Editing Autogyro (section)

== Principle of operation ==

[[File:VPM M-16 engine and rotor.JPG|thumb|left|upright=1|The rotor head, pre-rotator shaft, and [[Subaru]] engine configuration on a VPM M-16 autogyro]]

An autogyro is characterized by a free-spinning rotor that turns because of the passage of air through the rotor from below.<ref name="bensen">{{cite web |url = http://www.gyrocopters.co.uk/html/dr_bensen_explains_all.html |title = How they fly - Bensen explains all |last = Bensen |first = Igor |author-link = Igor Bensen |access-date = 20 April 2014 |archive-url = https://web.archive.org/web/20150109111705/http://gyrocopters.co.uk/html/dr_bensen_explains_all.html |archive-date = 9 January 2015 |url-status = usurped |quote = air ... (is) deflected downward }}</ref><ref name="charLeg">{{cite web |author = Charnov, Bruce H. |url = http://www.hofstra.edu/pdf/ORSP_Charnov_Fall02.pdf |title = Cierva, Pitcairn and the Legacy of Rotary-Wing Flight |archive-url = https://web.archive.org/web/20160303183856/http://www.hofstra.edu/pdf/ORSP_Charnov_Fall02.pdf |archive-date = 3 March 2016 |publisher = [[Hofstra University]] |access-date = 22 November 2011 }}</ref> The downward component of the total aerodynamic reaction of the rotor gives lift to the vehicle, sustaining it in the air. A separate propeller provides forward thrust and can be placed in a puller configuration, with the engine and propeller at the front of the fuselage, or in a pusher configuration, with the engine and propeller at the rear of the fuselage.

Whereas a helicopter works by forcing the rotor blades through the air, drawing air from above, the autogyro rotor blade generates lift in the same way as a [[glider aircraft|glider]]'s wing,<ref name="fmweird">{{cite magazine |url = http://www.flyingmag.com/aircraft/mail-drop-gyroplane-facts |title = Mail Drop: Weird Gyroplane Facts |magazine = Flying Magazine |first = Peter |last = Garrison |author-link = Peter Garrison |date = 2 October 2015 |access-date = 4 October 2015 |quote = The operation of a gyroplane's freewheeling rotor is often compared to that of an autorotating helicopter's ... It's better to think about a glider, because what the gyroplane's rotor blades are doing is gliding around the central mast. |archive-url = https://web.archive.org/web/20200425220702/https://www.flyingmag.com/aircraft/mail-drop-gyroplane-facts/ |archive-date = 25 April 2020 |url-status = live }}</ref> by changing the angle of the air<ref name="bensen" /> as the air moves upward and backward relative to the rotor blade.<ref>{{cite web |url = http://www.phenix.aero/PHE-1210.html |title = Gyrocopter - What is it? |website = Phenix |access-date = 8 December 2010 |url-status = dead |archive-url = https://web.archive.org/web/20101226014001/http://www.phenix.aero/PHE-1210.html |archive-date = 26 December 2010 }}</ref> The free-spinning blades turn by [[autorotation (helicopter)|autorotation]]; the rotor blades are angled so that they not only give lift,<ref name="auto">{{cite encyclopedia |title = Autorotation |website = dictionary.reference.com |edition = unabridged v&nbsp;1.1 |type = definition |publisher = Random House, Inc. |access-date = 17 April 2007 |url = http://dictionary.reference.com/browse/Autorotation |archive-date = 17 March 2012 |archive-url = https://web.archive.org/web/20120317235049/http://dictionary.reference.com/browse/Autorotation |url-status = live }}</ref> but the angle of the blades causes the lift to accelerate the blades' rotation rate until the rotor turns at a stable speed with the drag force and the thrust force in balance.

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| video1 ={{YouTube|XCEYfW8DyxQ |Takeoffs and Landings}} of [[Groen Hawk 4]]
| video2= {{YouTube|nsDQ9avFtng | Jump takeoff}} of [[Pitcairn Aircraft Company#Aircraft|Pitcairn PA-36]] in 1941 <!--[[AHS International]] channel-->
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Because the craft must be moving forward with respect to the surrounding air to force air through the overhead rotor, autogyros are generally not capable of vertical takeoff (except in a strong headwind). A few types such as the [[Air & Space 18A#Design|Air & Space 18A]] have shown short takeoff or landing.

Pitch control is achieved by tilting the rotor [[wikt:fore and aft|fore and aft]], and roll control is by tilting the rotor laterally. The tilt of the rotor can be effected by utilizing a tilting hub ([[Cierva Autogiro Company|Cierva]]), a [[Swashplate (helicopter)|swashplate]] ([[Air & Space 18A]]), or servo-flaps. A [[rudder]] provides [[Yaw (rotation)|yaw]] control. On pusher configuration autogyros, the rudder is typically placed in the propeller [[slipstream]] to maximize yaw control at low airspeed (but not always, as seen in the [[McCulloch J-2]], with twin rudders placed outboard of the propeller arc).{{citation needed|date=April 2015}}