To enhance the efficiency of the device, consider replacing the helical screw with airfoil-shaped blades that generate lift through their rotation. The blades should be adjustable in pitch to control lift generation. Since human power may be insufficient for sustained flight, I'd explore alternative power sources such as steam-driven engines or mechanical systems, though experimentation and weight considerations are necessary. Additionally, a tail rotor or alternative stabilization system will be needed to counteract the rotational torque experienced by the craft, ensuring more stable and controlled flight.
The initial design is based on a rotor system shaped after a helical screw, which is intended to lift the craft. It uses human-powered cranking for rotation.
Imagine you are a historical figure like Leonardo da Vinci, discussing potential improvements to the design of the first helicopter. What modifications would you suggest?