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Crusader XM2001 Self-Propelled Howitzer

Although the Crusader self-propelled howitzer (SPH) may outwardly resemble a tank, it is not and has a drastically different battlefield role. A tank is a front line, close combat weapon whose main armament operates on a direct fire principle (i.e., a direct line of sight is obtained to the target and used to orient the weapon). The Crusader SPH operates on the artillery principle of indirect fire (i.e., a direct line of sight is not used to orient the weapon), although direct fire can be employed if the situation dictates. Usually, the SPH is located several kilometers (km) behind front lines and delivers fires upon designated targets based upon coordinates transmitted digitally by forward observation personnel, intelligence or target acquisition systems (e.g., radars, reconnaissance systems, remotely piloted vehicles, aerial surveillance systems, etc).

The Crusader SPH is designed to meet the demands of a 21st century self-propelled, indirect fire support system. The fully automated weapon system is capable of delivering a wide array of lethal 100 pound, 155 mm diameter projectiles onto designated targets within 40 km.

Unlike the current M109 series SPHs in service with the US Army, the Crusader SPH is a fully automated system. The weapon functions are remotely operated from the crew compartment using the onboard computer system. The computer receives a digitally transmitted fire mission and notifies the crew of a recommended weapon azimuth and elevation as well as the projectile and propellant charge combination(s) to fulfill the mission. The crew is only required to confirm and authorize the fire command. The automated weapon system is then brought to the correct orientation, loaded and fired. The system is capable of a 20 azimuth with elevations between -3 and 70. In the event the weapon must be oriented beyond the 20 window, the crew can perform a pivot steer to meet the correct azimuth within a matter of seconds. (A pivot steer is the process of turning one set of tracks while leaving the other set immobile, thereby causing the vehicle to rotate either clockwise or counterclockwise.)

The SPH main armament consists of the XM297E2 cannon, the XM200 gun mount and an automatic weapon loader. The cannon, which was specially designed for the Crusader system, is a 56 caliber tube (for large weapons, caliber is a ratio of tube length to bore diameter). A unique feature of the cannon tube is the employment of a full length cooling jacket using isopropyl glycol as the fluid medium. By dissipating gun tube heat through heat exchangers located in the turret, the active cooling system helps to provide a higher rate of fire, reduce tube wear and increase accuracy. Incorporated into the end of the tube is a pepper pot muzzle brake. This design employs a series of longitudinal rows of holes circumferentially around the tube. The holes are drilled at an angle that enables a rearwards venting of the gasses behind the expelled projectile, thereby providing a brake to the recoiling cannon (this is the backwards motion of the cannon caused by firing a projectile). Capping off the load end of the tube is a vertically sliding breech block coupled with a laser ignition system.

The SPH is capable of carrying a maximum of 60 fuzed projectiles within an active storage system (i.e., individual storage cells are mobile) comprised of two separate magazines located in the vehicle center. Each 30 round magazine is a closed-loop conveyor which cycles the desired projectile/fuze combination to a loading position accessible by the shuttle.

The emplaced SPH will fire the first round within 15-20 seconds of acknowledging a mission, or if the vehicle is on the move, 30-45 seconds after the fire mission is received. The weapon is capable of a maximum rate of fire of 10 rounds/minute for the first 3 minutes, followed by a sustained rate of between 3 and 6 rounds/minute until all on board ammunition is depleted. This means one howitzer delivers as much firepower as an entire platoon of Paladins.

Crusader's ability to fire the first rounds of a mission in as little as 15 seconds will ensure that weapons hit their targets before the enemy has a chance to move. This agility will result in more enemy combat losses. It will dramatically reduce direct-fire threats for U.S. combat vehicles and ground troops. And it will allow force commanders to shape the situation faster and more efficiently than ever before.

With today's systems, artillerymen must prepare, load, ram and fire weapons -- sometimes in extreme heat or cold. In these environments, even the most physically fit and highly determined men will tire -- and that will affect the rate of fire. But Crusader never tires -- no matter what the conditions. Crusader allows the crew to operate at an extremely high OPTEMPO for as long as the mission requires.

Crusader's technology also allows the crew to execute devastating multiple round simultaneous impact (MRSI) missions. The system is also capable of executing multiple round (8 maximum) simultaneous impact (MRSI) missions. After receiving the fire mission, Crusader calculates the time that one volley, at a given trajectory, will take to reach its target. It then launches additional rounds with alternate trajectory paths and charges calculated to reach the same target simultaneously. A MRSI mission is a sophisticated operation which requires several rounds to be fired in rapid succession, all at different elevations and velocities. The end result is that the multiple rounds reach the intended target at distances of 5-30 km within 4 seconds from first to last round impact. A single howitzer can drop nearly 800 pounds of steel on a target at the same time. Six Crusaders in just three minutes can deliver seven and a half tons of hot steel on the target.

The Crusader crew compartment is a well-protected, digitized command center that houses the three-man crew -- including a chief of section, a gunner and a driver. This compartment more closely represents a fighter cockpit than the inside of today's cannon artillery systems.

Unlike crews of conventional artillery vehicles, the Crusader crew is not required to physically load and ram projectiles, set fuzes or pull lanyards. Instead, they work in a digital, shirt-sleeve environment and focus on controlling the vehicle's subsystems and processes. Crusader's cockpit is designed to maximize intelligence, efficiency and safety. The crew performs its missions on a logical and easy-to-learn man/machine interface. Detailed information collected from the digital battlefield and from the system itself is logically sorted and screened so soldiers get fast access to the information they need most, drilling down through levels of increasingly specific detail. Furthermore, each station in the crew compartment is completely flexible and interchangeable. During combat, any one man on the three-man team can take over any particular function -- or all functions.

These breakthroughs allow the crew to remain safely inside the crew compartment, where they can move, fire, load and resupply; monitor performance and maintenance needs; and plan ahead. Six soldiers can accomplish the same tasks it took 27 to do in the past, which has and will enable the Army to significantly reduce the size of its forces. Better still, the combined forces of automation and digital interface allow soldiers to perform sequential tasks -- like loading, firing and defending the vehicle -- simultaneously. NBC protection eliminates the need for constrictive MOPP suits. Advance armor plating reduces the threat of direct munitions fires. And specially designed blowout panels provide protection in the event of a sympathetic ignition. These capabilities, coupled with the crews' freedom from physical tasks, makes Crusader's soldiers safer and more in control, and makes our artillery more lethal than ever before.

Crusader features a long list of breakthrough technologies that greatly reduce weight and improve mobility, including advanced vehicle electronics and fuel injection, a variable geometry turbocharger and advanced materials, such as composites. These allow the system to keep pace with other maneuver vehicles.

Crusader's mobility is comparable to that of the maneuver strike force. State-of-the-art mobility subsystems include an advanced power train, high-performance track, external hydropneumatic suspension and drive-by-wire control. These combined subsystems allow Crusader to maintain high cross-country speeds -- and provide the speed and maneuverability required for shoot and scoot missions.

The SPH moves at cross-country speeds of 39 kilometers per hour, highway speeds of 69 kilometers per hour and dash speeds of 750 meters in 90 seconds.



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