One of the proposals relating to the development of the army and the construction of new armored vehicles was presented by the Department of Public Works. Later, it led to the construction of three cars, known as the “Bob Sample Tanks”. Also at the beginning of 1940, the New Zealand military received a second sentence. The representative of the American company General Motors E.J. Scofield presented his version of the promising tank. The proposed machine had a number of specific features, but still was able to interest a potential customer. After reviewing the documentation and layout of the tank, the military department approved further work. Over the next few months it was planned to build and test a prototype of a promising armored vehicle, and then to establish mass production and supplies to the troops.
Tank E. J. Scofield. Photo Archives New Zealand / Archives.govt.nz
The designer took into account the very limited possibilities of the New Zealand industry, which led to the appearance of a number of characteristic features. At the heart of the new tank was to lie the chassis of the existing serial commercial truck. Also, the design of various units is simplified as much as possible, which allowed them to be produced in New Zealand. It was proposed to use a combined wheel-tracked propulsion, in theory capable of increasing the mobility of technology. Armament was to consist of several British-made Vickers machine guns. The proposed appearance of the tank, in the opinion of the author of the project and the military, allowed in a relatively short time to perform all the required work, as well as to achieve sufficiently high performance.
The use of wheeled-tracked undercarriage became the reason for the appearance of a non-standard design of a combat vehicle. In addition, the main features of the base units had a significant impact on the architecture and layout of the tank. In particular, because of the need to reduce the processing of existing power plants and transmissions, it was necessary to use the front engine layout.
Scheme of the machine, side view. Figure Pro-tank.ru
As the basis for the Scofield tank, the Chevrolet RHD commercial truck chassis with the wheel formula 4х2 was chosen. The chassis borrowed part of the frame, engine, transmission and wheels. At the same time, it was planned to supplement the existing units with some new details. Such a revision of existing systems, above all, was associated with the need to use tracks. The use of some new parts allowed us to simplify the design of the transmission, providing the possibility of movement both on wheels and on tracks.
An original armored casing was developed, designed to accommodate all the necessary devices and protect them from possible shelling. The body received inclined frontal sheets located at different angles to the vertical. Behind the upper frontal part, a kind of increased height was provided with observation instruments and a machine gun installation. Behind the wheelhouse, in the aft of the hull, a turret was placed. The sides of the hull were vertical. In the rear of the hull, a cutout was provided for the placement of some transmission units and the chassis. The tower received a cylindrical body with a beveled frontal part, accommodating armory installation. The roof of the tower was divided into an inclined front section and the rear half, which served as the hatch.
In front of the case was placed carburetor engine power 85 hp, borrowed from the base of the commercial chassis. The engine mated with a mechanical transmission, held over the bottom of the hull. The transmission of torque was carried out on the axis of the rear drive wheels. The transmission included some units that are responsible for making the turn when driving on tracks.
View from above. Figure Pro-tank.ru
The proposal to use the combined propulsion led to the development of an unusual chassis. Its largest unit was a tracked propulsion unit. On both sides of the hull were placed four support rollers, placed on trolleys with suspension Horstmann. The design of these units was borrowed from the British Universal Carrier armored personnel carrier. In front of the machine were placed the guide wheels, in the stern - leading. Outside, the chassis was covered with two large plates of complex shape. To enhance the chassis was equipped with an external beam connecting the installation of the support rollers and the guide wheel.
A characteristic feature of the crawler propulsion design E.Dzh. Scofield was the removal of aggregates off the side of the hull. Directly in front of the side was attached a front pair of road wheels. The guide wheel, in turn, was placed on the retaining beams at some distance in front of the front sheet.
Forehead and stern views. Figure Pro-tank.ru
The wheeled chassis had two bridges. The front wheels had a control system and were installed between the front track assemblies. When changing the propulsion unit, they fell to the ground and could be used for their intended purpose. The wheels were protected from shelling by a curved shield fixed above them. The axles of the crawler drive wheels were used as the basis for the rear axle. It was proposed to mount automobile wheels on the protruding trunks, after which the tank could go onto the highway. A characteristic feature of the wheeled chassis was the complete absence of elastic suspension elements. Because of this, even on a good road, the crew could encounter considerable shaking.
During the transition to the wheel propulsion, the crew had to install the rear wheels, after which the vehicle was hung on wheels using existing drives. The elements of the tracked undercarriage mounted on the longitudinal beams rose above the ground. The lower branch of the caterpillar was suspended from the chains by means of chains, due to which it rose above the ground to a height of about 10. When moving to a crawler movement, the driving wheels were removed and placed in round covers placed in the stern of the boards.
According to reports, the trained crew to replace the propulsion unit took no more than 10 minutes. In this case, the transition from the wheels to the tracks was carried out a little faster - in 7 minutes. To prepare the chassis, the crew had to leave the limits of the armored hull, due to which these procedures could not be carried out in a combat situation.
Experienced car, put on a wheel drive. Photo Archives New Zealand / Archives.govt.nz
Behind the engine in the case was placed the office of management with the jobs of the driver and one of the shooters. At the starboard was a control post with a set of necessary instruments. Watching the situation the driver should have been using the inspection hatch in the front sheet. Outside of the battlefield, it was possible to significantly improve visibility with a lifting roof. With the help of moving mechanisms, the roof rose up, forming a large gap above the sides. After moving the roof to the top position, the driver could raise his seat and watch the road “over the side”. Due to the relatively low height of the tower, the rise of the roof was possible only when it was turned. Otherwise, the roof interfered with a machine gun.
