M109 155mm SP Howitzer
The 155-mm M109 series, Self-propelled medium howitzers are highly mobile combat support weapons. They are air transportable in phase III of airborne operation. They have a cruising range of 220 miles at speeds up to 35 miles per hour. Combat loaded, The M109 series weighs 27.5 tons. The 155-mm projectile weights 98 pounds.
The M109 series howitzer is a vehicle that provides armored combat support, is air transportable, internally loaded, and has excellent ground mobility. It allows firing in a 360 degree circle through its primary armament, the 155mm cannon assembly, and its secondary armament, the M2 heavy barrel caliber 50 machine gun. The system is capable of both direct (line of sight) and indirect (out of the line of sight) firing.
The M109 has a crew of six, consisting of commander, gunner, three ammunition members and the driver. The hull is made of all-welded aluminium armour. The driver is at the front of the hull on the left, the engine is to his right and the turret is at the rear. The driver has a single-piece hatch cover that opens to the left, with three M45 periscopes in front that can be covered by small metal flaps to prevent damage. The commander is seated on the right side of the turret and has a cupola that can be traversed through 360°, a single-piece hatch cover that opens to the rear and an M27 periscope. Pintle mounted on the forward part of the commander's cupola is a 12.7 mm (0.50) M2 HB - also local defence machine gun. The gunner is seated on the left side of the turret and has a square single-piece hatch cover that opens to the right.
The all-welded aluminium armour turret at the rear of the hull has a square hatch in each side that opens to the rear, and twin doors in the turret rear. Twin doors are provided at the rear of the turret for ammunition resupply. Mounted at the rear of the hull, each side of the hull door, is a large spade which is lowered manually to the ground before firing.
The Detroit Diesel engine is coupled to an Allison Transmission XTG-411-4A cross-drive transmission which is at the front of the hull. The torsion bar suspension consists of seven dual rubber-tyred roadwheels with the drive sprocket at the front and the idler at the rear. There are no track-return rollers. The tracks are of the single-pin, centre guide type with replaceable rubber pads.
The M109 is fitted with night vision equipment but did not have an NBC system prior to the introduction of the M109A4. The basic vehicle can ford to a depth of 1.828 m without preparation. It can be fitted with an amphibious kit consisting of nine air bags, four each side of the hull and one at the front. The bags, which are not carried on the vehicle as part of its normal equipment, are inflated from the vehicle and it can then propel itself across rivers by its tracks at 6.43 km/h.
In the American army, the M-109 is deployed at 54 units per armoured division and mechanized division (3 battalions of 18 vehicles equipping 3 batteries of 6 M-109).
The M109 was the first model, with a very short barrel, double baffle muzzle brake, large fume extractor, and a maximum range of 14,600m. The M109A2/A3/A4 howitzers uses M185 cannon and achieves a range of 23,500 meters. The replacement of the 23 caliber long barrel with the M284 cannon 39-caliber barrel on the M109A5/A6 increased the range capability to 30,00 meters. The M109 Family of howitzer continues to improve at considerable cost savings for the customer.
The M109A2-A5 series of howitzers gives the customer the maximum flexibility to tailor modifications to meet desired missions requirements and can accommodate future technology. The M109A2-A5 series is economical to purchase, operate, and maintain. It continues to be backed by the extensive life-cycle sustainment support of the weapon's proponent, The U.S. Army's Tank-Automotive and Armaments Command - Armament and Chemical, Acquisition and Logistics Activity (ACALA). Modifications of the Howitzers may vary to accommodate customer-desired capabilities. Each conversion is packaged in a kit for ease of shipment and delivery.
Life cycle sustainment support for the M109 FOV is currently provided by multiple government and commercial organizations using many different processes to deliver both services and materials. Duplicative infrastructure and processes are common. Engineering/technical support is performed by multiple contractors and Army commands. Maintenance, overhaul, and repair is achieved through a complicated structure of organic shops that depend on the commercial sector for parts and other government agencies for technical guidance and funding. The production contractor and government supply system acquire and provide parts for initial provisioning, production, modification, repair (field and depot), overhaul, and war reserves. The current support infrastructure limits opportunity for a coordinated effort to achieve cost-reduction, implement best-business practices, improve weapon system performance, and modernize equipment. Accountability is widely dispersed.
The US Army TACOM-ARDEC Acquisition Center and the Product Manager for Paladin/FAASV sought a single contractor for a Fleet Managemer for the M109 Family of Vehicles (FOV). The Fleet Manager (FM) was to be the single world class focal point for the M109 FOV life-cycle sustainment support, to include supply, engineering and limited life cycle support functions by having one point of contact and focal point for all M109 FOV life-cycle program management and weapon system support. The Pilot Program critical objective was to validate 20-30% sustainment savings.
The M109 Family of Vehicles Fleet Management Pilot Program started as a bold experiment, but was gradually reduced in scope until leadership decided it was no longer worth doing. Fleet Management identified many obstacles that future experiments must address and resolve early in the development phase. Fleet Management brought to light some inefficiencies that responsible organizations could "fix" on their own (i.e. reduce inventory, establish long term contracts and co-locate inventory with users).
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