Sikorsky H-5 (English Wikipedia)

"Rotary Wing". United States Army Aviation Museum. Army Aviation Museum Foundation, Inc. Archived from the original on 5 November 2016. Retrieved 25 May 2016.

asmac.ab.ca

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"SIKORSKY S-51 DRAGONFLY". muzej vazduhoplovstva beograd. Retrieved 3 November 2018.

"HO3S". National Naval Aviation Museum. Naval Aviation Museum Foundation. Retrieved 25 May 2016.

"Sikorsky S-51 (H-5A) 'Executive Transport'". New England Air Museum. Retrieved 25 May 2016.

"DRAGONFLY". Pima Air & Space Museum. Pimaair.org. Archived from the original on 30 June 2016. Retrieved 25 May 2016.
"DRAGONFLY". Pima Air & Space Museum. Pimaair.org. Retrieved 25 May 2016.

"Building 5: Helicopters and last propeller fighter." Archived 6 June 2011 at the Wayback Machine Royal Thai Air Force Museum. Retrieved: 11 January 2011.

"Sikorsky XR-5". Smithsonian National Air and Space Museum. Archived from the original on 24 June 2016. Retrieved 25 May 2016.

"S-48/R-5 Helicopter". sikorskyarchives.com. 2012. Retrieved 26 July 2016.
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Close, Robert A. (Cmdr). "Helo Operations". U.S. Naval Academy Alumni Association & Foundation. Archived from the original on 14 February 2012. Retrieved 25 October 2019.

Petite, Bob (16 November 2018). "The first operator: Helicopter Air Transport". www.verticalmag.com. MHM Publishing. Retrieved 21 October 2019.

"What Happens When You Mail a Letter." Archived 5 February 2012 at the Wayback Machine Popular Science, December 1951.
Close, Robert A. (Cmdr). "Helo Operations". U.S. Naval Academy Alumni Association & Foundation. Archived from the original on 14 February 2012. Retrieved 25 October 2019.
"Sikorksy H-5". canadianwings.com. Archived from the original on 21 October 2014. Retrieved 18 October 2014.
"Building 5: Helicopters and last propeller fighter." Archived 6 June 2011 at the Wayback Machine Royal Thai Air Force Museum. Retrieved: 11 January 2011.
"Rotary Wing". United States Army Aviation Museum. Army Aviation Museum Foundation, Inc. Archived from the original on 5 November 2016. Retrieved 25 May 2016.
"Sikorsky XR-5". Smithsonian National Air and Space Museum. Archived from the original on 24 June 2016. Retrieved 25 May 2016.
"DRAGONFLY". Pima Air & Space Museum. Pimaair.org. Archived from the original on 30 June 2016. Retrieved 25 May 2016.
"Helicopters." Archived 29 June 2012 at the Wayback Machine Evergreen Aircraft & Space Museum. Retrieved: 27 October 2012.
"A80 Sikorsky S-51". RAAF Museum. Archived from the original on 29 March 2022.