Armoured car

the museum model
"I shall make covered chariots, that are safe and cannot be assaulted; cars which fear no great numbers when breaking through the ranks of the enemy and its artillery. Behind them, the infantrymen shall follow, without fearing injury or other impediments"

Leonardo's idea of sowing panic and destruction among the enemy troops was embodied in his design of a tortoise-shaped car, reinforced with metal plates, with an inner turret and armed with guns. The car was to be operated from inside by 8 men, who would turn the cranks to move the wheels. The notes on the drawing show that Leonardo had thought of replacing the men with horses, although he was soon turned off the idea by the thought that the animals might become restive in such a narrow and noisy environment. The firing direction would be decided by the men in the upper part of the car, from where they could see the battlefield through slits or portholes.
Codex Arundel, sheet 1030