American heritage
The creation of the first post-war army trucks took place not without the influence of the American design school. By and large, in the Soviet Union there was nothing to be particularly focused on in this regard. The first developments on all-wheel drive all-terrain vehicles (ZIS-36 and GAZ-33) date back to the beginning of the 40s, but they, for obvious reasons, did not receive proper development. The immediate serial predecessor of the ZIL-157 was the ZIS-151, which was developed in 1946 and was largely based on the technical solutions of the Lendleigh Studebaker US6 and International M-5-6. But it cannot be said that the 151st car was a complete copy of the American: in the fall of 1946, an experienced ZIS-151-1 with single-sided rear wheels (10, 5 - 20) was built, which was noticeably ahead of the future production model on the road.
However, the influence of the military experience of operating the Studebakers outweighed, and the ranks of the Soviet Army preferred the two-slope wheels of the basic version. One of the arguments in favor of this decision was the allegedly greater survivability of the twin wheels on the battlefield. The opinion of Ivan Likhachev, the director of the plant, who for some reason did not like single-wheel wheels, was also important. In this regard, Evgeny Kochnev writes in his book "Automobiles of the Soviet Army" that the adoption of the largely unsuccessful "two-slope" ZIS-151 for ten years stopped the progress of domestic all-wheel drive technology for the military.
Interestingly, initially the ZIS-151's cross-country ability was so low that in state trials in 1949, they also tried to put gable wheels on the front axle. Naturally, this decision only worsened the cross-country ability, especially on sand, snow and thick mud. Now sticky mud, clay and snow clogged not only the wheel clearance on the rear wheels, but also in front. In addition, the mismatch between the front and rear tracks seriously increased the resistance to movement on the most innocuous off-road. As a result, the production vehicle ZIS-151 turned out to be overweight, not fast enough (no more than 60 km / h) and uneconomical, for which it received the nickname "Iron".
Duplex wheels not only caused excessive losses in the transmission and chassis, but also forced to carry two spare wheels with them at once. Off-road, drivers often had to remove the inner wheels in order to somehow reduce the resistance to movement. And the main drawback of the car was the lack of reliability of most of the units, with which the factory workers had to fight throughout the entire life cycle of the model. It was also one of the reasons for the slowdown on the next generation single-slope truck.
Georgy Zhukov saves the situation
However, the ZIS-151 became the basis for a constant creative search for the engineers of the Moscow Automobile Plant, the developments on which eventually became the most important in the design of the ZIL-157 and ZIL-131. Such an example was a series of experimental vehicles ZIS-121, on which from 1953 to 1956. worked out more powerful motors, reinforced frames and chassis, long-awaited single wheels and locking all differentials. The most important innovation of the experimental trucks was the system for regulating the internal tire pressure with external air supply.
Initially, the wheel inflation system was developed for the ZIS-485 three-axle army amphibious vehicle, the creators of which, in turn, were guided by the American GMC DUKW-353 amphibious vehicle. On amphibians, the reduced pressure in the wheels was vital when leaving the reservoirs on the marshy coast: this seriously increased the area of the contact patch of the tread with the ground. A definite drawback was the external air supply, the hoses and pipes of which could be seriously damaged when overcoming ordinary bushes. The second important advantage of the inflation system was the obvious increase in tire bullet resistance, which was decisive when installing it on the BTR-152V. However, no one seriously thought about the advantages of installing such systems on trucks for the army: it seemed that the gigantic expenditure of material on implementation would never pay off. As often happens, chance helped in this situation. In 1952, a group of engineers went to fetch potatoes at one of the farms near Moscow. It was late autumn. In order to avoid freezing the product, a huge amphibian ZIS-485 was dispatched as a kind of "thermos". The body of this waterfowl was much better protected from wind and snow (and the heat from the engine pretty much heated the body-boat) than the ZIS-151, which were blown from all sides, of which there were two copies in the group.
