Sikorsky R-4

Sikorsky R-4 (USA mereväes ja rannavalves Sikorsky HNS-1, Suurbritannias Hoverfly) on kahekohaline, kolmeharulise rootori ja radiaalmootoriga Ameerika Ühendriikide helikopter, mille konstrueeris Igor Sikorski. R-4 oli esimene masstoodetud ning esimene Ameerika Ühendriikide armee õhuvägede, mereväe, rannavalve ja Suurbritannia kuningliku õhuväe ning mereväe poolt kasutusse võetud helikopter.

Kasutajad

Vaata ka
 Vought-Sikorsky VS-300
 Sikorsky H-5
 Focke-Achgelis Fa 223 Drache
 Flettner Fl 282
 Platt-LePage XR-1

Viited

Kirjandus
 Cocker, Maurice. Aircraft-Carrying Ships of the Royal Navy. Stroud, Gloucestershire, UK: The History Press, 2008 .
 

 McGowen, Stanley S. Helicopters: An Illustrated History of Their Impact (Weapons and Warfare Series). Santa Barbara, CA: ABC-CLIO, 2005. .
 
 Myall, Eric and Ray Sturtivant (ed.). The Hoverfly File. Tunbridge Wells, Kent, UK: Air-Britain (Historians) Ltd., 1998. .
Sturtivant, Ray. RAF Flying Training and Support Units since 1912, Air-Britain (Historians), England, 2007, 
 United States Air Force Museum Guidebook. Wright-Patterson AFB, Ohio: Air Force Museum Foundation, 1975.
 Williams, Dr. James W. A History Of Army Aviation: From Its Beginnings To The War On Terror. Bloomington, IN: Iuniverse, 2005. .

Välislingid
 Sikorsky S-47/R-4 page at the Sikorsky Archives
 Sikorsky R-4 page at the National Museum of the United States Air Force
 RAF Museum Sikorsky R4 Hoverfly webpage
 Photo gallery of Sikorsky R-4B Hoverfly I
 Freeman AAF contains the story of America's first Helicopter School
 HELIS.com Sikorsky R-4/HNS-1/Hoverfly I Database
 New-England Air Museum R-4 exhibit Google street view

Sõjaväehelikopterid