Leonardo da Vinci's swing bridge

Da Vinci drawings brought to life

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Part of Leonardo’s genius lies in the fusion between engineering and art. To have that imagination and combine it with both mechanical understanding and the ability to create meaningful – and beautiful – drawings has inspired engineers for the last half millennium.

Some of Leonardo's inventions were deemed impossible, while many inspired real and recognisable objects that are part of our daily lives, albeit requiring modern materials and technology to make them workable. Here we look at a selection of Leonardo’s drawings and real-life versions created from them.


Inspired once more by nature, Leonardo looked to birds and bats when trying to replicate flight. His early design was essentially a glider and, unlike most of his concepts, is one that could well have worked back in the early 16th century. It had a frame made of pine covered with a membrane of silk, and while it would never get off flat ground it could conceivably have worked if launched from a high place.

Leonardo da Vinci's aeroplane

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To turn it into a flying, rather than a gliding, machine, Leonardo then added flapping action into his plan, a hand crank providing both vertical and twisting motion to resemble a bird’s movement. The ideas were, of course, well ahead of their time, and ultimately no one has been able to usefully replicate nature’s flying beasts – propellers, engines and jets being our own engineering evolutionary path.

Armoured tank

Reportedly Leonardo was a pacifist, yet several of his inventions were designed for military applications. One of them, the armoured tank, was a full 400 years ahead of its time, as tanks weren’t introduced in anger until the First World War. As with many of his inventions, Leonardo was inspired by nature, the turtle in this case. The angle of the shell provided an effectively thicker protective layer (for the same weight) against the cannonballs of the day than vertical sides would have done.

Leonardo da Vinci's armoured tank

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It has been observed that this actual design could not work as the wheel drives are operating against each other. The assumption is that Leonardo did this deliberately in case the design fell into the wrong hands. The wheels are also a bit thin to plough through mud, but perhaps had the device been built such practicalities would have been ironed out. Cannons poke out from under the skirt in all directions.

Ball bearing

One of the backbones of mechanical engineering is the ball bearing, patented by Philip Vaughan, a Welsh inventor, in 1794. It could be argued that it played a critical part in the industrial revolution, or certainly made the ride much smoother. As a consequence almost any modern moving object has less friction to worry about.

Ball bearings had been referenced in Egyptian and Roman times but it was Leonardo who came up with the design that we would recognise now: rollers or balls captured in a cage to reduce the friction between two moving surfaces.

The ball bearing was probably developed for and became part of Leonardo’s helicopter design, but also featured in other of his designs for machines.


Probably Leonardo’s most iconic invention was the helicopter – named his ‘helical air screw’. This machine didn’t quite provide lift in the same way as modern helicopter rotor blades, but the basic theory may have inspired Sikorsky when he developed the first working helicopter in 1939.

Leonardo da Vinci's helicopter

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Leonardo’s device was made principally of reeds and linen and was powered by four men on a platform who used cranks to turn the shaft – though the power they generated would never have been enough to lift the machine. The lighter weight and stronger materials of the 20th century combined with engine power were needed to bring this vision to reality. Another feature of the design was the world’s first ball bearing (see previous item), which reduced friction between the platform and rotating shaft.

Machine gun

Once again this isn’t the work of an obvious pacifist, although apparently Leonardo’s theory was that such a fearsome device would break the enemy’s spirit. The problem he was trying to solve was the time taken to reload guns, and he came up with a number of arrangements to allow individual barrels to be reloaded in sequence or in the case of his 33-barrel ‘organ’, three banks of guns would sequentially fire, cool and reload.

Leonardo da Vinci's machine gun

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However, it took the development of the automatic reloading mechanism in the 19th century to make such devices practical. Like many of Leonardo Da Vinci’s drawings featured here, this was really a concept rather than an invention.

Canal lock gates

Pound locks isolate sections of water in canals so that the level can be raised or lowered to assist boat traffic. They had been used for centuries in Asia but required huge manual effort, as the gates, operating like a portcullis, needed to be moved against the force of the water they were confining. Leonardo invented the mitre lock gate system, which is still in use today. Two gates meet at an angle pointing upstream, so the force of the water pushes them tightly closed. Water is then released using sluices to equalise the levels so the gates can be opened. It is a simple system yet still remains largely unchanged from Leonardo’s blueprint.

Self-propelled cart

A motor car without the motor! Leonardo tried to develop a horseless carriage but came up against the familiar problem of being restricted by the power output from one person. The self-propelled cart used an array of springs that drove a set of gears. After being released, each spring needed to be rewound by the ‘driver’.

Leonardo da Vinci's self-propelled cart

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This driver would also have had steering responsibilities as the front wheel was articulated, although it could be set to go either straight or at a defined angle. This combination of predetermined motion and direction have led some to regard the self-propelled cart as the first robot.

Swing bridge

Bridges became a recurring theme for Leonardo, both for civil infrastructure and military mobility. This one was part of Leonardo’s vision for a city in which canals played an important role for drainage and transport. With 90-degree rotation around a large vertical hinge, the single-span bridge would allow boats to pass along the canal when open. It is operated by an arrangement of ropes, hoists and wheels, and the actual structure has wheels or rollers to enable smoother operation. A counterweight tank also makes it more manoeuvrable.

Leonardo da Vinci's swing bridge

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It wasn’t until 1876 that the first swing bridge was opened for business. The Tyne Swing Bridge was developed by William Armstrong and used hydraulics rather than ropes and winches for its operation.

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