Helicopter (English Wikipedia)

Alex de Voogt. The Transmission of Helicopter Technology, 1920-1939: Exchanges with von Baumhauer. Int. j. for the history of eng. & tech., Vol. 83 No. 1, January 2013, 119–40. web extract Archived 25 October 2021 at the Wayback Machine

aerofiles.com (Global: low place; English: 7,155^th place)

"American airplanes:Bell". aerofiles.com. 20 April 2009. Archived from the original on 2 January 2010. Retrieved 23 December 2009.

aerospaceweb.org (Global: 8,491^st place; English: 8,160^th place)

"Helicopter Yaw Control Methods". aerospaceweb.org. Archived from the original on 19 September 2015. Retrieved 1 April 2015.
"Early Helicopter History". Archived 5 December 2004 at the Wayback Machine Aerospaceweb.org. Retrieved: 12 December 2010

af.mil (Global: 439^th place; English: 283^rd place)

nationalmuseum.af.mil

"Sikorsky R-4B Hoverfly". National Museum of the United States Air Force™. Archived from the original on 3 December 2013.

ajdovscina.si (Global: low place; English: low place)

Občina Ajdovščina. "Ivan Slokar – letalski izumitelj, gospodarstvenik, jezikoslovec (1884–1970)". Archived from the original on 4 March 2016. Retrieved 30 March 2016.

archive.today (Global: 14^th place; English: 14^th place)

Skinner, Tony. "Eurosatory 2010: Industry celebrates first helicopter biofuel flight". shephard.co.uk, 17 June 2010. Retrieved 12 December 2010.

aviation-safety.net (Global: 417^th place; English: 408^th place)

"ASN Wikibase Occurrence #76027". Aviation Safety Network. Archived from the original on 4 October 2017. Retrieved 4 October 2017.

aviationtoday.com (Global: 9,924^th place; English: 6,010^th place)

Kay, Marcia Hillary. "40 Years Retrospective: It's Been a Wild Ride" Rotor & Wing, August 2007. Accessed: 8 June 2014. Archived 8 June 2014 at the Wayback Machine.

bbc.com (Global: 20^th place; English: 30^th place)

n/a, n/a (11 May 2018). "Nasa will send helicopter to Mars to test otherworldly flight". BBC. Archived from the original on 6 July 2018. Retrieved 11 May 2018.

books.google.com (Global: 3^rd place; English: 3^rd place)

John M. Seddon, Simon Newman. Basic Helicopter Aerodynamics Archived 30 April 2016 at the Wayback Machine p. 216, John Wiley and Sons, 2011. Retrieved 25 February 2012. ISBN 1-119-99410-1. Quote: "The rotor is best served by rotating at a constant rotor speed"
Croucher, Phil. Professional helicopter pilot studies Archived 27 November 2015 at the Wayback Machine page 2-11. ISBN 978-0-9780269-0-5. Quote: [Rotor speed] "is constant in a helicopter".
Taking Flight: Inventing the Aerial Age, from Antiquity Through the First World War. Oxford University Press. 8 May 2003. pp. 22–23. ISBN 978-0-19-516035-2.
Donald F. Lach. (1977). Asia in the making of Europe. Volume II, A Century of Wonder Archived 15 September 2015 at the Wayback Machine. p. 403
Leishman, J. Gordon (2006). Principles of Helicopter Aerodynamics Archived 25 September 2015 at the Wayback Machine. Cambridge University Press. p. 8. ISBN 0-521-85860-7
"New Helicopter Rises in Vertical Flight". Popular Science. Bonnier Corporation. March 1931. p. 70.
"Helicopter with Six Blades Succeeds in Tests". Popular Mechanics. Hearst Magazines. March 1931. p. 460.
"Twin Turborotor Helicopter". Archived 15 September 2015 at the Wayback Machine Popular Mechanics, August 1954, p. 139.

cavalrypilot.com (Global: low place; English: low place)

"FM 1-514 Chptr 3 – Rotor System Operation". 18 February 2014. Archived from the original on 18 February 2014. Retrieved 3 May 2024.

centennialofflight.net (Global: low place; English: 8,660^th place)

