M1 Abrams Block III - a promising tank that did not see the light
In the early eighties, the Pentagon began a research program aimed at creating advanced equipment for the ground forces. It was supposed to create several new combat vehicles for various purposes, including the main tank.
The tank, developed under the new program, was to be a replacement for existing M1 Abrams combat vehicles. It was assumed that the first production tanks of the new model would go to the troops around the mid-nineties.
Project M1 Abrams Block III
The aim of the project, which received the designation M1 Abrams Block III, was to create a promising main tank, which in its characteristics surpasses the existing equipment of this class. As the main methods of improving the characteristics, the new layout of the internal volumes of the corps, an uninhabited fighting compartment with an automatic weapon system, as well as the use of a number of new units of the power plant and electronic equipment were called.In addition, it was assumed that in the design of the new armored vehicle some units of existing tanks would be used, with the help of which it was possible to simplify and cheapen the production of promising technology.
The main tank M1 Abrams Block III, as conceived by the designers of General Dynamics Land Systems, was supposed to have a radically new layout for American tank building. To increase the level of protection, it was proposed to increase the thickness of the upper front part of the case, as well as to place it at a large angle to the vertical. This layout of the front of the hull allows you to create a relatively large single volume to accommodate the entire crew. In front of the hull of a prospective tank, it was proposed to place the jobs of three tankers (commander, driver and gunner) side by side. With this, it was possible to improve the layout of the internal volumes of the hull, as well as to increase the level of protection of tankers.
In the middle part of the hull of the new tank should have been placed a tower with a weapon, equipped with a set of automation. The latter was supposed to carry out the loading and pointing of the gun on the commands of the crew. The proposal to create an uninhabited fighting department meant the development of the original automatic loader and a number of other equipment.
The engine and transmission were to be placed in the rear of the hull. Such a placement of the power plant was tested in practice and would not require additional research.
SRV Experimental Machine
In mid-1983, the construction of the first experimental machine called the SRV (Surrogate Research Vehicle) was completed. The SRV was designed to explore the new layout of the units inside the tank hull. The main objective of the SRV test was to work out the placement of the crew in a single volume in front of the hull. The basis for the experimental machine SRV was the chassis of the tank M1 Abrams. During the construction of the SRV base body has undergone significant changes. Due to the specific placement of the workplaces of three tankers, the front part of the hull had to be significantly lengthened. The power plant and chassis remained the same. On the pursuit mounted weight imitator turret monitors assembly. According to some reports, the SRV was later equipped with a laser system, which made it possible to carry out preliminary studies of the characteristics of the gun.
Tests of the experimental SRV machine allowed to study the pros and cons of accommodating the crew in a single volume.The main advantage of this hull layout was the ability to provide a higher level of crew protection. In addition, the placement of other units was simplified. At the same time, the original location of the tankers affected the complexity of the onboard equipment: the gunner and the commander needed relatively complex systems to monitor the situation and control the armament. However, these difficulties did not stop the project.
The first prototype of the new tank - TTB
At the end of testing the experimental machine SRV, the construction of a new prototype started. The basis for the experimental prototype of the TTB (Tank Test Bed) was the chassis of the M1 Abrams tank, refined based on the experience of testing the SRV machine. The TTB machine also had a single volume for the crew in the front of the hull, but differed in units mounted on the tower chase. The new prototype was equipped with a combat module with an uninhabited fighting compartment and a M256 120-mm smooth-bore gun mounted on original mounts.
Inside the body of the TTB car were the units of the automatic loader. 44 unitary shells were proposed to be placed in a double-row carousel shop with a vertical arrangement of cells.At the command of the crew, the automatics had to remove the projectile of the desired type from the cell and feed it to the loading line.
Next to the weapon it was proposed to place a piece of sighting equipment. In view of the non-standard accommodation of the crew, it was necessary to develop a special system using video cameras.
TTB prototype tests took place in the late eighties. Verification of the experimental vehicle showed that the proposed concept has great prospects and may be useful for creating new armored vehicles. However, it was necessary to continue research and design work. Some elements of the perspective car needed further refinement.
Increased tank firepower
At one of the stages of the M1 Abrams Block III project, there was a proposal concerning a significant increase in firepower. In the eighties, American gunsmiths worked on the project of a promising smooth-bore gun XM291, which had a caliber of 140 mm. The gun itself, automatic loader for it (XM91) and a family of 140-mm ammunition were developed in the framework of the ATAC project. The use of the XM291 cannon could lead to a significant increase in the combat capabilities of tanks.So, the muzzle energy of the XM291 gun was about twice that of the M256. In combination with the family of new ammunition, this was to significantly improve the performance of armored vehicles.
