Title: Ancient Egyptian chariots: detailed analysis on design and functional aspects.
Author: prof. Alberto Rovetta N. BO-2

Manoeuvrability calls for an optimal track length to wheel diameter ratio. In order to check on this aspect of the chariots a comparison was made with the equivalent ratios of contemporary sulkies, being these vehicles designed with the best technology actually available for races on flat grounds.
The conclusion was drawn that more than three thousand years ago some of the technical and scientific principles used in machine mechanics today were employed with astounding results.

All ancient vehicles, especially those dating before our age, have been lost owing to their wooden structure. An exception are the chariots of the Egyptian Pharaoh Tut Ankh Amun time, seven of which are located in Cairo and one in Florence. The Authors have examined some aspects of the construction of the chariots to show that in those times technical capabilities were extremely developed. In fact, it was necessary to secure the following characteristics: sturdy construction to reach a good speed (around 40 Km/hour), manoeuvrability (especially quick turns), steadiness (avoidance of toppling), durability and comfort. In the years that ancient chariots were built the only material available was wood. Metals were employed only in very limited amounts. It is interesting to note that the choice of different kinds of wood was extremely sophisticated, in particular those employed for the axle arms and naves where the need of endurance is paramount.

Sulkies are built to achieve a net reduction in the horse's energetic cost of locomotion, thereby enabling the horse to travel faster. Being this the purpose, Egyptian chariots can be rated as inferior in design. One of the reasons is that the rider is standing because a greater visibility is required, but at the same time offers more resistance to the air and does not keep his weight down, as he should. Nevertheless it is remarkable that in Australia a sulky called "The Hittite Special" [Walsh] was built according to a modified design derived from a Hittite chariot. The rider was in a sitting position. This sulky performed very well and won races.
One astounding aspect of our comparison between ancient and modern vehicles is the finding that the ratio track/wheel diameter is almost the same. The Egyptian chariot, for those times, was really a masterpiece of technology.

Future possible developments
A real surprise was the discovery that the average pressure on bearings is of the order of 30 kPa (that is 3 grams per mm2). This value is low and also acceptable in modern mechanical systems. It ensures a low consumption and deformation of the parts, and a minimum bending moment of the ankle arm in the nave.