Since the early forties, the American defense industry has been actively engaged in the creation of new self-propelled artillery installations with various weapons. Medium tanks and vehicles of other classes were used as the basis for such armored vehicles. In particular, several promising combat vehicles, including self-propelled guns, were created on the basis of the M24 Chaffee light tank. Not all projects of such machines reached mass production and were able to get into the troops, but some developments turned out to be very successful. So, one of the first in the series was the M41 Howitzer Motor Carriage ACS, also known under the unofficial name Gorilla.
It should be noted that the self-propelled gun M41 HMC did not appear immediately. The terms of reference for the creation of a promising self-propelled gun with 155 mm howitzer armament appeared at the end of 1942, but the project did not immediately receive military approval. In accordance with the requirements, a promising ACS should have been able to accompany tank formations and support them with fire. The chassis of the M5 Stuart light tank was proposed as the basis for the new armored vehicle. It was to be equipped with an M1-type howitzer and a set of necessary equipment.
The project of a promising self-propelled gun was designated T64. The development of a new car did not take long: the preliminary design was approved already in December 42nd. Soon, all the remaining design work was completed, which made it possible to proceed to the construction and testing of new equipment. According to reports, in the T64 project it was proposed to use the basic layout ideas already worked out in the framework of the M12 GMC ACS project. For example, to free up space for placing a gun mount, it was planned to transfer the engine of the base tank from the stern to the central part of the hull.
M41 HMC prototype at the Aberdeen Museum. Photo Wikimedia Commons
In the first months of 1943, the first prototype of the T64 SPG entered trials and, overall, performed well. The existing chassis of the serial tank did not have significant flaws, which could open the way to the troops for the new self-propelled gun. However, the War Department decided otherwise. There was a proposal to develop the so-called. Light Combat Team is a family of armored vehicles for various purposes, built on the basis of a common chassis. In order to achieve the maximum possible performance, it was decided to build a new family based on the new M24 Chaffee light tank.
At the end of 1943, a new project was launched with the designation T64E1, the purpose of which was to transfer the artillery unit of the base T64 to a new tank chassis. At the same time, the chassis of the M24 tank should have been appropriately redesigned. Work on the new project began in January 44th and, due to a number of circumstances, lasted until the end of the year. The design of the T64E1 ACS was completed only in December.
The Chaffee armored vehicle had a typical layout for American tanks of that time. In the front of the hull, transmission units were installed and the control compartment was located. An engine was mounted in the stern, connected to the transmission using a long propeller shaft. The latter, in turn, took place under the floor of the fighting compartment. It was impossible to maintain a similar layout when installing a 155-mm gun, so the authors of the T64 and T64E1 projects resorted to significant design modifications that had already been tested on earlier vehicles with similar weapons. Due to the lack of a turret with weapons, the engine was moved to the central part of the hull, shortening the propeller shaft. This method freed a large volume in the rear of the hull, which was given under the open fighting compartment.
The body of the self-propelled guns, as in the case of the base tank, was made of armor parts with a thickness of 15 to 38 mm. According to other sources, the maximum thickness of self-propelled armor did not exceed 12, 7 mm. The T64E1 retained the basic features of the base car body, but received some new units. The frontal projection was protected by three inclined sheets. The central engine compartment was covered with a horizontal roof. In the stern, the frontal and side sheets of the deckhouse were provided. Due to the correct layout of the units, the bottom of the hull was the floor of the fighting compartment. Also, the body had a folding stern sheet connected to the opener.
Aft self-propelled gun. Photo Aviarmor.net
The promising T64E1 self-propelled gun was equipped with two 110 hp Cadillac 44T24 petrol engines installed in the middle of the hull. Through the propeller shaft, two fluid couplings, two planetary gearboxes, a double differential, a range multiplier and a manual gearbox, the engine torque was transmitted to the front drive wheels. In order to simplify and reduce the cost of mass production, it was decided not to make drastic changes to the composition of the power plant. In fact, only the location of the engine has changed, due to the need to install new weapons.
The chassis of the M24 Chaffee base tank passed to the T64E1 ACS without any changes. On each side of the hull there were six double road wheels with individual torsion bar suspension. Also, some of the road wheels were equipped with additional shock absorbers. Due to the relatively small diameter of the road wheels, the upper branch of the track was supported by four rollers (on each side). The driving wheels were located in the front of the hull, the guides were in the stern. The chassis track consisted of 86 tracks 586 mm wide.
In the aft compartment of the hull, it was proposed to mount racks for ammunition and a mount for a gun. To simplify the design, these two products have been combined into a common unit. A rack with cells for ammunition was connected to the bottom and sides of the hull, and a gun mount was located on its lid. With the help of manual drives, the calculation could direct the gun 20 ° 30 'to the left or 17 ° to the right of the vehicle axis horizontally, and the vertical guidance angles were limited to -5 ° and + 45 °. In the cells of the rack of the fighting compartment, there was room for 22 shots of separate cap-loading.
The 155mm M1 howitzer (also known as the M114) was proposed as the primary weapon for the T64E1. This gun was equipped with a 24.5 caliber rifled barrel and had a piston bolt. The barrel was mounted on hydropneumatic recoil devices. For use by the M1 howitzer, several types of shells were offered, high-explosive fragmentation, smoke, chemical, lighting, etc. The maximum initial velocity of the projectiles reached 564 m / s, the maximum firing range was about 14, 95 km.
