Largest rotor system

The XH-17, known as the Flying Crane, was the first helicopter project for the Hughes Aircraft Company, USA. Constructed in largely a mish-mash of parts from other aircraft types, it first flew on 23 October 1952 but eventually proved too cumbersome and inefficient for series production and was retired in 1955. With a rotor diameter of 129 feet and 11 inches (39.62 metres), its main claim to fame was that it flew with what was, and still is, the world’s largest rotor system ever fitted to a helicopter. Note: Some sources give a diameter of 134 feet. I have used the more conservative number – it is still a record.