Largest Helicopter in the World

The largest helicopter ever built was a massive aircraft developed in the Soviet Union during the 1960s called the Mil V-12. The V-12 was a rather unusual test vehicle that featured two rotors mounted side by side at the ends of a large wing. Each rotor had a diameter of nearly 115 ft (35 m). The helicopter was so enormous that the distance from the edge of one rotor disk to the other was almost 220 ft (67 m), even wider across than the wingspan of a Boeing 747!
Even more remarkable was the lifting capacity of this powerful craft. The V-12 had a maximum takeoff weight of 231,485 lb (105,000 kg), nearly twice that of the second largest helicopter, and set a record in 1969 for carrying a payload of 88,635 lb (40,205 kg). So massive was the V-12 that this payload weight alone is greater than the maximum takeoff weight of the third biggest helicopter in the world! These impressive figures have earned the V-12 the record as the world's largest helicopter according to the FAI and the Guinness Book of World Records.

Only two V-12 prototypes were built, yet despite its amazing size and lifting power, the design was considered a failure by its manufacturer and Soviet authorities. The V-12 was simply too big and difficult to maneuver to be a practical machine. A production model would have been called the Mi-12, but these plans were cancelled following evaluation of the two test vehicles. One of the V-12 prototypes was retired to the Russian Air Force Museum in Monino while the second is reportedly housed at the Mil factory near Moscow.