Developed in the early 1950s to meet a Soviet Army requirement and first flown in June 1957, the Mi-6 was the largest-yet helicopter created in the Soviet Union. Its notable features included a power-plant consisting of two turbo-shaft engines (for the first time on a Soviet helicopter) and stub wings offloading the main rotor in forward flight; the cabin was big enough to accommodate artillery systems and tactical ballistic missiles. Built by two plants, the Mi-6 saw service with the Soviet Air