M4A1 Abrams Tank UpgradeThe M4A1 is essentially an M1 Abrams hull combined with a number of new upgrades, primarily to allow the preexisting M1 Abrams to continue to operate in a limited capacity within the military. While much larger and heavier than modern tanks, they still are extremely effective and powerful despite being in the process of replacement, and thus can still serve effectively in the main-battle tank role, especially in defensive positions, but are not as widely used on the frontlines of combat due to their relatively large logistics requirements (including their fuel consumption). Nonetheless they are as effective in the role as the more modern tanks, in regards to the strength of their armor and destroying enemy tanks, despite being much larger and heavier and harder to deploy overseas. There are a few primary upgrades, with the largest being to the electronics, weapons, and engine. The engine is perhaps the largest change, utilizing an engine based on the highly efficient
Leopard 2. The engine is a partial hybrid, unlike the Leopard 2, but is based on the V12 diesel engine, which is roughly 2-3 times more efficient than the standard M1 abrams. This gives significantly longer ranges to the vehicle, and reduces the fuel load requirements, but is not as efficient as modern hybrid engines. While the new engine is a tremendous change, fundamentally it substantially easier to replace by linking it to the drive train of the vehicle, which is a fairly easy change to make in comparison to upgrading the vehicle to full hybrid electric. Given the aging engines of the M1 Abrams vehicles, replacing them with a newer, more efficient engine was a natural upgrade that was easy to implement during the life cycle of the vehicle. Combined with a partial generator, the vehicle is a partial hybrid, using electricity for some of it's power to conserve energy while idling, moving short distances, receive the effects of regenerative breaking and achieve an extra boost to power, but is predominately still powered via direct transmission of mechanical forces to the drive train. The battery powered electric motors can provide extra power to the tank's drive train for short spurts, but can only move the tank at 8 mph under their own power, providing a small boost to the vehicles drive train power but not completely replacing the standard lay-out of the vehicle. This makes the vehicle electric assisted, but not electric powered. It does help for short spurts at full speed to accelerate more quickly, however.
The vehicle has several weapons upgrades, including an optional autoloading cannon mechanism, an additional 40mm Bofors MK IV Bushmaster chain gun, and several remote control machine guns. This reduces the need for crew to expose themselves, which increases their safety and provides better monitoring capabilities for greater situation awareness. On top of this is an improved 120mm cannon, which can use etheir standard 120mm rounds, such as the M829A4, or use electromagnetic assistance increase the power of the round. Out of the several thousand M1 abram hulls, approximately 85% were chosen for refitting, still being sufficient in performance to be selected for the program. After nearly 30 years of use the tanks have been in severe need of repairs, and the upgrade program is as much a part of the repair program to keep the tanks operational as they are an upgrade to the M1's performance. The vehicles largely can be considered gutted internally, with the gun, engine, and most of the electronics being replaced, as well as new tracks and a slightly improved drive train and suspension system. Many of the components of the tank have further been replaced to keep the tanks operational, although these components are more or less identical in function to the tanks in their initial production. These repairs and changes have resulted in relatively little financial input required to make the tanks operational again, or approximately 1.5 million dollars on the already 5 million dollars. Because most of the tank's price is in it's armor and hull, replacing other features of the tank are considered relatively inexpensive, and are thus easier to perform. This makes the M4A1's upgrades somewhat of a financial decision, but is nonetheless an effective fighting tank on it's own.
Engine - MTU MB 873 Ka-501 liquid-cooled V12 twin-turbo diesel engineWhile the Honeywell AGT1500C turbine engines of the M1 Abram were extremely powerful and reliable, they were not fuel efficient, and consumed large amounts of fuel to produce the same amount of power of similar engines, such as those used by the German Leopard II. This has proven to be a problem overseas, where fuel consumption has proven to be a major logistics hassle, and fuel trucks are commonly targeted by insurgents over the heavily armored vehicles, thus putting the crews of the fuel trucks at risk. With roughly 70% of casualties being from soft skinned vehicles in recent wars, an emphasis has been placed on reducing fuel requirements for the vehicle, to reduce the necessary fuel load and their numbers of trips, which has resulted in a slightly modified German engine being used to increase fuel efficiency. With the same horsepower, or 1500 BPH, and roughly the same reliability, the engine provides greater fuel efficiency over the standard Honeywell engine, while keeping roughly the same performance. The original M1A2 abrams at 72 tons had an operational range of approximately 265 miles with a 500 gallon tank, compared to a 340 mile operational range with a 317 gallon tank for the
Leopard II. For the same fuel capacity the Leopard II would have a roughly 540 mile operational range, although it would be slightly less given the heavier weight, or approximately 15% less. This gives the Leopard II engine roughly twice the fuel efficiency over the M1, or slightly higher given that the operational range is almost always shorter than the maximum range of the vehicle. Combined with the partial hybrid system, it gives approximately 2.4 times the fuel effiency, and with this variant of the M1 abrams being 67 tons, compared to 72 tons, based on minor changes to the vehicle which helped to reduce it's total weight, the vehicle has roughly twice the range of a standard M1 abrams.
The engine differs from the Leopard II in that it's a partial hybrid system utilizing a small amount of electricity built up from waste heat ot power the engine. This further increases the energy efficiency by about 20%, but unlike electric motor powered vehicles does not completely replace the drive train of the vehicle. The vehicle can be propelled to 8 mph under the electric energy alone, but largely this results in higher fuel efficiencies by recapturing some waste energy.
TUSK Replacement (Tank Urban Survival kit)The
TUSK kit, or Tank Urban survival kit, while very effective, added quite a bit of extra weight to the overall tank. With many of these newer design elements no longer being needed or being reduced in weight as a result of being integrated with the tanks, there is a minor weight saving benefit, with the tank going from 72 to 67 tons, or shaving 5 tons as a result of the newer systems. The TUSK became an urgent necessity in Iraq and Afghanistan, where close-quarters infantry combat and engagement became a common reality for tanks. This included explosive reactive armor on the side of the tanks to help stop weaker rounds like the RPG-7 from damaging the main armor, automated machine gun turrets, rear protecting SLAT armor and a telephone for infantry to call the tank crew on the vehicle. The weight reduction is achieved by a thinner, higher strength explosive reactive armor, a replacement to the outer shell of the Tank with slightly stronger steel, and more effective and lighter SLAT armor. As time has progressed armor materials have grown stronger and can be more closely integrated with the tank, reducing it's overall weight. These weight gains are lost immediately by the addition of new automated weapon systems resulting in little if any function increase in the change of weight. This includes the 40mm Bofors, 120mm and 60mm mortar weapons systems, multiple machine guns and automatic grenade launchers and the 120mm MAC gun, with adds a few tons to the vehicle.
Electronics upgradesThe vehicles make use of the M1A2 v3 Shepard upgrades, with a few notable changes, largely by adding radar detection and guidance systems.