With more muzzle energy compared to existing weapons, the XM291 gun was noticeably lighter. The difference in weight XM291 and M259 exceeded 90 kg. The design of 140-mm guns allowed the replacement of the barrel. After a relatively quick procedure (about an hour), a tank equipped with an XM291 cannon could use standard 120mm ammunition. Especially for use with this gun was created automatic loader XM91.
More on ATAC firing system
The 140 mm HM – 291 cannon, which is part of the ATAS system of the US Army, with a bolt
The 140-mm smooth-bore promising tank gun (ATAC) system consists of an XM-291 cannon, an XM-91 automatic loader system, and a 140-mm ammunition family.
It was expected that the ATAS system would be the main armament of the future main battle tank M1 Abrams Block III of the US Army, the main part of the planned modernization of armored systems.
The ATAS system was installed on the test bench of the advanced element technology (CATT-B).It was created on the basis of the M-1A1 Abrams tank chassis and, in addition to the ATAS system, had a promising unified propulsion system (AIPS), a hydropneumatic suspension, the standard architecture of the ground forces wind sensors, a Rockwell multi-sensor target detection device based on CDC ADA fire control system, light track, modular armor, advanced warning device for a chemical attack, a system for collective defense against weapons of mass destruction and an integrated machine protection system with countermeasures, detection devices Ia threat and smoke means.
Prior to installation on a CATT-B stand, the ATAS system was installed in an upgraded M-1 tower on a standard M-1 tank chassis. It is also distinguished by an automatic loader developed by the Benet Lab, a modified M-1A1 fire control electronic equipment, a Rockwell multi-sensor target detection device, a standard M-1 gunner's main target sight, and a new fire control calculator. In this car, the gunner is placed on the right, as in the M – 1 tank, and the tank commander is placed on the left in the place usually occupied by the loader.
The 140 mm XM-291 cannon is a powder tank gun with a monolithic installation and a recoil mechanism that fires ammunition consisting of two parts (projectile and charge), its muzzle energy is twice the muzzle energy of the standard 120 mm M-256 gun installed in modern tanks M – 1A1 and M – 1A2 Abrams. The gun is equipped with a heat insulating cover, powder smoke extractor and is 91 kg lighter than the standard 120 – mm gun M – 256.
With a simple barrel replacement that takes one hour, this system can also fire 120-mm solid conventional and prospective ammunition.
During the operation of the XM-91 automatic loader, developed by the Benett Laboratory of the US Army, a selected type of ammunition is recognized, a telescopic camera containing a unitary projectile is moved to the charging hole, and the loading door is opened. Then the rammer mechanism moves forward and grabs the edge of the sleeve base, the projectile locking mechanism that holds the unitary projectile in place, turns off, and the inner compartment moves forward.
The docking of the inner compartment with the breech breech takes place at full lengthening and the shot is sent to the cannon.The rammer head and the inner compartment are then retracted to their original position and the loading door closes. The discharge procedure is similar, and for this procedure a reloading hole is provided in the rear of the automatic loader.
The ammunition transfer mechanism was developed by Lockheed Martin from an ammunition-mounted ammunition tower installed in a niche, ready for immediate use, containing 17,120-mm or 140-mm rounds, the ammunition in the body contains 22 140-mm rounds of two parts or 33 unitary 120-mm shots.
Automatic loading occurs at a rate of 8–12 shots per minute. The rammer is provided by Brunswick Defense.
The ATAS system’s ammunition family consists of three projectiles: the XM-964 kinetic action projectile, the XM-965 projectile, and the XM-966 training projectile for both shots.
Each shot consists of a projectile and a charge. The charge, which is identical for all three projectiles, consists of the base of the shortened part and the detonator block (similar to that of a standard 120-mm liner), a combustible side wall, an ignition system and a propelling charge.
The final of the project M1 Abrams Block III
The development of the M1 Abrams Block III tank and a promising weapon for it continued until the early nineties. During the project, some success was achieved, and the new tank could get into the troops until the end of the decade. Nevertheless, the political situation in the world affected the fate of the project. After the collapse of the Soviet Union, the American and European military began to believe that the former potential enemy no longer posed a danger, and therefore reduced the cost of promising projects. A large number of programs were frozen, and some were closed. Among others, the project for the creation of a promising main tank came under reduction.
All work on the M1 Abrams Block III project was suspended and then discontinued. It was decided to further develop the tanks along the path of improving the existing machines of the M1 Abrams family without any major design changes. One result of this approach to upgrading armored vehicles was the cessation of work on the 140 mm XM291 gun.