Monday 20 December 2021

Object 430

One of the most important principles in tank building is that one must start working on a tank's successor as soon as it is accepted into service. Various intermediate stages are developed on the way to the next tank, some of which remains as drafts or technical projects, and some even reach the full scale model stage. One such vehicle that never came to be was the Object 430 tank designed in 1953.

Object 430 model.

Factory #75 designed the Object 430 in two variants: one with an 8D12-U engine and one with a 4TPD engine. In both cases, the Object 430 was a medium tank with a single turret, rear transmission and engine compartments, and more rational use of internal space compared to existing tanks.

The Object 430's rational and dense layout made it 170 mm narrower and 115 mm lower compared to the T-54. At the same time, the the turret ring was widened from 1815 to 2200 mm. The sides of the hull were cleared from ammunition racks, fire suppression systems, and other components, which increased the useful volume of the fighting compartment and improved the crew's comfort.

Object 430 model as seen from the front.

Object 430 model from the back.

The narrower hull of the Object 430 as well as new design of the engine and suspension allowed the increase of turret armour by 20-40%, installation of a stabilized 100 mm D-54 gun with muzzle velocity of 1050 m/s, and increase of ammunition carried on board to 55 rounds compared to the T-54's 35.

The 580 hp 8D12-U engine and improved efficiency transmission gave the Object 430 high mobility. Total fuel capacity of 1000 L gave it a higher cruising range, and ground pressure of 0.75 kg/cm² gave it good off-road performance.

Object 430 model from the side.

Comparison of the silhouettes of the T-54 (dotted line) and Object 430.

The second variant of the Object 430 with a 4TPD engine carried 58 rounds of ammunition for the main gun and 1200 L of fuel (compared to the T-54's 730 L) without reducing the fighting compartment volume.

First variant

The first variant of the Object 430 had a rear engine and transmission compartment separated from the fighting compartment by a rigid waterproof bulkhead. The front of the hull contained all devices and mechanisms necessary for combat as well as ammunition.

Drawings of the Object 430 variant with the 8D12-U engine.

The front of the hull contained an ammunition rack with 29 rounds in the right and the driver's seat on the left. The fighting compartment and turret were in the center. The fighting compartment contained the 100 mm D-54 gun and stabilizer, coaxial 7.62 mm machine gun, 11 rounds of main gun ammunition, three crewmen, radio, and sights.

Four rounds (two per side) were carried in the hull. Two rounds were carried in the rear of the turret. Five more were carried in an automatic magazine located on the right side of the fighting compartment turntable. 15 more rounds of ammunition were kept in wet racks on the left and right side. This solution allowed the loader to use either the front or rear racks, improving the rate of fire.
Cutaway of the Object 430 first variant.

The engine compartment was tightly laid out with the goal of optimal use of space and easy access to components for installation and removal. The engine was located along the center of the tank and linked directly to the gearbox.

Four batteries were located to the left and right of the engine in the lower part of the hull towards the fighting compartment (where they could be accessed from). The wet ammunition racks and a 390 L fuel tank were above them. Two 50 L tanks were located between the ammunition racks and transmission; the right one held fuel, the left one held oil.

Object 430 first variant top view with the fighting and engine compartments shown.

A 260 L fuel tank was located in the front of the hull and an 80 L oil tank was located in the rear. Additional 300 L of fuel was carried on the fenders outside of the hull. In total, the tank carried 1000 L of fuel and 130 L of oil.

Ejectors were mounted to the left and right of the transmission on the rear plate in sealed boxes. Air filters were located behind the engine between the cooling compartments and above the transmission. They could be accessed through a hatch. A heater was located on the left, running along the engine. The fuel pump, injectors, water pump, and oil pump could be accessed through hatches in the engine deck and from under the tank,

Ammunition racks and fuel tanks of the Object 430 first variant.

Second variant

The second variant of the Object 430 also had a rear engine and transmission compartment with a fighting compartment in the front.

The 29 round ammunition rack and driver's workspace were located in the front as well. The turret and fighting compartment were moved 150 mm back compared to the first variant, which allowed a 500 mm wide hatch to be placed above his seat.

Cutaway of the Object 430 second variant.

The fighting compartment contained the 100 mm D-54 gun, stabilizer, coaxial machine gun, 39 rounds of ammunition, three crewmen, radio, and sights.

28 rounds were carried in a perpendicular rack near the engine compartment bulkhead. Four rounds (two per side) were carried on the sides of the hull, two rounds in the rear of the turret, and five rounds in an automatic magazine located on the right side of the fighting compartment turntable. The tank carried 68 rounds of ammunition in total.

Object 430 second variant from above, fighting compartment and engine shown.

Two air cleaners were located on the rear plate above the transmission. Ejector compartments were located to the left and right of the engine. Four batteries that could be accessed from the fighting compartment were located to the left and right of the engine. Two fuel tanks with a total of 360 L capacity were located above the batteries.

