The history of almost every enterprise shows that not all the prototypes are destined to enter serial production. Wheeled tractors and rocket carriers, produced at the Minsk Automobile Plant [MAZ] Special Design Bureau [SKB], have always been admired for their weight and size. The fact that there were these special chassis in the Soviet era is known only by a few designers and troops. The sunset of the period of the board of councils, which occurred in the 1980s, was marked in world history by the fact that new models of giant tractors were created on the territory of the special design bureau MAZ. Their uniqueness was confirmed not only within the territory of the USSR, but throughout the world.
In the 1980s, thanks to this giant multi-wheeled missile carrier, a hundred engineers received flats, and the general designer was awarded a personal elevator. The very same MAZ-7904, released in a single copy and then became one of the most powerful and most secret tractor in the world, was never put on alert duty. The chassis could only be used in a desert area. Because of the easy detection of such a vehicle by space means, it was proposed to create a chassis for traffic in the middle zone of the Soviet Union, in a wooded area.
MAZ 7904 is the offroad 6-axle twin-engine chassis with two 2-seat cabins and 12 huge wheels with diameter of 2.8 meters. Its payload is really incredible — 220 tonnes. The only purpose is installing the parts of the first missile complex 'Celina'. The main engine was a turbocharged marine diesel 12CHN18/20 (M-351) V12 with a capacity of 42.4 liters and output of 1500 hp located in the front between the cabins. It was connected to the two hydromanual 4-speed gearboxes. Wheel configuration is 12x12. The 1st, 2nd, 5th and 6th axles were driveable. Each wheel has its own hydroair suspension.
In the early 1980s, the confrontation between the United States and the Soviet Union in the "Cold War" reached its highest point since the time of the Caribbean crisis. The two superpowers were demonstrating each other nuclear muscles. As a result, in February 1980, an order was issued by the Minister of Automotive Industry of the USSR, in which the Minsk Automobile Plant was required to develop a special wheel conveyor of extra-large payload for an autonomous transport and launcher of the Celina missile system. The designed machine was assigned the MAZ-7904 index.
To manage the project was entrusted, by that time it was far from young, B. Shaposhnik, the very one under the leadership of which the first Soviet career giants MAZ-525 and MAZ-530 were born, and also all subsequent military tractors MAZ and multi-axle chassis for the Elbrus, "Pioneer" and "Poplar". However, this time before Shaposhnik and his bureau there was an uneasy task. The fact is that the weight of the launch equipment, the transport-launch container and the missile for the Celina complex was 220 tons, and the MAZ-7904 itself had to have 140 tons of loaded weight. Thus, a new transport chassis with a rocket had to weigh 360 tons. In the project, a machine of unheard-of weight and dimensions was drawn, the development of which required enormous effort.
In February 1981, an interdepartmental meeting was held at the Minsk Automobile Plant, attended by the ministers of the automobile, defense and electrical industries, the deputy defense minister for armament, the commander-in-chief of the Strategic Missile Forces, the chief designer of the MIT and the Celina missile complex, missile complexes OKB-1 of the Barrikady plant, other high-ranking chiefs and designers. Naturally, the project "Celina" and the MAZ-7904 transport chassis developed for him were discussed.
At this meeting, Shaposhnik, referring to the complexity of the task, demanded the expansion of the staff of the design bureau for 100 people and the allocation of hundreds of apartments for them. Shaposhnik's demands were immediately fulfilled: the Minister of Automotive Industry, V. Polyakov allocated an additional salary fund for 100 specialists, and the USSR Defense Ministry paid 100 apartments for their resettlement. In addition, on the initiative of Polyakov, in the building where Shaposhnik's office was located, an elevator was built, especially so that the elderly designer could go up to the third floor and not go up the stairs, and repair was done in the designer's office.
