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

Leonardo da Vinci’s armored vehicle design was powered by cranks and gears.

Drawn around 1487, the vehicle resembles a large conical armored shell mounted on wheels. Several people inside would turn cranks, and a system of gears would transfer their effort to the wheels. The outer covering was intended to protect the crew while allowing weapons to be fired from openings around the vehicle.

The design is often called Leonardo’s tank or fighting vehicle, but it was never built for Renaissance warfare. A frequently discussed problem is that the gearing in the surviving drawing appears to make the vehicle move backward if constructed exactly as shown. Historians and engineers debate whether this was an error, a deliberate security measure, or a consequence of incomplete documentation.

Leonardo’s vehicle was not an engine-powered tank in the modern sense. Its importance lies in combining armor, mobility, and concentrated firepower in one concept. Modern reconstructions generally modify the gearing so that the vehicle can move forward.