01/31/2012. Remarks by Ray Watkins: "In 1945 Sikorsky began the design of a new commercial helicopter, the model S-52, to follow the S-51 which had been developed from the R-5D. It had a semi-monocoque metal fuselage with a three-wheeled landing gear and a fully-enclosed cabin for three occupants. It was the first US helicopter with all-metal blades for the main and tail rotors. The S-52 first flew in 1946 and set world records for speed and altitude in 1948.

In 1949 the US Army placed a contract for four test samples of an enlarged version to carry four personnel. The resulting model S-52-2 had a four-wheel landing gear and was given the Army designation of YH-18A. As the Model S-52-3 the type was produced for the USN and USMC, serving as the HO5S-1, and for the USCG, where it served designated HO5S-1G.

The picture shows the first production HO5S-1 for the USMC for whom 79 were produced (BuNos. 125516 to 125527, 126696 to 126705, 128601 to 128620, 130101 to 130137). Eventually 125516 came on the civil register as N6994C, went to Canada where it was registered CF-GWE. Subsequently it returned to the USA and became N9433H. Another HO5S-1, BuNo. 125526, came on the civil registry as N4645S."