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The Kaman K-MAX (Company designation K-1200) is an American helicopter with intermeshing rotors (synchropter) built by Kaman Aircraft. It is optimized for external cargo load operations, and is able to lift a payload of over 6,000 pounds (2,722 kg), which is more than the helicopter's empty weight. A remote controlled unmanned aerial vehicle version is being developed and is being evaluated in extended practical service in the war in Afghanistan. In June 2015, Kaman announced restarting the K-MAX production due to 10 commercial orders.〔(Kaman restarts K-Max production on new commercial orders ) Flightglobal〕 First deliveries are planned early 2017.〔(Kaman Resumes Commercial K-MAX Helicopter Production ) Helis〕 ==Development== In 1947 Anton Flettner, a former German teacher and inventor, was brought to the United States as part of Operation Paperclip. He was the developer of the two earlier synchropter designs from Germany during World War II: the Flettner Fl 265 which pioneered the synchropter layout, and the slightly later Flettner Fl 282 "Kolibri" (Hummingbird), intended for eventual production. Both designs used the principle of counter-rotating side-by-side intermeshing rotors, as the means to solve the problem of torque compensation, normally countered in single–rotor helicopters by a tail rotor, fenestron, NOTAR, or vented blower exhaust. Flettner remained in the United States and became the chief designer of the Kaman company.〔("Anton Flettner"; Hubschraubermuseum Bückeburg )〕 He started to design new helicopters, using the Flettner double rotor. The K-MAX series are the latest in a long line of Kaman synchropters, the most famous of which is the HH-43 Huskie. The first turbine-powered helicopter was also a Kaman synchropter.〔("Twin Turborotor Helicopter" ). ''Popular Mechanics'', August 1954, p. 139.〕 The K-1200 K-MAX "aerial truck" is the world's first helicopter specifically designed, tested, and certified for repetitive external lift operations and vertical reference flight (Kaman received IFR Certification in 1999), an important feature for external load work. Other rotorcraft used for these tasks are adapted from general-purpose helicopters, or those intended to primarily carry passengers or internal cargo. The K-MAX can lift almost twice as much as the Bell 205 using about the same engine. The aircraft's narrow, wedge-shaped profile and bulging side windows give the pilot a good view of the load looking out from either side of the aircraft. The transmission has a reduction ratio of 24:1 in three stages, and is designed for unlimited life.〔'K-MAX Intermeshing Rotor Drive System' 53rd Annual Forum Proc., AHH, 1997.〕 The rotor blades (turning breaststroke style)〔 are built with a wooden spar and fiberglass trailing edge sections. Wood was chosen for its damage tolerance, fatigue resistance and to take advantage of field experience and qualification data amassed from a similar spar on the HH-43 helicopter, built for the U.S. Air Force in the 1950s and 1960s.〔('Composites take off ... in some civil helicopters.' ) 1 March 2005. Retrieved: 26 June 2011.〕 The pilot controls blade pitch with tubes running inside the mast and rotor blades to move servo flaps that pitch the blades,〔Chandler, Jay. "(Advanced rotor designs break conventional helicopter speed restrictions (p. 2) )" . ''ProPilotMag'', September 2012. Accessed: 10 May 2014. (Archive 2 )〕 reducing required force and avoiding the added weight, cost and maintenance of hydraulic controls.〔 The K-MAX relies on two primary advantages of synchropters over conventional helicopters: The increased efficiency compared to conventional rotor-lift technology; and the synchropter's natural tendency to hover. This increases stability, especially for precision work in placing suspended loads. At the same time, the synchropter is more responsive to pilot control inputs, making it possible to easily swing a load, or to scatter seed, chemicals, or water over a larger area. A K-MAX has been used for demolition work by having a wrecking ball as a slung load. Thirty-eight K-1200 K-MAX helicopters have been built.〔 As of January 2015, 11 of these were not airworthy or have been written off in accidents, 5 are in Limbo at Kaman,〔(The Kaman K-MAX Current Status ) SwissHeli.com by Markus Herzig〕〔http://www.sust.admin.ch/pdfs/AV-berichte//2142_e.pdf〕 and in March 2015 the number of operational K-MAXes was 21.〔 The production line was shut down in 2003, but may restart if the U.S. Marine Corps orders more autonomous K-MAXs. In February 2014, Kaman revisited the idea of resuming K-MAX production, having recently received over 20 inquiries for firefighting, logging or industry transport requirements additionally to requests for the military unmanned version.〔(Kaman Aerospace Soliciting Interest in New K-MAX® Production ) Businesswire〕〔(Heli-Expo 2014: Kaman looks to restart K-MAX production ) Shephardmedia〕 Ten firm orders may convince Kaman to produce K-MAX again.〔Head, Elan. "(Production potential )" p. 44 ''Vertical Magazine'', April/May 2014. Accessed: 8 July 2014.〕 Kaman has received deposits, and if enough orders come through, deliveries could occur by 2017 at a production rate of one per 6-8 weeks.〔 The K-MAX line has flown 300,000 hours as of 2014, and costs $1,200 per flight hour to operate.〔 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「Kaman K-MAX」の詳細全文を読む スポンサード リンク
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