4- 5,645 shp ea.
121 ft. 4 in.
2- 114 ft. 10 in.
The Mil V-12 (Mi-12) is the largest helicopter ever to fly. It first flew on July 10, 1968.
The helicopter is the creation of Mikhall Mil, who some consider among the world's best designers of rotorcraft. The Mil V-12 is his most ambitious creation. It is bigger than a Boeing 727 airliner. Fully loaded it is as heavy as nine large helicopter gunships. Everything about the Mil V-12 is enormous. The twin rotor giant rotorcraft shattered every record for helicopter payload, and made every previous helicopter produced seem toy-like.
Two prototype Mil V-12 aircraft were built. They never met design specifications and the program was canceled. One aircraft remains on display in Russia. The second is said to be at the Leontjewitsch Mil plant in Lyubertsy-Panki.
The helicopter features two-rotors mounted to a wing on top of the fuselage. This is the only example of such a system ever used by Mil, and rare for any relatively modern helicopter. A tail rotor is not necessary for aircraft control, and thus eliminated in the design. The D-25 turboshaft engines driving the rotors are also used on other large Mil helicopters.
The helicopter uses wings to support its weight while flying. Their unique design made their outboard portions wider than where the wings met the airframe. Trailing edge flaps were used initially, but were later fixed in place.
The Mil V-12 has a fuselage and tail unit similar to a fixed wing transport. Its flight crew of six consists of a pilot, co-pilot, flight engineer, electronics operator, navigator, and radio operator. The cargo hold measuring 92 ft. (28.15 m) by 14 1/2 ft. (4.4 m) is be able to handle multiple loads, including troops or handling crews. Rear clam shell doors and a ramp facilitate large cargo loading. Passengers and smaller cargo can be loaded through a side door. Inside the fuselage are four cargo winches and a reinforced floor to handle heavy loads. Optional ferry tanks can be carried inside of the helicopter to increase range.
The flight controls of the Mil V-12 are hydraulically operated, but the helicopter can also be operated manually. Flying is done with the aid of an auto stabilization system. A ground mapping radar is fitted under the helicopter's nose. Fuel is carried in two external tanks as well as the outer wing structure. The large central vertical stabilizer of the helicopter provides stability in forward flight. It is supplemented by two smaller outboard tail fins.
Production of the Mil V-12 commenced in 1965 with its first prototype. In 1969 the helicopter set a number of payload to altitude records. However the problems of operating such a large helicopter were also large. A major cause of the helicopter's problems was the engine and wing being suspended with complex bracing to the fuselage. Engine vibrations carried through the bracing to the fuselage and undercarriage could not be overcome.
The first helicopter built was damaged in a crash in 1967, caused by resonance and control systems problems. The second Mil V-12 produced made its highly acclaimed first public appearance at the Paris Air Show. However, it rarely flew again.