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 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 155-mm Projectile weights 98 pounds.
The 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.
1 M185 Cannon (M109A2/A3/A4) M284 Cannon (M109A5) 2 Caliber 50 Machine Gun, M2 3 Panoramic Telescope Shield and Indirect Fire Telescope 4 Cannon Mount M178 (M109A2/A3/A4) M182 (M109A5) 5 Cab 6 Hull 7 Direct Fire Periscope
PERFORMANCE SPECIFICATIONS
MAJOR ITEM:
Model........................................................M109A2/A3/A4/A5
Line Item Number.......................................K557667NATIONAL STOCK NUMBER
M109A2........................................................2350-01-031-0586 M109A3........................................................2350-01-031-8851 M109A4........................................................2350-01-277-5770 M109A5........................................................2350-01-281-1719
WEIGHT:
Classification
Empty...................................................................52,000 lb (23,586kg)
Combat Loaded....................................................55,000 lb (24,948kg)WIDTH
Overall.................................................................124 in.(3.1M)
HEIGHT
Overall.................................................................120.43 in(3M)
Lowest operable height........................................109.93 in(2.8M)
Ground clearance.......................................................18 in(0.45M)LENGTH
M109A2/A3/A4 w/armament...................................359.38 in(9.12M)
M109A5 w/armament..............................................361.38 in(9.17M)
M109A2/A3/A4/A5 w/o armament..........................243.75 in(6.19M)SPEEDS
High Speed..........................................35 mph (56.3kmph)
Low Speed............................................6 mph (10kmph)
Range..................................................217 miles (349km)PRIMARY ARMAMENT (TWO CONFIGURATIONS)
Cannon assembly.........................................................................M185 (M109A2/A3/A4)
....................................................................................................M284 (M109A5)
Cannon Tube Length....................................................................238 in. (6.05m) (M185)
....................................................................................................240 in. (6.09m) (M284)
Cannon Mount.............................................................................M178 (M109A2/A3/A4)
....................................................................................................M182 (M109A5)
Maximum Range (M109A2/M109A3/M109A4)..........................18,000m
....................................................................................................RAP 23,500m
Maximum Range (M109A5).........................................................22,000m
....................................................................................................RAP 30,000m
Maximum Rate of Fire..................................................................4 rds/min for 3 min
Sustained Rate of Fire..................................................................1 rd/min for 60 min
...................................................................................................1 rd/ 3 min thereafter
SECONDARY ARMAMENT
Machine gun................................................................................Caliber 50, M2, Heavy barrelAVAILABLE MODIFICATIONS
Modifications of the Howitzers may vary to accommodate customer-desired capabilities. Each conversion is packaged in a kit for ease of shipment and delivery.
Differences between models
M109 SPH
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.M109A1 SPH
The M109A1 featured a new longer barrel, and various other improvements, with a maximum range of 18,100m.M109A2 SPH
The M109A2 is a new production weapon which incorporated 27 mid-life improvements to the M109A1. The improvements provide for increased Reliability, Availability, and Maintainability(RAM) and safety characteristics as well as enhanced operational capabilities.
The M109A2 has the long tube M185 cannon installed in the M178 gun mount. The cab has a rear bustle rack which provides an increased ammunition stowage capacity. It has an all weather ballistic shield mounted over the panoramic telescope; counterbalanced travel lock and provisions for mounting the M140 alignment device.
M109A3 SPH
The M109A3 is a depot converted M109A1 incorporating the 27 mid-life improvements. The operational characteristics of the M109A3 are virtually identical to the M109A2. Some M109A3s have three contact arm assemblies: all M109A2 have five contact arm assemblies.
M109A4 SPH
The M109A4 is a M109A2/A3 improvements include the addition of Nuclear, Biological, and Chemical/ Reliability, Availability, and Maintainability (NBC/RAM) product improvement kits. The driver and cannoneer no. 2 have an air purifier and two heaters mounted in the hull. An air purifier and four heaters are mounted in the cab for the rest of the crew. NBC Mission Oriented Protective Posture (MOPP) gear is stored in the new cannoneer seats and stowage boxes.
The traversing mechanism is operates with a hydraulic clutch in the M109A4 instead of operating with an electric clutch as in the traversing mechanism in the M109A2/A3 howitzers. A clutch valve with an override valve provides for power traversing in the event of an electrical failure to the clutch valve solenoid. The M109A4 has two hydraulic filters mounted outside of the power pack. The M109A2/A3s have one internal hydraulic power pack filter.
The M109A4 has a combat override switch to allow for emergency starting. The slave start receptacle has been moved from the battery compartment to the driver's compartment. The M109A2/A3 100 amp alternator has been replaced by a 180 amp alternator. Crew compartment subfloor drains have been added to provide for the drainage of DS2 used in the NBC decontamination process and provide for the drainage of excess water.
M109A5 SPH
The M109A5 is a modified M109A4 it consists of two major improvements: a new M284 cannon and a new M182 gun mount. These improvements provide the M109A5 with greater range and allow for sustained fire for prolonged periods of time.
INTERNATIONAL VARIANTS
On 24 May 2000 the government of Egypt requested a possible sale of 279 M109A2/A3 155mm self-propelled howitzers, support equipment, spare and repair parts, publications and technical data, personnel training and training equipment, U.S. government and contractor engineering and logistics personnel services, and other related elements of logistics support. The estimated cost was $48 million. Egypt will use these howitzers to replace aging Soviet towed artillery and to complement the modernization of the M1A1/M60A3 divisions.
- M109A3G, German version of the M109, many improvements including new ordnance..
- M109L, Italian M109 fitted with ordance of FH-70..
- M109AL, Israeli version..
- M109 Taiwan uses the M108/109 chassis but with a 155mm weapon in an open mount. The short barrel version uses ordnance of the towed M114, more recent version has new and longer ordnance..
- M992, Field Artillery Ammunition Support Vehicle, uses M109 chassis with fully enclosed rear hull to carry 155mm ammunition..
- FDC, Fire Direction Centre or Fire Control Centre, uses M992 chassis and hull..
THE FUTURE OF THE M109
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. The M109 Family of howitzer continues to improve at considerable cost savings for the customer. 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).
