US Army Air Force 43-46560 when delivered in 1944, this Hoverfly was transferred to the US Coast Guard (who had trained pilots and and mechanics with the type 1943 - 45) in 1946. Working for a time as a cropduster after 1948, the helicopter was acquired by the National Naval Aviation Museum in 1984.

'The first helicopter to land at NAS South Weymouth.' Originally commissioned as an R-4B, US Army serial 43-46576. Note the blimp mooring masts and hangar. Photo from: National Archives at Boston

On 18 September 1946, Sabena DC-4 OO-CBG crashed 35 km (22 miles) southwest of Gander on a transatlantic proving flight. Two USCG helicopters, a HOS-1 and this HNS-1, were airlifted to Gander, reassembled and test-flown within 48 hours. The helicopters took survivors from the crash site to the shore of Gander Lake where they were transferred to a PBY Catalina, 48314. 051 is BuNo 39051, originally commissioned as an R-4B, 43-46586. Photo from: US Coast Guard

Rescue helicopter pioneer Cdr Frank Erickson, US Coast Guard, demonstrating a Sikorsky HNS-1, originally ordered as an R-4B, US Army serial 43-46544. Photo by: Rudy Arnold / Smithsonian Institution

Ex USAAF R-4B Hoverfly I 43-46560 transferred to the US Navy and designated HNS-1 and operated by the US Coast Guard.