Despite the large number of difficulties associated with the weight of the machine, in June 1983 the first (and then it turned out to be the only one) MAZ-7904 was ready. It was a two-cubic giant of fantastic dimensions - its length was 32.2 m, width - 6.8 m, and the height from the ground to the roofs of parallel cabs - 3.45 m. The backbone of this dinosaur was a powerful welded support frame on which were fastened two hydromechanical 4-speed transmissions with two reverse gears. All this design rested on 12 huge wheels, more than 3 meters in diameter. These wheels were purchased by the Soviet Union in Japan, from the Bridgestone campaign known today to all car owners. MAZ-7904 was created as an all-terrain chassis, so it had a full drive with a 12 × 12 wheel formula, and the ground clearance was almost half a meter.
The first and, as it turned out, the only MAZ-7904 was ready by June 1983. The weight of the tractor was 140 tons. As the main engine on the conveyor was used ship V-shaped 12-cylinder diesel M-350 with a capacity of 1500 liters. from. production of Leningrad "Zvezda". To this, another 330-liter diesel was installed on the machine to provide power to auxiliary systems, such as the hydraulic pump of the steering system, the compressor of the brake system, and so on.
The tractor had a length of 32.2 m, a width of 6.8 m, and the height of the level of the roofs of two parallel cabs was 3.45 m. The cabins for the sake of weight reduction, by the way, were made of fiberglass by the Osipovichi plant of automobile units. MAZ-7904 relied on the ground with twelve wheels Bridgestone, specially purchased from the famous Japanese manufacturer Bridgestone under the guise of wheels for three quarry dump trucks. At that time, the domestic tire industry could not provide production of tires designed for such loads (each wheel accounted for 30 tons), and the size of the wheels was impressive - about three meters in diameter. Naturally, all wheels had a drive. It was carried out onboard through two synchronized hydromechanical transmissions. The two front and two rear axles of the conveyor were controllable, which provided a turning radius of only 50 m.
Factory tests the tractor passed near Minsk. The tractor drove out of the factory gate under the cover of night and returned back to dawn. Time coordinated with the military: the departure for testing was authorized only if the sky was clear from the western satellites scurrying over Soviet Belarus. Under such conditions, it is difficult to conduct a full cycle of tests, and it was decided to transport the tractor for further tests to Kazakhstan, to Baikonur. According to one of the cover story MAZ-7904 was developed only as a conveyor for large-sized blocks of the "Energia" rocket, which should not have caused particular wariness among the opposing side. Besides, to test the tractor in the conditions for which it was intended, was much more correct.
The military sought to create conditions for a group of 10 such giants to constantly cruise within a closed multi-kilometer route in the middle of the steppes of Kazakhstan. Each of these dozens of chassis had a so-called "house". It looked like a hangar. Within the framework of one of them (and maybe several), it was planned to equip the hangar with a launcher with a rocket. At the same time, that for the enemy it will be an impossible task to find out in which or in what hangars the installation is located. This idea can not be called new at that time. On the territory of the USSR, there was already a single train running, and even their group. He was disguised as a commodity or a passenger train. At the same time, an intercontinental nuclear missile was located inside it, ready to strike back at the Pentagon in any unexpected for the enemy.
Unfortunately, the idea of the nuclear "houses" moving along the ring did not come true. The only built MAZ-7904 did not even mount a "home" with either a rocket or without. Tests in Kazakhstan, during which the tractor passed 4100 kilometers, while developing a maximum speed of 27 km / h, showed that the MAZ-7904 has a very significant drawback - the bearing surface was subjected to excessive specific pressure, and each wheel was carrying a huge load in it 30 tons.
The result of this was a reduced patency, poor handling and rigidity of the stroke. All this made the tractor unsuitable for the secret transportation of nuclear weapons - the movement of the machine was limited only to those areas and areas where it could move without interference. Because of its excessive mass, the tractor could only move along certain "favorable" roads, and not a meter to the side. In addition, the military leadership has revised the strategic objectives and the missile system "Celina" has lost its relevance. To replace it was to come the renewed missile system "Tselina-2", which needed its gigantic conveyor MAZ-7907, but that's another story.
As of 2007, the tractor was stored in one of the hangars of sites 42 and 43 at Baikonur, where in due time it was tested. At the beginning of 2007 it became clear that after long years of storage of the car in the hangar of the Zenit launch (this area was owned by the civil organization "Design Bureau of Transport Engineering"), it collapsed under the influence of rust. In 2010, she was cut for scrap metal.
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