constructed in Norway.  A stone model of Leonardo’s bridge was evaluated in 2019 by MIT researchers. The self-supporting 1:500 scale model was built from 126 3D-printed stone cross-sections, held together without mortar. Researchers concluded that the bridge would have been able to support its own weight, and maintain stability under load and wind shear forces.

Weapons of War

Leonardo da Vinci was a man of his time and the need for military engineers provided him with employment, travel opportunities, and the chance to continue his scientific work unhindered.  Renaissance Italy was a collection of independent city-states who became engaged in incessant warfare with each other. This provided a market for technically advanced weapons needed to gain a military advantage over the enemy.

Leonardo had studied and absorbed both classical and contemporary works on military engineering.  In his famous 1482 letter to the Duke of Milan, he listed nine categories of military engineering among the many skills in which he was proficient, including new weaponry, bridging, bombarding machines, and trench draining.

Leonardo assured the duke:

“When a place is besieged, I know how to cut off water from the trenches and construct an infinite variety of bridges, mantlets [portable wall shelters used for stopping projectiles], and scaling ladders, and other instruments pertaining to sieges [including catapults].  I also have types of mortars that are very convenient and easy to transport. … when a place cannot be reduced by the method of bombardment either because of its height or its location, I have methods for destroying any fortress or other stronghold, even if it be founded upon rock. … If the engagement be at sea, I have many engines of a kind most efficient for offense and defense.

In Leonardo's notebooks there is an array of drawings for most of what he claimed, although there is little evidence that any of his weapons of war were actually built in his lifetime.

The following paragraphs describe Da Vinci’s plans for fighting vehicles (a scythed chariot and an armored tank), cannons (a mortar, a three-barrel mobile cannon, and machine gun cannon), and a giant crossbow.

Fighting Vehicles.

Scythed Chariot.  Leonardo’s scythed chariot is reminiscent of scythed Persian chariots in 400 BC, but vastly more sophisticated.  The chariot, propelled by horses, carries in front of it four scythes mounted on a revolving gear, turned by a shaft driven by the wheels of a cart behind the horses.  The whirling scythes in front would render infantry ineffective to attack or stop the chariot.  The wheels and scythes behind would wreak havoc and protect the rider from attack in the rear.

Tank.  The concept was designed while Leonardo da Vinci was under the patronage of the Duke of Milan in 1487.  Sometimes described as a prototype of modern tanks, Leonardo's tracked armored vehicle had a conical cover inspired by a turtle's shell.  The covering was to be made of wood and reinforced with metal plates that add to the thickness.  Slanting angles would deflect enemy fire. The machine was powered by two large cranks that turned a sequence of wheels operated internally by four strong men.  The vehicle was equipped with an array of light cannons, placed around the perimeter.

The gears of the design were located in a reversed order, making the vehicle unworkable. This is thought by some sources to have been a deliberate mistake by Leonardo as a form of security, in case his design was stolen and used irresponsibly.  It is almost impossible to fix this problem successfully without taking away power from its forward movement and strength.  Regardless, the vehicle would have been too heavy to move and would have lacked the battlefield mobility seen in modern tanks that make them so effective.

The armored vehicle was designed to intimidate the enemy rather than to be used as a serious military weapon.  Due to the vehicle's impressive size (almost 30 feet in diameter), it would not be capable of moving on rugged terrain.  

Da Vinci drawings of scythed chariot and tank.

 

In 1916, more than 400 years after Da Vinci’s work, during the First World War, the British Mark I tank became one of the first functional tanks to be used in battle, and it was recognized as a major milestone in the development of armored warfare.

Cannons. 

Mortar.  Leonardo's notebooks show cannons which he claimed "to hurl small stones like a storm with the smoke of these causing great terror to the enemy, and great loss and confusion."

Leonardo drawing of two mortars with explosive shells.

Triple Barrel Mobile Cannon.  As a military engineer, one of Leonardo da Vinci’s key beliefs was that mobility was crucial to victory on the battlefield.  This idea is seen in many of his war inventions, from his mobile bridges and ladders to many of his weapon designs.  

During da Vinci’s time, cannons were generally used at home in stationary defensive positions rather than on the battlefield.  This was because they were heavy and took a lot of time to reload. Da Vinci designed a triple barrel cannon to address both of these problems - a fast and light weapon that could do a lot of damage on the battlefield.

The design featured three thin cannons that would be front-loaded and adjustable in height. Unlike a traditional cannon, where one shot would be fired before reloading, da Vinci’s cannon allowed soldiers to load three shots at once, enabling them to fire more frequently. The lighter weight and large wheels allowed the gun carriage to be moved around to different areas during battle.

Leonardo drawing of three-barrel mobile cannon.

 

Machine Gun Cannon.  Da Vinci’s platform-mounted 33-barreled cannon featured 33 small-caliber guns connected together.  The cannons were divided into three rows of 11 guns each, all connected to a single revolving platform.  Attached to the sides of the platform were large wheels.

