During World War II, the American army operated a significant number of armored personnel carriers and artillery tractors of several models. Equipment with a half-track undercarriage was widespread during this period. The continuation of work in two important directions led to the appearance of an interesting model of an auxiliary vehicle, which solved several problems during the war, and subsequently had a significant impact on the further development of American armored vehicles. It was the Armored Utility Vehicle M39.
The prerequisites for the emergence of a new transport vehicle were quite interesting. In 1943, the M18 Hellcat anti-tank self-propelled artillery mount, armed with a 76 mm cannon, was put into production. By the middle of next year, it became clear that this machine, with all its advantages, no longer fully meets the current requirements and therefore must be replaced. To replace the existing equipment, a new self-propelled gun M36 was created. In the fall of 1944, the serial production of the M18 was curtailed, the operation of such equipment was supposed to continue until it was completely replaced with new machines.
General view of the transport vehicle M39. Photo Afvdb.50megs.com
The M18 self-propelled gun had an insufficiently powerful gun, but its chassis could still be of interest to the military and be used in a new role. Already in the summer of 1944, a proposal appeared to modernize tank destroyers with alteration into auxiliary vehicles. Through a relatively simple alteration, a serial self-propelled gun could become a multi-purpose transport armored vehicle, suitable for use in different roles. Such a transport should have had noticeable advantages over existing half-tracked vehicles. It could be advantageously distinguished by the higher level of protection provided by a different armored hull, and the improved mobility achieved by a fully tracked chassis.
The new general-purpose vehicle project received the working designation Armored Utility Vehicle T41. This name remained until early 1945, when the vehicle was officially adopted under the designation Armored Utility Vehicle M39. For convenience, the class of equipment reflected in its name was often abbreviated to AUV.
The authors of the T41 project proposed a fairly simple way to convert SPGs into transport equipment. From the production vehicle of the M18 Hellcat type, the turret with the gun and all the original equipment of the fighting compartment should be removed. In addition, the roof was removed from the hull. In the vacated places, it was proposed to mount a variety of equipment necessary for the carriage of goods or passengers. All other components and assemblies of the existing chassis remained unchanged.
ACS M18 Hellcat. Photo Wikimedia Commons
In accordance with the main ideas of the project, the basic self-propelled gun had a relatively thin booking, which, however, made it possible to obtain high mobility and ensure sufficient survivability on the battlefield. After dismantling the tower and installing new equipment, a promising multi-purpose vehicle should have retained similar qualities and even increased mobility by reducing weight.
The new transport vehicle retained the main body of the base sample. The M18 self-propelled gun received armor up to 12.7 mm thick. The frontal part of the hull had a wedge-shaped profile and a large opening for servicing the transmission, covered with a removable cover. Behind the upper inclined sheet was a small horizontal section of the hull roof with crew hatches. The low fencing niches, formed by several inclined sheets, remained unchanged. The shape of the stern also did not change: it still consisted of several sheets installed vertically or with an inclination.
Removing the turret made it possible to rework the turret platform in order to solve new problems. The former fighting compartment lost its roof, which made it easier to access the inside of the vehicle. To increase the useful volume and additional protection of passengers, a low armored cabin was added on top of the original hull. It consisted of four trapezoidal sheets assembled into a truncated pyramid-shaped structure. The frontal sheet of such a cabin had a small cutout in the upper part - it was intended for mounting a machine gun mount. The sides of the cabin had narrow parts that slightly covered the inner compartment. Also, on the upper side parts and at the stern, it was planned to install lattice baskets for the transportation of various property.
M39, aft view. Photo Afvdb.50megs.com
The hull layout was refined in accordance with the new role of the machine, but at the same time it was not radically reworked. In the front of the hull, a small compartment has been preserved for accommodating transmission units, behind which a two-seater control compartment was placed. A large central volume under the wheelhouse could perform the functions of a cargo compartment or an airborne compartment, depending on the task at hand. The stern still contained the engine compartment. Thus, the changes affected only the central part of the hull, which had lost the standard fighting compartment.
