Helicopter
Helicopter
The helicopter was used as a way of transportation. It was designed in 1493 and was all based on theory.It was never actually built. It looks like an Archimedian screw. If it had been made it would have been powered by four men on a capstan who would push bars around the central shaft when turning the spiral. These days his invention is created and helps much of the United States government. It is also much more modernized.