The largest rotary-wing machine ever created by mankind (10 photos)

How the USSR built the giant B-12 helicopter.





The B-12 (or Mil B-12) is a Soviet transport helicopter, which in overall dimensions is more similar to the mainline Boeings. The helicopter turned out to be so huge that it never went into production - the designers managed to assemble two prototypes. But even they set several world records and were awarded the title of the largest rotary-wing machines ever created by mankind. Below is the history of the development and creation of the B-12.

Why would such a helicopter be needed?

"The B-12 is the heaviest and most powerful helicopter ever built in the world" - this is the short description on the Internet. However, specialized resources and bloggers are a little less reserved in their definitions. The machine is often called a "rotor-wing titan", more similar in weight to large aircraft. If we compare it with helicopters, including modern ones, then no one has surpassed the primacy (in this parameter).

But why did the USSR need such a helicopter? The idea for its creation came in the early 1960s, during the height of the Cold War. The military wanted to be able to quickly transfer troops and equipment to designated points and regions.

At the same time, aircraft for such a thing - at least many of the machines available at that time - were not suitable or required significant design changes. New models - the Antonov Design Bureau already had plans to develop the An-22 cargo plane - were being developed, but this required much more time and resources.

In addition, cargo planes, unlike helicopters, also required runways. And their construction, again, turned out to be labor-intensive (and not possible in all regions).



Mikhail Mil with a model of the V-12

In general, in 1959, the Mil Design Bureau (named after its director Mikhail Leontyevich Mil, a Soviet engineer, designer and doctor of technical sciences) was given the task of creating a helicopter capable of transporting various loads weighing up to 30 tons (later the appetite increased to 40 tons).

At that time, there were only a few helicopters in the world that were theoretically capable of transporting such significant objects in terms of mass. In particular, the Mi-6, and that was with reservations. But even its carrying capacity turned out to be (at least for the tasks at hand) insufficient.

More like an airplane

The standard single-rotor design was not suitable for the B-12 given its size. As a result, the designers chose a twin-rotor transverse design with two rotors mounted on the wingtips.





The latter, by the way, have an unusual shape: they rise up and become wider. Such a design was considered safer (and had better airflow). All this together increased the load capacity and ensured the stability of the machine in flight.

The power plant used four D-25VF engines (with a capacity of six thousand horsepower each), which were borrowed from the already serial Mi-6. They provided the helicopter with the power necessary for lift. "The arrangement of the engines and the gear system presented a complex engineering task, since the synchronization of the two propellers was designed to ensure maximum efficiency without abnormal loads on the structure," the network specifies.



The fuselage of the B-12 resembled the design of a conventional aircraft, but with a huge cargo compartment capable of accommodating large-sized cargo. To understand: the length of the prototype B-12 was 37 meters, the width was 34.4 meters (excluding the span of the blades, each of which was another 35 meters in diameter), and the height was more than 12.5 meters.

In terms of dimensions, the helicopter was close to the Boeing 737, a long-haul airliner. In addition: the B-12 had a very impressive maximum takeoff weight of 105 tons. To simplify: the B-12 could accommodate up to 196 people and a normal load of up to 20 tons (the maximum, up to 40 tons, according to the designers, was also maintained).



The pilot's cabin (or rather, the cabin - the second, the upper one was slightly separated and intended for the navigator), as expected, was located in the front part of the helicopter. The cargo compartment occupied the central and rear parts. Access to the main cargo compartment, for which everything was started, was provided by powerful doors that allowed loading equipment and containers. In general, a similar layout was borrowed from the above-mentioned An-22.



The B-12 could rise to an altitude of 3.5 kilometers - a good result, especially for helicopters of that time, but not the most impressive. The speed is also average - 240 kilometers per hour cruising and 260 kilometers per hour maximum. The flight range was planned at 500 kilometers.



Tests and records

The tests of the machine were carried out in several stages: initially, the systems were checked on the ground, then relatively short ascents into the air were carried out, after which they moved on to full-fledged test flights.



Thus, the first official flight of the B-12 took place on July 10, 1968. The tests that took place shortly before, on June 27, were considered unsuccessful - the helicopter control system turned out to be too sensitive, minor rocking of the control column was perceived as a control action. As a result, the system had to be redesigned. It is good that the prototype got off with damage to the chassis.

During ongoing tests and demonstrations at air shows (including international ones - for example, at the Paris Air Show in 1971), the B-12 set several world records. The most impressive was lifting a load weighing 44.2 tons to a height of 2,255 meters - it was beaten, but many years later (in 1982) by the Mi-26.



Later, during the ongoing testing programs, many more nuances were revealed, some systems were improved. But the helicopter did not change globally - and, it seems, met most of the requirements. Inside, the B-12 was also not particularly noisy even with the engines running.

Why the B-12 never went into production

There are several reasons. Here are the main ones:

By the 1970s, stationary deployment of intercontinental ballistic missiles began. Simply put, their transportation by air began to lose relevance.

Development of strategic aviation and rail transport, which became more convenient and economically feasible for transporting equipment.

Great difficulty in using and especially servicing such a huge machine. The B-12 required special sites for takeoff and landing, as well as specialized technical personnel, which significantly complicated the introduction of the helicopter to the masses.

As a result, only two prototypes of the B-12 were assembled, after which the project was closed. However, its developments and engineering solutions were not in vain. They were used in the design of other helicopters, including the Mi-26, which was mentioned above.

And one more thing: the B-12 is sometimes called the Mi-12 - and it would have become so if it had gone into production. But since this did not happen, the giant, from a formal point of view, remained at the prototype stage.