A 450 L fuel tank was located in the front of the hull. Two 40 L tanks were located in the back. 350 L of fuel was carried outside the tank on the fenders. In total, the tank carried 1200 L of fuel. A 90 L oil tank was located in the very rear of the hull.

Ammunition and fuel carried on the second Object 430 variant.

Both Object 430 variants had a casut turret with variable thickness sides and 2200 mm wide turret ring. A 30 mm thick rolled roof was welded to the top of the turret. It contained two hatches: one for the commander with five observation devices and a stabilized sight and one for the loader with a 14.5 mm KPVT AA machine gun mount.

Unlike all other existing medium tank turrets, the Object 430 turret had no welded frame thanks to the special design of D-54 trunnions. The trunnions were located inside the turret directly.

Object 430 turret.

Object 430 hull.

Object 430 armour thickness compared with the armour of the T-54.

The hull and turret armour protected from a 100 mm shell traveling at a speed of 930 m/s in a 100 degree arc for the turret and 50 degree arc for the hull. The hull and turret of the Object 430 were considerably better protected than those of the T-54 and in some cases even surpassed the IS-4 and Object 730. The armour was not even compared to that of foreign tanks, as they all had considerably weaker protection.

Protection diagram for the hull of the Object 430.


Two suspension variants were developed for the Object 430. In both cases, the suspension element was a torsion bar, 52 and 46 mm in diameter with a 380 and 220 mm long swing arm respectively. The suspension travel was 329 mm (full) or 200 mm (in motion) for the first variant and 255 and 200 respectively for the second.

Torsion bar suspension with a road wheel.

The use of outboard bearings reduced the load on the swing arm hub compared to the T-54 and allowed the torsion bar to be longer, which gave the road wheels more travel.

Piston type hydraulic shock absorbers were installed on the first and sixth road wheel on each side in both variants.


The tracks of the Object 430 consisted of cast links with two guide horns linked together with smooth rings. Four variants of tracks were developed for the Object 430, mostly differing in the joints.

The first variant used a pin joint. The track pin was 30 mm thick and fixed in one of the loops. Only two friction points existed in the pin and endured half as much pressure. These tracks would last approximately three times as long as tracks on the T-54.

First variant of the tracks.

The second variant had a pin joint with an expanded friction surface. In this case, the highly hardened track pin was fixed in one of the loops and was contained in an insert which was also highly hardened and fixed in the other loop. The greater friction surface and 1.87 times less pressure than on the T-54 as well as the high hardness of the components would radically reduce the wear of the joint and increase its lifespan.

Second variant of the tracks.

The third variant proposed in the project was a pinless track where the slipping friction was handled by bearings. The friction surfaces were also expanded, which reduced the pressure and therefore the wear, increasing the lifespan of the track.

Third variant of the tracks.

The fourth variant was also pinless where rolling friction was used instead. The ball bearings in this design had a 320 mm wide friction surface, which would greatly increase the lifespan of the track given proper materials and hardening.

Fourth type of the tracks.

In any case, the track would consist of 90 560 mm wide links per side with a pitch of 137 mm. Unlike any other domestic tank track, the Object 430 had rubber pads build into face. The use of a rubberized track and a metal road wheel saved about 300 kg of rubber compared to the T-54 and generally reduced the weight of the running gear, which improved the vehicle's mobility by reducing its unsprung mass and improving the function of the rubber itself.

Model of the Object 430.

Calculations showed that the rubber would heat up less than on the T-54 at a speed of 48 kph and ambient temperature of 40 degrees. The rubber pads would only heat up to 55 degrees, whereas the T-54's rubber rims would heat up to 115 degrees in the same conditions.

These qualities of the Object 430's running gear would both reduce restrictions when driving at high speeds in hot climates and improve the lifespan of the rubber and tracks as a whole.


The new medium tank project showed that a better layout of mechanisms and an improved design of said mechanisms could increase the tactical-technical characteristics of a medium tank while keeping its weight down to 35.5-35 tons. 

This increase in parameters was significant, surpassing those of Western tanks and in some cases even the IS-3, IS-4, and Object 730. The main factors that allowed factory #75 to achieve this were the founding principles of this project:
  • Simplicity of the design and layout.
  • Maximum use of the tank's internal volume.
  • Reduction in weight of all components without exception.
  • Simplicity in design and production for all components.
  • Economy of expensive or rare materials.
In addition to its high tactical-technical characteristics, the Object 430 was supposed to match modern requirements for ease of production, low cost, and length of service applied to all modern fighting vehicles. Nevertheless, its designers were already working on a new tank by the spring of 1954 and the Object 430 was off to the archives.


  1. Shame. What ideas got reused from Object 430 in mass-produced tanks?

    Also, typo - Ctrl+F

  2. *Ctrl+F 'keeping its weight down to 35.5-35 tons.'