"Helicopters". Centennial Of Flight. American Aviation Historical Society. 2003. Retrieved 6 December 2025.
Day, Dwayne A. "Skycranes" Archived 4 February 2014 at the Wayback Machine. Centennial of Flight Commission. Retrieved 1 October 2008.
Rumerman, Judy. "Early Helicopter Technology". Archived 20 February 2014 at the Wayback Machine Centennial of Flight Commission, 2003. Retrieved 12 December 2010
Rumerman, Judy. "Helicopter Development in the Early Twentieth Century" Archived 20 February 2014 at the Wayback Machine. Centennial of Flight Commission. Retrieved 28 November 2007.
Day, Dwayne A. "Jacques Bréguet—Gyroplane-Laboratoire Archived 24 February 2014 at the Wayback Machine". Paragraph 10. Centennial of Flight. Retrieved 24 September 2015.
Day, Dwayne A. "Igor Sikorsky – VS 300". Archived 20 February 2014 at the Wayback Machine Centennial of Flight Commission, 2003. Retrieved 9 December 2007.

comune.milano.it (Global: 9,808^th place; English: low place)

"Scheda del Parco Forlanini" (in Italian). Comune di Milano. Archived from the original on 21 April 2024. Retrieved 13 March 2024.

defensemedianetwork.com (Global: 9,545^th place; English: 6,077^th place)

"World War II German Helicopters – Flettner Fl 265 and Fl 282". Defense Media Network. Archived from the original on 31 May 2024. Retrieved 31 May 2024.

dtic.mil (Global: 833^rd place; English: 567^th place)

apps.dtic.mil

"Model for Vortex Ring State Influence on Rotorcraft Flight Dynamics" (PDF). Archived (PDF) from the original on 25 February 2014. Retrieved 22 February 2014.

dvidshub.net (Global: 3,349^th place; English: 1,938^th place)

"2nd Battalion, 4th Infantry Regiment honors 33 of their own". dvids. Archived from the original on 12 August 2020. Retrieved 10 February 2020.

dynamicflight.com (Global: low place; English: low place)

Loss of Tail Rotor Effectiveness Archived 4 June 2016 at the Wayback Machine, Dynamic Flight Inc. Accessed 11 May 2016.

ecfr.gov (Global: 5,608^th place; English: 3,261^st place)

[1] (Definitions and Abbreviations) of Subchapter A of Chapter I of Title 14 of the U.S. Code of Federal Regulations

etymonline.com (Global: 287^th place; English: 321^st place)

Harper, Douglas. "helicopter". Online Etymology Dictionary.

europa.eu (Global: 68^th place; English: 117^th place)

easa.europa.eu

"EASA-Annual-Safety-Review-2011" (PDF). Archived (PDF) from the original on 24 March 2014. Retrieved 18 May 2013.

faa.gov (Global: 1,009^th place; English: 607^th place)

Helicopter Flying Handbook, FAA, 2024, Chaper 4 "Helicopter Components, Sections, and Systems" https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/helicopter_flying_handbook

fai.org (Global: 4,927^th place; English: 3,925^th place)

"FAI Record ID #13094 – Straight distance. Class E former G (Helicopters), piston Archived 6 October 2014 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"FAI Record ID #13093 – Straight distance. Class E former G (Helicopters), piston Archived 5 March 2016 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"FAI Record ID #13086 – Straight distance. Class E former G (Helicopters), piston Archived 22 December 2015 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"FAI Record ID #13059 – Straight distance. Class E former G (Helicopters), piston Archived 22 December 2015 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"FAI Record ID #13084 – Altitude. Class E former G (Helicopters), piston Archived 7 February 2015 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"FAI Record ID #13062 – Duration in closed circuit. Class E former G (Helicopters), piston Archived 7 March 2016 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"Record File n°11659". Fédération Aéronautique Internationale. Archived from the original on 3 December 2013. Retrieved 5 June 2013.
"Record File n°784". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°15171". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°754". Fédération Aéronautique Internationale. Archived from the original on 3 December 2013. Retrieved 10 September 2013.
"Record File n°9918". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°9917". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°11597". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 17 August 2012.
"Record File n°15629". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 17 August 2012.

flightglobal.com (Global: 223^rd place; English: 162^nd place)

"Helicopter market report Q3 2018". Flightglobal. 17 October 2018. Archived from the original on 18 October 2018. Retrieved 18 October 2018.

fs.fed.us (Global: 2,133^rd place; English: 1,364^th place)

Butler, Bret W. et al. "Appendix A: Glossary: Fire Behavior Associated with the 1994 South Canyon Fire on Storm King Mountain, Colorado research paper". Archived 2 October 2008 at the Wayback Machine U.S. Dept. of Agriculture, Forest Service, September 1998. Retrieved 2 November 2008.

gama.aero (Global: low place; English: low place)

"GAMA General Aviation Shipment Report 2017" (PDF). General Aviation Manufacturers Association. 21 February 2018. Archived from the original (PDF) on 4 March 2018. Retrieved 4 March 2018.

google.de (Global: 2,106^th place; English: low place)

