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International Defense Review March 1, 2001 SECTION: EQUIPMENT PROFILE; Vol. 34; No. 3 LENGTH: 4574 words HEADLINE: M109 - modernizing for the millennium BYLINE: SCOTT R GOURLEY BODY: With about 6,000 systems in international service, the M109 self- propelled howitzer is a familiar presence in global ground force inventories. Originally introduced to US Army ground forces in 1963, it was based on a 1950s design that in its M108 version incorporated a 105mm cannon with an 11km range, or in its M109 iteration a 23 caliber-length 155mm tube that provided maximum ranges of 15km (unassisted) and 20km (assisted). The 'basic' (M109A0) model was followed in US inventories by the 1973 introduction of the M109A1, which featured a 39 caliber-length cannon (M185) that extended maximum projectile delivery range to 18km, or to 24km when firing the M549 rocket assisted projectile (RAP). The year 1978 saw the introduction of two new models: the new-build M109A2 and the M109A3, an M109A1 upgraded to M109A2 standard. Both models introduced a range of safety and reliability/availability/maintainability improvements. The early 1990s saw the introduction of two additional models: the M109A4 and the M109A5. The M109A4 program involved installation of approximately 1,000 nuclear, biological, and chemical/ reliability, availability, and maintainability (NBC/RAM) upgrade kits that were assembled, packaged, and delivered to the US Army by Barnes & Reinecke, Inc (BRI). The M109A5 also introduced a new cannon (M284 cannon assembly with M182 gun mount) that further extended the firing range to 30km, using the M549 RAP in conjunction with the M203 charge (NATO Zone 8). Around the world, the US M109 upgrade pathway has been accompanied by a range of parallel upgrade programs conducted on various international howitzer fleets. As in the US example, international upgrades have generally focused on the introduction of new ordnance and vehicle technologies, designed to extend range, improve reliability, and enhance overall system survivability. One representative international example can be seen in the mid- 1990s upgrade of 96 Spanish M109 systems to a newly-designated M109A5Espana (M109A5E) configuration. Spanish modernisation The initial phase of the M109A5E upgrade program involved the physical survey of 96 existing Spanish Army M109 systems located at multiple sites throughout Spain. This survey, which was co-ordinated by the US Army Security Assistance Command (USASAC) and designed to identify the 'baseline configuration' for the Spanish howitzer fleet, was conducted by a team consisting of BRI personnel, Spanish Army representatives, and representatives from the US Army's Armament and Chemical Acquisition and Logistics Activity (ACALA), located at Rock Island, Illinois. In addition to three different M109 configurations in the Spanish Army fleet, survey team members held discussions with howitzer crews and system maintenance personnel in an effort to identify any unique operational characteristics of the Spanish M109s. Based on this survey information, the team assembled a single M109A5E upgrade package that BRI representatives highlight for "[eliminating] the kit redundancies and costs necessary in a sequential upgrade (M109 to M109A1 to M109A3 to M109A4/A5)". A prototype transformation process focused on development of the upgrade kit and upgrade instructions specifically created for the Spanish Army depot facility in Segovia, Spain. Completion of the prototype upgrade was followed by a Spanish government request for an additional 93 system kits, each kit containing more than 1,100 individual items. At about the same time, Spanish representatives also decided to incorporate the improved M284 155mm cannon and associated components in the overall M109A5E package. The cannon change mandated expanded USASAC co-ordination of Letterkenny Army Depot for refurbished turrets, Rock Island Arsenal for gun mount modifications, and Watervliet Arsenal for production of M284 cannons. The resulting 93 M109A5E upgrade kits were delivered to Spain by BRI at the end of October 1996. Other recent international M109 modification activities have featured the installation of a modification kit developed by Rheinmetall Landsysteme GmbH. Originally developed to meet the needs of the German Army, the Rheinmetall upgrade featured installation of a new 39-caliber 155mm barrel that increased the range of the new M109A3G configuration from 18.6km to 24km firing unassisted L15 projectiles and to 31km with base-bleed projectiles. Upgrade of the German M109s was also followed by the installation of the Rheinmetall 39-caliber barrel in the Norwegian Army's M109s. In addition to such 'pure upgrade' programs, some international M109 modernization packages are developed and fielded as a combination of upgrades to existing systems combined with new system acquisitions. An example of this can be found in the 1990s Austrian M109A5Oe program. During the period 1992-95, United Defense LP developed a prototype vehicle and technical data package for the Austrian M109A5Oe variant. This development process was followed by the manufacture of 54 'new build' M109A5Oe systems at United Defense facilities in York, Pennsylvania, during 1995-97, and the subsequent delivery of an additional 125 upgrade kits for in-country