The Soviet MI-6 Super Helicopter

Over 900 of the Soviet Mil MI-6 super helicopters were built between 1959–1980. It was, at the time of its launch, not only the world's fastest helicopter, but by far its largest and it still holds a world record set in 1962.

From the Soviet Press, 1958:

The world's most powerful helicopter has recently made its bow as the latest aviation creation from the designing office of Mikhail Mil.

The plane is the MI- 6, and its mammoth body easily accommodates whole bulldozers and huge tractors. It would even have room for two average size passenger cars or three of the smaller versions. All could be put aboard under their own power through the use of the helicopter's folding ramp.

Designed to carry some 70 to 80 passengers, the MI- 6 was test flown with a payload of more than 24,000 pounds and easily lifted this cargo to the world record height of 7,874 feet.

The MI- 6 has two turboprop engines and its main propeller has five blades. It will be used to deliver freight and supplies of all sorts to remote villages, to prospectors in the tundra and distant steppe areas, to explorers and scientists in the frozen arctic, or to construction sites far beyond established highways.

One of the special safety features of the helicopter is its ability to continue in flight with only one motor in operation. Another is characteristic of being able to glide to a landing without any power whatever as the “whirly -bird's" great propellers ease it to the ground.