"Patent US970616 – Flying-machine". Archived from the original on 13 April 2016. Retrieved 30 March 2016.

guinnessworldrecords.com (Global: 550^th place; English: 453^rd place)

"First electric helicopter". Guinness World Record. 4 August 2011. Archived from the original on 17 April 2014. Retrieved 4 August 2011.

helicopter-history.org (Global: low place; English: low place)

Leishman, J. Gordon, Technical Fellow of AHS International. "Paper". Archived 1 October 2008 at the Wayback Machine 64th Annual Forum of the American Helicopter Society International, on the aerodynamic capability of Cornu's design, arguing that the aircraft lacked the power and rotor loading to lift free of the ground in manned flight.

helicopterflight.net (Global: low place; English: low place)

Helicopter pedal turns, LTE and the Critical Wind Azimuth Archived 4 June 2016 at the Wayback Machine, Helicopter Flight Inc, Accessed 11 May 2016.

helicoptervietnam.com (Global: low place; English: low place)

"Helicopters". Archived 11 July 2011 at the Wayback Machine Helicopter Vietnam. Retrieved: 16 February 2011.

helikopterhysteriezwo.blogspot.jp (Global: low place; English: low place)

"Moments in Helicopter History (9) – Hermann Ganswindt". helikopterhysteriezwo.blogspot.jp. Archived from the original on 10 August 2016. Retrieved 23 May 2016.

helis.com (Global: 8,765^th place; English: 6,895^th place)

Fay, John. "Helicopter Pioneers – Evolution of Rotary Wing Aircraft". Archived 7 November 2006 at the Wayback Machine Helicopter History Site. Retrieved: 28 November 2007
"Pioneers – 1900/1930". Archived 4 May 2007 at the Wayback Machine Helicopter History Site. Retrieved: 3 May 2007

heliventuresnc.com (Global: low place; English: low place)

"Helicopter Pilot Training Schools, Careers – Heliventures". heliventuresnc.com. Archived from the original on 2 April 2015. Retrieved 1 April 2015.

idtechex.com (Global: low place; English: low place)

"Challenges of Aircraft Hybridization". IDTechEx. Archived from the original on 24 March 2014. Retrieved 29 April 2013.

imirus.com (Global: low place; English: low place)

accessintelligence.imirus.com

Lombardi, Frank (April 2015). "Under the big top". Rotor & Wing. p. 48. Archived from the original on 13 April 2015. Retrieved 12 April 2015.

imss.fi.it (Global: low place; English: low place)

"Enrico Forlanini" (in Italian). Mille anni di scienza in Italia. Archived from the original on 18 January 2020. Retrieved 13 March 2024.

jstor.org (Global: 26^th place; English: 20^th place)

Hirschberg, Michael J. (1999). "A Perspective on the First Century of Vertical Flight". SAE Transactions. 108: 1120. ISSN 0096-736X. JSTOR 44729509. Archived from the original on 31 May 2024. Retrieved 1 June 2024.

kauaihelicoptertoursafety.com (Global: low place; English: low place)

"Helicopter Accidents in Hawaii". Archived 10 January 2016 at the Wayback Machine kauaihelicoptertoursafety.com. Retrieved: 12 December 2010.

latimes.com (Global: 22^nd place; English: 19^th place)

"Crash Death, 3rd in 8 Years, Not Expected to Halt Future Shows". Los Angeles Times. 3 May 1993. Archived from the original on 6 December 2010. Retrieved 12 December 2010.
"31 U.S. troops, 7 Afghans killed as insurgents down NATO chopper". Los Angeles Times. 6 August 2011. Archived from the original on 7 August 2011. Retrieved 6 August 2011.

liu.se (Global: 9,195^th place; English: 7,457^th place)

ctrl-c.liu.se

Savine, Alexandre. "TsAGI 1-EA". Archived 26 January 2009 at the Wayback Machine ctrl-c.liu.se, 24 March 1997. Retrieved 12 December 2010.

loc.gov (Global: 70^th place; English: 63^rd place)

"The Inventive Wright Brothers" (PDF). Library of Congress. Archived (PDF) from the original on 18 October 2017. Retrieved 29 December 2017.

michaeljohnsonmp.com (Global: low place; English: low place)

Johnson, Pam. Delta D2 Archived 16 February 2011 at the Wayback Machine page 44 Pacific Wings. Retrieved 2 January 2010

milanolinate-airport.com (Global: low place; English: low place)

"L'aeroporto di Milano Linate" (in Italian). Aeroporto di Milano Linate. Archived from the original on 12 March 2024. Retrieved 13 March 2024.

