Largest helicopter in the world (MIL MI-12 / V-12)

Mil V-12 CCCP-21142 at the Central Museum of the Air Forces.

The Mil Mi12, known in the Soviet Union as V-12, is a 120-seat heavy transport helicopter powered by four Soloviev D-25VF turboshaft engines. The Mil Mi-12 (NATO reporting name 'Homer') project started in 1965. The prototype flew first in 1968. This giant helicopter had fixed wings and was lifted by two Mi-6 rotors mounted at the ends of outrigger wings. Both rotors were driven by two 6500shp Soloviev D-25VF turbine engines each, mounted side-by-side at the tips of the wings. The four 6500shp Soloviev D-25VF turbines giving the Mil Mi-12 helicopter a maximum speed of 260km/h, with a 35400kg load or 120 passengers and 500km range. Three prototypes were built, with the first written of in a non-fatal heavy crash landing. The Mil Mi-12 never entered production.