On little-known developments of Soviet automakers, using the MAZ-543 as an example
We have SUCH devices!!!
But we won’t tell you about them...
But we won’t tell you about them...
After the collapse of the USSR, many of our citizens, and those who no longer lived here, took to vilifying everything Soviet. Soviet automakers, incapable of making high-quality all-wheel-drive vehicles, came under particular criticism. For, according to the poorly informed public, while foreign designers were creating such technical masterpieces as the Quattro, Synchro, Fomatic, Fomotion, and other super-selective models, ours were only able to produce the Niva, which VAZ has been refining and updating for almost half a century, with no end in sight to this protracted creative process. Yet, for some reason, the Niva's quality has steadily declined over the years.
It's a paradox, though...
In fact, Soviet designers also had much to be proud of, but they weren't always able to share their unique developments with the general public. Many projects were classified and carried out in special design bureaus and closed workshops at pilot plants.
One example.
In 1954, SKB-1 was established at the Minsk Automobile Plant, and Boris Lvovich Shaposhnik was appointed its director. The SKB's design team developed and, in 1956, built a unique 8x8 chassis in metal as prototypes. This design went into production in 1958 under the designation MAZ-535A and was used in the Soviet Army for towing trailers, which typically carried large vehicles. missiles:
The first batches of MAZ-535A and MAZ-537 were manufactured at MAZ, then the design documentation for them was transferred to KZKT to organize their serial production.
This chassis then became the basis for the design of other models for the army, but telling about them would require writing a separate thick book.
Therefore, I will limit myself to a brief essay on only the most famous of them – MAZ-543.
The first prototype of the vehicle was manufactured in 1958, but its serial production began only in 1962 under the designation MAZ-543.
This car was later nicknamed "Hurricane":
Several “civilian” models were created on the same chassis, among which the most famous was the MAZ-543P with a flatbed platform (1966-1974):
In 1974, production of a new civilian version began on the same MAZ-543 chassis, now designated MAZ-7310 (1973-1991). This was a tractor with an all-metal high-sided platform with a load capacity of 20 tons.
Since 1986, the production of the following models of the family with increased carrying capacity began: 7313 (21 tons) and 73131 (23 tons) on the unified chassis of the Oplot army family.
The Odessa January Uprising Plant and its successor, Krayan OJSC, also mounted equipment for heavy, dual-purpose multi-purpose hydraulic truck cranes on the civilian MAZ-73101 and MAZ-73131 chassis.
Essentially, civilian vehicles were simply modified military trucks without shielded electrical equipment, blackout devices, communications equipment, or other specialized equipment. They all had their own markings, but they were not widely used in the national economy due to their high cost and size, which prevented them from being used on public roads. Therefore, according to Soviet classification, they were classified as "off-road vehicles."
The 543 chassis and its subsequent modifications had a number of interesting design features, which can be best illustrated using the 7310 model as an example.
The truck, with dimensions of 11567x2975x2950 (mm), had two separate two-door fiberglass cabins, with the driver in the left one.
The basis of the power unit was a light-alloy 12-cylinder diesel engine D12A-525A with a maximum power of 525 hp at 2000 rpm, tracing its lineage back to the famous tank B-2. High-strength alloy steels were used in the chassis, which allowed the vehicle to achieve a curb weight of 23 tons with a payload capacity of 20 tons.
The transmission was a three-speed automatic (GMCP). The suspension was independent, lever-and-torsion bar, with a ground clearance of 400 mm. Light-alloy rims were fitted with low-pressure tires with an off-road tread pattern. These features contributed to the vehicle's excellent off-road capability and smooth ride.
The cargo platform, measuring 7222 x 2848 x 707 mm, had 5 folding metal sides.
But the most interesting was the transmission developed by a team led by lead designer Anatoly Khristoforovich Lefarov, who devoted his entire life to the study and design of differentials for wheeled vehicles and published several books describing these mechanisms and their properties.
It used 7 differential mechanisms.
The main (inter-bogie) differential (D in the diagram) was symmetrical, low friction, and equipped with a lock.
A freewheel clutch (MSX in the diagram), also called a “freewheel differential”, was installed in the transfer case of the front bogie.
The two front steering axles use self-locking disc differentials (SD in the diagram).
The transfer case of the rear bogie and its drive axles were equipped with MSH.
What was this needed for?
When driving a high-performance wheeled vehicle in conditions of poor tire traction, the power transmission must be rigidly coupled (either with locked differentials or a drive without them, such as the center differential in the UAZ). When turning, a loose connection is required, i.e., unlocked differentials.
When the drive is locked, a high turning torque is generated, causing the vehicle to strongly prefer straight-line driving, and its maneuverability becomes unsatisfactory. With a long wheelbase, the impact of this negative factor becomes especially noticeable (the MAZ-7310 chassis has a 7700 mm wheelbase). On hard roads, when turning curves, parasitic power is generated in the transmission, accelerating wear and tear on its components and increasing the risk of failure along the way.
Consequently, there were (as is always the case in vehicle design) two mutually conflicting requirements that could have been satisfied by introducing 7-speed manual transmissions with 7 locking mechanisms. However, this would have excessively complicated the transmission design and distracted the driver, who would have had to frequently engage and disengage multiple locking mechanisms while driving.
The transmission solutions described above, applied by the Minsk designers, made it possible to achieve an acceptable compromise.
Before turning, the driver first unlocked the main clutch. Then, after turning the steering wheel (equipped with power steering), thanks to the properties of the MCS, the first axle was automatically disengaged from the powertrain, then the outer wheel of the third axle, and then the entire third axle. After this, the vehicle's movement was provided by the wheels of the second and fourth axles.
And with the smallest turning radius on a flat surface, the outer wheel of the 4th axle could also become disconnected, as a result of which the car was moved by only 3 of its 8 wheels with the minimum possible (for such dimensions) moment of resistance to turning.
And most importantly, the transmission operating modes changed automatically, without the need for complex electronics with numerous monitoring devices such as wheel speed sensors, steering angle sensors, etc.
Let me remind you that such a complex transmission was made by Soviet designers in the late 50s of the last century.
Subsequently, designers at the Minsk Automobile Plant developed even more complex basic chassis with 12x12 and 12x14 wheel arrangements, which gave birth to several more models of military vehicles carrying weapons.
So some Soviet automobile designers also had something to be proud of. But since their designs were primarily used by the military, the resulting vehicles were kept secret. Therefore, although they were occasionally shown to the Soviet people during parades on Red Square, the unique features of their technical design were known only to a small number of specialists.
Even now, their detailed description can only be found in rare specialized literature.
In conclusion, it is worth mentioning an interesting fact: the birthday of the Russian Strategic Missile Forces, celebrated on December 17, where vehicles created by SKB-1 were primarily used, coincided with the birthday of B. L. Shaposhnik.
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