For half a century, the basis of US self-propelled artillery has been the self-propelled guns of the M109 family. The last modification of this self-propelled gun, called the M109A6 Paladin, entered service in the early nineties. Despite the rather high characteristics, the Paladin self-propelled gun no longer fully meets the requirements for modern self-propelled guns. For this reason, shortly after the start of production of the M109A6 combat vehicles, a new project, the XM2001 Crusader, was launched. While still in its earliest stages, this project received a lot of praise. It was sometimes argued that thanks to the new self-propelled gun, a real revolution would take place in artillery.
The first studies on promising artillery systems began in the mid-eighties, but projects for such combat vehicles appeared much later. In the mid-nineties, when the development of the XM2001 ACS began, it was supposed to complete the project within the next ten years. The first serial self-propelled guns of the new model were planned to be built in 2004, and in the next to begin their operation in the troops. It should be noted that the timing of this or that part of the project has changed several times. So, at the beginning of the two thousandth years, when the experienced self-propelled gun "Crusader" went for testing, the adoption was postponed to 2007-2008. The need for troops was estimated at 800 combat vehicles.
The project of a promising self-propelled gun was developed by United Defense and General Dynamics. In accordance with the customer's requirements, the new combat vehicle was supposed to surpass the existing equipment in a number of parameters. It was required to increase mobility, fire efficiency and survivability. In addition, it was necessary to reduce the complexity of maintenance. Such requirements led to the fact that the development companies decided to use a large number of new automated systems, and this ultimately had a decisive impact on the appearance of the self-propelled artillery unit.
During the development of the project, the ACS Crusader changed its appearance several times. For example, in early versions of the project, the combat mass of self-propelled guns exceeded 60 tons. However, the requirements for mobility forced to change the project, reducing the combat weight of the vehicle by almost one and a half times - to 40 tons. Subsequently, this parameter changed several times within small limits. The dimensions and weight of the self-propelled gun were reduced primarily due to the need to transport it with existing military transport aircraft.
During the XM2001 project, it was supposed to reduce the crew, which accordingly affected the layout of the internal hull volumes. So, in front of it was placed a control compartment with jobs for three crew members (driver, commander and gunner). In the middle and aft parts of the hull were the engine-transmission and fighting compartment. The power plant was a 1500 hp LV100-5 gas turbine engine. and diesel Perkins CV12 of the same power. Both engines could provide the ACS with high mobility. In addition, it was assumed that the use of a gas turbine engine would allow for the unification of several types of modern armored vehicles. Ultimately, the ACS prototype received a gas turbine engine.
The new tracked undercarriage included seven road wheels per side and a rear drive wheel. The hydropneumatic suspension, according to calculations, could provide sufficient cross-country ability and a smooth ride even at high speeds. During tests, the XM2001 ACS accelerated on the highway to a speed of 67 km / h. When driving over rough terrain, it was possible to develop a speed of 48 km / h. The cruising range on the highway exceeded 400 km. With such mobility, a promising self-propelled gun could quickly leave the firing position and avoid retaliation.
The entire crew of the self-propelled gun "Crusader" was to be located in the general control compartment, which made special demands on the electronic equipment of the combat vehicle. The crew's workplaces were equipped with a set of electronic equipment designed for navigation, calculating guidance angles, monitoring the state of vehicle units, etc. The self-propelled gun was also equipped with a tactical information exchange system that allows the crew to use third-party target designation.
The transfer of the crew's workplaces to a single volume inside the hull, isolated from the fighting compartment, forced the authors of the project to start creating automated systems for the supply of ammunition and weapons control. Inside the turret, equipment was installed that was capable of independently receiving ammunition from an armored carrier, placing them in stowages and loading the gun. The gunner or commander could only give the command to start the necessary procedure and, if necessary, indicate the type of ammunition required. All further operations were performed automatically. For aiming the gun, automatic systems were also used, which were responsible both for calculating the aiming angles and for turning the turret or lifting the barrel. The installation system of the gun made it possible to shoot with an elevation angle of the barrel from -3 ° to + 75 °.
In the XM2001 self-propelled gun turret, it was proposed to install the XM297 155 mm caliber gun with a 56 caliber barrel. This gun, already at the stage of calculations, showed its high prospects in terms of the range of fire. To improve accuracy when firing unguided projectiles, it was equipped with an integrated liquid barrel cooling system. The problem of reducing recoil was solved by original recoil devices and a muzzle brake. When developing the gun, it was decided to chrome the bore and the chamber to reduce wear.
