by Shana Priwer
Unfortunately, Leonardo's initial flapping-wing designs required balance, coordination, and strength. Even Da Vinci realized this would be too much to expect from most people! For that reason, Leonardo also focused on simpler designs. One of these was for a glider system with birdlike wings. In this device, which must have been inspired by a bat or other small winged creature, the user would climb in, jump off a mountain or tall tree, and balance primarily by moving the lower body in conjunction with the wings. Leonardo created another version of the design where the “pilots” moved their legs up and down, and another one in which a spring-loaded mechanism did most of the work.
Leonardo spent a lot of time working on the flapping system mechanism. Unfortunately for him, he paid little attention to the role feathers play in flight. This turned out to be one of his greatest oversights! Plus, as his flying machines got more complicated, they also got heavier and heavier—and therefore less likely to actually succeed. Aeronautical engineering in the fifteenth century was virtually nonexistent, so history can easily forgive Leonardo's technological mistakes.
Of all his flying machines, the sketches for Leonardo's glider are particularly interesting because he laid out the drawings in plan, section, and elevation on a single sheet. This degree of precision indicates he probably intended to build a scale model. Toward the end of his life, Leonardo focused primarily on fixed-wing craft, such as gliders, that relied more heavily on the concept of lift than on the physical act of flapping. These, at least, had some hope of actually getting off the ground some day!
The “Codex Atlanticus,” one of Leonardo's notebooks, contains many designs and notes on machines. It includes descriptions of flight patterns he observed in birds and displays several designs for aircraft with movable wings. He also mentions test flights that may actually have been conducted from Mount Ceceri—supposedly a student of his broke a leg while conducting such a flight! Unlike most of Leonardo's inventions, which were never built, Leonardo (or his unwitting students) tested at least a few of his designs for flying machines. How successful they were, though, is another story.
60
Leonardo's whirlybird
Why limit yourself to “traditional” flying machines? In addition to parachutes, gliders, bat wings, and other assorted fliers, Leonardo created some of the world's first helicopter designs. While he borrowed the form from some of his previous designs, he created something radically different in terms of structure and mechanics.
Leonardo's helicopter design used a corkscrew-shaped propeller instead of the blades seen on modern helicopters. The occupants rode in a basket that would have been made of wooden poles, with their feet planted on a platform that ended shortly before the screw-shaped blade began. Leonardo's idea, according to his notes, was to use a spring-loaded system that would wind up the helicopter and then release it. He used this idea again in his design for a car (see number 67). If this screw spun fast enough, he hypothesized, the entire machine would rise from the ground. What's unclear is whether or not the occupants would have been spinning along with the blade! The very idea is enough to give most people motion sickness, so it's probably good that he didn't make anyone test it out during his lifetime.
The major problem with Leonardo's design was its weight. It simply would have been too heavy to lift off the ground. In addition, while his idea of the human-powered machine was decidedly humanistic in concept, the reality was that no person would be able to generate enough power to actually take his helicopter up into the air. Leonardo gave the typical man (and woman) way too much credit in this case.
After many years of failed designs, Leonardo's dream came to fruition when Igor Sikorsky, a Russian aviator and inventor, studied Da Vinci's sketches and notes and, in 1910, began drawing prototypes for a working helicopter. Leonardo would have been proud—and probably would have taken the first test flight.
61
The world before Xerox
The responsibility of reproducing written works prior to the fifteenth century fell to monks, who were both literate and skilled in the art of transcription. Their task was not an easy one; they had to copy each word and illustration by hand from one piece of paper to another. Without even getting into the terrible inefficiency, there were several obvious problems with this method. The monks made lots of mistakes, and they were hard to fix. With each copy all the illustrations had to be completely redrawn, and it's unlikely that the transcription monks were artists of Leonardo's caliber. Say hello to stick figures! It probably wasn't that bad, but there was also little point in reproducing a book of drawings. In addition, the paper used most often in the pre-Renaissance era was parchment made from animal skin, and like most things of natural origin, it simply didn't last forever. The fact that each and every book had to be made by hand created very high costs, making literature unaffordable for most people.
Things began to change in 1446 when Johannes Gutenberg came roaring into the world of reproduction, creating the first printing press and altering the courses of literature, education, and society at large. It's impossible to overstate the importance of the printing press. Gutenberg combined movable type (previously invented in China) with ink, brass plates, and paper to create an array. Letters could be formed into words, and the results could be printed.
The outcome of the printing press was immediate and immense. All of a sudden, people could afford to buy books. Kids had no excuse not to go to school! Many more people learned to read and write, and society had to keep up with this influx of newly educated workers. The fun didn't stop with books—both text and music could be printed, and more and more people wanted sheet music. And don't forget about the papermaking industry—it developed new methods for creating paper more quickly, cheaply, and efficiently. There was money to be made here, and everyone wanted a share.
