Soviet 80s Future tank projects. Object “ 490” , Object “490A” (Rebel), “490A” with 152 mm gun (Boxer).

Work on the future Soviet tank was officially conducted in Kharkov design bureau from the beginning of the 1980s under the guidance of N. A.  Shomin, chief designer of the KMDB.  Initiative work on the new medium tank of the 80-s NST-80 [New Medium Tank] began even earlier, from 08.17.1977, when the group of designers approved by N. A. Shomin was formed.

The layout of the future tank was represented by two projects - a two men crew Object “ 490” developed by E. A. Morozov and Object “490A” with a crew of three, a low-profile turret and low-profile turret, the design of which was headed by V. R. Kovalyukh, deputy chief designer of the KMDB.

Wooden model of the tank Object “ 490” and a reloading and supply vehicle on it’s chassis designed by E. A. Morozov, 1:10.

Layout of “Object 490” by E. A. Morozov had a risky solution requiring a further reaserches associated with a crew of two people, which increased the requirements for information support and controls, while the decisions on the automatic loader were concise and not causing problematic issues.

The reloading and supply vehicle was designed to rearm and refuel the tank, and assist the crew with service. It was possible to rearm the tank from inside the vehicle, five replaceable autonomous autoloader containers were stored on the vehicle as well as fyel and other consumables.

Object 490 "Poplar". Unknown Soviet future tank of 80s

Wooden model of the tank Object “490A”, 1:10.

The tank had a low-profile turret with removed weapons, the driver was located to the left (along the tank), to his right there was an internal fuel reserve of 1290 liters .  The gunner and the commander were placed to the left in the tower one after another.  The commander of the gunner to the left of the gun.  Landing and leaving the tank was provided through a hatch in the tower.

 By 1982, a full-size wooden model of the “Object 490A” tank was made.  Later the undercarriage was made and a prototype tank.

Initial design featured rather conventional decisions with crew placed one after another at the left side of tank hull. Isolated fuel tank was placed to the right from the driver. The autoloader was placed at the right side of the battle compartments’ and was isolated from the crew.

Kharkov design bureau, 1981.

Lower row: Protopopov I.L., Kovalyukh V.R., Abramov A.A., Kretov A.M., Gerasimov V.N., Portnoy V.Ya.

  Top row: Gnedash N.F., Bershov AV, Pivnev A.I., Zavadsky A.M., Sakharov M.I., Baisov M.Ya., Apukhtin Yu.M., Ritz A.R.  , Tsarev V.V.

In the “Object 490A” tank, in spite of the relative simplicity of the layout, there was a risky decision – it relied on not yet fully developed and time consuming solutions of it’s autoloader associated with variable form charges (shape of the charge changed during loading).

Within the framework of the themes “Commonwealth”, “Rebel” and “Taran”, samples of a 125-mm caseless loading tank gun with an elegant solution of a breach node and a 152-mm LP-81 and LP-83 high firepower guns were achieved.

The new gun design most promising feature was the usage of variable form charges. They allowed to place a rounds in the autoloader as compact as possible.

The choice was made in favor of the object “490A”.  The main efforts were thrown on his development.  E. A. Morozov continued his development, he proposed a variant of the tank 490 with a crew of 3 people, this option was the most simple to implement and resembled later French tanks Leclerc, Japanese Type-10 and Korean K-2 Black Panther.

Contour of the round with variable form charge.  View from above.

Such form allowed maximal usage of the space of the autoloader.

 The emphasis in the design process was on an unconventional gun installation and on ammunition, based on the so-called "charges of a variable form."  Strictly speaking, these charges ruined the tank, despite the progressive solutions laid down in it by other systems, because they [charges] did not appear on time.  This led to a radical change in the design of the automatic loader with all the ensuing consequences [development of Object “477”]. From E. Vavilonsky .

The object “490A” (research theme Rebel) had 125 mm gun of increased power installed with charges of a variable form, the placement of weapons made it possible to ensure a sufficiently high, by Soviet standards, the declension angle of the gun - 8 °.  Since 1980, the department No. 31 of the “Burevestnik” research institute has been developing gun design for the charges.

Test rig of the tank Object "490A"

Test rig of the tank Object "490A", only the hull survived till nowadays, turret was used for shooting trials.

Fate of another prototype is unknown.

Test rig of the tank Object "490A" cut section. It had a lot of differences from the tank proposed for manufacture.

Soviet researchers predicted the level of armor protection of Western tanks, so the assessment of the level of Western tanks “Leopard- 3” and “MBT- 90” [Abrams replacement] was 680...700 mm equivalent of steel rolled homogenous armor. 

