Resurrected Weapons: XM2001 Crusader

Crusader was a program to replace the M109 Paladin self propelled howitzer in US Army service. It had a number of innovative features, but development issues and changing army requirements would doom the project. It also happens to be one of my favorites, so let’s take a look.

Crusader was originally a part of the Armored Systems Modernization (ASM) program, as the Advanced Field Artillery System (AFAS), with its companion Future Ammunition Resupply Vehicle (FARV). These were two fifths of the ASM program, with the other three parts being the Block III MBT, the Future Infantry Fighting Vehicle, and a Combat Mobility Vehicle. The fall of the Soviet Union led to ASM being restructured, and only the AFAS and FARV components would get significant development funding in the 90s.

The most important part of any artillery piece is the gun, and Crusader’s was unique. Originally (around 1991), the US Army had settled on using an innovative liquid propellant gun, but this had considerable and persistent teething problems. This gun was (clearly) an entirely different beast than previous systems and by 1996, the delays were becoming intolerable. Tired of the issues, the US Army re-engineered Crusader to use a conventional, solid-propellant gun, albeit one with modular propellant charges. This would be the first major revision that would drive the program costs through the roof.

The new gun used relatively conventional modular (solid) propellant charges, but still had some fancy new features. It had a very long L56 barrel and a liquid cooling system. The barrel had a jacket for isopropyl glycol, and there were a pair of heat exchangers in the turret to keep the gun cool. This would allow for higher rates of fire and better accuracy, since the gun wouldn’t have to deal with as much thermal expansion. As a result, Crusader could fire up to 8 rounds in a MRSI1 fire mission, and be capable of sustained rates of fire of 10-12 rounds per minute. Both of these figures are class-leading.

An additional feature helping Crusader get this rate of fire was the ammunition handling system. The crew of three men were completely isolated from the ammunition. Loading shells, setting fuses, loading propellant charges, and setting primers were all accomplished by an automatic loader system. The Crusader prototypes had two 30-round magazines, and each magazine carried its own set of propellant charges.

Resupply was handled by the XM2002 (the FARV). This vehicle could refuel and rearm XM2001 with a full set of 60 shells and 270 charges in under twelve minutes. Each XM2002 carried a double load of shells and charges. Fuel was transferred at a rate of 29.5 gallons per minute. The reloading port on the XM2001 could also handle manual loading of shells and propellant charges.

Crusader also had a new gas turbine engine. This was the LV100-5, which was also intended to be used to re-engine the US Army’s Abrams fleet. The LV100-5 had 25% less fuel consumption than the AGT-1500 while moving, and 50% less fuel consumption when idling. It was, of course, less fuel efficient than a diesel engine of similar power and vintage like the MTU 883.

Originally, Crusader weighed in at 60 tonnes. By the early 2000s, the US Army’s “Ever Lighter” fetish was in full force, and Crusader would be redesigned again with the goal of making it more air transportable. The goal was an air-transportable weight of 40 tonnes. To accomplish this, the XM2001 was redesigned to have a pair of 25 round magazines instead of a pair of 30s, with a corresponding reduction in propellant charge module storage. The armor was redesigned to be lighter, and to be an easily-removable set of modules like what was on the Puma. The power pack was also redesigned. This yielded a combat weight of 50 tonnes and the target air-transportable weight. But while a C-5B could now carry two Crusaders, Congress balked at the ridiculous unit cost. The program was eventually terminated in favor of the self-propelled howitzer portion of the Future Combat System, which would be no more successful.2

And now, what do I think? Well, I really like the Crusader, even if it is a classic American attempt to pack too much innovation into one can. The core concept of fully automated ammunition handling, isolated from the crew, is a great one, and one that I buy into. I could even get behind the liquid-cooled gun, though I would be just as happy if the “A0” version had a conventional gun, with plans to add the liquid cooling later. I also kinda like the LV100-5 engine, though again I would be content with an MTU 883. I think the version of choice is what the early 2000s prototypes were: 60 tonne beasts that could outgun anything on the battlefield. I have no desire to cut any weight from the program.

Verdict: Funding Approved by the Borgundy Army Armor Development Board

  1. Multiple Rounds Simultaneous Impact. 
  2. Thanks a lot, Shinseki and Rumsfeld. /sarcasm I really, really hate the “super light future army” nonsense, but that is a rant for another time. 

2 thoughts on “Resurrected Weapons: XM2001 Crusader

  1. Checkmate

    A very inovative system, but… glycol cooled barrel with heat exchangers, modular proppellant charges, double ammo rack, what I assume is automated selection and handling… the inside of that turret must’ve made the Shuttle look primitive…
    The K9 Thunder also uses an automated replenishing vehicle. Might wanna check it out.
    Any ideea on the range of this thing?

    1. parvusimperator Post author

      Technically two ammo racks (two belts, basically) for reasons that are unclear to me. And yes, it was a very complicated internal system. Though the crew was totally isolated from all of the ammo handling.

      The K9 Thunder will have its day, fear not.

      Range estimates are a little unclear. The goal was 50+ km, but I haven’t been able to figure out with what shells. And it unfortunately never got a chance to mess around with some of Denel’s fancy rounds.

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