Soviet helicopter successfully flown in 1949-50.
The Yak-100 was developed in competition with the Mi-1, and bore a striking resemblance in size, shape and weight to the American Sikorsky S-51. It did not enter production, however, and in fact Yak-100 was the design bureau's designation, not that of the armed forces. A second prototype of the Yak-100 flew in 1949 and the two helicopters were tested until June 1950, when it was decided to drop the project.
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