Mi-4 (“Hound” according to the NATO classification) is a Soviet multi-purpose helicopter designed by the experimental design bureau named after M. L. Mil’ in the early 1950s. Mi-4 was the first combat-transport helicopter of the Soviet armed forces. It has the same components as those of an American Sikorsky S-55, but its carrying capacity is twice heavier.

Full album is here: Helicopter Mi-4 - First Combat-Transport Helicopter Of The Soviet Armed Forces