All the guns in the assembly would be loaded and then, during battle, the first row of 11 would be fired. The platform would then be rotated to properly aim the next row of cannons.  The idea was that while one set of cannons was being fired, another set would be cooling, and the third set could be loaded.  This system allowed soldiers to repeatedly fire without interruption.

Da Vinci drawing of his machine gun cannon (top) and two cannon with an array of horizonal barrels.

 

Leonardo da Vinci’s design for the 33-barreled cannon is generally regarded as the basis for the modern-day machine gun - a weapon that didn’t really develop for commercial use until the 19^th century.

Giant Crossbow.  Leonardo designed a massive crossbow (27 yards across) that was to be mounted on a cart and used in siege warfare to attack enemy fortifications.  It was capable of firing large arrows, bolts, large stones, or possibly flaming bombs over long distances, and was capable of penetrating the walls of fortresses and castles.

It was designed to be mounted on a cart and was operated by a team of soldiers.  The device would have six wheels (three on each side) for mobility, and the bow itself would be made of thin wood for flexibility.  For use, a soldier spins a crank to pull back the bow and loads the artillery. The soldier would then use a mallet to knock out a holding pin and fire the weapon.

Da Vinci drawing of giant crossbow.

 

Human Flight

Among the many subjects Leonardo studied, the possibility of human mechanical flight held particular fascination.  He produced more than 35,000 words and 500 sketches dealing with flying machines, the nature of air, and bird flight.  These investigations of flight are scattered throughout the many da Vinci notebooks.

Given his close observance and use of nature as a foundation for many of his ideas, emulating natural flight was an obvious area of interest. 

Leonardo’s detailed drawings of bird flight and his designs for flying machines demonstrated an understanding of aerodynamics and the principles of flight.  He recognized the importance of lift, thrust, and drag in achieving flight, and incorporated these concepts into his designs.

Da Vinci discussed the crucial concept of the relationship between the center of gravity and the center of lifting pressure on a bird’s wing.  He explained the behavior of birds as they ascend against the wind, foreshadowing the modern concept of a stall.  He demonstrated a rudimentary understanding of the relationship between a curved wing section and lift.  He grasped the concept of air as a fluid, a foundation of the science of aerodynamics.  Leonardo made insightful observations of gliding flight by birds and the way in which they balance themselves with their wings and tail, just as the Wright brothers would do in the early 20^th century as they evolved their first aeronautical designs. 

The following sections detail Leonardo’s work on gliders, ornithopters (flying machines), the helical aerial screw (forerunner of the helicopter), and parachutes.

Glider.  Early Da Vinci gliders had an articulated wing with a system of belts passing between the thighs and around the body of the flyer.  He later reduced the structure to a simple form with wings directly attached to the human body.

 

Da Vinci drawing of early glider concept.

Leonardo's last glider design had a wingspan of nearly 80 feet, a design like no other device he had ever sketched or built.  Da Vinci reached beyond nature to conceive a free-flying craft with flat surfaces to support it and a man in the still air.  It had double wings, cellular open-ended boxes for stability, as box kites of like construction.

Ornithopter (Flying Machine).  Most of Leonardo’s aeronautical designs were ornithopters, machines that employed flapping wings to generate both lift and propulsion.  He sketched such flying machines with the pilot prone, standing vertically, using arms, and using legs.  He drew detailed sketches of flapping wing mechanisms and means for actuating them. 

He even commented on the pilot’s position in a potential flying machine, and how control could be achieved by shifting the body weight, precisely as the early glider pioneers of the late 19^th century would do.  He noted the importance of lightweight structures that aircraft would require.  He even hinted at the force Newton would later define as gravity.

Birds, bats, and kites were sources of inspiration for Leonardo’s flying machines.

One of Leonardo da Vinci’s flying machine concepts had a wingspan that exceeded 33 feet, and the frame was to be made of pine covered in raw silk to create a light but sturdy membrane.   The machine would be operated by a single person who would lie down on a central board.  The two wings would operate through a system of ropes and pulleys, with the operator’s legs providing power by working two small stirrups at the opposite end.  Pushing down on one stirrup caused the wings to move down, while pushing down on the other stirrup caused the wings to move up.  Doing this over and over caused the wings to flap up and down like a bird.

 

Da Vinci drawing of flying machine concept.  The pilot lies on central board (shown in foreground).  Thin wings are shown across top of drawing.

The machine also had a hand crank for increased energy output, and a head piece (rudder) for steering.  The pilot’s feet, hands, and head were all to be involved in flying the machine!

Unfortunately, as da Vinci himself probably realized, while the flying machine may have flown once it was in the air, a person could never have created enough power to get the device off the ground.

Helical Aerial Screw (Precursor to the Helicopter).  The helical aerial screw was a design for a rotary-wing aircraft and consisted of a large, spiraling blade that would rotate in a manner similar to a screw, providing lift and propulsion.  The concept was based on a water screw, but intended to push against the fluid of the air instead of water.

