In 1928, the Yaroslavl State Automobile Plant No. 3 mastered the production of the promising Y-4 truck. From the previous I-3, it favorably differed in the main characteristics obtained through imported power units. However, the number of engines and other devices of foreign production was limited, as a result of which it was not possible to build even one and a half hundred such trucks. Therefore, already in 1929, the designers of YAGAZ had to redo the project again for a new engine. The resulting truck was named Ya-5.
The Ya-4 truck was a modification of the previous Ya-3, deeply modernized in technical and technological terms. Its main difference was the engine, clutch and gearbox of the German company Mercedes. 54 hp engine (according to other sources, 70 hp) provided an increase in running characteristics, and also allowed to increase the payload to 4 tons. However, the USSR bought only 137 power units from Germany, and therefore the production of the Ya-4 did not last too long.
Serial truck Ya-5. Photo Wikimedia Commons
Understanding the current situation, at the beginning of 1929, the YAGAZ design bureau began to rework the existing project. The leadership of the automotive industry found an opportunity to purchase new foreign-made power units, this time it was about American-made components. The designers had to take into account the features of the new engines and transmissions, and with their use, create an updated version of the Ya-4 truck.
During the tests and operation of the Ya-4 machines, it was possible to collect a considerable amount of data on the operation of certain units, as well as on the convenience of the drivers. All this information should also be taken into account when creating a new modification of the truck. Finally, the new engine with increased power provided wider technical and operational capabilities. It soon became clear that the modernized version of the car was seriously different from the base one, and therefore could be considered a new model.
The new project was designated as Ya-5. In this index, the letter indicated the city of origin of the car, and the figure indicated not only the project number, but also the carrying capacity of the car. The new power unit made it possible to transfer the modernized truck to the five-ton class. Thus, the Yaroslavl designers have developed and brought to the series the first domestic "five-ton".
In general, I-5 was considered as a deep modernization of the existing I-4. The project provided for the preservation of the main features of the architecture and a number of units, but proposed a number of innovations of a technical and technological nature. As before, the car was built on the basis of a rigid metal frame with a front engine and received a rear-wheel drive two-axle chassis. The truck was supposed to be equipped with an onboard body, but later other configuration options were created.
The chassis of the car. The underestimated position of the engine is clearly visible. Photo Gruzovikpress.ru
The frame for Ya-5 was borrowed from a previous project. It was a riveted unit assembled from standard steel channels # 16 (spars) and # 10 (cross members). On such a frame, the engine under the hood, the driver's cab and the cargo platform were sequentially installed. In fact, the frame for the Ya-5 differed from the existing one only in the location of the mounts for the power unit and transmission parts.
Especially for the new car, the USA purchased Hercules-YXC-B gasoline engines with a capacity of 93.5 hp. The inline six-cylinder engine was supplied complete with a carburetor, magneto and other devices. The engine was supplemented with a brass radiator of a honeycomb design, developed at YAGAZ. The engine was coupled with a Brown-Lipe multi-plate clutch. We also purchased 554 gearboxes from the same manufacturer. The power unit was installed on the front of the frame, slightly "falling through" down between the side members. As a result, the engine fan did not completely cover the radiator, and the cooling of the power plant deteriorated.
From the gearbox, the torque was fed to the horizontal propeller shaft of an open arrangement. It was connected to an inclined shaft placed in a conical casing. The latter connected the frame of the machine with the main gear case and provided the transfer of loads. The main gear remained the same, developed for the Ya-3 truck.
The undercarriage structure has been strengthened, but has retained the general features. A front axle with steerable single wheels was used. The rear axle with the main gear was completed with dual wheels. Both axles were fixed on semi-elliptical springs, and the rear had a larger number of sheets.
Chassis design. Figure Gruzovikpress.ru
The American power unit was almost the same in size and shape as the German one. Thanks to this, the I-5 retained the existing hood. The functions of its front wall were performed by a radiator. There were blinds in the side walls, and a pair of longitudinal hatches in the lid. Electric headlights were installed in front of the radiator. For access to the engine, the sides of the hood were hinged.
