Science Technology: Self-propelled howitzers on a light chassis
In a previous article the emergence of such a technical phenomenon as combat vehicles of the “technical” class was considered. Machines of this type at a low price are distinguished by maneuverability, tactical and strategic mobility, ease of camouflage, unpretentiousness in maintenance and repair.
It is these qualities that caused the widespread use of machines of this class, both in irregular formations and in the armies of a number of countries.
But, with the undoubted advantages, the “technical” has a number of drawbacks, the main of which is the impossibility of installing heavy weapons systems on them. Attempts at home artillery to mount automatic cannons or light MLRS on jeeps are not able to radically solve the problem of fire support for units or detachments using "technical", in addition, unskilled weapons installation is not only short-lived, but often leads to fatal consequences for the crew.
Thus, both for irregular formations and for regular army units using vehicles of this class, the need arises to create powerful fire support equipment on a relatively light wheeled chassis. But, to solve such a problem, the technical potential of industrialized countries is necessary. The US Department of Defense, which created the 25th light infantry division within the framework of the light infantry development program, could not help but realize that for the combat use of units on high-speed vehicles, means of amplification on the chassis with comparable dynamic characteristics are needed. As an illustration: a unit moving in jeeps cannot be equipped with tracked self-propelled howitzers as a means of reinforcement - they simply will not be able to keep up with high-speed and maneuverable vehicles.
Self-propelled anti-tank systems, mortars and other types of heavy weapons can be used as reinforcements. But, one of the most interesting examples of such systems is a self-propelled howitzer on a heavy jeep chassis.
At first glance, this problem has no technical solution: the recoil force of a modern howitzer is tens of tons, which completely excludes the possibility of its installation on a relatively light wheeled chassis.
There are various ways to reduce the recoil of an artillery gun. The simplest and most effective is the use of a muzzle brake, a device that redirects powder gases exiting the barrel in the opposite direction to the breech of the gun. But this method is not applicable for a light chassis, since the shock wave from the muzzle brake can cause significant damage to the openly located crew of the combat vehicle. A much more preferred option is to use an automation circuit with rolling parts of the moving parts.
The Rock Island Arsenal has been implementing this scheme for many years, according to American terminology this scheme is called “soft recoil” - “soft recoil”, and the artillery systems that use it are referred to as the so-called “Rock Island line”.
The basis of this scheme is the principle of counter acceleration of the rolling parts of the gun before the ignition of the charge, which can significantly reduce the recoil force. This, in turn, reduces the load on the carriage through the trunnions, allowing you to significantly reduce the weight of the gun platform compared to a conventional howitzer with a full barrel rollback. At the beginning of the low-recoil cycle, the rolling parts of the gun are in a position in the middle of the barrel length, under pressure of a locked recuperator filled with nitrogen. When the trigger is lowered, a shot is fired and the recuperator stopper is released, the mass of the rolling parts, including the barrel, begins to move forward. A special sensor monitors the movement and speed of this mass, and only when the latter reaches a certain speed does it ignite the charge.
The recoil force produced by the shot must first stop, and then move in the opposite direction the mass of recoil devices and the barrel. Thus, recoil energy is reduced by 70 percent. The remaining energy is used to return the barrel and recoil devices to their original position for the next shot cycle.
A striking example of solving this technical problem was the Hawkeye family of machines (Hawkeye), created by the American company Mandus Group and the Rock Island Arsenal (RIA).
This family of vehicles uses the swinging part of the 105 mm American M137A1 howitzer. Vertical and horizontal guidance drives are digitally controlled. Self-propelled howitzer can be equipped with an electronic or optical sight, or both at the same time. For direct fire there is a telescopic sight, with a computerized aiming mark, superimposed on the field of view with a ballistic computer.
The possibility of creating a fully automated "digital" version of a self-propelled howitzer, with automatic guidance drives and a loading mechanism.
The estimated firing range of the prototype with standard M67 shells with a charge of No. 7 is 11.5 km, and M927 with active rockets with the same charge is 16.7 km.
Currently, several prototypes of self-propelled howitzers are being tested, differing in chassis and equipment used.
SHERPA HAWKEYE 105 uses a 105 mm howitzer mounted on an all-wheel drive chassis of the French army vehicle Renault Sherpa Light, as an option, a heavier chassis of a military truck manufactured by Mack can be used. This prototype howitzer is equipped with the Selex Galileo LINAPS artillery positioning system, which includes a FIN3110 inertial laser gyroscope and an integrated GPS receiver.
The recoil force produced by the shot must first stop, and then move in the opposite direction the mass of recoil devices and the barrel. Thus, recoil energy is reduced by 70 percent. The remaining energy is used to return the barrel and recoil devices to their original position for the next shot cycle.
A striking example of solving this technical problem was the Hawkeye family of machines (Hawkeye), created by the American company Mandus Group and the Rock Island Arsenal (RIA).
The HMMWV HAWKEYE 105 uses the same swinging part of the 105 mm M137A1 howitzer, but on the chassis of the M1152A1 Humvee army vehicle belonging to the well-known Hammer family
This prototype uses the MG 9000 digital fire control system and the Northrop Grumman LN-270 navigation system.
A lightweight version of this howitzer system was also tested using a heavy duty FordF250 chassis.
We conclude: the technical solution proposed by the Rock Island Arsenal allows you to create a new class of weapons. How popular he will be - time will tell.
Previously Science Technology wrote about the features of the Archer technology