Ural 300 Series: Floating and Five-Axis
With the index "D"
If we compare the circulation of the Ural issue with a gasoline engine and other army trucks, it turns out that “only” 110 thousand cars got out of the gates of the Miass factory. This really is not so much: ZIL-131 and GAZ-66 sold almost million copies. There are several explanations for this.
First, the lion's share of all Urals was taken by the Ministry of Defense. There were not many modifications to civilian structures; appetites were more modest. Until 1967, the 375th Urals didn’t go into the peaceful life sector at all, as they were all equipped with built-in blackout. But in the village and in the transport department, they did not particularly grieve about this. The 180-horsepower (initially 175-horsepower) ZIL-375 gasoline engine was good for everyone, except for its excessive fuel consumption - this economic factor could not be ignored in the national economy. And secondly, the cost of even the basic on-board vehicle was rather big, not to mention the numerous modifications. Some sources say that the total number of variations of the Ural-375 exceeded two hundred. At the same time, of course, even a small part of all this diversity was not produced at the Ural plant, passing orders to third-party offices.
Ural-375D
As already mentioned in the first part of the story, On the conveyor "Ural" with a carburetor engine, I got it not brought to mind. In particular, even after a 25-mile run as part of state trials and elimination of the most serious shortcomings, the truck’s “portfolio” had weak coupling, a cooling system, a transfer case, a cardan drive, a front suspension, a steering, wheels with tires and pneumatic hydraulics of the brake drive. Nevertheless, the Ural-375 with a rag roof was collected and sent to the troops. It is noteworthy that on serial machines, the carrying capacity was 500 kg higher than the calculated one and reached 5 tons. The winch reduced it to 4500 kilograms.
Ural-375S
Ural-375D was a charismatic machine
As soon as a sufficient number of vehicles had accumulated in the troops, it turned out that it was inconvenient to operate a heavy truck designed to work in both heat and cold, with a tarpaulin cap instead of a roof. The barrel was blown out of all the cracks, the heater could not even cope with the fogging of the windows, and the operation of the BM-21 multiple launch rocket system could even cause a fire. And the appearance of the car with bodies whose profile exceeded the height of the cabin (KUNG KP-375) was absurd. It was like this: the body is insulated from severe frosts by reinforced polystyrene foam, and the driver's cab - with a rag roof. Therefore, in 1963, the military instructed Miass to deliver an all-metal cabin.
So there was the most massive truck of the 300th series “Ural-375D”, which, together with the version of the “DM”, was released intermittently until 1991. The cars with the “D” index received, in addition to the new cab, a simplified transfer case that provides the car with only four-wheel drive, as well as a powerful cabin heater. By the way, with the disabled front axle on the first Ural-375 machines, a bit paradoxical happened story. It was originally thought that a bridge without a drive would reduce fuel consumption (after all, they thought about it in Miass), but the opposite happened: the front wheels lost torque, and gluttony increased. It turned out to be the front tires, in which the dynamic radius increased during traction and the rolling resistance decreased. As a result, the Ural-375D simplified the transmission scheme, which increased reliability and increased efficiency.
The Ural-375 (in the picture) was replaced by the more advanced Ural-375D
In addition to the D version, Miass also produced the Ural-375A version, designed to install a K-375 type body. He was distinguished by a spare wheel located vertically on the rear overhang of the frame. By the way, the rear overhang for modification “A” was lengthened to accommodate the overall kung by 355 mm, and the total carrying capacity dropped to 4,7 tons. For countries and regions with a hot climate, there was a modification of 375DU, and for the northern latitudes, the Ural-375K version was developed.
The trucks were brightly painted to contrast more strongly in the snow, and were also equipped with a warmed cabin, a battery cover, double glazing and an additional stove in the cabin. The factory workers assured that the machine could be operated even at minus 60 degrees.
Narrow specialization
In parallel with the launch of the basic version in serial production, a cargo platform with a two-axle drive was hitched to Ural. For this purpose, the 375C tractor was suitable, which was also originally in the production range. As a result, in the early 60s, the Ural-380 appeared with a mechanical drive on the axis of the 12-meter Ural-862 semi-trailer with a 10 × 10 wheel arrangement. At the same time, the bridges on the semi-trailer were unified with the Ural bridges and also equipped with swap. This monster-road train, named “Ural-380-862”, had a gross weight of more than 25 tons, could accelerate to 67 km / h and in difficult road conditions consumed more than 100 liters of gasoline per 100 km of track. The drive to the active semi-trailer to save fuel and resource was disconnectable.
Ural-380-862 10x10
The layout of the elements of the equipment "Perimeter" on the example of ZIL-131: 1 - scraper type knife, 2 - two-arm levers, 3 - flexible canopy, 4 - knife extensions, 5 - hydraulic cylinders, 6 - oil pump, 7 - hydraulic distributor, 8 - oil tank , 9 - safety valve
In the early articles about the remarkable military automobile industry of the USSR there was already a mention about the experimental program "Perimeter", which, in particular, got ZIL-131. It was an attachment for self-digging, the theoretical studies of which were carried out by the military in the 60s as part of the Okop research work. Military all-wheel drive should have been able to dig out for themselves shelter in full profile, without involving engineering units. But the ZIL-131 gave up quickly - the transmission could not withstand shock loads, yet the units were largely from the civil 130th. But the newcomer “Ural” was originally designed to meet the strict requirements of army operation and, according to the military, had to endure the hardships of the “Perimeter”.
The experimental machine with specific scraper equipment even got its own name - 375DP, but also could not withstand heavy self-digging procedures. In total, the military took almost ten years of testing ZILs, Urals and KrAZs with Perimeters in order to understand the unsuitability of machine components for such work. Work with a scraper hitch led to active wear of gears of the gearbox and gearboxes, destruction of the transfer case bearings, breakdown of main gearboxes, and twisting of the axle shafts. When they calculated the costs of premature repair of equipment, as well as the specific consumption per cubic meter of soil, it turned out that it was much more efficient to dig trenches with military excavators or even earth-moving machines.
That floating Ural
Among the "Urals" there were many exotic modifications. Perhaps one of the most unusual was the floating prototype. This happened in the wake of the search projects of the 70s, when the Ministry of Defense demanded the supply of a wide range of floating vehicles, as much as possible unified with serial land analogues. Attached to the Ural-375 in US they tried to seal it along the "water line" and equipped with removable polyurethane foam floats. OCD received the name "Float", and the car - the corresponding index "P". But it was not possible to make the Ural’s cabin airtight without a complete overhaul, and the driver had to put on a rubberized L-1 suit to overcome the water barrier. This could be understood in the conditions of the warm season, but what was the driver to do in the autumn-spring period? For speed and controllability, the floating truck was equipped with a 55-centimeter-diameter screw, the drive for which was pulled from the input shaft of the transfer case. On the Klyazma River in 1976, the "Float" could only reach 2,8 km / h with the help of rotating wheels, using a propeller exclusively, the speed of movement increased to 7,95 km / h. It is interesting that the pressure control system in the wheels was adapted for pumping air into the chassis and transmission components in order to avoid water penetration. Also, a powerful pump was installed in the back to remove sea water.
Ural-379B
Ural-379A
Ural-395
Previously, work on floating trucks was carried out with the experimental three-axle vehicles Ural-379A, Ural-379B and the four-axle Ural-395. These were search options for the modernization of traditional Urals, they had a hoodless and so-called semi-hood layout. These machines remained in the category of experienced ones, which saved many soldiers' lives - the long hood of the Urals often became salvage in the event of a fatal collision with a mine.
To be continued ...
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