Leonardo drawing of helical aerial screw concept.

 

The design comprised a large structure, built on a solid circular platform, with a central vertical pole supported by three diagonal members meeting at a small circular plate about half way up the pole. The upper half of the pole was the supportive axis for a large spiraling sail of linen with a diameter over 15 feet, stiffened with starch. The inner edge of the sail wound clockwise around the pole, while the outer edge of the sail was connected by ropes or wires to a ring that rotated around the lower platform. The design envisioned a crew of four men on the wooden platform turning cranks to rotate the shaft.

With enough rotation, da Vinci believed the invention would lift off the ground.  Unfortunately, due to excessive weight and lack a powerful enough drive for the screw, da Vinci’s invention would not have been able to take flight.

In 1939, the Sikorsky VS-300 became the first functional helicopter to fly a sustained, controlled flight, and it was recognized as a major milestone in the development of rotary-wing aircraft.

A helicopter is now an essential tool for a wide range of applications, including military operations, search and rescue, and medical transport.

Parachute.  One of da Vinci’s notes declared: "If a man has a tent made of linen of which the apertures (openings) have all been stopped up, and it be [about 23 feet] across and in depth, he will be able to throw himself down from any great height without suffering any injury."

Da Vinci’s parachute design called for the use of a sealed linen cloth kept open by a series of wooden poles in a pyramid arrangement. The whole contraption was about 23 feet wide and high, not unlike a giant open umbrella, except for its pyramid form.  Its canopy differed from the rounded shapes of modern parachutes.  It involved a wooden frame that many assumed would be too heavy for the device to work properly.  It also lacked a hole at the top, which later scientists deemed necessary in order to keep the whole in balance during a descent from great height. 

Da Vinci drawing of parachute.

 

It was not until 1783 that Louis-Sébastien Lenormand, a French physicist, was credited with creating the first fully functional parachute.  In the 1800s, a harness and the idea of packing or folding the parachute into a container was introduced.  The modern design combining a harness, foldability, and a ripcord was not patented until 1920.

The parachute is now an essential piece of equipment for many high-altitude activities, including skydiving, BASE jumping, and military operations.

Conclusions

Other Da Vinci inventions not discussed above include catapults to launch projectiles against defenses, double-hulled boats to protect from outside damage, self-propelled carts powered by springs, an early diving suit to be used in the submerged destruction of enemy ships, concentrated reflected solar power via concave mirrors to heat water for Florence, detailed maps (cartography) of selected cities in Italy; and on and on - truly a remarkably numerous and varied set of innovative ideas.

Leonardo da Vinci may well have been the greatest inventor during the Renaissance.  Unfortunately, he had very little effect on the technology of his time.

Da Vinci drew thousands of sketches and diagrams of his inventions, with explanatory notes, which he preserved in his notebooks.   But he didn’t publish his extensive notebooks during his lifetime.  Even if he had published his work, almost none of da Vinci's ahead-of-his-time conceptual inventions could have been built then, the inventions being limited by available Renaissance era technology, too costly, or impractical.  Even more problematic, most of Leonardo’s inventions only became known about 150 years ago, almost 400 years after Leonardo’s death, because of the long delay in publishing and analyzing his manuscripts.

There is little doubt that had his work been publicized in the Renaissance era it would have advanced the knowledge of the time.   

His inventions continue to inspire engineers and scientists to this day.

Personal notes:  As a retired aeronautical engineer, I have a few comments: 

1.     As far as I can tell, without having studied his original notebooks, some of Da Vinci’s drawings are little more that doodles or cartoons, e.g., the drawings I included above of the three-barrel cannon and the parachute.  I don’t know if his notes were in sufficient detail to represent a preliminary design.

2.     I sense that having finally discovered Leonardo’s conceptual inventions, today’s articles on his work, go out of their way to exaggerate their importance.  In doing research for this blog, many sources claim in the first paragraph that Da Vinci invented the airplane, helicopter, tank, car, submarine, gun, calculator, alarm clock, etc. 

3.     Some of Leonardo’s inventions, specifically how he proposes they could work, are ridiculous, and he must have known it.  Two examples:  his flying machine and the aerial screw.  Both involve person-power, or multiple-person-power, acting in a heavy wooden structure, to achieve flight.  With all that he knew about bird and bat flight, Leonardo had to have known his concepts were impossible.  So how are we to interpret his conceptual designs?  Was he imagining future light-weight structures and adequate propulsion systems?  Or was he just fantasizing?

4.     Though most of Da Vinci’s inventions were “ahead of their time,” and thus weren’t built during his lifetime, I don’t understand why some of his military inventions were not constructed immediately, particularly some of his portable bridges.

5.     Even with these “qualifiers,” I remain very impressed with Leonardo’s inventive concepts - truly way ahead of his time.  What curiosity, observations, dedicated study and experimenting!  An amazing person with an amazing mind!