The ability to reprint ancient treatises and documents also factored in to the aims of the Renaissance—the classics could be brought to life. People could read Vitruvius, Aristotle, and other ancient Greeks and Romans. In addition, wealthier people who already had access to books started requesting a greater variety of literature, in different languages. There was suddenly a demand for poetry! Almanacs! Many new types of books were created, and they quickly became popular.
Always true to form, Leonardo approached the printing press critically. The predecessor to the printing press was block printing, a method where a block of wood would be carved out to leave raised letters. In Gutenberg's updated printing press model, letters (type) were placed by hand along a track, and these letters were movable, meaning they could be reset for each new page of text. While Leonardo didn't propose completely reinventing the printing press, he had an idea to add a second track that would increase the machine's efficiency He wanted to publish a treatise on this idea, but like most of his works, it remained undiscovered until well after his death.
The printing press had immense ramifications for Leonardo's future work. And everyone—future artists, inventors, school children—has benefited from being able to read the master's original work.
62
Under the boardwalk, down by the sea
Leonardo was a considerate soul. Not only was he interested in the design of boats and other watercraft, he also thought about the needs of sailors themselves. One thing we can't credit Leonardo with, though, is inventing diving. The ancient Greeks used a technique called breath-hold diving to search for food, gather sponges, and perform military reconnaissance. The Greeks and Romans swam underwater to escape enemy detection, probably by breathing through reeds. Some people supposedly experimented with breathing from an air-filled bag underwater, but the recycled carbon dioxide likely put an end to those trials.
Swimming, diving, and generally working with water were ideas Leonardo pursued constantly. He tried to expand the length of time someone could stay underwater, and he also wanted to find ways to protect the submerged diver. Aside from dangerous fish, there were underwater plants to brush against, sharp rocks to
step on, and too many other obstacles. Many of Leonardo's oceanic inventions were never tested, but some are quite similar to actual devices that can be purchased today.
One of his most futuristic ideas was a full deep-sea diving suit. Preliminary research into deep-sea exploration was beginning to take hold in the Renaissance, and Leonardo's ideas were influenced by this new interest in visiting the ocean depths. As with most things of a technological nature, the primary impetus (and, in most cases, funding) was likely the military. Italians had to become smarter about their battles, and water approaches were one way to take advantage of the natural terrain.
Leonardo's sketches show divers who were basically frogmen, prepared for land and sea at the same time. Their diving suits included land requirements such as regular clothes, ropes, and weapons. He also sketched out an “air sack” that may have sparked later inventors to create oxygen tanks. One such diagram shows the diver with a large, impact-resistant air tank attached to his chest so that he could dive far beneath the surface, but this chamber was so bulky, swimming with it might have been impossible! Leonardo's suit was to be made of leather or other durable animal skin, and cane hoses allowed the diver to move and breathe easily. He tried to reinforce these connections with metal, so that the pressure of being deep underwater wouldn't threaten the diver's safety. It seems Leonardo intended this suit for relatively shallow diving, because the pipe providing air to the diver went directly to the surface. The top of the tube also featured a bell-shaped float, so that the air openings would always remain above water. Modern divers have actually built a suit from Leonardo's notes, and they reported that it functioned quite well.
In true biblical spirit, Leonardo developed ideas in 1480 to let humans walk on water. Unlike Jesus, though, Leonardo's water walkers had to use special floating devices to keep them from sinking. This addition probably kept Leonardo from being deemed a heretic, and also added a touch of practicality, if you can call it that. These floats would have been attached to the feet of the user, who would have balanced by holding on to long poles. Not surprisingly, Leonardo doesn't seem to have ever built or tested a real version of this device.
Many of Leonardo's sketches for water-based machines focused on convenience. For example, he designed a glove with webbing in between the fingers, imitating a duck's webbed feet. These gloves would have been worn in the water, creating smoother and faster self-powered transportation. They also would have spared the wearer's hands from sticks, stinging fish, and other hazards. One of his sketches shows gloves proportionally as large as the flippers that swimmers wear on their feet! He also designed a life preserver that would allow people to remain afloat while in the water. While some of his inventions seem outlandish, others were practical and useful—the dreamer definitely had his pragmatic side.
63
Containing the forces of nature
Water: the basis for all life on earth, the universal solvent, and a general requirement for all living things. It has fascinated humans throughout recorded history, and Leonardo was no exception. He went to great depths to study water and all its properties. His observations were right on target. For example, he noted that water could easily change in character depending on the environment. Leonardo studied the various ways in which water came from the heavens, noting it could fall as rain, melt as snow, run in rivers, and actually come from the earth itself. He understood water's power to revitalize plants and people, but he was also aware of its ferociousness, as we can tell from his studies of storms and his sketches of powerful swirling waves.
Like his interest in blood flow and circulation, Leonardo was interested in river flow and water motion. As an artist he was always in motion, so you can definitely see the correlation. He studied currents and waves, observing how surfaces that repeatedly came into contact tended to degrade over time. He may have actually been the first to suggest the concept of erosion, and realizing how destructive water can be, he probably even feared the disaster caused by swollen rivers. As it turns out, his concern was well founded. The Arno River, near Florence and Pisa, erupted over its banks at least twice during Leonardo's lifetime, once in 1466 and again in 1478. These cataclysmic events influenced Leonardo's water management and manipulation designs.