Ya-5 became the first truck from YAGAZ to receive an enclosed cab. The cab frame was made of wood and sheathed with metal sheets (front and side) and boards (rear wall). The roof was made of plywood. The windshield, as before, could rise. More than half of the side was given under the opening door. The glazing of the doors had a power window and fixing nuts. A 120-liter fuel tank was kept under the driver's seat.
In the Ya-5 project, an improved steering mechanism was used, but its characteristics also left much to be desired. Due to the heavy loads on the steered wheels, it was necessary to use a steering wheel with a diameter of 522 mm. However, in this case, the management was not easy. The cab floor had a standard set of three pedals. Under the driver's right hand was the gear lever. The designers have retained the previously used vacuum booster brake system.
A standard drop-side body developed in previous projects was installed behind the cab. This time, the truck could take on board a payload of up to 5 tons. However, in some conditions, for example, when working off-road, the vehicle load had to be reduced.
In the workshop of the Yaroslavl State Automobile Plant. Photo Gruzovikpress.ru
The new power unit had almost no effect on the dimensions and weight of the truck. The overall dimensions and performance of the chassis remained at the level of the base I-4. The curb weight increased to 4.75 tons with the possibility of transporting 5 tons of cargo. The maximum speed on the highway was supposed to rise to 50-53 km / h. Fuel consumption was 43 liters per 100 km of track - the tank should have been enough for about 300 km.
The first Hercules engines and other American-made products arrived in Yaroslavl by mid-1929. By this time, YAGAZ had almost completed the production of Ya-4 trucks, and the receipt of new components made it possible to build experienced Ya-5s. The machine, built with extensive use of used components, quickly passed all the necessary tests and received a recommendation for serial production.
Until the end of 1929, YAGAZ managed to build 132 new cars, probably including experimental ones. The next year, the production of equipment increased to 754 units. 1931 saw the peak of production - 1004 cars. Subsequently, the rate of release decreased. In 1932 and 1933, 346 and 47 trucks were assembled. Only one, the last, Ya-5 was handed over in 1934 - just before the start of production of the next sample.
Already in 1929, the production of a specialized chassis I-6, intended for the construction of buses, began. It was an I-5 chassis with an increased base. This parameter increased by 580 mm - up to 4.78 m. Cars of the Ya-6 type were transferred to auto repair shops in different cities, where one-volume bus bodies were built according to the standard project. The design of such a unit was determined by the capabilities of the manufacturer, and both metal and wood were used. The floor of the passenger compartment was at the level of the cargo platform, which is why stairs were provided under both doors of the bus.
Bus model on the Y-6 chassis. Photo Denisovets.ru
It should be noted that it was the Ya-6 buses that caused the reduction in the production of Ya-5 trucks. In 1931, the deliveries of imported power units were completed. As a result, it was decided to create a new truck with domestically produced units. At the same time, it was decided to leave some of the imported motors for buses. Until 1932, YAGAZ built 364 I-6 chassis, most of which became public transport.
In 1931, YAGAZ received an order for the production of I-5 trucks for Mongolia. In accordance with its conditions, the machines were to receive onboard platforms of a new design. For more convenience, they were installed lower than in the basic configuration. At the same time, wheel arches had to be arranged in the platform. Loading was carried out through the tailgate. There were also some changes in the cabin trim. This version of the truck received the nickname "Mongolka". Several dozen cars were produced, and all went to a friendly country.
By the efforts of different organizations, both with the participation of YAGAZ and without it, on the basis of the five-ton Ya-5, various machines for various purposes were created. In place of the standard cargo platform, tanks, vans, etc. were placed. Chassis Ya-5 and Ya-6 were used in the construction of fire trucks, and the longer chassis proved to be better in this role.
One of the diesel trucks Ya-5 "Koju" before the next motor rally. Photo Autowp.ru
During the operation of the equipment, various problems were identified. For example, overly “heavy” steering has become one of the main criticisms. This problem was eliminated in 1932, when serial trucks began to be equipped with a new steering system of the "Ross 302" type. In the future, such devices were sent to auto repair shops for installation on the previously released Ya-5 and Ya-6.
