In 1929, the Yaroslavl State Automobile Plant No. 3 mastered the production of the country's first five-ton truck Y-5. The release of this technique did not last long - it was curtailed in 1931 due to the lack of the necessary engines. Nevertheless, the growing economy needed five-ton trucks, and soon YAGAZ presented a new car with the required characteristics. On the basis of the discontinued Ya-5, a new model was developed called the YaG-3, which later became the basis for several other machines.
Truck I-5. Photo Wikimedia Commons
It should be recalled that in the early years, the development of the domestic automotive industry, primarily the freight one, faced serious problems in the field of engines. Soviet industry was not yet able to supply in large quantities all motors with the desired characteristics, and imports were associated with certain difficulties. Difficulties in finding suitable engines had the most serious impact on the development of Yaroslavl cars.
The problem of motors
The first domestic five-ton Y-5 was equipped with a Hercules-YXC-B gasoline engine with a capacity of 93 hp. American production. Deliveries of foreign engines, which began in 1929, made it possible to build a little less than 2,300 Ya-5 trucks, as well as more than 360 Ya-6 bus chassis. However, in 1931, new decisions were made that hit the production of trucks. By this time, the supply of American engines had stopped, and the available stock of such products, according to the order of the industry leadership, should have been used in the construction of buses and some other equipment. As a result, the Ya-5s were left without engines and could no longer be produced in the existing configuration.
YAGAZ design department headed by V. V. Danilov began a new search for solutions and suitable components to continue the production of five-ton trucks. It was found that the only real alternative to the imported product is the Moscow AMO-3 engine - a copy of one of the Hercules engines. This engine produced only 66 hp, but there was no choice. Yaroslavl designers began to recycle the Y-5 machine for a new engine.
Assembling YAG-3. Photo Russianarms.ru
At the design stage, it became clear that the new truck would be significantly different from the previous one, and therefore it should be considered a completely new machine. This led to the emergence of its own designation. By the end of the design work, a new nomenclature of Yaroslavl equipment was adopted. In particular, the YAG index appeared - "Yaroslavl Truck". A number from the engine designation was added to these letters, and the finished car was named YAG-3.
The power unit for the YAG-3 could only be based on the AMO-3 carburetor engine, which was inferior in its characteristics to the foreign Hercules-YXC-B. For this reason, the new car had to differ from the Ya-5 for the worse. Calculations showed that a 66-horsepower engine would make it necessary to reduce the carrying capacity from the original 5 to 3.5 tons. However, the designers found a way to keep this parameter at the same level. To do this, they had to redesign the transmission and sacrifice speed.
New modernization
The process of converting the Ya-5 truck into the new YaG-3 was not easy. To install a new power unit, some design improvements were required. In addition, the design department of YAGAZ found ways to improve the design of the machine in technical and technological terms. At the same time, solutions that have already been worked out and time-tested, including those that were forcedly applied due to technological limitations, were retained.
The base of the machine remains the same frame, assembled on rivets from standard channels. The front end has been slightly modified to match the design of the new engine, but otherwise remains the same. The layout has hardly changed. The engine and gearbox were located in the front of the frame, behind which the cab was located. The frame was supplemented with a new wider bumper connected to the wheel fenders.
Truck YAG-4. Figure Carstyling.ru
Under the hood was a 66 hp AMO-3 inline six-cylinder petrol engine, as well as related equipment, including a Zenit-type carburetor. The engine of the new type was less demanding on cooling in comparison with the "Hercules". This made it possible to reduce the volume of the cooling system, reduce the cellular radiator, and with it the entire hood. In addition, the number of louvers on the sides of the bonnet has been reduced.
Through a dry clutch, the engine interacted with the AMO-3 gearbox. This product had four forward gears and one reverse. The box was controlled using a standard floor lever. A propeller shaft connected to the main gear of the rear axle departed from the box. As before, the shaft was housed in a tapered casing, which provided a mechanical connection between the bridge and the frame.
The management demanded to maintain a payload of 5 tons, but the lower power engine did not allow it to be done using the existing transmission. Yaroslavl engineers decided to sacrifice the mobility of the machine. The gear ratio of the rear final drive was increased from the original 7, 92 to the maximum allowable 10, 9. Further change of this parameter threatened with excessive loads and destruction of the units. The redesigned final drive gave an increase in traction characteristics, but significantly reduced the maximum travel speed.
The chassis remains the same. It included a front axle with single steered wheels, suspended on leaf springs. The rear axle had the same suspension, but differed in the presence of a transmission and a gable tire. Both axles were equipped with power-assisted pneumatic braking systems.
Serial YAG-4. Photo History-auto.info
The design of the cabin from Ya-5 during the development of the YaG-3 did not change. Planks and metal sheathing sheets were installed on a wooden frame. Doors were provided in the sides. There were lifting windshields and door glazing. The latter was equipped with a power window. The ergonomics of the cab, including the composition of the controls, have not changed.
The cargo area, like the cab, was borrowed unchanged from the previous truck. A wooden platform with drop sides was used. In the future, local auto repair shops could remove the standard body and install new devices in its place, turning the truck into a special technique.
The use of the new engine made it possible to reduce the size of the hood, but the overall dimensions of the YAG-3 did not differ from its predecessor. Length - 6, 5 m, width - 2, 46 m, height - 2, 55 m. The curb weight has hardly changed - 4750 kg. Carrying capacity - 5 tons. Like Ya-5, the new car had a total weight of about 9, 7 tons. Recycling of the main gear ensured the preservation of the carrying capacity, but the maximum speed dropped to 40-42 km / h.
