The Mil V-12 and Mil Mi-26 are both heavy-lift helicopters developed by the Soviet Union’s Mil Moscow Helicopter Plant. The V-12 has a maximum takeoff weight of 44,098 kg (97,200 lb) and the Mi-26 has a maximum takeoff weight of 56,000 kg (123,456 lb), making the Mi-26 the heaviest helicopter ever built.
In terms of size, the V-12 has a rotor diameter of 30 meters (98 ft) while the Mi-26 has a rotor diameter of 32.15 meters (105.5 ft). The V-12 is also slightly shorter, with a length of 43.34m (142 ft) compared to the Mi-26’s length of 40.05m (131.2 ft). The Mi-26 is therefore larger than the V-12.
The reason for the difference in weight and size between the two aircraft is primarily due to their design. The V-12 has eight rotors arranged in four tandem pairs, while the Mi-26 has a single main rotor with eight blades. The V-12 was powered by four engines, one for each tandem pair of rotors, while the Mi-26 is powered by two engines. The Mi-26 also has a larger cargo bay, capable of carrying up to 20 metric tons (44,092 lb) of cargo, compared to the V-12’s capacity of 20,000 kg (44,092 lb).