nasa.gov (Global: 75^th place; English: 83^rd place)

nasa.gov

"What Is a Helicopter? (Grades 5-8) NASA". 21 May 2014. Archived from the original on 14 September 2024. Retrieved 18 November 2024.

ntrs.nasa.gov

Wall, Berend G. van der; Harris, Franklin D. (September 2022). "Henrich Focke — Inventor of the First Successful Helicopter" (PDF). ntrs.nasa.gov. Archived (PDF) from the original on 30 March 2023. Retrieved 1 June 2024.

natlib.govt.nz (Global: 2,685^th place; English: 1,516^th place)

paperspast.natlib.govt.nz

"Asboth Helicopter". Archived 25 November 2011 at the Wayback Machine The Evening Post (New Zealand), 27 April 1935.

news.google.com (Global: 59^th place; English: 45^th place)

"Helicoptre Lifts Itself and Man". Youngstown Vindicator. 1 July 1909. Retrieved 23 November 2022.

openlibrary.org (Global: 325^th place; English: 255^th place)

Sto slovenskih znanstvenikov, zdravnikov in tehnikov (Open Library). OL 19750086M.

pilotfriend.com (Global: low place; English: low place)

Pilotfriend.com "Leonardo da Vinci's Helical Air Screw". Archived 24 September 2015 at the Wayback Machine Pilotfriend.com. Retrieved 12 December 2010

planecrashinfo.com (Global: low place; English: low place)

"Accident Details (1982 Nicaragua Mi-8 crash)". PlaneCrashInfo.com. Archived from the original on 29 November 2017. Retrieved 13 April 2018.

popasmoke.com (Global: low place; English: low place)

"Incident Date 19720711 HMM-165 CH-53D 156658+ – Hostile Fire". Marine Corps Combat Helicopter Association (via popasmoke). Retrieved 9 February 2020.
"Incident Date 050126 HMH-361 CH-53D – BuNo unknown – incident not yet classified – near Ar Rutbah, Iraq". Marine Corps Combat Helicopter Association (via popasmoke). 20 November 2007. Archived from the original on 2 July 2010. Retrieved 12 December 2010.

road.cc (Global: low place; English: low place)

"Video: Canadians win long-unclaimed $250,000 prize for pedal-powered helicopter". John Stevenson. 22 July 2013. Archived from the original on 7 March 2014. Retrieved 6 February 2014.

robinsonheli.com (Global: low place; English: low place)

"Safety Notice SN-11" (PDF). Robinson Helicopter Company. October 1982. Archived from the original (PDF) on 11 August 2013. Retrieved 22 February 2014.

rotaryaction.com (Global: low place; English: low place)

"Rotary inaction". rotaryaction.com. Archived from the original on 7 October 2014. Retrieved 27 October 2021.

rotor.org (Global: low place; English: low place)

"HUMS: Not Just for Heavy Iron Anymore". Helicopter Association International. Archived from the original on 19 September 2020. Retrieved 3 December 2020.

si.edu (Global: 340^th place; English: 295^th place)

siris-thesauri.si.edu

"Smithsonian National Air and Space Museum Washington: Zaschka Helicopter (1927)". Archived from the original on 29 May 2016. Retrieved 11 November 2016.

airandspace.si.edu

"Focke-Achgelis Fa 330A-1 Bachstelze (Water Wagtail) | National Air and Space Museum". airandspace.si.edu. Retrieved 31 May 2024.

nasm.si.edu

Connor, R.D; Lee, R.E. (27 July 2001). "Kaman K-225". Smithsonian National Air and Space Museum. Archived from the original on 1 January 2008. Retrieved 9 December 2007.

slovenska-biografija.si (Global: low place; English: low place)

Slovenska akademija znanosti in umetnosti. "Slokar, Ivan (1884–1970)". Archived from the original on 4 March 2016. Retrieved 30 March 2016.

thefreedictionary.com (Global: 614^th place; English: 572^nd place)

"helicopter". The Free Dictionary. Archived from the original on 31 October 2014. Retrieved 30 October 2014.

theguardian.com (Global: 12^th place; English: 11^th place)

"Chechen gets life for killing 127 Russian soldiers". theguardian.com. 30 April 2004. Archived from the original on 22 January 2018. Retrieved 12 November 2021.

time.com (Global: 61^st place; English: 54^th place)

"A Successful Helicopter". Time. 3 March 1923. p. 23. Archived from the original on 11 April 2021. Retrieved 2 March 2021.

