ModelVideos US Army's first turbine-powered helicopter, developed from the S-52. Rejected in favor of the Bell 204 (UH-1 Iroquois) List of Operators of S-59 XH-39 Construction Numbers C/N Built as Year History 52-004 S-52-2 1950 N74150 52-007 YH-18 1951 49-2890 52-008 YH-18 1951 49-2891,N7741