Between 1487 and 1490, Italian inventor Leonardo da Vinci came up with the concept of the aerial screw, also known as the flying machine, flying propeller, or helicopter. From the perspective of aviation, rotorcraft history, and the history of other rotary wings, Leonardo da Vinci’s aerial screw ranks among the first aeronautical propeller and helicopter prototypes. Da Vinci’s aerial screw gave inspiration to the further research and development of aerial crafts, which only happened centuries later.
Leonardo sketched many aircraft: a parachute, an ornithopter, a hang glider, and the aerial screw.
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History of the Aerial Screw
While working as a military engineer for the Duke of Milan, Ludovico Sforza, Leonardo da Vinci considered the possibility of the first human flight after his studies of perpetual motion, his spring-powered cart of 1478, and his da Vinci Tank of 1485.
In his Codex Atlanticus and the Codex on the Flight of Birds, Leonardo detailed his extensive aeronautical research on bionic ornithopters between 1485 and 1490, specifically with the parachute and gliding flight of birds of prey.
After a string of failed trials, da Vinci switched his focus from studying ornithopters with oscillating wings to those with fixed, gliding wings. The Chinese bamboo-copter from 320 AD (which reached Europe during its lifetime) and Archimedes’ screw from the 3rd century BC (used since antiquity to raise water) led Leonardo to create the aerial screw.
Construction of the Aerial Screw
The aerial screw consisted of a conical propeller screw on a rigid linen canvas for gliding.
A steel blade-escape spring served as the main axis of Leonardo’s aerial screw prototype. It was based on his self-propelled cart of 1478, which operated on a clockwork principle.
There was also a long, strong, flexible reed armature cable, and the whole device was reassembled like a monster crossbow or a capstan catapult with four handspikes (a lever for prying or leverage).
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How Did the Aerial Screw Work?
The top part of the pole acts as the central axis for a big, starched linen sail with a 16 to 33 feet (10 to 16 m) radius that spins around it. A revolving ring on the bottom platform is attached to the outside edge of the sail, which is rotated clockwise around the shaft. The plan called for a crew of many people to take turns turning the sail.
It was the first time that a rotor in the form of a spiral was applied to flight.
According to da Vinci’s notes, “The armature underpinning the above canvas will be made of long, strong reeds; a small paper model can be made with a thin steel blade as the axis, forcibly subjected to a twisting movement; when freed, it turns the propeller.”
Among others, the following contemporary theories have been influential on Leonardo in creating the aerial screw, as he explains them in his notebooks:
- “If this Archimedes’ screw can force water to move against its natural direction, i.e., from bottom to top, it’s likely that a suitable screw can move in the same way in the other fluid that surrounds us, air.”
- “The force with which a thing moves against air is equal to the force of air against the thing.”
In the Paris Manuscript B of the Manuscripts of the Institut de France (“Institute of France”) from 1487–1490, Leonardo da Vinci included the following annotations in reverse-coded writing beside his depiction of the aerial screw (Ms B, f.83 v):
- “Let the end of the screw be an iron cable the size of a rope, and from the center to the circle there are 8 fathoms [6 feet / 1.8 m)].”
- “If this instrument, which has the shape of a screw, is well made, that is to say, made of linen cloth whose pores are clogged with starch, and if it is rotated rapidly, I estimate that this screw will make its nut in the air and it will rise. Take the example of a wide, thin ruler violently moved through the air; you will see that your arm follows, in its movement, the edge of this board.”
The documents seized by Napoleon Bonaparte in 1795 from the Ambrosian Library included a sketch of this flying machine on the verso of the 83rd Paris Manuscript B.
Aerial Screw’s Significance
The principle of propeller-driven aircraft flight was truly visionary for its time, when the only available propulsion power was that of humans, animals, or natural muscular propulsion. The available mechanical devices included capstans, levers, tackles, gears, sprockets, springs, or pulleys, but they were also largely insufficient to feed this revolutionary, visionary idea.
In order to put Leonardo da Vinci’s research on aeronautical lift into practice, it would need the invention of powerful engines in the 19th century, more than 300 years after the aerial screw.
Flaws of the Aerial Screw
When the original drawing in manuscript B is analyzed, the aerial screw concept calls for a canvas spiral with a diameter of 16 to 33 feet (10 to 16 m). It’s unclear how this spiral rotor could be designed to turn quickly, given that it would have to bear the weight of the machine and its ultimate pilot.
If every little hole in the canvas were sealed, it would be impermeable but still not very resistant. There was no mechanism to prevent the craft from turning the other way when Leonardo developed miniature flying versions of the aerial screw.
Unfortunately, there were not enough lightweight and robust materials available, nor was there a strong enough drive for the screw, to make a full-scale implementation practicable.
Leonardo da Vinci’s aerial screw sketch is best understood as the theoretical expression of a concept that will eventually be implemented in practical forms like the helicopter and the propeller.
Legacy of the Aerial Screw
More than 300 years after Leonardo da Vinci’s aerial screw, French inventor Frederic Sauvage patented marine propellers for the first time in 1832. It was used on the paddle steamer for the first time around 1880.
The Daimler Airship, Gottlieb Daimler’s first motorized airship design from 1888 with the first single-cylinder Daimler gas engine, used a cloth propeller to successfully lift off the ground.
Inspired by this and the Chinese bamboo-copter of the 4th century, French inventors Gustave de Ponton d’Amecourt and Gabriel de La Landelle created their propeller with a counter-rotating rotor (which they dubbed “hélicoptère”) in 1861. It had two aerial propellers in a coaxial arrangement and a rotor that rotated in opposite directions (contra-rotating or coaxial rotors).
In 1933, the French aviator Louis Charles Breguet built the Bréguet-Dorand Gyroplane Laboratoire. The Gyroplane Laboratoire is widely regarded as the world’s first operational helicopter in history.
A Drone Based on the Aerial Screw
A drone built using Leonardo’s aerial screw design made its first flight in 2022. This drone was propelled by the same flying machine concept developed by the great polymath.
References
- Paris, Institut de France, Leonardo da Vinci, Manuscript B, f. 10v (MS… – Researchgate.net
- It’ll Never Work: Planes and Helicopters – Google Books
- Leonardo Da Vinci, 1452-1519 – Google Books
