|
A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight. Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which connects through a combination of drive shaft(s) and gearboxes along the tail boom. The blade pitch is typically controlled by a swashplate connected to the helicopter flight controls. Helicopters are one example of rotary-wing aircraft (rotorcraft). ==History and development== The use of a rotor for vertical flight has existed since 400 BC in the form of the bamboo-copter, an ancient Chinese toy.〔Leishman, J. Gordon. ''Principles of Helicopter Aerodynamics''. Cambridge aerospace series, 18. Cambridge: Cambridge University Press, 2006. ISBN 978-0-521-85860-1. pp. 7-9. (Web extract )〕 The bamboo-copter is spun by rolling a stick attached to a rotor. The spinning creates lift, and the toy flies when released.〔 The philosopher Ge Hong's book the ''Baopuzi'' (Master Who Embraces Simplicity), written around 317, describes the apocryphal use of a possible rotor in aircraft: "Some have made flying cars (飛車 ) with wood from the inner part of the jujube tree, using ox-leather (straps) fastened to returning blades so as to set the machine in motion."〔Joseph Needham (1965), ''Science and civilisation in China: Physics and physical technology, mechanical engineering'' Volume 4, Part 2, page 583-587.〕 Leonardo da Vinci designed a machine known as an "aerial screw" with a rotor based on a water screw. The Russian polymath Mikhail Lomonosov developed a rotor based on the Chinese toy. The French naturalist Christian de Launoy constructed his rotor out of turkey feathers.〔 Sir George Cayley, inspired by the Chinese toy in his childhood, created multiple vertical flight machines with rotors made of tin sheets.〔 Alphonse Pénaud would later develop the coaxial rotor model helicopter toys in 1870, powered by rubber bands. One of these toys, given as a gift by their father, would inspire the Wright brothers to pursue the dream of flight. Before development of powered helicopters in the mid 20th century, autogyro pioneer Juan de la Cierva researched and developed many of the fundamentals of the rotor. De la Cierva is credited with successful development of multi-bladed, fully articulated rotor systems. This system, in its various modified forms, is the basis of most multi-bladed helicopter rotor systems. The first successful attempt at a single-lift rotor helicopter design used a four-blade main rotor, as designed by Soviet aeronautical engineers Boris N. Yuriev and Alexei M. Cheremukhin, both working at the ''Tsentralniy Aerogidrodinamicheskiy Institut'' (TsAGI, the Central Aerohydrodynamic Institute) near Moscow in the early 1930s. Their TsAGI 1-EA helicopter was able to fly in low altitude testing in 1931-32, with Cheremukhin flying it as high as 605 meters (1,985 ft) by mid-August 1932.〔(video ).〕〔Savine, Alexandre. ("TsAGI 1-EA." ) ''ctrl-c.liu.se,'' 24 March 1997. Retrieved 12 December 2010.〕 In the 1930s, Arthur Young improved the stability of two-bladed rotor systems with the introduction of a stabilizer bar. This system was used in several Bell and Hiller helicopter models. The Hiller system variant using airfoiled paddles at the flybar's ends has been used in many of the earliest designs of remote control model helicopters, from their 1970s origins onwards to the very early 21st century. In the late 1940s, the making of helicopter rotor blades was a job that inspired John T. Parsons to be a pioneer of numerical control (NC). NC and CNC turned out to be an important new technology that later affected all machining industries. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Helicopter rotor」の詳細全文を読む スポンサード リンク
|