The XM2001 "Crusader" was born in a 1990s initiative intended for the United States Army to replace its aging line of M109 "Paladin" Self-Propelled Howitzers (SPHs). The 27-ton Paladin was brought online during the 1960s and fought in many of the high-level American conflicts since its inception, seeing considerable export to allied nations around the world and consistently modernization for the changing battlescape. The upgraded form today (2013) remains the effective M109A6 variant. The XM2001 would have directly succeeded the line as a highly-advanced indirect fire weapons platform until the project was terminated in 2002.
The program received traction in 1995 with United Defense heading the initiative and supported by defense powerhouse General Dynamics. The program would also field an accompanying ammunition/fuel resupply vehicle to pair with the main XM2001 force as the "RSV" ("ReSupply Vehicle"). A prototype resupply vehicle was delivered in 1999 with a prototype XM2001 gun platform following in 2000. By the end of the program in 2002, the product had fired over 4,000 155mm shells during testing. However, authorities deemed the system lacking the required precision in landing consecutive rounds while vehicle mobility proved wanting. On the whole, the XM2001 was becoming an (expectedly) expensive venture with not benefit in replacing the still-effective M109 line - negating the need for continuing the costly developmental program.
The Crusader vehicle was intended to showcase many battlefield-centric advances of the period. These included enhanced crew survivability features (such as composite armor and fire suppression system), increased autonomous function (auto-loading) and digital processing ( for improved aiming/accuracy). An automatic loading system reduced the crew workload and number to three personnel, two found in the turret. The main gun was specifically developed to launch multiple rounds in such succession as to land them in the same target area with disastrous effects. The XM2001 platform was to offer tremendous improvements in indirect fire support accuracy while keeping pace with the main armored force spearheaded by Abrams tanks and Bradley support vehicles.
The XM2001 was given a well-faceted, combat hull and turret design shape. There proved a short, sloping glacis plate at front, leading up to the hull roof line. The turret was centrally located with extensive overhand over the engine compartment, essentially covering the entirety of the hull roof area. The turret overhang allowed for increased internal stowage of ready-to-fire munitions seated in horizontal compartments. The engine compartment was, itself, slightly raised from the roof line. Access for the crew was by way of turret roof hatches. The crew numbered three - driver, commander and gunner. The driver was situated at the front-left of the hull with the remaining crew in the powered turret. This was a departure from preceding SPH systems that required a crew no less than four or five - the additional members serving as dedicated loaders.
The heart of the XM2001 system was its experimental XM297E2 series 155mm main gun firing its experimental "smart" munition. The gun was set on a specialized mount within the faceted turret emplacement and sported the requisite breech access, integrated recoil mechanism and horizontally-slotted muzzle brake to go along with the stated auto-loading feature. The system allowed for a rate-of-fire between 10 and 12 rounds-per-minute. When secured for transport, the XM296E2 weapon was locked by way of a hinged structure found at the front of the vehicle.
The vehicle was outfitted with an LV100-5 series turbine engine developing 1,500 horsepower (similar to the one used in the M1 Abrams to provide for logistical friendliness). This allowed for a recorded road speed of up to 30 miles per hour based on published performance specifications. Running gear was of a conventional track-and-wheel arrangement with double-tired road wheels numbering seven to a track side. The drive sprocket was at rear with the track idler at front. There were no track return rollers in play and no side skirt armor was envisioned. The hull was suspended atop a torsion bar suspension system to provide for the needed cross-country capabilities.
The sole completed XM2001 vehicle is a grounds showpiece at Fort Sill in Lawton, Oklahoma.