modernization of ex- British Army M109A2/A3s to M109A5Oe configuration in the1997-2000 time frame. According to the Austrian program director, Dr F Felberbauer, the user's key demands for the M109A5Oe were a 30km range, improved responsiveness, 'shoot-and-scoot' and autonomous operations capability, and the ability to fire newer generations of projectile. It was decided a 39-caliber cannon should be retained because, in the Austrian view, 52-caliber tubes are too long for maneuvering in Alpine villages (and 47-caliber tubes marginal for the same reason). In order still to achieve the required full 30km range, the Austrian Army is using 47kg ERFB Base Bleed projectiles in combination with a Swiss Zone 8 charge modified by Nitrochemie with a special increment (also referred to as 'Zone 8.9'). An unexpected bonus with some of the M109s acquired from the UK, was that the angle of the forcing cones of their M185 cannon had already been modified by Royal Ordnance to be able to fire higher pressure charges (NATO Zone 8), obviating the need to fit the uprated M284 cannon. Other items incorporated by the Austrians included an APU for training purposes; an enhanced Swiss electrical system and 16- channel slip ring to improve traverse capability (according to Felberbauer with the previous drives, it had not been possible to traverse the turret at cant angles greater than 3); a NAPOS navigation and position system (that automatically switches from navigating mode to ballistic mode when the powered travel lock is unclamped from the barrel); and a Intertechnik rammer. Upgrade activities Today's M109 user faces a dizzying array of system upgrade alternatives ranging from the enhancement of individual operating characteristics to a revolutionary change in overall system character. In addition, upgrade alternatives are offered in a range of production/co-production arrangements performed by a number of competing industry sources. Moreover, new manufacturers are continuing to enter the M109 upgrade market on a regular basis. South Africa's LIW is one of the recent arrivals on the M109 upgrade market. In response to a United Arab Emirates (UAE) desire to standardize critical component upgrades between its G6 and M109 howitzers, LIW is currently conducting its initial M109 upgrade program, which it began in the fall of 2000. The first LIW contract reportedly covers the supply and integration of existing M109 position and navigation subsystems with a new Kentron fire-control system. Instead of the older optical dial sights - subsystems that mandated the physical 'laying' of firing units through mechanical survey processes - LIW is equipping the M109s with dual (inertial and Global Positioning System [GPS]) position/navigation sensors. The sensor combination provides ring laser gyroscope-based gun laying accuracy to within 1mil, an onboard accuracy that translates to the ability to conduct fire missions immediately after arrival at a firing position. The positioning systems are further linked to a weapon management system computer for receipt of firing data as well as a projectile muzzle velocity radar that will measure and store projectile velocities and other data, further increasing system accuracy. Additional LIW M109 upgrade activities include modification and installation of a remotely-operated barrel travel lock, installation of a semi-automatic hydraulic push rammer, and installation of an auxiliary power unit in the rear of the turret to power all turret subsystems, including a new air-conditioning unit. With more than 30 years of experience in complete and partial overhaul programs for a range of M109 series howitzers, Netherlands company RDM Technology, BV offers a flexible range of upgrade options. Pointing to an experience founded on licensed M109 production starting in the 1960s and running through the 1980s, company program descriptions highlight a range of continuing upgrades conducted through the 1980s and 1990s. Recent program examples include the overhaul of 30 Canadian M109s, the upgrade of 126 systems for the Netherlands, and the further upgrade of 85 former Netherlands Army M109s to an M109L47 standard for the UAE. Beginning in 1997, the company started the development of what it terms "the ultimate upgrade of the M109", that includes installation of a new 52-caliber long-range barrel. Firing trials of the new 52- caliber design, known as the M109-2000 Technology Demonstrator, started in late 2000 and continue at this time. In addition to the new 52-caliber cannon, the M109-2000 includes a range of enhanced subsystems like the Intertechnik flick rammer and Rheinmetall Landsysteme GmbH (previously KUKA Wehrtechnik GmbH) ammunition handling kit (the ammunition handling kit has also been ordered for the German Army's M109A3G systems noted earlier). Taken together, RDM offers a spectrum of flexible upgrade alternatives under the umbrella title of "M109 Howitzer Improvement Program (HIP)". Company descriptions note that the M109 HIP "aims at an extension of the howitzer's lifetime by introducing newly designed systems and components to provide the howitzer with the necessary firepower and other features nowadays required in modern theaters. The Improvement Program is accomplished by using only existing and proven systems and components and can be adjusted in accordance with the customer's wishes. Apart