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Picture 2:
This is another General Dynamics photograph, this time illustrating the forward turret interior. The image includes a good view of the 120mm M256 cannon breech, directly in the center of the promotional photo. First, let's identify the location of the new components located up here in the turret, and then we will examine each component in more detail. The vertical white cylindrical object hanging down from the left side of the forward turret roof, with a black grid pattern at the bottom end, is the base of the new Commander's Independent Thermal Viewer (CITV). His display viewer for the CITV, looking a bit like a small television screen, is over on the right side of the turret. Returning to the left side of the turret again, and below the base of the CITV, is the SINCGARS set (Single Channel Ground/Air Radio System). Here it is seen as a two-piece, stacked, black box arrangement with many switches and one large plug on each box.
To the right of the SINCGARS equipment is the black semi-automatic breech of the 120mm smooth bore Rheinmetall main gun. The 120mm gun fires the M865 TPCSDS-T and M831 TP-T training rounds, the M8300 HEAT-MP-T, and the M829 APFSDS-T which includes a depleted uranium penetrator. The shell casings for these rounds are self consuming when fired. Normally there would be a deflector shield behind the breech to direct the base stub that is left after firing down to the floor, but it has been removed for this photo. Further to the right, and a bit further forward in the turret, is the gunner's station. The Gunner's Primary Sight (GPS) is the smaller sight that has switch boxes both below it and to its right, and also uses a brow pad directly above. The gunner's turret/gun joystick control (black) is below and to the left of the GPS. Above and a bit closer to us we can see the two screens of the Commander's Integrated Display and gun sight, with the CITV display and associated controls on the left, and the Command and Control Display (CCD) on the right.
Notice that both the coax machine gun and the gunner's sighting telescope are mounted on the right side of the 120mm gun, right next to the gunner. Ammunition feed for the coax MG loops over the gun barrel from the tall vertical ammo bin on the left to the weapon that you can just barely see mounted on the right. Notice the lack of any recoil guard behind the 120mm gun. As I mentioned earlier, the small deflector behind the breech is missing-- we will see it in a later photograph.
Picture 7:
This is a General Dynamics cut-away sectional drawing of the early M1A2. The tank is fairly typical in general layout of most modern, non-autoloading MBTs in action today; with the driver sitting out in front and a three man crew back in the turret. You can get a feel for the general thickness of the composite depleted uranium armor by the thickness of the plate in front of the semi-reclining driver. When inside the vehicle I was surprised by how small the interior of the turret was (even though it is comparatively roomy when you have been in other modern MBTs). When you are outside looking at the turret it looks huge. Of course, this is due to the thickness of the front and side turret armor as well as the ammo bin in the rear bustle.
Back inside the turret again, the gunner sits forward and to the right of the gun in the traditional American style. The commander is seated directly behind him, and the loader (not shown in this drawing) operates freely on the left side of the gun. All turret main ammunition is stored in a separate bin in the turret bustle with special blow-out panels mounted on the turret roof, and also in a small bin on the other side of the firewall low down in the hull, behind the commander's seat. To access the main bin in the turret bustle, the loader pushes a knee switch that electrically opens the internal blast doors. He should do this each time he retrieves a round for the cannon so that most of the time in action the doors are kept closed. To finish with this particular sketch, the drawing includes the unique Abrams powerplant at the rear, which is still a 1500 hp gas turbine engine that allows a 21.6 hp/ton power to weight ratio.
Picture 8:
Another drawing from General Dynamics provides us with a 3D general view of the major components inside of the tank. Visible are the gunner and commander's seats, and the loader's seat, which is folded on the left side of the turret. The turret bustle blowout panels are visible on the rear turret roof, and up forward on the roof is the Gunner's Primary Sight box. At the rear of the tank is the gas turbine engine with its associated air intakes, filters, batteries, and exhausts. Although often debated, the turbine engine does allow some interesting advantages over a similarly powerful diesel. For instance, it will run on any hydrocarbon fuel including gasoline, aviation gas, diesel, or alcohol fuel, although the preferred fuel in the US Army is high quality diesel. The turbine engine is 2,000lbs (900kg) lighter than a comparable diesel (allowing more armor) and has 30% fewer parts (less maintenance). The turbine will start at -25 degrees F (-31 degrees C) and is much quieter than a diesel, actually quieter than the tank's track noise, and produces a very small smoke signature.
The flip side to the argument is that fuel consumption is very high in the turbine; this is a very thirsty engine. There have been a number of studies over the years involved with potentially replacing the turbine with a diesel, but these have generally proved that the turbine continues the best choice for the Abrams. Recently, an upgraded turbine has been tested with a transverse mounting in the engine compartment that provides additional space in the engine compartment. This configuration is potentially beneficial, as the newly acquired space can be filled with an under-armor auxiliary power unit (APU) and/or additional ammo storage. Up to this point, the Abram's APU was mounted either on the right-rear hull of the tank (early versions), or up in the turret bustle. Of course, the use of an APU allows tanks to perform electrical and hydraulic functions which require power without the main turbine engine running. These functions include not only providing electricity to operate radios, night vision equipment, computers, and fans, but also hydraulic power to rotate the turret as well as a pneumatic source to provide pressurized air in nuclear, biological and chemical warfare environments.
More inside
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(I really just forgot to mention it)
