M109 (Paladin)

History

The 155mm armed M109 self-propelled howitzer (SPH) was developed concurrently with the 105mm armed M108 SPH. Both share the same hull and turret design, the main difference being the choice of weapons. In the long run, the M108 was eventually abandoned in favor of the more powerful M109 offering, which had a very long lifespan, thanks in part to a robust design and modernization program. Its support by the U.S. Army and U.S.

Marine Corpsand subsequent combat use during the Vietnam War (1955-1975)led to its widespread acceptance by other global armies allied with the United States. Production of the M108 and M109 systems began in 1962, but production of the M108 ended the following year.

The M109 was produced until 1969 and under several related brands: General Motors (Cadillac Automotive Division), General Motors (Allison), and Chrysler - interestingly, they all came from the same Cleveland plant. Bowen-McLaughlin-York increased production in 1974 to meet the new demand.

The original M109 production vehicle was equipped with a short-barreled T255E4 main gun, which proved effective, but caused excessive wear due to the propellant used. This resulted in a small modification to the design, introducing a longer barrel in the XM185.

The conversion of the existing M109 fleet to the new M109A1 standard began in 1972, reaching operational levels the following year. In 1974, more M109A1s were built to support the existing stock, these were built by Bowen-McLaughlin-York and named M109A1B.

When completed, the M109 is a traditional SPA form by modern standards. It installs the power unit on the front right and the driver on the front left of the front body. The turret is placed at the rear of the vehicle, and the large main gun is mounted on the front panel. A cupola was granted the commander's position and could be fitted with a .50 or .30 caliber machine gun for air/local defense. The vehicle features a tracked wheel arrangement, including seven twin-tire wheels on one side of the hull.

The drive sprocket is in the front, the chain idler is in the rear, and no chain idler is used. A small door in the rear of the fuselage allows crew access, as do the side panels, roof hatch and hatch above the cockpit. The main gun was equipped with a massive muzzle brake and was clamped to the hull during movement. Despite the 155mm caliber, the barrel has a small overhang. The operator consisted of six people - driver, commander, two gunners and two loaders.

The transect of the tower is a full 360 degrees.

After a period of field service, further modifications were ordered, which included larger turret operations to accept more onboard ammunition storage. New gun mounting hardware was also installed and the flotation unit seen in the original production model was dropped. With these changes, the U.S. Army adopted the M109A2 standard and the 823 x A2 model between 1976 and 1985.

The existing M109A1 and M109A1B models were all converted to the A2 standard and these became the M109A3.

The next major revision of the M109 series was in the mid-1980s, just before the end of the Cold War. As the threat of nuclear war has not yet abated, it was considered prudent to provide the M109 crew with some form of localized protection from nuclear, biological and chemical (NBC) agents, so an NBC kit was added to the M109. The existing marks M109A2 and M109A3 then become M109A4 in this way. The upcoming M109A5 introduces the M284 series 155mm main gun, replacing the original M185 model, and is equipped with a 440hp diesel engine.

As expected, the maximum range of the artillery has been increased, as has the performance of the vehicle. The M109A5+ means the M109A5 has an updated Fire Control System (FCS) and other more subtle internal changes.

Following Operation Desert Storm (1991), the M109A6 Paladin entered service in 1992 as the fully upgraded M109 brand - considered by many to be the ultimate evolution of the series. The A6 variant has improved armor protection for crew and systems, etc., and further increases the onboard ammunition depot.

Introduced automatic FCS to support weapon placement and improve accuracy. NBC kit and crew comfort have been further addressed, while additional attention has been paid to the weapon. Unassisted engagement range now peaks at about 18.6 miles, while Rocket Assisted Projectiles (RAPs) add additional range.

By this time, the crew had been reduced from six to four.

The M109 was supplied with additional ammunition and ammunition on site by the M992 vehicle. This development is basically a turretless M109, but with a fixed superstructure and a crew of three.

Vehicles typically follow the M109, providing the required type of ammunition on demand, and the shells are fed through a port on the rear of the M109.

The M109 was an export on the world stage, one of the most successful armoured vehicles of the Cold War and one of the best SPG/SPGs in America since the end of WWII (1939-1945). Operators range from Canada to South America, Europe and the Middle East. It is possible that countries that used SPGs during the Cold War kept inventories of Soviet equivalent machines or American-made M109s.

Many are still in service today - such is the effectiveness of the vehicle family in combat.

Combat service through the Vietnam campaign, the Yom Kippur War (1973), the Iran-Iraq War (1973), the Gulf War (1991), most recently the US-led Iraq campaign (2003-2011), and the 2006 Lebanon War. The British Army relied on the M109 until 1993 when they replaced these units with the locally designed and developed AS-90 system.

The XM2001 Crusader described elsewhere on this page was at one point intended as the American successor to the M109 series. This promising program finally came to an end in May 1992 - marking an extended lifespan for existing M109 vehicles.

Specification

Basic

Roles

Dimensions

Performance

Performance

Armor

39x155mm projectile.

500x12.7mm ammo.

M992 Ammunition Support Vehicle Resupply.

Changes