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In recent years, the U.S. Army has spared no expense in developing a new generation of self-propelled howitzers, this model is tentatively designated as the XM1299 155 mm self-propelled howitzer, with a 58 times caliber barrel and a new loader, and its preliminary test range has reached 70 kilometers. This range is not much higher than the range of the current M109A6 155mm self-propelled howitzer in service with conventional ammunition of up to 39 kilometers, but the US military is not satisfied with this, hoping to increase the range of artillery to 100 kilometers through new technologies in the future. In order to achieve this goal, the US military will not only develop a new barrel of the XM907 type, but also develop rocket-boosted artillery shells, automatic loaders, and new fire control systems. The XM1299 155mm self-propelled howitzer developed by the US military will certainly have an important impact on the research and development of self-propelled howitzers in other countries in the world with its commendable advancement.
XM1299 self-propelled gun on test
58 times the diameter of the gun barrel
It is reported that the XM1299 is a new type of rocket artillery developed and produced by the US Army on the basis of the M109 A series of artillery, and adopts a number of new technologies: including the use of 58 times the diameter of the artillery barrel, the use of advanced extended-range ammunition technology, the use of advanced loader technology, the use of advanced integrated information system, etc.
The double diameter is a multiple of the length and caliber of the barrel, the longer the double diameter, the longer the firing range, and the reason why self-propelled guns pay so much attention to the double diameter is to increase the firing range. The XM1299 is a modified version of the M777A2 howitzer barrel with an XM907 gun barrel of 58 times the caliber. To this end, the barrel was increased by 1.8 meters, the weight of the barrel was increased by 450 kg, and the theoretical maximum firing range was increased to 70 km. Higher chamber pressures can lead to longer ranges, but they also pose a higher risk of bore explosions, and high temperatures and friction can also drastically reduce barrel life. In order to meet these demanding requirements, the materials and manufacturing processes of the barrel will naturally become more and more complex.
The new generation of self-propelled howitzers uses the XM907 barrel, which has been redesigned to expand the chamber volume and use a very long XM654 "super launcher" semi-flammable cartridge to reduce the impact of gunpowder firing on the chamber. In order to reduce the effect of overheating caused by the high rate of fire, the integrated gap cooling barrel is adopted, and its general principle is as follows: the coolant is provided by the gun mount to the wall between the gun barrels, and then flows back to the gun mount through a special cooling pipe outside the gun barrel, and the coolant circulation is completed with the help of the recoil of the gun. The artillery stationing and retreating reversing machine adopts a modular hydraulic stationing and retreating mode, which has a compact structure and a large stationing and retreating force. In order to save valuable interior space, the station-and-retreat retractor is arranged outside the barrel.
The XM1299 is designed to take the chassis and turret of the current M109A7 gun and replace it with a newly designed 155 mm caliber gun
Advanced extended-range ammunition is adopted
In addition to being part of the "Extended Range Artillery Artillery" (ERCA) program, the XM1299 self-propelled howitzer is also part of the U.S. Army's "Long Range Precision Fire" (LPRF) program. Thus, the XM1299 self-propelled howitzer is equipped with two types of ammunition.
One is a new ram extended-range shell. The shell itself carries a solid-fuel ramjet engine, which can be mixed with solid fuel during the flight, and the shell can be accelerated again after the shot. The other munition is a guided munition, also a product of the above-mentioned Long Range Precision Fire (LPRF) program. This guided munition combines ultra-long range and precision destruction effectiveness. The XM1299 self-propelled howitzer uses a rocket-extended range grenade with less added resistance, and this ammunition uses the so-called ram range extension technology, which allows the maximum range to exceed 100 km.