Improvement of US MBT technical level

This required the transition to a more powerful 152 mm caliber gun. Significant growth of firepower, protection and mobility level was planned to be achieved in dimensions and with the mass of the existing serial tanks –  46 tons.

Object “490A” (research theme “Boxer”)

Weight 46 tons.  Main armament 152 mm smooth-bore gun with rounds with charges of a variable form, coaxial with 7,62mm PKT machine gun. Ammunition consisted of 40 rounds, 32 of them were in autoloader. APFSDS RHA penetration at 2000 m was 700 mm (minimum level), HEAT - 1100, GL-ATGM - 1200 mm .

The equivalent horizontal thickness of the hull and turret armor is 700 mm against APFSDS and 1300 from the CE (minimum level).  The bottom of the hull is steel + composite + steel, 100 ... 60 mm , designed to protect against of 10 kg HE explosion beyond the gull. The roof and hatches had 200 mm were composite armor.  Hull sides are 185 (multilayer composite armor) + 80 mm side screens.  The fuel compartment in hull - armor 16 mm . Local protection of crew members with steel+composite lining.

The automatic loader of 152 mm armed “490A” was changed, the ammunition was placed in two mechanized packs in the front and rear sectors of the cabin.  Shots in trays with a fixation system were placed horizontally.  In the center of the aft cabin was located the mechanism for lifting shots, which arrived at the rendered weapon installation through the hatch in the roof of the crew compartment.  From stacking shots came in a circular conveyor located under the platform of the crew. 

Placement of ammunition and crew positions in the tank Object "490A"

Active protection - the installation options "Arena", "Dozd" [Rain], "Standart" were considered.  APS provided protection against ATGM, RPG, artillery shells [HEAT], APSDS and submunitions (attack from above).  Protective shots were placed around the perimeter of the tank hull.  Radar - on the sides of the turret.

A variant of the Object “490A” Boxer tank with 152 mm gun and future “Standart” APS, 1984.

Due to the placement of the ring conveyor under the cabin of the fighting compartment, the height of the tank hull increased.  Compared with the original version, the length of the aft part of the casing of the armament module was reduced; one machine gun was mounted on the upper part of the casing.

Mobility

The motor compartment was unified in terms of basic dimensions for the installation of a diesel engine  product “ 495” (6TD) and a gas turbine product “29G” (both with power 1250 hp).  Considered the use of the engine product 495 with electromechanical or hydro mechanical transmission.

The main engine version was 1250 hp variant 6TD.  The option of installing a gas turbine engine, the 29G product with a hydro-volumetric turning mechanism, which in the mid-80s for some time began to be considered as the main engine for serial and advanced tanks, was also worked out. The final decision on the choice of the engine for the prospective came only in the late 80-s, the collapse of the USSR prevented the implementation of the plan. As a result of our joint work with Kharkov, a joint decision was made to adopt for the subsequent development a unified motor compartments with the Kharkov designed 6TD-2 engine, but with athe tank engine support systems created by the Tagil designers [From the book Chief Designer Vladimir Potkin.  Tank breakthrough.  Digest of articles.].

Transmission schematics of Object “ 187” with “459AM” (6TD-2) engine.

Chassis of the test rig was created on the basis of the T-64 with coaxial torsions, the tank was supposed to use the chassis with non-axial torsions (2/3) of differentiated stiffness.  Hydraulic shock absorbers with a two-stage characteristic, also considered a variant with bladed shock-absorber.  The use of the undercarriage based on the “Object 434” [T-64 series] type provided less weight by ~ 2 tons compared with the undercarriage of the “Object 219” type.

The final design

The final design of a tank with 152 mm gun with rounds with charges of a variable form was developed in 1984-85, but was not made in metal with the adoption of a final decision on the transition to a new type of autoloader because of  delays with charges of a variable form.  Thus, the layout of the future tank underwent regular changes, as a result of which the tank Object “ 477” known under designation of research work “Boxer” and “Molot” [Hummer] was created, the layout of which was approved in 1985.  From the diaries of Yu. M. Apukhtin: 05/12/85.  Shomin finally approved the layout.  Kovalyukh achieved that the design of the automatic loader is not ring-shaped, but with a closed circuit with replenishing from the hull storage behind the combat compartments.  Let's see what happens.

One of the missed opportunities was the design of the tank object “ 490” with a three men crew.  The tank had a classic layout, ammunition and fuel was completely isolated from the crew.  The automatic loader was located in a turret niche and had a simple scheme similar to many modern developments (“Leclerc” e.t.c.).  The restrictions on the length of the rounds were not so tight as in other projects.

Object “ 490” with a three men crew.