The Mil V-12 holds the title for the largest helicopter ever built. The plane was built with the aim of producing a vertical take-off aircraft capable of carrying missiles or other loads. It was during the cold war and the Soviet Union and the US were racing with each other thus the government was looking to have the most powerful vehicles in order to assist the military in case of a conflict.
The plane has a length of 37 meters and weighs 69,100 kg. The wingspan across rotors reaches an astonishing 67 meters. It's operated by a six-person crew and has double-height cockpit.
The pilot, co-pilot, flight engineer and electrical engineer are positioned in the lower cockpit while a navigator and a radio operator are located in the upper cockpit where they have the advantage of improved visibility. The V-12 is capable of carrying 120 passengers and can reach a speed of up to 260km/h. A pair of D-25VF turbines was fitted at the tip of each wing to power the rotors.
The large cargo hold measuring 28.15m long by 4.4m wide can carry various kinds of loads including very bulky ones. as well as carry troops and handling crews. While on the ground the helicopter is supported by a large fixed tricycle landing gear with two wheels on each unit.
Despite its impressive size and power the Mil V-12 could not justify its role since it was built while the cold war was ongoing thus it had no purpose. Another downside was that the performance of the V-12 never matched that of other large trans-port helicopters. There were considerations to use it for commercial purposes but this never happened and thus the plane was eventually abandoned.
Today the helicopter can be found at the Central Air Force Museum in Moscow, Russia.