tudelft.nl (Global: 7,640^th place; English: 6,190^th place)

lr.tudelft.nl

H.J.G.C. Vodegel and K.P. Jessurun. A Historical Review of Two Helicopters Designed in the Netherlands. 21st European Rotocraft Forum, 1995, Saint Petersburg, Russia. web extract^{[permanent dead link]}

tufts.edu (Global: 155^th place; English: 138^th place)

perseus.tufts.edu

GEN ἕλικος helikos (the κ being romanised as a c); see ἕλιξ and ἕλιξ (as an adjective). Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
πτερόν in Liddell and Scott.

uasweekly.com (Global: low place; English: low place)

"Kawasaki successfully tests the Ninja H2R-powered unmanned helicopter". UASweekly.com. 29 October 2020. Archived from the original on 1 November 2020. Retrieved 31 October 2020.

umd.edu (Global: 1,747^th place; English: 1,277^th place)

terpconnect.umd.edu

Leishman, J. Gordon. Principles of Helicopter Aerodynamics. Cambridge aerospace series, 18. Cambridge: Cambridge University Press, 2006. ISBN 978-0-521-85860-1. "A History of Helicopter Flight". Archived from the original on 13 July 2014. Retrieved 15 July 2014. Web extract

uni-salzburg.at (Global: low place; English: low place)

cs.uni-salzburg.at

The JAviator Quadrotor^{[permanent dead link]} – Rainer K. L. Trummer, University of Salzburg, Austria, 2010, p. 21

usarmyaviation.com (Global: low place; English: low place)

The UH-60 permits 95–101% rotor RPM UH-60 limits Archived 18 August 2016 at the Wayback Machine US Army Aviation. Retrieved 2 January 2010

ushst.org (Global: low place; English: low place)

"USHST Loc-I / UIMC / LALT Final Report" (PDF). U.S. Helicopter Safety Team. October 2017. Retrieved 2 October 2025.
"USHST Helicopter Safety Enhancements". U.S. Helicopter Safety Team. Retrieved 2 October 2025.

vtol.org (Global: low place; English: low place)

Hirschberg, Michael J. and David K. Dailey, "Sikorsky" Archived 18 December 2007 at the Wayback Machine. US and Russian Helicopter Development in the 20th Century, American Helicopter Society, International. 7 July 2000.
"Vertiflite, March/April 2012 – AHS Online Store". Vtol.org. Archived from the original on 24 March 2014. Retrieved 28 April 2013.

web.archive.org (Global: 1^st place; English: 1^st place)