When, on the way back, the convoy with potatoes got into a snow drift, the ZIS-485 had a tire pressure regulation system at the right time, with the help of which it was several buildings ahead of the rest of the cars. In addition, when driving on loose snow, the rear single-sided wheels of the car, which, I recall, did not have the ZIS-151, played an important role. For more accurate experimental data, a chassis from a ZIS-485 was installed on the truck and drove into the snow of the frozen Pirogov reservoir. The very first tests showed an increase in the traction capabilities of the experienced ZIS-151 by 1.5-2 times compared to the basic version of the machine. It would seem that the advantages are obvious, and even now take the tire inflation system and put it on new cars. But the future ZIL-157 had to literally wade through the thorns to the conveyor.
In 1954, comparative races of serial all-wheel drive vehicles and promising developments for the army were organized. Among them was the experienced ZIS-121V (future ZIL-157) with a wheel pumping system, which, on swampy soil, was second only to the ZIS-152V armored personnel carrier, also equipped with pumping. Deputy Defense Minister Georgy Konstantinovich Zhukov was present at the tests, following the results of the tests, in an ultimatum form, he demanded that the factory workers urgently introduce a novelty into wheeled vehicles for the army. The Stalin plant eventually became the first in the world to master such a complex technique in mass production. It was possible to get rid of the vulnerable rod of the external air supply in 1957, when the engineers of the then ZIL, G. I. Pral and V. I.
"Cleaver", "Zakhar", "Truman" and so on
In March 1956, the ZIS-157 was recommended for mass production, albeit with reservations. In the conclusion of the commission, it was pointed out that the steering was too sensitive, which on rough terrain could lead to injuries. The design asked for a power steering, but the engineers limited themselves to a shortened gear reducer bipod. This reduced the transmitted shock, but the high steering effort remained. Until the very end of the release, this problem on the ZIL-157 was never resolved: the driver had to literally wind up on the steering wheel all the time. Why didn't the power steering appear on the car? There is no answer, especially since both the ZIL-130 and ZIL-131 had an amplifier in the steering control. In addition to single-wheel wheels on the rear axles, the ZIL-157 differed from its predecessor in a large tire profile, which had a positive effect on the ground clearance: on the ZIL it was 0.31 m, on the ZIS - 0.265 m. The machines were equipped with six-cylinder in-line carburetor motors (on the ZIL-157 110-strong, on the ZIS-151 - 92-strong), which explained the characteristic long wedge-shaped hoods. But only ZIL received the nickname "Cleaver" among the people and the army.
In addition, the only spare wheel of the 157 was hidden under the body, which made it possible to bring the platform close to the cab. This, in turn, increased the exit angle to 43 degrees. An echo of the Lendliz legacy in the design of the 157th ZIL can rightfully be considered a complex transmission with as many as five cardan shafts. This, firstly, remained in the new car from the predecessor of the ZIS-151, and, secondly, in the opinion of the military, it seriously increased the survivability of the truck on the battlefield. For example, the scheme allowed, in the event of damage to the cardans going to the middle and front axles, to move on one rear axle. It turned out to be expensive, difficult and difficult, but, nevertheless, in production, the truck with the same transmission lasted in various modifications until 1985. In parallel with the "Kolun", a more advanced ZIL-131 was produced (about which there is a series of articles on "Voennoye Obozreniye"), and it already had a transmission scheme with an average passage bridge. Of course, the 131st ZIL was in many ways superior to the 157th car, but Zakhar had one indisputable plus - this is the maximum engine torque, which it reached already at 1100-1400 rpm. On heavy off-road terrain, such actually diesel engine parameters allowed the car a lot - experienced drivers assure that the ZIL-157 surpassed the almost reference GAZ-66 in this discipline.
Evolving from the virtually unsuccessful ZIS-151, the Cleaver turned out to be a real Kalashnikov assault rifle for the Soviet Army in terms of its combination of properties - just as unpretentious and reliable. At the same time, the car turned out to be in demand in the markets of developing countries, and in China its licensed copy under the name Jiefang CA-30 was produced from 1958 to 1986.
Over time, the ZIL-157 technique, rooted in World War II machines, became obsolete, and the engineers put a lot of effort into the development of the design. But that is another story.
The end follows …