The XM297 gun retained separate loading, traditional for its artillery class. For greater flexibility of use, it had to use the modular propellant system MACS. By changing the number of modular charges, you can adjust the firing range within certain limits. In the automated packing of the fighting compartment of the ACS Crusader, 48 shells of various types and 208 propellant modules were placed. The number of modules sent to the chamber was calculated immediately before the shot, along with other firing parameters.
Working on the project of a new ACS, the employees of United Defense and General Dynamics paid great attention to the rate of fire. An important "skill" of a modern artillery system is the method of firing MRSI (the so-called flurry of fire). This means that the self-propelled gun can make several shots, combining the power of the propellant charge and the angle of elevation of the gun, as a result of which several shells fall on the target with a minimum interval. This shooting technique allows you to inflict damage on the enemy in the shortest possible time and before he has time to react. In this regard, the XM2001 project used a whole range of measures aimed at increasing the rate of fire.
The main work to ensure a high rate of fire fell on the automatic loader. Within a few seconds, she had to remove a projectile of the required type from the stowage, send it to the chamber, extract a given number of propellant charge modules, also send them into the chamber, and then close the shutter. With an estimated rate of fire of 10 rounds per minute, the automation had to do all these operations in 4-5 seconds. To improve reliability, the XM297 gun was equipped with an original laser ignition system. The MACS charge modules had a completely combustible shell, which eliminated the need for automation to remove the sleeve or pallet. When firing according to the MRSI method, the Crusader self-propelled guns could fire a series of up to eight shots.
The XM297 cannon could use the entire range of 155 mm shells that existed in the late nineties. Depending on the mission being performed, the Crusader self-propelled gun could fire high-explosive, smoke, incendiary, DPICM cluster (anti-tank and anti-personnel) or SADARM (anti-tank) types. When using conventional shells not equipped with a gas generator or rocket engine, the firing range reached 40 km. It was planned to include a guided Excalibur projectile with a maximum firing range of up to 57 km in the range of ammunition for the new ACS.
Simultaneously with the XM2001 self-propelled artillery installation, the XM2002 armored ammunition carrier was created as part of the Crusader project. Both vehicles had a common chassis and were 60% unified. The ammunition carrier differed from the self-propelled gun in that, instead of the turret, an armored casing and equipment were placed on the roof of its hull and equipment intended for storing and transferring projectiles and propellant modules. In addition, the carrier could transport fuel. All operations for reloading ammunition and pumping fuel were carried out automatically. The crews of the two cars only controlled the progress of the processes, without leaving their workplaces. It took no more than 12 minutes to fully load ammunition and refuel. The carrier's crew consisted of two people.
High speed, rate of fire at the level of 10 rounds per minute, the ability to fire according to the MRSI method and other features of the "Crusader" project have become the reason for many positive assessments. According to various experts, the survivability of the XM2001 ACS was 3-4 times higher than that of the M109A6 Paladin. The combat effectiveness was also high. Calculations showed that in 5 minutes a battery of six self-propelled guns can bring down to 15 tons of shells on the enemy's heads. To do this, however, combat vehicles needed to work together with ammunition carriers.
At the end of 1999, the first prototype of a promising self-propelled gun went for testing. The XM2001 combat vehicle fully confirmed all the calculated characteristics, although during the tests some problems were identified that were soon corrected. Trips around the range and shooting at conditional targets continued for several years. So, in November 2000, the self-propelled gun "Crusader" reached a rate of fire of 10, 4 rounds per minute, which was the maximum value of this parameter during the tests.
High running and fire characteristics made the XM2001 Crusader ACS an outstanding example of artillery technology. However, in May 2002, after a series of successful tests, the Pentagon notified United Defense and General Dynamics of the termination of the project. The reason for this was the economic features of a promising self-propelled artillery installation. The use of a large number of new automated systems developed specifically for the new ACS affected its price. According to the calculations of that time, each of the production machines "Crusader" would have cost the budget $ 25 million. For comparison, the German self-propelled howitzer PzH-2000, slightly inferior to the XM2001 in performance, at that time cost no more than 4.5 million.
A thorough analysis of the characteristics and capabilities of the new self-propelled gun has clearly shown that superiority in firepower or survivability cannot compensate for a significant loss in price. Because of this, the work on the Crusader program was curtailed. It should be noted that the developments on this project have not been lost. Soon after the closure of the project, United Defense received a new contract for the creation of advanced artillery systems. This order of the military meant the improvement of existing developments for use in new projects.