On the track and on the conveyor
The widespread use of ready-made units and the maximum unification with several trucks of the latest models made it possible to accelerate the development work on the YAG-3 theme. Already in the first months of 1932, YAGAZ completed the design and soon built prototypes for testing. Design performance has been validated on the tracks. Indeed, the car carried a 5-ton load, but moved slower than its predecessor.
YAG-4, view from a different angle. Photo History-auto.info
In a different situation, the YAG-3 would not have gone into production, but the circumstances were in favor of this machine. The Yaroslavl Automobile Plant could build the required number of new trucks, and the AMO enterprise could provide it with the required number of power units. Thus, the YaG-3 was worse than the Ya-5 in a number of characteristics, but at the same time, unlike it, it could be produced further. By the middle of 1932, YAGAZ established full-scale serial production of new cars with Moscow engines.
The production of YAG-3 continued until 1934. In about two years in Yaroslavl, he built 2,681 cars of this model. Only flatbed trucks were built; special equipment based on them was manufactured locally by the forces of various workshops. The finished equipment was transferred to various structures of the Red Army and the national economy. First of all, five-ton vehicles were required by the ground forces, construction organizations and the mining industry. Other customers were not ignored either.
During operation, serial YAG-3s confirmed their strengths and weaknesses. The main advantage of this car was its high carrying capacity. In this respect, Yaroslavl trucks at one time had no equal. At the same time, the new car differed from its predecessor in its speed and dynamic characteristics. The 66-horsepower engine impeded acceleration and limited speed. At the same time, some of the problems typical of previous cars remained, primarily related to ergonomics.
New engine and new model
The main problems of the YAG-3 truck were associated with an insufficiently powerful power unit based on the AMO-3 engine. At the first opportunity, the Yaroslavl Automobile Plant (the name was introduced in 1933) replaced the existing machine units with new devices. Such a restructuring affected only the equipment of the hood and transmission, but the resulting car was decided to be considered completely new. She was given the name YAG-4.
Dump truck YAS-1, the body is raised. Photo 5koleso.ru
Instead of a power unit from the Moscow AMO-3 truck, the new YAG-4 was proposed to use elements of the latest ZIS-5 machine. The engine of the same name developed 73 hp. and in its design differed little from the old AMO-3. A four-speed ZIS-5 gearbox was connected to the engine. The installation of a new power unit required the existing car to be modified, but did not lead to its radical restructuring.
YAG-3 and YAG-4 did not have any external differences associated with the use of different engines. The only noticeable difference to the exterior was the size and shape of the front bumper. On the YAG-4, a part of a larger width was used, which completely covered the wheel wings. Despite the use of a new engine, the main characteristics remained the same.
The production of YAG-4 machines was launched in 1934 and led to a halt in the construction of YAG-3. YAG-4 production lasted for two years; during this time, almost 5350 trucks were built. The main recipients of such equipment were the army and various enterprises in need of lifting vehicles.
In 1935, YaAZ developed their first dump truck - YAS-1. This machine was based on the YAG-4 design and had a number of characteristic features. First of all, it was equipped with a hydraulic pump driven by a new transfer case through a separate propeller shaft. Oil was supplied to two hydraulic cylinders, which were responsible for lifting the body. The rear of the chassis frame has been reinforced to transfer loads from the swing body. The body itself was made on the basis of the existing one. At the same time, the sides were fixed and reinforced, and the inner surface was covered with a steel sheet. The tailgate was attached to the axle at the top and swayed freely with the locks open.
New devices for the YAS-1 dump truck weighed almost 900 kg, which should have led to an increase in the curb weight in comparison with the basic YAG-4 truck. Because of this, the payload had to be reduced to 4 tons. The driving characteristics remained the same. It took 25 seconds to raise and lower the body.
The same type of car from a different angle, you can consider the body structure. Photo of the magazine "M-hobby"
Since 1935, YaS-1 and YaG-4 were produced in parallel. Before the end of production of basic trucks, YaAZ managed to build only 573 dump trucks. Such equipment was intended mainly for construction and mining organizations working with soil and other bulk cargo.
Family development
The first cars of the YAG brand, built on the basis of the Ya-5, were produced until 1936. For several years, the Yaroslavl Automobile Plant managed to build more than 8600 flatbed trucks and heavy-duty dump trucks. This technique has been active in various industries and has contributed to the construction of our economy. However, despite the possibility of building in large numbers, YAG-3 and YAG-4 did not fully suit the automakers and operators. Further development of the design and the creation of new samples were required.
In 1936, the YAG-6 truck went into production. It retained some of the features of its predecessors, but at the same time it had serious differences. For several years, this car became the most massive five-tonne of the Yaroslavl Automobile Plant. Its assembly continued until the early forties and was stopped only during the Great Patriotic War. It should be noted that production was curtailed due to the unavailability of some units. If they were available, YaG-6 would continue to roll off the assembly line and replenish the Red Army's vehicle fleet, bringing the victory closer.
The Yaroslavl truck Ya-4 became the founder of a whole family of high-capacity vehicles, and the next Ya-5 eventually turned out to be the basis for all subsequent vehicles. When creating the first cars of the YAG brand, the development of all previously laid down ideas continued, and eventually led to the appearance of the next YAG-6 truck. This car of the five-ton class, like its predecessors, is worthy of separate consideration.
