The Largest Helicopter Ever Built.
The Mil V-12 had the potential to change air travel forever. For a number of reasons, the gigantic helicopter fell far short of its lofty promises but gave engineers a unique window into the world of large-scale rotorcraft.
Unlike fixed-wing aircraft, helicopters are dynamic and can operate without virtually any infrastructure whatsoever. While a massive runway is required for a conventional cargo lifter, a helicopter can land on little more than an open patch of dirt.
The potential of massive rotor-powered airlifters cannot be understated. Such aircraft could provide massive advantages in military operations, landing in combat zones with virtually no support. During peacetime, the massive helicopters could transport massive loads to extremely remote parts of the Soviet Union.
On the commercial side, these aircraft could allow airlines to serve unconventional routes, connecting cities that do not have major airport facilities. Upon noticing this immense potential, Soviet engineers sought to create the ultimate helicopter.
In the early 1960s, the Soviet Union considered building a helicopter with a comparable capacity to the large Antonov turboprop. Unlike the 4-engine plane that needed a runway for taking off and landing, the helicopter, which would soon be designated as the Mil V-12, would have been able to collect the cargo at the source and deliver it directly to where it needed to go without the need for runways.
Alleviating the need for road, rail, or river transport, this huge helicopter would have been handy for transporting Cold War-era military hardware, such as intercontinental ballistic missiles. When engineers began to design the helicopter, they wanted to build a machine similar to the Boeing CH-47 Chinook with rotors at the front and tail. However, it never reached full-scale production.
The size of the helicopter that they tried to create had certain limitations, which ultimately led them to look at a traditional single-rotor and side tail rotor design. This proved a non-starter, forcing them instead to select a transverse layout. This system with rotors mounted on either side at the tips of a wing alleviated the need for a tail rotor.
After exhaustive testing, the first Mil V-12 prototype eventually began construction using a conventional airframe with a stretched skin and high-strength metal. The aircraft's fuselage measured over 27.5m in length, and it had a wing span of over 66m across both rotors.
The two-floor cabin and crew section was located at the front, with the pilot, co-pilot, flight engineer, and electrical engineer in the lower cockpit. Meanwhile, people such as the radio operator and navigators used the upper section.
At the rear of the aircraft, the helicopter featured clamshell doors and a drop-down cargo ramp. Side doors in the fuselage also gave access to the cargo hold. Situated above the back of the fuselage was a modestly sized tailfin. Power for the helicopter was provided by two Soloviev engines. The first prototype of the Mil V-12 flew in 1968.
Meanwhile, the second prototype was revealed to the West at the 1971 Paris Air Show. The NATO gave it the reporting name 'Homer.' Before the French trip, the Mil V-12 entered the history books by setting two load-carrying records.
In February 1969, it lifted 31 tonnes to a height of 2951m and then, that August, ferried 40.2 tonnes to an altitude of 2254m.
While the Mil V-12 was primarily designed for military transport use, there was also talk of a passenger-carrying version being built for Aeroflot. To give an idea of how big the helicopter was, if a passenger version had been built, it would have been able to carry 196 passengers: the same amount as a two-class Airbus A321neo.
Engineers at the Mil Design Bureau also thought that the Mil V-12 would be especially useful for mining and logging operations in remote parts of Siberia where there was little or no road access. By the time production was ready to begin, the Soviet Union no longer needed the rapid deployment of intercontinental ballistic missiles, heavily decreasing interest in the massive V-12.
As such, all work was subsequently stopped on the Mil V-12, and work began designing the Mil Mi-26. While the development of the Mil V-12 played a role in the building of the Mi-26, the prototypes are still the largest helicopters ever built. In their short career, they set several more records.
In addition to the two records mentioned earlier, the Mil V-12 set another six during its short operational career. Of these, four reportedly remain current today. The six other records consisted of the maximum altitude achieved with payloads of 15, 20, 25, 30, 35, and 40000kg. The first four of these were achieved in the February 1969 flight to 2950m, with the other two set that August at 2254m.
The goals of the V-12 project, however, still do exist and multiple other nations around the globe would try their hands at building powerful vertical takeoff and landing transport aircraft.