M41 HMC schematic front-right view. Figure M24chaffee.com
In the fighting compartment, it was also proposed to transport additional weapons for self-defense, consisting of two Thompson submachine guns and three M1 carbines. A stationary machine gun was not provided for the turret.
Like other self-propelled guns of the American design of that time, built on the chassis of existing tanks, the promising T64E1 machine could not fire on the move. For shooting, one had to take a position and fix on it. To hold the armored vehicle in place, it was proposed to use a feed opener. This device consisted of two support beams and a blade with stops for burrowing into the ground. Taking into account the experience of previous projects, the opener was equipped not with a hydraulic drive, but with a manual winch. After arriving at the position, the crew had to lower the opener and then back it up, burying it in the ground. Before leaving the position, it was required to move forward, and then raise the opener.
The crew of the T64E1 self-propelled gun was supposed to consist of five people: the driver, the commander and three gunners. For obvious reasons, all crew members took part in firing the main weapon.
Due to the preservation of the main units of the base armored vehicle, the promising self-propelled gun in size and weight differed little from the Chaffee tank. The length of the self-propelled guns reached 5.8 m, width 2.85 m, height - about 2.4 m. The combat weight reached 19.3 tons.
M41 HMC schematic, rear-left view. Figure M24chaffee.com
The preservation of the basic power plant, as well as a slight increase in the weight of the machine, made it possible to achieve sufficiently high mobility characteristics. The speed of the self-propelled gun on the highway reached 55 km / h, the cruising range reached 160 km. It remained possible to overcome various obstacles with parameters at the level of the M24 tank.
For joint work with the T64E1 ACS, several types of ammunition transporters were offered. Initially, it was planned to use a T22E1 type transporter based on the T64E1 with self-propelled guns. In the aft part of the T22, there were racks for storing ammunition. In the future, it was decided to abandon the T22E1 and use the new M39 machines. In practice, along with self-propelled guns, not only specialized tracked vehicles were often used, but also ordinary trucks.
The use of a ready-made chassis not only affected the speed of project development, but also reduced the time required to build a prototype. Design work was completed at the beginning of the winter of 1944, and already in December, the first prototype of the promising T64E1 self-propelled guns with howitzer weapons was assembled. Soon the car went to tests, where it showed the correctness of the chosen solutions, and also confirmed the calculated characteristics. The prototype was tested at the Aberdeen Proving Grounds.
The presented sample fully complied with the requirements, and after the tests it was put into service. The order for acceptance into service was signed on June 28, 1945. The self-propelled gun received the official designation M41 Howitzer Motor Carriage. Soon after the start of operation, the new military equipment, like other armored vehicles before it, received an unofficial nickname: Gorilla ("Gorilla"). Perhaps this nickname was to some extent related to the unofficial name of the M12 ACS, also known as "King Kong".
Combat use of self-propelled guns, the rack of the fighting compartment is clearly visible. Photo Aviarmor.net
Without waiting for the end of the tests, the American army signed the first contract for the supply of T64E1 / M41 vehicles. Already in May 45, the order for the production of 250 serial self-propelled guns was received by Massey-Harris, which was engaged in the construction of light tanks M24 Chaffee. This fact made it possible to a certain extent to simplify and speed up the construction of self-propelled guns.
The well-established process of tank production allowed the contractor to immediately start building new self-propelled guns. However, until the end of World War II, only 85 new type of combat vehicles were manufactured. Later, the start of production did not allow the "Gorillas" to go to war, but the troops still began to master the new technology. According to a number of sources, after the end of the war, it was decided to abandon the further construction of self-propelled guns. The army handed over 85 built vehicles, and the production of the rest was canceled.
A number of M41 HMCs were transferred by the United States to foreign countries. There is information about the transfer of one self-propelled gun to the British military, who were supposed to test and study it. Also, some of the built machines were sent to France, where they were adopted and operated for a certain time, until a new technique of a similar class appeared.
ACS M41 Howitzer Motor Carriage appeared too late to get into the Second World War. Nevertheless, the world was still restless, because of which this technique was still able to take part in the hostilities. In 1950, most of the M41 was sent to Korea to participate in the war that began there. Despite the relatively small number, self-propelled guns were actively used in all sectors of the front and provided a full-fledged solution to the assigned tasks. As expected at the development stage, self-propelled artillery mounts clearly demonstrated their advantages over towed guns.
ACS M41 in the Chinese Museum. Photo The.shadock.free.fr
The intensity of the operation of Gorillas in Korea is well illustrated by the fact that it was precisely such a technique, which was part of the 92nd Field Artillery Battalion, that fired two "anniversary" shots at the enemy, which were 150,000 and 3,000,000 during the campaign. At the same time, artillery formations armed with the M41 suffered some losses. At least one such self-propelled gun in relatively good condition even became an enemy trophy.
The Korean War was the first and last armed conflict in the career of the M41 HMC ACS. The operation of this technique continued until the mid-fifties, after which it was considered unpromising. Due to the moral and physical obsolescence of the chassis and weapons, the further use of the Gorilla ACS did not make sense. In the second half of the fifties, all available vehicles of this type were decommissioned. Most of them went for recycling.
According to reports, only two self-propelled artillery mounts of the M41 Howitzer Motor Carriage type have survived to this day. One of them - according to some reports, this is the first prototype - is kept in the Museum of the Aberdeen Proving Ground. Another copy is in the Beijing War Museum (China). Probably, this machine was used in the Korean War and became a trophy of the Chinese troops, after which it was transferred to the museum.