Leishman, J. Gordon, Technical Fellow of AHS International. "Paper". Archived 1 October 2008 at the Wayback Machine 64th Annual Forum of the American Helicopter Society International, on the aerodynamic capability of Cornu's design, arguing that the aircraft lacked the power and rotor loading to lift free of the ground in manned flight.
"helicopter". The Free Dictionary. Archived from the original on 31 October 2014. Retrieved 30 October 2014.
"What Is a Helicopter? (Grades 5-8) NASA". 21 May 2014. Archived from the original on 14 September 2024. Retrieved 18 November 2024.
"FM 1-514 Chptr 3 – Rotor System Operation". 18 February 2014. Archived from the original on 18 February 2014. Retrieved 3 May 2024.
"Helicopter Yaw Control Methods". aerospaceweb.org. Archived from the original on 19 September 2015. Retrieved 1 April 2015.
"Kawasaki successfully tests the Ninja H2R-powered unmanned helicopter". UASweekly.com. 29 October 2020. Archived from the original on 1 November 2020. Retrieved 31 October 2020.
"Jay Leno's EcoJet Concept". businessweek.com, 2 November 2006. Retrieved 12 December 2010.
John M. Seddon, Simon Newman. Basic Helicopter Aerodynamics Archived 30 April 2016 at the Wayback Machine p. 216, John Wiley and Sons, 2011. Retrieved 25 February 2012. ISBN 1-119-99410-1. Quote: "The rotor is best served by rotating at a constant rotor speed"
Croucher, Phil. Professional helicopter pilot studies Archived 27 November 2015 at the Wayback Machine page 2-11. ISBN 978-0-9780269-0-5. Quote: [Rotor speed] "is constant in a helicopter".
Johnson, Pam. Delta D2 Archived 16 February 2011 at the Wayback Machine page 44 Pacific Wings. Retrieved 2 January 2010
"Helicopters". Archived 11 July 2011 at the Wayback Machine Helicopter Vietnam. Retrieved: 16 February 2011.
The UH-60 permits 95–101% rotor RPM UH-60 limits Archived 18 August 2016 at the Wayback Machine US Army Aviation. Retrieved 2 January 2010
Lombardi, Frank (April 2015). "Under the big top". Rotor & Wing. p. 48. Archived from the original on 13 April 2015. Retrieved 12 April 2015.
"Helicopter Pilot Training Schools, Careers – Heliventures". heliventuresnc.com. Archived from the original on 2 April 2015. Retrieved 1 April 2015.
Day, Dwayne A. "Skycranes" Archived 4 February 2014 at the Wayback Machine. Centennial of Flight Commission. Retrieved 1 October 2008.
"Rotary inaction". rotaryaction.com. Archived from the original on 7 October 2014. Retrieved 27 October 2021.
Butler, Bret W. et al. "Appendix A: Glossary: Fire Behavior Associated with the 1994 South Canyon Fire on Storm King Mountain, Colorado research paper". Archived 2 October 2008 at the Wayback Machine U.S. Dept. of Agriculture, Forest Service, September 1998. Retrieved 2 November 2008.
Kay, Marcia Hillary. "40 Years Retrospective: It's Been a Wild Ride" Rotor & Wing, August 2007. Accessed: 8 June 2014. Archived 8 June 2014 at the Wayback Machine.
n/a, n/a (11 May 2018). "Nasa will send helicopter to Mars to test otherworldly flight". BBC. Archived from the original on 6 July 2018. Retrieved 11 May 2018.
"GAMA General Aviation Shipment Report 2017" (PDF). General Aviation Manufacturers Association. 21 February 2018. Archived from the original (PDF) on 4 March 2018. Retrieved 4 March 2018.
"Helicopter market report Q3 2018". Flightglobal. 17 October 2018. Archived from the original on 18 October 2018. Retrieved 18 October 2018.
Leishman, J. Gordon. Principles of Helicopter Aerodynamics. Cambridge aerospace series, 18. Cambridge: Cambridge University Press, 2006. ISBN 978-0-521-85860-1. "A History of Helicopter Flight". Archived from the original on 13 July 2014. Retrieved 15 July 2014. Web extract
"Early Helicopter History". Archived 5 December 2004 at the Wayback Machine Aerospaceweb.org. Retrieved: 12 December 2010
Goebel, Greg. "The Invention of the Helicopter". VectorSite.net. Archived from the original on 29 June 2011. Retrieved 11 November 2008.
Fay, John. "Helicopter Pioneers – Evolution of Rotary Wing Aircraft". Archived 7 November 2006 at the Wayback Machine Helicopter History Site. Retrieved: 28 November 2007
Donald F. Lach. (1977). Asia in the making of Europe. Volume II, A Century of Wonder Archived 15 September 2015 at the Wayback Machine. p. 403
Leishman, J. Gordon (2006). Principles of Helicopter Aerodynamics Archived 25 September 2015 at the Wayback Machine. Cambridge University Press. p. 8. ISBN 0-521-85860-7
Rumerman, Judy. "Early Helicopter Technology". Archived 20 February 2014 at the Wayback Machine Centennial of Flight Commission, 2003. Retrieved 12 December 2010
Pilotfriend.com "Leonardo da Vinci's Helical Air Screw". Archived 24 September 2015 at the Wayback Machine Pilotfriend.com. Retrieved 12 December 2010
"The Inventive Wright Brothers" (PDF). Library of Congress. Archived (PDF) from the original on 18 October 2017. Retrieved 29 December 2017.