from qualifying the individual components, the improved howitzer has been qualified with all the additional features integrated in the howitzer. The results of these tests have clearly shown that the basic system is perfectly capable of absorbing the effects of the various added systems to the basic system, including the upgrading with long range 47-caliber and 52-caliber guns." HIP program upgrades include items like a remotely-controlled barrel travel lock, enhanced navigation and fire-control systems, automatic or semi-automatic loading options, and a new cannon - in 39, 47, or 52 caliber-length options - to provide increased range. Additional new components include: NBC subsystem, hydraulic subsystem; charge racks; ballistic cover; driver's night sight; recuperator cylinder; auxiliary power unit; air conditioning unit; an automatic explosion detection/fire suppression subsystem; and an M109L47 engine upgrade kit. In clarifying some of the different company upgrade options and 'marketing designations' that have been assigned to RDM's various M109 enhancement activities, Hans Blaauw, General Manager for Marketing and Sales, notes that "RDM has been active in development of M109 upgrades and improvements over the past 15 years, in the mean time, several names have come up for different M109 upgrade versions. "RDM has developed a modular M109 improvement package consisting of some 30 different improvements and upgrades from which a customer can choose, based upon his own priorities and available budget," he adds. The ballistic upgrade possibilities RDM offers in place of the baseline M185 39-caliber barrel include a new 39-caliber gun, comparable to the M284 (able to fire NATO Zone 8 charges), a 47- caliber gun (as supplied by RDM to the UAE Armed Forces), and "a 52- caliber gun NATO standard", fabricated by Royal Ordnance. Blaauw describes the 47-caliber gun as "according to the Joint Ballistic Memorandum Of Understanding [JBMOU] but not NATO standard". (According to Blaauw, its 21-liter chamber gives the L47 the same muzzle velocity for a given projectile/charge combination as the 39 and 52-caliber barrels. Therefore, despite the fact that 47 caliber is not supported by NATO, the NATO firing tables can be used for the L47 without modification.) Ultimate upgrade "The M109-2000 represents the ultimate upgrade using all of the remaining upgrade potential within the M109. It consists of the 52- caliber gun upgrade and all the other modular improvements we have. This has been built into our M109-2000 Technology Demonstrator to prove its functionality. The M109-2000 has an improved firing range [40km with M864/DM652 base bleed], rate of fire [burst three rounds 10s/nine rounds in 54s] and improved accuracy. The M109 can be used in autonomous roles and has 'shoot-and-scoot' capabilities. It is interoperable with modern ammunition and charge systems and within a modern digital battlefield. Also crew safety, ergonomics, environmental aspects, survivability, availability, reliability, maintainability and operational cost are improved. The last aspect has been mainly achieved by reducing the M109's crew from 6 to 4 persons. RDM's modular upgrade program offers a performance comparable to new modern SP guns for a fraction of the cost," he says. In terms of specific program designations, Blaauw summarizes that "Other names for our M109 variants are certain versions where a customer or potential customer selects a combination of different elements of the modular upgrade package. The M109L47 is the system we supplied to the UAE, consisting of a 47-caliber gun upgrade, a semi-automatic projectile loader, remotely controlled travel-lock and some six other options. The M109A5++ is a configuration in which the A2/A3 version is upgraded to A4/A5 with the standard US RAM-PIP kit. The first + is because instead of the M284 gun in the A5 we install the L52 gun which gives 10km more range. The second + is for the installation of several systems that are not normally included in the M109A5, such as a semi-automatic projectile loader and a navigation and fire control system." Another company offering a variety of M109 upgrade alternatives is SW Thun (formerly SW Swiss Ordnance Enterprise Corporation). As one of several international M109 upgrade providers, SW Thun has developed a package of modular system enhancements focused on firepower, reliability/maintainability, and survivability. Firepower enhancements stem from the installation of a new 47- caliber armament system. With more than 400 cannons already ordered, the L47 Swiss type-classified cannon system fires all NATO standard ammunition at ranges up to 36km. (The combination of the Nitrochemie Zone 9 charge and the 47-caliber gun increases the range of older projectiles, including the M107 to 25km and of base-bleed cargo rounds to approximately 36km). In addition, its fully chrome-plated bore eliminates barrel erosion and helps guarantee constant muzzle velocities with no range loss or increased dispersion zone during the entire life span of the barrel. Other barrel design features reportedly include 60-groove rifling with reduced rifling angle to permit firing of the older projectiles (viz the M107) with Zone 9 charges. Coupling the cannon with a semi- automatic loading system, together with increased onboard stowage of 40 rounds and 64 charges, also supports