One of his grandest ideas to control water was a scheme to divert the actual path of the Arno River. Leonardo was in Imola in 1502, working as the chief engineer for Cesare Borgia. During this time he used his skills in cartography to accurately plot out the course of the river, and in 1503 he presented a plan to redirect the river between Imola, Florence, and the sea. He had the support of influential Renaissance politician and philosopher Niccolo Machiavelli. Leonardo and Machiavelli were two of the most respected figures of the day, and their positions lent significant authority to their scheme.
At one point, Leonardo also decided to revamp the Florentine canal system. The general goal was to construct a series of channels that, passing through Pisa, would eventually lead to the sea. This effort would have improved the city's waterpower and irrigation, in addition to the commercial benefits. These canals would have used steps and locks powered by oversized siphons. In his engineering studies, Leonardo suggested digging large ditches that would eventually connect to the river. Ships could have sailed through Florence and into the hillier, mountainous areas for easier pickup and delivery of goods. It also would have helped with the Florentine wartime effort.
Unlike many of Leonardo's projects, this one was at least started! Hundreds of men began working on the canals under the supervision of Colombino, a master hydraulic engineer. Unfortunately, these canals were never completed, as Leonardo had to return to Florence to work on a fresco in the Palazzo Vecchio. In Leonardo's absence, Colombino took a few liberties with the design and made some disastrous engineering changes. According to some reports, the Arno actually did flow into its new path for a short time, but the river promptly reverted to its previous course and the project was eventually abandoned.
64
Harnessing the power of water
On dry land, Leonardo spent time studying and designing aircraft, including elaborate helicopters, gliders, and parachutes. Never one to limit himself, he was also fascinated with aquatics and devoted years to designing machines that worked with water. Given the sheer amount of water surrounding Italy, he picked a great hobby. It is likely that he was first exposed to aquatic engineering while apprenticed to Verrocchio, who was, among other things, a hydraulics engineer.
Why this interest in aquatics? From his observations, Leonardo knew water was inherently contradictory. He described it as the vetturale di nature (vessel of nature). It's only fitting that such a force of nature would have intrigued Leonardo. Between about 1485 and 1490, Leonardo developed several schemes for machines that worked in water. One design was for a water pump that could drain an entire port! This pump would have been useful when pylons had to be driven into water, or when a building's foundation had to be built underwater. He also developed pumps that could remove water from a ship (or anyplace else) through a valve.
Leonardo's “Codex Atlanticus” contains many designs for water-controlling devices. For example, he came up with several ideas for sluice gates, or movable panels, that could drop down to divert the flow of a river or canal. He also made detailed three-dimensional sketches for dredges (machines that could clean the bottom of locks and canals), which used mooring ropes to wind up the dredge and force it along the shoreline to the next point.
Some of Leonardo's drawings show machines that use water to achieve another purpose. He sketched a hydraulic saw that used water to power the blade; this device could have been used for cutting logs and other large objects. He also worked on a design that improved the Archimedian screw, an ancient device used to pump water out of a well or uphill. This design was similar to both his helicopter studies and a later waterwheel design. Waterwheels, though developed years before the Renaissance, were of great interest because of their capacity to quickly replenish sup
plies (such as the local water tower) that could be exhausted during battle.
Leonardo also created a water clock, which set off an alarm based on the amount of water flowing from one container to another. At its most basic, the water clock consisted of a stone jar or other container from which water dripped. A second vessel was filled at a continuous rate. As the volume of water increased, people could use markings inside the container to see how much time had passed. It might not have the cachet of an hourglass, but it apparently worked quite well if you didn't mind the sound of dripping water!
65
The ocean liners of the future
Being the all-around inventor that he was, Leonardo tried his hand at designing all sorts of vehicles. He sketched schematics for many types of land- and watercraft, including the world's first paddleboat. His three-dimensional pen-and-ink sketches dating to 1482 show a pointed hull—a smart design idea, since it increased speed and enhanced navigation. He thought that if a boat could be propelled with paddles mounted on a rotating cylinder, the boat could move faster and more smoothly than with oars. His sketches were highly detailed in some places; he specified gears, belts, and large cylinders connecting the entire assembly.
Hull designs for ships were not new—even Stone Age humans figured out how to carve out the inside of a tree and use it for a canoe. Leonardo added his own special flare by improving on existing hull designs in both shape and ergonomics. In addition to a single-hull design, Leonardo sketched out a double hull that would make the ship stronger and better able to ward off enemies. This idea has endured into modern times, double-hull steel ships being quite common. He also worked on ways to resurrect sunken ships, one of which involved attaching tanks filled with air to the sides of a ship. The idea was that after an attack, ships could simply use these tanks to float back to the surface.