"Enrico Forlanini" (in Italian). Mille anni di scienza in Italia. Archived from the original on 18 January 2020. Retrieved 13 March 2024.
"L'aeroporto di Milano Linate" (in Italian). Aeroporto di Milano Linate. Archived from the original on 12 March 2024. Retrieved 13 March 2024.
"Scheda del Parco Forlanini" (in Italian). Comune di Milano. Archived from the original on 21 April 2024. Retrieved 13 March 2024.
"Moments in Helicopter History (9) – Hermann Ganswindt". helikopterhysteriezwo.blogspot.jp. Archived from the original on 10 August 2016. Retrieved 23 May 2016.
"Pioneers – 1900/1930". Archived 4 May 2007 at the Wayback Machine Helicopter History Site. Retrieved: 3 May 2007
"Patent US970616 – Flying-machine". Archived from the original on 13 April 2016. Retrieved 30 March 2016.
Hirschberg, Michael J. and David K. Dailey, "Sikorsky" Archived 18 December 2007 at the Wayback Machine. US and Russian Helicopter Development in the 20th Century, American Helicopter Society, International. 7 July 2000.
Slovenska akademija znanosti in umetnosti. "Slokar, Ivan (1884–1970)". Archived from the original on 4 March 2016. Retrieved 30 March 2016.
Občina Ajdovščina. "Ivan Slokar – letalski izumitelj, gospodarstvenik, jezikoslovec (1884–1970)". Archived from the original on 4 March 2016. Retrieved 30 March 2016.
"FAI Record ID #13094 – Straight distance. Class E former G (Helicopters), piston Archived 6 October 2014 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"A Successful Helicopter". Time. 3 March 1923. p. 23. Archived from the original on 11 April 2021. Retrieved 2 March 2021.
"FAI Record ID #13093 – Straight distance. Class E former G (Helicopters), piston Archived 5 March 2016 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
Rumerman, Judy. "Helicopter Development in the Early Twentieth Century" Archived 20 February 2014 at the Wayback Machine. Centennial of Flight Commission. Retrieved 28 November 2007.
Alex de Voogt. The Transmission of Helicopter Technology, 1920-1939: Exchanges with von Baumhauer. Int. j. for the history of eng. & tech., Vol. 83 No. 1, January 2013, 119–40. web extract Archived 25 October 2021 at the Wayback Machine
"Smithsonian National Air and Space Museum Washington: Zaschka Helicopter (1927)". Archived from the original on 29 May 2016. Retrieved 11 November 2016.
Zaschka, Engelbert (18 May 2016), "^HD Engelbert Zaschka – ein Universalgenie und Erfinder: Musik, Fahrzeuge & Flugzeuge [SWR-Doku 2016]", The Zaschka Innovation, archived from the original on 6 November 2016, retrieved 11 November 2016 – via Youtube.com
"Asboth Helicopter". Archived 25 November 2011 at the Wayback Machine The Evening Post (New Zealand), 27 April 1935.
"FAI Record ID #13086 – Straight distance. Class E former G (Helicopters), piston Archived 22 December 2015 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
Cheryomukhin TsAGI 1-EA (ЦАГИ 1-ЭА) first Soviet helicopter. 30 April 2012. Archived from the original on 29 August 2016. Retrieved 30 March 2016 – via YouTube.
Savine, Alexandre. "TsAGI 1-EA". Archived 26 January 2009 at the Wayback Machine ctrl-c.liu.se, 24 March 1997. Retrieved 12 December 2010.
"FAI Record ID #13059 – Straight distance. Class E former G (Helicopters), piston Archived 22 December 2015 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"FAI Record ID #13084 – Altitude. Class E former G (Helicopters), piston Archived 7 February 2015 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
"FAI Record ID #13062 – Duration in closed circuit. Class E former G (Helicopters), piston Archived 7 March 2016 at the Wayback Machine" Fédération Aéronautique Internationale. Retrieved: 21 September 2014.
Day, Dwayne A. "Jacques Bréguet—Gyroplane-Laboratoire Archived 24 February 2014 at the Wayback Machine". Paragraph 10. Centennial of Flight. Retrieved 24 September 2015.
"American airplanes:Bell". aerofiles.com. 20 April 2009. Archived from the original on 2 January 2010. Retrieved 23 December 2009.
Wall, Berend G. van der; Harris, Franklin D. (September 2022). "Henrich Focke — Inventor of the First Successful Helicopter" (PDF). ntrs.nasa.gov. Archived (PDF) from the original on 30 March 2023. Retrieved 1 June 2024.
Hirschberg, Michael J. (1999). "A Perspective on the First Century of Vertical Flight". SAE Transactions. 108: 1120. ISSN 0096-736X. JSTOR 44729509. Archived from the original on 31 May 2024. Retrieved 1 June 2024.
"World War II German Helicopters – Flettner Fl 265 and Fl 282". Defense Media Network. Archived from the original on 31 May 2024. Retrieved 31 May 2024.
"Sikorsky R-4B Hoverfly". National Museum of the United States Air Force™. Archived from the original on 3 December 2013.
Day, Dwayne A. "Igor Sikorsky – VS 300". Archived 20 February 2014 at the Wayback Machine Centennial of Flight Commission, 2003. Retrieved 9 December 2007.
"Twin Turborotor Helicopter". Archived 15 September 2015 at the Wayback Machine Popular Mechanics, August 1954, p. 139.