higher firing rates for the upgraded system. Reliability and maintainability enhancements include a new electrical system (with a 16-channel slip ring) and fault-finding diagnostics. Numerous survivability features in the Swiss upgrade design include: enhanced tactical flexibility through the use of a new navigation/positioning system to facilitate first-round delivery, and 'shoot-and-scoot' options through a remotely operated travel lock; driver night vision enhancements; plus fire extinguishing systems in both crew and engine compartments. The upgrade also further enhances crew survivability with design features including blast-proof sliding door separation between the crew compartment and the propellant magazine and additional magazine compartment pressure-relief features. The latest M109 upgrade configuration to enter US Army inventories is the M109A6 Paladin. As with earlier models of the M109 system, the M109A6 Paladin 155mm self-propelled howitzer provides the primary indirect-fire support to heavy divisions and armored cavalry regiments. The enhanced Paladin configuration is achieved through extensive modifications to existing M109-series vehicle hulls and the subsequent introduction of an entirely new turret structure. Enhanced subsystems Some of the new or enhanced subsystems incorporated in the Paladin upgrade include an onboard ballistic computer and navigation system, secure radio communications, a modified 39-caliber M284 cannon with improved M182A1 gun mount, automatic gun positioning, automotive improvements, improved ballistic and NBC protection, driver's night- vision capability and built-in test equipment. Additional chassis upgrades include a remotely actuated travel lock (for quicker emplacement and displacement), longer torsion bars (to help support the new turret) and a low heat-rejection engine with improved cooling system. Described by US service representatives as "the first digitized combat vehicle in the US Army's inventory," Paladin has significantly improved responsiveness, survivability, lethality and reliability compared to the earliest M109s. Like the M109A5, it uses the M284 cannon which is an enhanced version of the M185 with a modified torque key to allow use of the M203 charge, but in addition it has a new cab with improved protection, and the Honeywell Automated Fire Control System (AFCS) which gives it its autonomous operations capability. The first 164 Army Paladin systems were manufactured under a September 1991 Low Rate Initial Production (LRIP) contract that resulted in First Unit Equipped (FUE) status in April 1993. A subsequent full-scale production (FSP) multiyear contract covered 630 howitzer conversions, with additional options for 83 systems and a follow-on order for 73 more Paladins, bringing the total number of units produced under FSP to 786. The final vehicle conversion contracted under this series of contracts was delivered to the US Army in late June 1999 (164 LRIP + 786 FSP = 950 M109A6s currently in US Army service). M109A6 Paladin conversions through the middle of 1999 were conducted by United Defense's Paladin Production Division (PPD), established on Letterkenny Army Depot (LEAD) property. The physical location facilitated the establishment of a 'Paladin Enterprise' workshare agreement between the depot and United Defense. Following receipt of their 950th M109A6, US Army fleet planners indicated that a portion of the army's remaining M109 howitzer inventory would receive the M109A5 upgrade, which includes some automotive and crew NBC protection improvements and Paladin's M284 cannon and M182A1 gun mount. In addition, Army National Guard planners revealed ongoing efforts to seek funding for additional M109A6 upgrades. One result of those efforts could be seen in a Fiscal Year 2000 United Defense contract for the upgrade/manufacture of seven additional M109A6 Paladins for Army National Guard units. The US$8.3 million contract, which was awarded by the US Army's Tank-automotive and Armaments Command (TACOM), marked a significant milestone in the M109A6 upgrade program since it reflected the first order for the remanufacture of existing M109A5 systems into M109A6 Paladin configuration since closure of the PPD that had been located at Letterkenny and the official transfer of army depot responsibilities for self-propelled howitzers from LEAD to Anniston Army Depot (ANAD). Recent schedules reflect deliveries of the seven newly upgraded systems beginning in November 2001 and continuing through January 2002. According to company spokesman Herb Muktarian, United Defense contract activities are being conducted in York, Pennsylvania and in Aiken, South Carolina. "Anniston Army Depot has a key role in the project by doing the tear-down of the inducted M109A5s," he says. "They are going to work on the new vehicle chassis: structurally modifying the hull for the M109A6 configuration; and integrating components like a new engine and other new subsystems so that the vehicle has 'zero miles/zero hours' when it comes out of Anniston. Essentially it's a new chassis that will then come up to York where we are going to manufacture and assemble brand new cabs [turrets] and then integrate the turret to the chassis for final testing in York." International Howitzer As a spin-off to United Defense's M109A6 engineering development activities, the company has