Leonardo da Vinci’s helicopter-like concept used a helical rotor to generate vertical lift.
The helical rotor was the central rotating element of Leonardo’s aerial screw. His drawing shows a spiral surface wrapped around a framework, with people turning a central mechanism. Leonardo reasoned that the screw could press against the air and raise the whole machine, an idea that resembles the lift-producing rotor of a helicopter.
The design should not be confused with a modern propeller. A propeller normally pushes an aircraft forward, while a helicopter rotor produces lift and can also control movement. Leonardo’s continuous spiral surface was also aerodynamically different from the separate blades used on practical rotorcraft.
No evidence shows that Leonardo built or tested the machine. Its proposed power source was insufficient, and the heavy frame and fabric would have prevented useful flight. Even so, the helical rotor demonstrates a specific mechanical approach to vertical flight rather than a general dream of flying.