Armament tank Scofield arr. 1940 G. consisted of two Vickers machine guns chambered for .303 British. One machine gun was mounted in a ball mount on the front section of the control compartment, to the left of the driver's access hatch. The second machine gun was in the swing turret. In the fighting compartment and in the control compartment were placed racks for the transport of ammunition in the form of a large number of cartridge tapes. A machine gun in the front hull sheet could be used for attacking targets in a certain sector, while the turret provided a circular attack.
Scofield Tank on trial. Photo Mp.natlib.govt.nz
A crew of three was to control the combat vehicle. In the control compartment, side by side, the driver and assistant driver were placed. The latter was also responsible for using the front machine gun. The shooter commander was stationed in the fighting compartment and used weapons in the tower. Observe the situation with a set of viewing slots in different parts of the hull and tower. Access to workplaces was provided by hatches in the roof of the hull and tower.
The length of the advanced machine-gun tank reached 4,2 m, width - 2,7 m, height - about 2,5-2,7 m. Estimated combat weight was 6 t. Using a relatively powerful 85-strong engine made it possible to rely on good mobility on rough terrain. In addition, it was supposed to develop a fairly high speed on the highway when using wheel propulsion.
E.J. Scofield and his colleagues completed the development of a new project in the early summer of 1940. Soon a wooden mockup was built. The New Zealand military familiarized themselves with this product, after which they demanded to build two prototypes. An order for the construction of full-fledged prototypes appeared 19 August. The authors of the project, having received the approval of the customer, decided to attend to the future construction of serial machines in advance. For this, Chevrolet ordered the delivery of an 48 CKD truck chassis with slightly higher performance. In the future, they were to become the basis for serial tanks.
Demonstration of the military. Photo by Nevingtonwarmuseum.com
For several reasons, by December 1940, E.J. Scofield and his colleagues managed to build only one prototype. From the full-fledged combat vehicle proposed by the project, he was distinguished by the absence of a reservation, instead of which structural steel was used with similar parameters. Despite this feature, an experienced tank took part in the tests, showing its real capabilities.
Soon after the start of the field tests, the testers had to face serious problems. First of all, it was difficult to operate the engine. Placing the power plant inside the case without large ventilation grilles led to its rapid overheating. In addition, inadequate was the cross on sandy soils. In some circumstances, when driving on tracks, the car risked remaining without fixed front wheels. The small gauge of the steered wheels reduced mobility and maneuverability. In addition, with a sharp turn, it could lead to the side of the tank. However, the overall mobility scores were quite good. On tracks, the tank developed a speed of about 25 miles per hour (about 40 km / h), on wheels - twice as much. Cruising when using wheels was 350 miles (up to 560 km).
Due to engine problems and the correction of other deficiencies identified during inspections, tests of the first version of the Scofield tank were seriously delayed. At the same time, at the end of 1941, it was decided to test the car in conditions close to actual operation. The purpose of the next test was to run on the tracks and rugged terrain of the South Island of New Zealand. The experienced tank overcame the path to the destination with some difficulties. The road back was more difficult. In addition, considerable difficulties arose during subsequent field testing.
The tank shows its mobility on tracks. Photo by Nevingtonwarmuseum.com
As a result, the combined chassis received an ambiguous assessment. The ability to move on wheels to increase speed and save track life was an obvious advantage. However, the power plant could not cope with the load and needed to be improved, at least, the cooling system. The armament complex in its present form also did not fully suit the military. Two machine guns had insufficient firepower to fight with some modern targets, because of which the tank had to get a small-caliber cannon.
The military department of New Zealand, not satisfied with the proposed combat vehicle, did not insist on the cessation of work. The author of the project, in turn, proposed to continue the development of the project in accordance with the updated requirements. E.J. Scofield planned to re-equip the tank, as well as remake its main units, with the result that the finished machine had to completely arrange the customer.
The army agreed with this proposal. At the beginning of 1942, the designer received an official order to create a new modification of his tank. The result of further design work was the emergence of a completely new project that retained only some of the features of the original development. The new version of the Scofield tank was put to the test at the end of the 1942 of the year, and later proved to be a good idea both in domestic and foreign tests.
Driving over rough terrain, view of the rear of the armored vehicle. Photo Aviarmor.net
The fate of the only built Scofield tank arr. 1940 unknown. Apparently, after the completion of the tests, the machine was sent for storage, but was further dismantled and disposed of as unnecessary. Despite historical value, a similar pattern was not kept. By this time, the cancellation of the construction of serial tanks of the first model led to interesting consequences. In mid-1941, New Zealand received 48 ordered US-made trucks. They did not become the basis for tanks, but found application in their original quality.
In the early forties, the New Zealand military and the designers had no experience in building and operating armored vehicles. As a result, this experience had to be obtained here and now. In addition, the existing production facilities left much to be desired. Because of this, the first developments in the important area were not perfect, and also not widely used. Thus, the “Bob Sample Tank” was built in only three copies, and the first project of E.J. Scofield led to the construction of only one prototype.
On the materials of the sites:
http://armor.kiev.ua/
http://militaryfactory.com/
http://aviarmor.net/
http://pro-tank.ru/