Widely recognized in the design of the tank is the idea of three elements that define its effectiveness: speed, firepower, and mobility. With regards to firepower, modern tanks have all come down to the unified design of a large main cannon mounted centrally within a turret. However, the concept of how this gun is operated has constantly evolved throughout years of war. Nowhere as prevalent can this be seen as with how the gun is loaded. With technological advancements, this has boiled down to the debate: autoloader or manual loader? Man versus machine? Each bears its respective strengths and weaknesses.
The History of Autoloaders
While the use of autocannons was already commonplace by World War 2, being used on various antiaircraft weapons and light armored vehicles, it would not be until the post-war era that autoloaders were formally introduced to tanks with their high caliber guns. Revolutionary designs such as the French AMX-13, Swedish Stridsvagn 103, and Soviet T-64 were among the first to practically implement this new technology. Autoloaders took the traditional four-man crew of tanks, and replaced the loader with a machine, leaving just the commander, driver, and gunner.
French AMX-13 tank. Interestingly, it used not only an autoloader but an oscillating turret- the entire turret assembly moved on a hinged joint.
Image Credits: Wikimedia Commons
The Design of Autoloaders
The two main styles of autoloaders used on contemporary tanks are known as bustle/cassette autoloaders and carousel autoloaders. To maintain relevance and simplicity, this article will not be covering other less common variants of autoloaders like the one on the M1128 Stryker Mobile Gun System. For both types of autoloaders, a computer system is used to identify and then load the shells.
With carousel autoloaders, ammunition is stored within the turret basket, under the hull in a carousel. The carousel rotates so that the chosen type of round is aligned with the gun, upon which a machine lifts it and rams it into the gun breach. This design is heavily used among Russian main battle tanks including the T-64, T-72, and T-14 Armata. Typically with carousel autoloaders, the propellant for a round and the round itself are both loaded separately as two pieces. Carousel autoloaders can store shells either horizontally as with vehicles like the T-90, or vertically like with the T-64.
Diagram of the carousel autoloaders used on Russian tanks
Image Credits: Sergo Borisov on Youtube
Bustle autoloaders also known as cassette autoloaders, work by storing ammunition horizontally in the bustle of the tank (rear of the turret). A conveyor system then cycles the ammunition to the designated type of round, and it is rammed into the gun breech. This style of autoloader is most notably used on tanks like the French Leclerc, Japanese Type 10 and Type 90, and the South Korean K2 Black Panther.
French Leclerc Tank. This vehicle uses a bustle autoloader.
Image Credits: Federation of American Scientists Military Analysis Network
Key Points of Autoloaders
Space and Size
One of the most significant benefits of using an autoloader is that it allows for a more compact vehicle design. By eliminating a member of the crew the overall size and silhouette of the vehicle can be made smaller, bringing about several advantages such as making the vehicle a smaller target and improving mobility. A trade-off in bustle autoloaders however is the need for a larger bustle to accommodate for the additional machinery of an autoloader and to store ammunition. The result is a larger turret profile.
Diagram comparing the dimensions of the American M-60 tank and the Soviet T-64. Soviet tank doctrine favored the usage of smaller, low-profile tanks.
Image Credits: armor.kiev.ua on LiveJournal
Rate of Fire
While autoloaders are reputed to be slower than a human loader, technological improvements have largely cut down on the difference in loading times. Further, current loading speeds are adequately fast that other factors of firepower such as target acquisition, present themselves as larger, more time-consuming issues. Autoloaders do however win out in terms of a sustained rate of fire. Autoloaders do not have to contend with issues such as fatigue that a human loader might have to during extended periods of combat. Additionally, ammunition location is not a problem for autoloaders as all rounds are readily available for it. With a manually loaded main gun, once rounds are depleted from the ready rack, the location of ammunition closest to the loader and the gun, more time is needed to extract rounds from other storage spots further in the vehicle.
Protection
Largely recognized is the need to protect the ammunition storage of a tank. When the ammunition storage is struck, there is a high chance of it “cooking-off,” meaning that the ammunition explodes, potentially resulting in a catastrophic event that destroys the vehicle. In modern tanks, the usage of blowout panels and armored ammunition compartments has greatly increased the chances of survival for crews and their tanks.
