In Leonardo da Vinci’s tank design, what powered the vehicle’s movement?

Leonardo da Vinci’s tank design was powered by cranks turned by people.

Leonardo drew the fighting vehicle in about 1487 for the ruler Ludovico Sforza. The machine had a conical, turtle-like armored shell with sloping surfaces intended to deflect missiles. Several men inside would turn cranks connected to the wheels, allowing the vehicle to move across the battlefield.

The design is commonly called Leonardo’s tank, although it was not a modern tank. It had no combustion engine, turret, or practical suspension system. Some reconstructions have also noted that the gearing shown in the drawing appears to make the vehicle difficult or impossible to drive as illustrated; this may have been an error or a deliberate concealment.

Leonardo’s proposal combined protection, mobility, and weapons in one machine. That combination resembles the basic idea of later armored fighting vehicles, but the Renaissance design was never built for combat.