for several years been marketing an "export only" M109 upgrade package, which it now calls the International Howitzer (the initial target customer was Kuwait - Ed, see IDR 5/1999, p62). The International Howitzer utilizes the same turret structure developed and fielded for the M109A6 Paladin. Designed to meet the higher firing loads of extended range ordnance, the cab structure houses a 52-caliber modified M284 155mm cannon supported in a modified M182A1 gun mount. The 52-caliber ordnance, which includes fume extractor and double baffle muzzlebrake, is built by Watervliet Arsenal and is extended-range JBMOU compliant. The ammunition loading design configuration provides International Howitzer with maximum firing rates up to three rounds in 15s and six rounds per minute, with optional semi-automatic loading system and laser ignition system or automatic primer feeder. The system has onboard carrying capacity for 39 complete rounds. The power pack is the same as that found on the M109A6 with the suspension upgraded to handle the higher firing loads. "The International Howitzer includes all the enhancements of the M109A6 Paladin system and also provides a 52-caliber 155mm cannon with improved rate of fire," explains David Phillips, Director of Artillery Programs for United Defense's Ground Systems Division. "This commonality, from our perspective, means that the International Howitzer is an operationally-capable and logistically- supportable M109 upgrade package." He adds that "our International Howitzer provides a new turret design structure that is common to the M109A6, and that turret design structure was designed specifically for the increased loads of a longer caliber-length cannon and extended-range ammunition. And that separates what we're offering from any other M109 upgrade on the international market. That's a clear discriminator. Clearly the design for the Paladin and the International Howitzer addresses the loads seen from extended-range armament, whereas the other international M109 upgrades have not addressed those loads into a redesign of the turret structure." Noting that "the design for Paladin addressed extended-range ordnance", Phillips adds that "from our standpoint, the smaller turret on the original M109 was designed to carry a 23-caliber cannon. And then that evolved through the M109A5 with increases in cannon lethality that led to a 39-caliber system. The Paladin was the first to address the impact of extended-range capabilities through a complete redesign of the turret structure." Adam Zarfoss, United Defense Program Director for Paladin and International Howitzer, says: "The Paladin upgrade addresses system- level improvements to the M109. During the development of the Paladin, it was determined that the old cab structure would not withstand the higher firing loads of extended-range ordnance over long periods of time. And the US Army designs everything for infinite fatigue life." In addition to the new cab structure, Phillips cites a second major discriminator based on Paladin's production history. "We are the M109 OEM [Original Equipment Manufacturer] and United Defense has used that new turret design on all 950 Paladins built to date as well as the seven that are currently under contract. And we've done that through co-operative co-production with the US Army depot system. And that's a program that really establishes a validated model for structuring a co-production program." Although declining to identify specific customer interest, United Defense representatives cite International Howitzer program interest from countries in the Middle East, Far East and Europe. They add that a pre-production prototype system has been developed and initial deliveries of upgraded International Howitzers could begin within 24 months of contract start. In addition to offering the domestic M109A6 and the export International Howitzer, Phillips adds that "United Defense stands ready to offer a full range of M109 enhancements - everything from M109A2 overhauls to A4 and A5 upgrades." He goes on to note that United Defense's expertise in flexible upgrade packages received two significant boosts with the company's recent acquisition of BRI and Bofors Defence. "From the early 70s and through even today, BRI has had the US government contract for M109A2 through the M109A5 System Technical Support [STS]," adds Phillips. "So, with their customer at TACOM Rock Island, they control the technical data package for the earlier version M109s. With the acquisition of BRI, United Defense is clearly the M109 OEM." Beginning with a basic design that started on paper in the late 1950s, the M109 self-propelled howitzer is entering its fifth decade of military service as a vital member of ground force inventories around the world. As such, the M109 series howitzer has few peers in the world of combat systems. One major reason for the M109's continuing viability is the wealth of upgrades that have been applied or are available from multiple sources around the world. Modern versions routinely deliver ordnance at twice the original M109's 15km maximum range with the latest technology and marketing demonstrators now reaching out to 40km. Likewise, artillery crewmen who served on early versions would hardly recognize today's automated and computerized cab designs with their multiple enhanced survivability features.