A scale model of Leonardo da Vinci's aerial screw, pictured here in an exhibit at the Sofia City Art Gallery in Bulgaria, gives visitors a glimpse of one of the inventors' most famous schemes for a flying machine. Sketched in 1493, the design called for a spiral-shaped, rotating surface made from iron wire and linen made "airtight with starch," and powered by a human passenger, according to the U.S. Centennial of Flight Commission report on early helicopter technology.
The screw, also known a the "air gyroscope," is credited as the first rotary-wing aircraft concept, but Leonardo's design would have been a flightless bird. According to the Centennial of Flight Commission, muscle power "would never have been sufficient to operate a helicopter successfully . . . there was no way to deal with the torque created by the propeller."
Read More
