Diferencia entre revisiones de «Boeing A160 Hummingbird»

El rotor del ''A160'' incluye palas cuyas rigidez y sección transversal varían con su longitud. Su baja carga y diseño rígido le permiten cambiar las RPM entre 140 y 350<ref name=pmA160>[http://www.popularmechanics.com/technology/military/robots/the-rise-of-the-drone-helicopter#fbIndex3 The Rise of the Drone Helicopter - A160T Hummingbird] {{wayback|url=http://www.popularmechanics.com/technology/military/robots/the-rise-of-the-drone-helicopter#fbIndex3 |date=20140820050027 }} ''[[Popular Mechanics]]''. Accessed: February 2011.</ref> using a [[Transmission (mechanics)#Multi-ratio systems|two-speed transmission]]<ref name=trimb/><ref>"[http://boeing.mediaroom.com/index.php?s=20295&item=495 Boeing A160T Unmanned Rotorcraft Shifts Gears in Flight, Passes 100 Flight-Hours] {{wayback|url=http://boeing.mediaroom.com/index.php?s=20295&item=495 |date=20160304051315 }}" ''Boeing'', 18 December 2008. Accessed: May 2014. [http://www.deagel.com/news/Boeing-A160T-Unmanned-Rotorcraft-Shifts-Gears-in-Flight-Passes-100-Flight-Hours_n000005467.aspx Mirror] {{wayback|url=http://www.deagel.com/news/Boeing-A160T-Unmanned-Rotorcraft-Shifts-Gears-in-Flight-Passes-100-Flight-Hours_n000005467.aspx |date=20160304192741 }}</ref> usando una [[Caja de cambios|transmisión de dos velocidades]] para optimizar la eficiencia a diferentes velocidades y altitudes, una técnica llamada "tecnología de rotor de velocidad óptima", inventada por Abe Karem.<ref name=goli>Golightly, Glen. "[http://www.boeing.com/news/frontiers/archive/2004/december/ts_sf04.html Boeing's Concept Exploration pioneers new UAV development with the Hummingbird and the Maverick]" ''Boeing Frontiers'', 2004. Accessed: May 2014. [http://web.archive.org/web/20130517102310/http://www.boeing.com/news/frontiers/archive/2004/december/ts_sf04.html Archive]</ref><ref>[https://www.google.com/search?tbo=p&tbm=pts&hl=en&q=ininventor:%22Abe+Karem%22 List of Karem patents]</ref> Es por estas características principalmente por lo que el Hummingbird puede volar con menos potencia (y por lo tanto usa menos combustible) que los helicópteros convencionales comparables,<ref name=put/> con sólo ajustar el paso de las palas y mantener el rotor a unas rpm constantes.<ref name=crouch>Croucher, Phil. [https://books.google.com/books?id=AovdKRWSqJAC&printsec=frontcover&dq=%22Professional+Helicopter+Pilot+Studies%22&hl=da&ei=LYZ4TdmcDMjRsgbj56TyBw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CD8Q6AEwAA#v=onepage&q&f=true Professional helicopter pilot studies] {{wayback|url=https://books.google.com/books?id=AovdKRWSqJAC&printsec=frontcover&dq=%22Professional+Helicopter+Pilot+Studies%22&hl=da&ei=LYZ4TdmcDMjRsgbj56TyBw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CD8Q6AEwAA#v=onepage&q&f=true |date=20160914142250 }} page 2-11. ISBN 978-0-9780269-0-5. Quote: [Rotor speed] "is constant in a helicopter".</ref><ref>The [[Sikorsky UH-60 Black Hawk|UH-60]] permits 95–101% rotor RPM [http://www.usarmyaviation.com/studyguides/index.php?folder=Documents/UH-60BlackhawkSpecific&download=Uh60limits.doc UH-60 limits] {{wayback|url=http://www.usarmyaviation.com/studyguides/index.php?folder=Documents/UH-60BlackhawkSpecific&download=Uh60limits.doc |date=20160818162950 }} ''[[US Army Aviation]]''. Accessed: 2 January 2010</ref><ref name=newman>John M. Seddon, Simon Newman. [https://books.google.dk/books?id=X_X3nOODGLgC&printsec=frontcover&hl=da Basic Helicopter Aerodynamics] {{wayback|url=https://books.google.dk/books?id=X_X3nOODGLgC&printsec=frontcover&hl=da |date=20161011083351 }} p216, ''John Wiley and Sons'', 2011. Accessed: 25 February 2012. ISBN 1-119-99410-1. ''Quote: The rotor is best served by rotating at a constant rotor speed''</ref><ref name=beck>Robert Beckhusen. "[http://www.wired.com/2012/06/hummingbird/#more-84749 Army Dumps All-Seeing Chopper Drone]" ''[[Wired (website).com|Wired]]'' June 25, 2012. Accessed: 12 October 2013. ''Quote: for standard choppers .. the number of revolutions per minute is also set at a fixed rate''</ref><ref name=trimb/>