An Encyclopedia of the History of Technology part 67. This one of a kind encyclopedia presents the entire field of technology from rudimentary agricultural tools to communication satellites in this first of its kind reference source. Following an introduction that discusses basic tools, devices, and mechanisms, the chapters are grouped into five parts that provide detailed information on materials, power and engineering, transportation, communication and calculation, and technology and society, revealing how different technologies have together evolved to produce enormous changes in the course of history | PART THREE TRANSPORT 617 in his paper of 1809. Versions of this toy powered by clock springs were made by the Swiss Jakob Degen in 1816 and by several later inventors. In 1842 an English engineer flew a model which was driven by jets of steam generated by the heat from a form of chemical firework from the rotor-tips and in 1863 the Vicomte Ponton d Amecourt built a model helicopter powered by a conventional reciprocating steam engine which was probably too heavy to fly. The Italian engineer Enrico Forlanini succeeded in flying a similar model for 20 seconds in 1877 by the expedient of pre-heating the boiler before attaching it to the model. The first serious attempts to build a full-size piloted helicopter were made in France in 1907 by Louis Breguet and Paul Cornu who were both aiming for a 50 000-franc prize offered for the first one-kilometre flight. Breguet s machine had four biplane rotors driven by a 18kW 24hp Antoinette engine. In September 1907 it hovered for a minute but was stablized by four assistants holding the machine s four corners. Cornu s machine also had an Antoinette engine driving two sets of two-bladed rotors when tested in November it successfully hovered just above the ground for several minutes. Two months later the prize was won by Farman s flight on a fixed-wing Voisin see p. 624 and Breguet and Cornu both abandoned their efforts Breguet turned his attention to fixed-wing machines. For the next thirty years a considerable number of inventors attempted to make a practical helicopter with no significant success. As an alternative to the power-driven rotor the Spaniard Juan de la Cierva produced an aircraft which he called the autogiro. This was a machine on which lift was produced from a rotor which was rotated after the manner of a windmill as the aircraft was pulled through the air by a conventional engine and propeller. In 1923 Cierva built a machine with hinged rotors free to flap up and down as they rotated which provided a