XM1299 self-propelled howitzer ammunition range extension technology In the design of the weapon, the composite technology of bullet shape and bottom row matching is adopted, so that the firing weapon can obtain the maximum range extension effect. The extended-range shell of the XM1299 self-propelled gun is also called the extended-range bottom row. This grenade is a rocket propellant in the tail of the warhead, which ignites as soon as the warhead is discharged. When the projectile flies, the gas is discharged from the bottom of the projectile, and the low-pressure vortex area of the bottom of the projectile is continuously filled, so as to greatly reduce the resistance of the bottom of the projectile, so that the total resistance of the projectile body decreases, and the range increase rate can reach 30%. Rocket-assisted cruise shells. XM1299 is equipped with XM1155 shells, which use ballistic flight at the initial stage, spread winglets to cruise in the middle section, and attack the top at the end, with a range of more than 100+ kilometers, and the shell uses a new MEFP high-explosive (HE) warhead that can produce multiple explosive projectiles (EFP) instead of submunitions, which can destroy the "Integrated Air Defense and Anti-Missile System" (IAMDS) and reinforce hard targets in an environment where GPS cannot be used.
Schematic diagram of the US XM1299 155mm self-propelled howitzer mounted on an automatic loader
Advanced loader technology is adopted
The US XM1299 155mm self-propelled howitzer is equipped with an automatic loader, and its structure is also ingenious, consisting of a projectile compartment, a projectile delivery mechanism, a projectile cartridge compartment, and a projectile cartridge delivery mechanism. Since the entire reloading process is automatically controlled by the computer, the reloading rate is increased, and its actual rate of fire reaches 10 rounds / min, which far exceeds the actual rate of fire of most other self-propelled howitzers. The automatic loader also has functions such as the selection of ammunition types, the selection of the number of modular charges, and the setting of fuses. The self-propelled howitzer used by the US XM1299 self-propelled howitzer allows the rate of fire of the gun to increase from the current 3 rounds per minute to 10 rounds per minute. The U.S. military also plans to make the XM1299's turret unmanned to avoid loss of personnel and increase the amount of ammunition carried in the turret.
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It adopts a scientific body balance layout
The U.S. Army X M1299 self-propelled howitzer is currently the world's longest self-propelled howitzer, which is prone to top-heavy when firing ammunition, in order to solve this problem, it is necessary to redesign the layout, because the new 58 times the diameter of the body tube both in length and weight compared with the original 52 times the diameter of the body tube has been improved a lot. If a new gun with 58 times the diameter is directly installed on the chassis of the M109A7 self-propelled howitzer, it will lead to an offset in the center of the vehicle and is prone to overturning accidents. The U.S. Army uses the current towed M777ER ultra-light howitzer's gun barrel to improve, because the M777ER was originally aimed at pursuing lightweight, so the use of the M777ER ultra-light howitzer's gun barrel technology can alleviate the overweight problem caused by the 58 times diameter design.
The XM1299 self-propelled howitzer is equipped with an advanced "Location and Navigation System" (APNS) and GPS satellite positioning system
Adopt an advanced integrated information system
The XM1299 self-propelled howitzer is equipped with an advanced "Location and Navigation System" (APNS) and GPS satellite positioning system. The gunner can easily control the automatic artillery system, automatic loader, and friend or foe identification system, and automatically complete a series of actions such as selecting the type of ammunition, loading, aiming, and shooting. The commander can control the tactical command console and the mobile planning auxiliary decision-making system, and maintain uninterrupted communication and information sharing with superiors and friendly neighbors through the digital inter-vehicle information system and the "Advanced Field Artillery Tactical Data System" (AFATDS).
The XM1299 self-propelled howitzer platform can be connected to the advanced field artillery tactical data system and other target detection and weapon systems, and can complete a series of operations such as independently receiving firing tasks, calculating firing elements, occupying firing positions, releasing the gun body marching fixer, aiming the gun at the target and hitting the target for the first time, both day and night, within one minute.
epilogue
As an industrial and military power in the world, the new generation of self-propelled howitzers researched by the US military represents the advanced level in the field of military industry, and is of great significance and worthy of attention for enhancing the combat capability of the US Army.