"A moved part will draw no benefit from having greater power than the force resisting it. However, if the power of the moving agent is equal to the power of the part it moves, the moved part will greatly benefit from its motion"
These models have been made to highlight Leonardo's remarkable intuition on the effect of air on projectiles fired by cannons. Although he doesn't develop a mathematical theory on trajectory, he has correct intuitions on the attrition action of the air and the importance of an aerodynamic shape to ensure trajectory stability and firing efficiency: thus the projectiles have a modern shape and wings.
The model is based on the drawing:
- Codex Arundel f. 54 r. (1500-1505)
London, British Library