The largest helicopter ever built was Soviet Union’s Mil V-12, which was able to carry 196 passengers. The empty weight of this giant was 69,100 kg.
The Mil V-12 could reach a speed up to 260km/h. At the same time a cruise speed of 241 km/h and a ferry range of 998 km. Moreover, operating ceiling of 3505 m, along with a combat range of 499 km. The wingspan across rotors reached astonishing 67 meters.
At this period Soviet Union and the US were racing with each other. For this reason, the government was looking to have the most powerful vehicles in order to assist the military in case of a conflict.
The true purpose of this helicopter was to use Mil V-12 to transport soldiers, equipment, and supplies. Particularly, Soviet intercontinental ballistic missiles (ICBMs) would have been moved on these helicopters.
Mil V-12 was designed by Mil Design Bureau. The cargo hold was produced to closely match with the famous Antonov An-22 strategic airlifter. The maximum gross weight of helicopter was 97,000 kg
Despite its impressive size and power, the project was not actually realized by the Soviet Union. The period was tough as from the end of the 1960s and much of the 1970s as the Cold War was ongoing. Therefore, Mil V-12 could not justify its role during this time.
It was a considered to deploy the type to for commercial usage, however it never happened. For this reason, the project was canceled. In 1983, the military introduced the Mil Mi-26 (Halo) to serve as a heavy lifter.