A radial nine-cylinder four-stroke Continental R-975-C4 gasoline engine with a capacity of 400 hp was placed in the aft compartment of the hull of the base ACS and, as a consequence, of the T41 transporter. Using a propeller shaft, the engine was connected to a transmission unit located in the front of the body. There was a 900T Torqmatic transmission with three forward speeds and one reverse. The power plant included fuel tanks with a total capacity of 625 liters.
The chassis was borrowed from the M18 without changes. Each side retained five double road wheels with rubber tires. The rollers had individual torsion bar suspension. All pairs of rollers, with the exception of the middle one, received additional shock absorbers. In the front of the hull there were drive wheels with toothed rims, in the stern - guides equipped with a track tension mechanism. Due to the use of small rollers, four support rollers were included in the undercarriage.
The 3-inch M6 cannon is one of the main payloads of the M39 tractor. Photo Wikimedia Commons
For self-defense, the armored auxiliary vehicle received a machine gun mount. In the upper part of the frontal sheet of the new wheelhouse, a support ring of the turret was placed, along which the support of the machine gun could move. With the help of such a device, the shooter could attack targets in any direction with significant elevation angles. A large-caliber machine gun M2HB was installed on the turret. The ammunition load of the weapon consisted of 900 rounds of ammunition in several belts, placed on the appropriate stowage inside the hull.
The car's own crew consisted of three people. On the left in the control compartment was the driver, at the starboard side - his assistant. Access to the control compartment was provided by two roof hatches. Behind the control compartment, in the main cargo and passenger compartment, was the commander. His duties included monitoring the surrounding space, as well as using a machine gun. For obvious reasons, the commander did not have his own hatch.
The payload was to be located in the central compartment of the hull, previously used as a fighting compartment. At the front and rear walls of the compartment, two sets of folding seats were placed for transporting soldiers. Together with three crew members, up to eight paratroopers could be on board. The AUV T41 project initially provided for the use of equipment as an artillery tractor, in connection with which the central compartment could also be used to transport ammunition. Boxes with shells could be stacked directly on the floor of the troop compartment. The calculation of the towed gun was also located inside the hull. The gun itself was proposed to be transported using a stern towing hook.
Transport M39 as a transporter of logs required for the construction of the dugout. Korea, October 1, 1952 Photo by US Army
The refusal to use the turret led to the fact that the T41 transport vehicle, with similar hull dimensions, was noticeably more compact and lighter than the base self-propelled gun. The length of the transport was 5, 3 m, width - 2, 4 m, height on the roof - 2 m. Combat weight was 15, 17 tons. A large number of artillery rounds could be placed in the cargo compartment. The number of shells transported depended on their type and the task assigned to the artillerymen.
The lightweight transport vehicle had a fairly high power density - more than 26 hp. per ton. Thanks to this, on the highway, she could reach speeds of up to 80 km / h, the fuel supply was enough for 160 km. It was possible to overcome uphills with a steepness of 60%, trenches with a width of 1.86 m or walls with a height of 91 cm. Water obstacles with a depth of up to 1.2 m were forded. Turning radius - 20 m. When towing an artillery gun, restrictions could be imposed on the maximum speed of movement, etc., aimed at preventing its damage.
By the fall of 1944, Buick, which produced the M18 Hellcat self-propelled guns, received an order for the manufacture of two experimental transport vehicles of the AUV T41 type. For the construction of this technique, two serial self-propelled guns were taken. The re-equipment of the finished vehicles did not take much time, thanks to which prototypes of the transporter tractor were soon brought to the test site. The use of a ready-made, tested and proven chassis made it possible to do without lengthy tests. The sufficiently high characteristics of the promising machine were already obvious.
