The Mi-8 is the world's most-produced helicopter, and is used by over 50 countries. Powered by a 2,010 kW (2,700 shp) Soloviev turboshaft engine, the V-8 first flew in July 1961. The prototype V-8 was designed in 1960 based on the Mil Mi-4 with a larger cabin. Powered by a 2,010 kW (2,700 shp) Soloviev turboshaft engine, the V-8 first flew in July 1961.The second prototype equipped with two 1,120 kW (1,500 shp) Isotev TV2 engines,