Leonardo da Vinci drew his sketch of the armored car—part of the Manuscript Popham, located today in the Biblioteca Reale in Torino, Italy—sometime around 1485 in Milan. It's likely that it was presented to the Duke of Milan, and thus appears neat and well laid out (Figure 3-1).
Its carriage was designed to support many light cannons, set up in a 360-degree firing range. For propulsion of the considerable weight, he designed a fancy, geared mechanism with cranks that could be pulled by men or draught animals located inside the carriage. A conical cover made of wood was meant to protect the crew. On top of the whole structure, a sighting turret granted the advantage of having a harbored outlook to the battlefield on a mobile platform.
Like the other engineers and artists during the Renaissance, Leonardo was eager to adopt antiquated ideas, using his inspiration for inventions and enhancements of classical concepts. For example, the armored car adopts the concept of the chariot and the "war tortoise," a rectangular formation of soldiers on the battlefield holding their shields on the side open to attack. When the men in the middle held up their shields above them, the resulting structure was almost impenetrable to the enemy. The small gaps between the shields allowed room for lances or spears.
The tremendous military technology improvements of the 15th century spawned new challenges to contemporary war strategy. With the appearance of fire weapons on the battle fields, usefulness of traditional tactics, weaponry, and fortress architecture rapidly decreased. Strategies became mandatory to integrate the firearms' ever-growing and already immense potential into battle operations and to cope with the threat they imposed both on troops and fortresses.
Figure 3-1. Leonardo's drawing of the armored car
This need became even more urgent as Italy had become Europe's battleground by the end of the 15th century. The factors that had made possible the cultural explosion of the Renaissance in Northern Italy—wealth, peace, being in the heart of European trade, natural resources—also made it a target in the European turf war that shredded the Italian political landscape until the 19th century.
Since 1490, two generations of Italians were faced with continuous war, as the kings of France, England, and Spain, the Pope, and the emperor of the Holy Roman Empire tried to establish control on the "fulcrum of Europe" with legions of mercenaries highly trained for killing.
In this atmosphere of imminent war, engineers and artists like Leonardo spent a lot of their imaginative power for military devices, and their employers were willing to spend enormous sums of money for their real or imaginary military needs.
Though an entrancing vision, Leonardo's armored car was technically unrealizable, according to all authorities, and certainly has never been built. The whole device would have been much too heavy to be moved over an uneven battleground. Any draught animal would have been uncontrollable in the narrow and dark interior once the cannons started firing, and there's even a design flaw in the drawing: the arrangement of the gears would have turned the front and rear wheels in different directions (Figure 3-2).
Note: There is some presumption that the "design flaw" in Leonardo's armored car may have been intentional. It's likely that Leonardo took that measure in order to keep his designs from being stolen.
Figure 3-2. Detail of the armored car’s gearing mechanism
When venturing the task of building any of Leonardo's inventions with LEGO, there's always the particular problem of interpreting the drawings appropriately. Leonardo's figures were mainly meant as mere sketches for internal work, far from being well-formed blueprints or building instructions comprehensible for other people.
This is the case with the sketch of the armored car; many of the details are left to the speculation of the beholder. Yet, we are lucky because modern computer-aided design (CAD) tools have been able to create 3D computer models of many of Leonardo's inventions, although the results still require a good deal of interpretation. But they are still much better than trying to refer to the often obscure and fragmentary originals.
The comprehensive Leonardo3 web site (www.leonardo3.net) with a wealth of information on Leonardo and his inventions includes many computer-generated images. Also, particularly helpful to me is the book Leonardo's Machines: Da Vinci's Inventions Revealed by Domenico Laurenza, Mario Tadei, and Edoardo Zanon (David & Charles Publishers, 2006), a magnificent folio with an abundance of 3D CAD images, exploded views, and background information.
How will you mimic the gearing mechanism with LEGO? How will you integrate the NXT motors in the propulsion chain? Figures 3-3 and 3-4 show a possible solution.
Figure 3-3. The armored car's gearing mechanism rebuilt with LEGO
Figure 3-4. Attachment of a motor to the axis that drives the gearing