M39 as an ambulance. Korea, October 14, 1952 Photo by US Army
In the autumn of the same year, the Hellcat manufacturing company received a contract for the serial production of the latest multifunctional machines. The manufacturer was supposed to receive the self-propelled guns available, where they needed to be repaired and re-equipped according to a new project. In October, the 44th Army received the first batch of 10 production vehicles. In November, the military received another 60 transporters. In December 1944 and January 1945, 163 and 180 vehicles were built, respectively. In February and March, the customer received another 227 vehicles. In March 1945, the production of the transport vehicle was discontinued. For six months of work, Buick has released 640 units of new technology. Interestingly, before the start of the 45th, the vehicles bore the working designation T41. The official name Armored Utility Vehicle M39 was given to them only at the beginning of the new year.
New armored vehicles quickly got to the front, where they began to be used for their intended purpose. The first "specialty" of the T41 / M39 was the transport of M6 anti-tank guns. In the role of a tractor for such a gun, the transporter could carry a crew and 42 76 mm projectiles. The use of the new machine as a tractor with other types of implements was not ruled out. In addition, M39 were often used to transport personnel or cargo, performing the functions of an armored personnel carrier or a protected truck.
It is known about the use of multifunctional transporters M39 as armored reconnaissance vehicles. The existing bulletproof armor and a large-caliber machine gun, combined with high mobility, allowed the crew to solve not only transport tasks. At the same time, in some cases, insufficiently powerful armor could seriously limit the combat potential of the vehicle, just as it was with the basic M18 self-propelled guns.
M39 as a Marine Corps armored personnel carrier. Korea, July 25, 1953 Photo by US Army
M39 armored vehicles were in operation until the very end of World War II. After the end of the fighting in Europe and the Pacific, the service of such equipment continued. While the basic M18 SPG was outdated for a long time, transporters based on it were still of interest to the army. The tractor / transport / armored personnel carrier remained in service until the early 1950s, when the US Army entered the Korean War.
The appearance of new models of armored vehicles with higher characteristics made it possible to reduce the activity of using the existing M39, however, even in such conditions, such vehicles did not remain without work. In Korea, auxiliary vehicles were used in secondary roles, as carriers of ammunition, armored personnel carriers and ambulances. The work of such a technique was to deliver soldiers or ammunition to the front lines, evacuate soldiers and wounded to the rear, etc. A full-fledged combat use of technology at the forefront, however, was ruled out. The lack of a roof exposed the crew and the landing force to increased risks. Newer samples already had a completely closed case, which allowed them to work in any conditions without endangering people. M39 in such a situation could only count on the role of auxiliary vehicles.
In 1953, the Korean War ended, but the service of the Armored Utility Vehicle M39 did not stop. Despite far from complete compliance with current requirements, a small number and a partially exhausted resource, the remaining armored personnel carriers could still find use in the army. It was decided to abandon this technique only in 1957. Some of the equipment went for disassembly, other vehicles were sold or transferred to the allies. Several units of this technique later ended up in museums and private collections.
American armored vehicle stored in Kubinka. Photo Wikimedia Commons
Of the 640 built AUV M39, 11 survived to this day. Most of the surviving samples are in the United States. Three cars in different condition remain in Germany. One car is in a private collection in the UK. During the Korean War, one sample of the M39 became a trophy of the enemy and soon ended up in the USSR. This vehicle is now kept in the Kubinka tank museum.
The Armored Utility Vehicle M39 multipurpose vehicle project was created as a simple and effective way to find use for obsolete self-propelled artillery installations. By not too complicated processing of the original design, a sample of armored vehicles was created, suitable for solving a wide range of tasks. This machine turned out to be so successful that it remained in service until the second half of the fifties and with a certain efficiency it solved various transport problems. Taking into account the service life, it can even be argued that the M39 transporter turned out to be much more successful than the basic M18 Hellcat ACS. In addition, it should be noted that the appearance of this vehicle had a significant impact on the further development of American armored personnel carriers.