Bustle autoloaders in particular stand to benefit due to the relatively small opening between the crew compartment and the ammo. Whereas tanks with a human loader require a large armored door to accommodate loading, bustle autoloaders only require an opening large enough for the shell to pass through to the gun. This means improved protection for the vehicle if it is struck while loading.
With carousel autoloaders, the threat of a catastrophic ammunition detonation is far greater due to it surrounding the crew in the turret basket. While Russian tanks such as the T-90 attempt to remedy this by placing armor between the crew and ammo, tanks using carousel autoloaders are at far greater risk of destruction during an ammunition cook-off. In the future, it is possible to see this problem negated through further automation. The Russian T-14 Armata for example, utilizes an unmanned turret, placing the crew in an armored capsule away from the gun.
The interior of an American M1 Abrams main battle tank. The Abrams uses a human loader and the open loading door can be seen to the right of the image.
Image Credits: Military Archive on Youtube
Crew Duties and Mechanical Reliability
While the removal of one crew member can be seen as a benefit to a tank using an autoloader, there is much speculation as to how this affects crew duties. With a three-man crew, any jobs normally performed would be compounded among a smaller number of people. This would include duties of mechanical maintenance of the vehicle, along with watch shifts and resupplying. The effect would be increased crew fatigue and as a result, worsened combat performance. The autoloader itself is also an additional piece of machinery that could potentially be damaged and rendered inoperable, resulting in a firepower kill of the tank.
Loading Position
A minor issue with autoloaders is their need to reset their gun to a set position upon loading. Due to the ammunition compartment’s inherent inability to move to align with the gun be it elevated or depressed, autoloaders require the gun to “reset” to a position flush with the loading mechanism. With early implementations of the autoloader, this was a significant issue because it meant that weapons sights had to be taken off-target to reload. Tanks like the French AMX-13 aimed to circumvent this by using what is referred to as an oscillating turret, where the entirety of the turret assembly is on a hinge connected to the hull. This, however, presented its own design issues including large vulnerabilities in armor protection. Due to the increasing reliance on computer systems for tank fire control, the issue of having to reset the gun could be seen as redundant.
Ammo Size
It should be noted that with larger calibers of shells, autoloaders are vastly superior to a human loader. Shells of caliber 152mm and above are heavy for example, making a manual loading process more difficult. This can already be seen with various modern self-propelled guns, utilizing them for their increased speed and efficiency compared to a human. As tank armor continues to improve, the prospect of enlarging gun caliber as a counter is certainly not unrealistic. This idea has been tested before, namely with the Component Advanced Technology Testbed (CATTB), an American tank prototype using a 140mm autoloaded gun on the chassis of the M1 Abrams. While this project was later canceled, it showcased the possible role of autoloaders in the future of anti-armor weapon systems.
CATTB. Note the large 140mm cannon and turret.
Image Credits: Unknown
Moving Forward
As the battlefield has evolved throughout the years, so has the tank. The autoloader as a component within tanks has been constantly changing to meet the needs of the men who crew them. From their earliest iterations on prototypes in World War 2, to the modern day, autoloaders enter themselves into one of the most critical aspects of firepower. With it, they bring all the mechanical reliabilities of a machine, but also all the nuances of their servicing needs. Today, many countries like Japan and Russia have already demonstrated their feasibility through numerous designs they have fielded. While their replacement of human loaders is still met with skepticism, it is undeniable that their role will inevitably expand moving into the future.
Sources and References
https://www.nap.edu/read/19457/chapter/5#18
https://www.ijsr.net/archive/v3i7/MDIwMTQxMTU4.pdf
https://archive.org/details/DTIC_ADA237212/page/n39/mode/2up?q=autoloader
https://archive.org/details/DTIC_ADA392790
https://www.globalsecurity.org/military/systems/ground/cattb.htm
http://www.army-guide.com/eng/product3648.html
http://fofanov.armor.kiev.ua/Tanks/EQP/al-640.html
Images (where applicable)
https://commons.wikimedia.org/wiki/File:AMX-13-.jpg
https://armor-kiev-ua.livejournal.com/6000.html
https://fas.org/man/dod-101/sys/land/row/leclerc.htm