Connor, R.D; Lee, R.E. (27 July 2001). "Kaman K-225". Smithsonian National Air and Space Museum. Archived from the original on 1 January 2008. Retrieved 9 December 2007.
"HUMS: Not Just for Heavy Iron Anymore". Helicopter Association International. Archived from the original on 19 September 2020. Retrieved 3 December 2020.
Loss of Tail Rotor Effectiveness Archived 4 June 2016 at the Wayback Machine, Dynamic Flight Inc. Accessed 11 May 2016.
Helicopter pedal turns, LTE and the Critical Wind Azimuth Archived 4 June 2016 at the Wayback Machine, Helicopter Flight Inc, Accessed 11 May 2016.
"EASA-Annual-Safety-Review-2011" (PDF). Archived (PDF) from the original on 24 March 2014. Retrieved 18 May 2013.
"Challenges of Aircraft Hybridization". IDTechEx. Archived from the original on 24 March 2014. Retrieved 29 April 2013.
"Vertiflite, March/April 2012 – AHS Online Store". Vtol.org. Archived from the original on 24 March 2014. Retrieved 28 April 2013.
"Model for Vortex Ring State Influence on Rotorcraft Flight Dynamics" (PDF). Archived (PDF) from the original on 25 February 2014. Retrieved 22 February 2014.
"Safety Notice SN-11" (PDF). Robinson Helicopter Company. October 1982. Archived from the original (PDF) on 11 August 2013. Retrieved 22 February 2014.
"Helicopter Accidents in Hawaii". Archived 10 January 2016 at the Wayback Machine kauaihelicoptertoursafety.com. Retrieved: 12 December 2010.
"Chechen gets life for killing 127 Russian soldiers". theguardian.com. 30 April 2004. Archived from the original on 22 January 2018. Retrieved 12 November 2021.
"Accident Details (1982 Nicaragua Mi-8 crash)". PlaneCrashInfo.com. Archived from the original on 29 November 2017. Retrieved 13 April 2018.
Cooper, Tom (29 September 2003). "Georgia and Abkhazia, 1992–1993: the War of Datchas". acig.org. Archived from the original on 3 March 2008. Retrieved 12 December 2010.
"ASN Wikibase Occurrence #76027". Aviation Safety Network. Archived from the original on 4 October 2017. Retrieved 4 October 2017.
"Crash Death, 3rd in 8 Years, Not Expected to Halt Future Shows". Los Angeles Times. 3 May 1993. Archived from the original on 6 December 2010. Retrieved 12 December 2010.
"31 U.S. troops, 7 Afghans killed as insurgents down NATO chopper". Los Angeles Times. 6 August 2011. Archived from the original on 7 August 2011. Retrieved 6 August 2011.
"2nd Battalion, 4th Infantry Regiment honors 33 of their own". dvids. Archived from the original on 12 August 2020. Retrieved 10 February 2020.
"Incident Date 050126 HMH-361 CH-53D – BuNo unknown – incident not yet classified – near Ar Rutbah, Iraq". Marine Corps Combat Helicopter Association (via popasmoke). 20 November 2007. Archived from the original on 2 July 2010. Retrieved 12 December 2010.
"Record File n°11659". Fédération Aéronautique Internationale. Archived from the original on 3 December 2013. Retrieved 5 June 2013.
"Record File n°784". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°15171". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°754". Fédération Aéronautique Internationale. Archived from the original on 3 December 2013. Retrieved 10 September 2013.
"Record File n°9918". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°9917". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 5 June 2013.
"Record File n°11597". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 17 August 2012.
"Record File n°15629". Fédération Aéronautique Internationale. Archived from the original on 5 January 2015. Retrieved 17 August 2012.
"First electric helicopter". Guinness World Record. 4 August 2011. Archived from the original on 17 April 2014. Retrieved 4 August 2011.
"Video: Canadians win long-unclaimed $250,000 prize for pedal-powered helicopter". John Stevenson. 22 July 2013. Archived from the original on 7 March 2014. Retrieved 6 February 2014.

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GEN ἕλικος helikos (the κ being romanised as a c); see ἕλιξ and ἕλιξ (as an adjective). Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.

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Hirschberg, Michael J. (1999). "A Perspective on the First Century of Vertical Flight". SAE Transactions. 108: 1120. ISSN 0096-736X. JSTOR 44729509. Archived from the original on 31 May 2024. Retrieved 1 June 2024.

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Zaschka, Engelbert (18 May 2016), "^HD Engelbert Zaschka – ein Universalgenie und Erfinder: Musik, Fahrzeuge & Flugzeuge [SWR-Doku 2016]", The Zaschka Innovation, archived from the original on 6 November 2016, retrieved 11 November 2016 – via Youtube.com
The first Hungarian helicopter (1929) on YouTube Retrieved: 12 December 2010.
Cheryomukhin TsAGI 1-EA (ЦАГИ 1-ЭА) first Soviet helicopter. 30 April 2012. Archived from the original on 29 August 2016. Retrieved 30 March 2016 – via YouTube.

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