Sikorsky S-70 Sikorsky S-70 The Sikorsky S-70 is an American medium transport/utility helicopter family manufactured by Sikorsky Aircraft. It was developed for the US Army in the 1970s, winning a competition to be designated the UH-60 Black Hawk and spawning a large family in US military service. New and improved versions of the UH-60 have been developed since. Civilian versions, and some military versions are produced under various S-70 model designations. The S-70 family was developed to meet a US Army requirement to replace the UH-1 Iroquois family of utility medium-lift helicopters in 1972. Three YUH-60A prototypes were constructed, with the first
Sikorsky S-9 completion the S-9 was found to be substantially heavier than anticipated and the engine only delivered 80% of its rated horsepower. Initial flight tests revealed very poor performance. The engine was replaced by a Gnome Monosoupape and further flights showed only a nominal increase in speed. The machine was eventually scrapped. Sikorsky S-9 The Sikorsky S-9 "Kruglyj" (Rounded One) was a Russian single engine prototype aircraft completed in the spring of 1913 by the Russian Baltic Railroad Car Works while Igor Sikorsky was the chief engineer of the aircraft manufacturing division. The S-9 was a three-seat mid-wing monoplane with constant-chord