Engines of American production were supplied to the USSR in large quantities, but it was not possible to establish the supply of spare parts. For this reason, operators had to cope on their own, get or make the necessary parts on their own. In case of serious breakdowns, the Hercules-YXC-B engine had to be replaced with a domestic one. Most often, the available AMO-3 or ZIS-5 were used. They had less power, but without serious difficulty they were mounted on the frame and mated with the transmission. However, after such a revision, the truck could not show the design characteristics.
In 1932, an experienced truck was built with an updated frame. It still consisted of channels of different sizes, but welding was used to connect them. The new frame had advantages over the serial one, but YAGAZ at that time could not master its production, and therefore was forced to continue the production of riveted units.
The development of domestic trucks at that time was hampered by the lack of its own high-power engines. Designers from different organizations proposed new motors, and one of these projects was implemented in conjunction with YAGAZ. The advent of a new diesel engine led to the construction of prototypes called the Ya-5 Koju.
YASP semi-tracked tractor. Photo Wikimedia Commons
In 1933, the Special Design Bureau under the economic management of the OGPU under the leadership of N. R. Brilinga has developed a promising automotive diesel engine with the tentative name "Koju" ("Koba-Dzhugashvili"). For the further development of the project, specialists from YAGAZ and the Scientific Automobile and Tractor Institute were attracted. In November of the same year, YAGAZ assembled a pair of prototype Koju engines, which were soon installed on serial Y-5 trucks. On November 15, several cars of different types with different engines, including the Ya-5 "Koju" cars, entered the Yaroslavl-Moscow-Yaroslavl race. Two experienced diesel trucks coped with the task.
In June of the next year, another race took place, this time I-5s covered the path from Moscow to Tiflis and back. The road 5,000 km long took more than a month. During this time, I-5 trucks have shown their prospects in the context of the use of diesel engines. Their chassis was better than others for such engines.
After the run, NATI began to fine-tune the Koju product and create new modifications, which took several years. In 1938, the bench engine showed 110 hp. at 1800 rpm. One of the new YAGAZ trucks equipped with such an engine showed a fuel consumption of about 25 liters per 100 km, while developing a speed of up to 70 km / h. The new engine was of great interest to car manufacturers, and in 1939 preparations began for its production at the Ufa Engine Plant. However, soon the plant was transferred to the People's Commissariat of the Aviation Industry, and the Koju project was closed due to the impossibility of starting production.
Since 1931, YAGAZ has been working on the issue of creating a half-track artillery tractor based on the Ya-5 truck. However, the plant was busy with other projects, and as a result, a similar development received from the Leningrad enterprise Krasny Putilovets. At the beginning of 1934, an experienced YASP tractor was built in Leningrad. In fact, it was a truck without a standard rear axle, instead of which a tracked bogie was mounted.
Fantasy on the further development of the platform. Perhaps such samples could appear in the future. Photo Denisovets.ru
During the tests, the only experienced YASP showed high technical characteristics and confirmed the possibility of using such equipment in the troops. At the same time, the workmanship of the tracked vehicle left much to be desired. Tests were constantly interrupted for repairs, which became a reason for criticism. After the completion of the checks at the landfill, the project was stopped, and fine-tuning was not carried out.
Backlog for the future
From 1929 to 1932, the Yaroslavl State Automobile Plant No. 3 built a little less than 2300 five-ton trucks I-5. Apparently, this number also included the I-6 chassis for buses and fire engines. Just a few months after the start of production, the Ya-5 became the most massive Yaroslavl truck at that time. He managed to keep this "honorary title" for a long time.
According to various sources, the mass operation of the Ya-5 trucks and machines on the Ya-6 chassis continued until the end of the thirties. Some samples remained in service until the early forties, but by that time they had become obsolete morally and physically, and also gave way to newer technology. Unfortunately, as the resource depleted, all trucks and other vehicles were written off and disposed of. Not a single car of the Ya-5 family has survived.
It should be noted that within the framework of the Ya-5 project, a successful appearance of a heavy-duty truck was finally formed, capable of carrying loads weighing several tons. In the future, the YAGAZ Design Bureau used this look when creating a number of new cars. The last trucks, which can be considered direct "descendants" of I-5, went into production in the early forties - 10-12 years after the appearance of their "progenitor". Thus, the Ya-5, like its predecessor, the Ya-4, could rightfully be considered a milestone development that had a serious impact on the development of domestic trucks.