Type 4 'Chi-To' Medium Tank prototype
After a series of false starts, the Japanese Army finally re-initiated its heavy tank program in early 1944. German heavy tanks were carefully evaluated, multiple foreign designs consulted, and German veterans shipped in at great danger in order to advise in the design of a new vehicle capable of maneuvering and operating successfully as a heavy tank in the rather unusual terrain conditions of the Asia-Pacific theatre.
The notable point of the 4 type medium tank is that it is a full-scale tank that was created for anti-tank battle from the beginning, unlike previous domestic tanks which were basically developed as infantry support tanks. However, the operational philosophy was simply based on the idea that "the enemy tanks are powerful" and was not intended for large-scale battles between tanks. The original 97 support tank was an infantry support tank. The variants and developments of this tank were improved for anti-tank combat, there was a limit to strengthening of the main gun and armor thickness that can be mounted due to the size of the original car body, the limit of engine power installed, and the suspension weight limit of traveling equipment.
In the general conditions of not only Japan but also the main battlefield Asian countries at that time, infrastructure was poor - roads, bridges and railways networks, and port capabilities of Japanese port facilities and transport vessels that are island countries, etc. It was underdeveloped compared to the Western powers. In Japan's tank design, weight reduction was required to be able to transport and operate under such circumstances.
Towards the end of the Second World War, Japan was no longer able to produce tanks in large numbers. The production of aircraft and ships required large quantities of raw materials. In addition, the Japanese were defeated on all fronts by allied forces. In a desperate attempt, Japan spent precious resources and money on well-armored and armed tanks that could only be produced in small numbers. The end result of this work was the Type 4 Chi-To, a thirty ton, all welded heavy tank with a maximum armor thickness of about 75mm. "Too little and too late" was the motto for the production of Japanese tanks between 1943 and 1945.
This design was changed by the revision of the weapons research policy in July 1943. Behind this change was the analysis of the two new tanks launched in the German-Soviet battle. From this point on, the thought of tanks in the Japanese Army has been changed from an infantry co-op to an emphasis on anti-tank combat. One of the attempts by Japanese engineers to design a very powerful tank was the Type 4 'Chi-To'. In July 1943, a Japanese delegation visited Hitler's Germany to view tanks there. The German 'Tiger' and 'Panther' tanks made a big impression on the Japanese. It was decided to purchase one copy of both models. However, the German vehicles never reached mainland Japan, tough the causes are unknown. An entirely new Japanese tank was designed that, in terms of armament and armor, had to be equivalent to the German tanks.
The Type 4 medium tank had good armor and good fire-power, but it was too late. The vehicle was armed with a powerful Type 5 75mm gun and two 7.7mm machine guns. Shells from the cannon could pierce 75mm steel up to a distance of one kilometer. Its main gun was converted from Type 4 75mm AA Gun and could penetrate the front armor of M4 Sherman from 1,000m distance. The anti-tank gun (long) was based on the Bofors 75mm high-intensity gun from Sweden , which was captured by the Japanese Army in the early days of China accident. The Japanese Army copied this and produced a Type-4 gun. The ammunition load was 65 rounds, of which 35 were stored under the vehicle floor and 30 were stored in the turret bustle.
The main armament was housed in a large, powered turret along with a coaxial machine gun. A single LMG was also mounted in the bow. Unusually, there was no LMG mounted to the rear of the turret in theType 4. As in most vehicles of the era, a provision was also made for an optional anti-aircraft machine gun, but this is one of the few vehicles in the Japanese arsenal in which photographs consistently depict it fitted. This may, indeed, reflect the increasingly desperate straights of the Japanese.
The large turret of the Type 4 consisted of three parts. The entire body was welded, and new attempts had been made to adopt cast turrets, which are not available in the previous domestic tanks. The cast turret casts and welds the left and right side armor plates and the rear armor plates separately. Bolting was used only for the back cast parts. Producing cast steel plates necessary for such a structure is a process that is unfamiliar to Japanese steel companies. In addition, since the molten cast steel shrinks when it cools and solidifies even when trial manufacture of the turret component, distortion of the cast component occurs and assembly is difficult.
Because of fuel shortages, the Type 4 was also one of the very few vehicles in the Japanese arsenal to have been designed from the beginning as a diesel. The fuel carried was 400 liters and the cruising range was 250 km. The track was 45 cm wide, and the traveling device was composed of seven single-sided rolling wheels, three upper rolling wheels, an activation wheel, and a guiding ring. The suspension method was the traditional spring-spring method. The super-wandering ability is 2.7m and the passing ability is 1.2m deep.
The engine was newly developed and designed by Mitsubishi from 1943. The Mitsubishi AL diesel engine (four-type diesel engine) was completed in the early 1944. This air-cooled engine could propell a tank weighing approximately 30 tons to 40 km/hr or more. Since the weight of this tank was expected to be 25t or more, when it was designed with the conventional controlled engine, the number of cylinders was increased to 20 cylinders, which made it too heavy. Therefore, the cylinder was increased in size and the displacement was increased to 37,700 cc, and it was newly developed. It was designed in pursuit of maintainability, cooling efficiency and reliability.
The first prototype was completed in 1944. Mitsubishi was responsible for the production of the tank. Lack of raw materials and allied bombing ensured that only six undercarriages were produced in 1945. Only two tanks were completed. Both tanks saw no action. As in the case of the Type 3 Chi-Nu, all crews were hand-picked, and it was hoped that the Chi-To would support massive armored assaults to drive the Allies back into the sea. In the event, the Allied invasion of Japan never happened, Japanese resources did not allow for the shipment of heavy vehicles overseas, and no such maneuvers took place. The tanks were dumped in Lake Hamana (near Shizuoka) to prevent American troops from taking possession of the tanks. One of the tanks was taken from the lake by American soldiers and was sent to the Aberdeen Proving Grounds for investigation, but there are various speculations about what happened later.
Some surviving examples were used during the 1950s as inspiration for Japan's post-war armored vehicle designs, which are currently considered to be among the best in the world. Certainly, the Type 4 was an impressive, modern design that would have given as well as it received, given the opportunity.
|Empty weight||18.8 tons|
|Armor||35 to 75 mm|
1 x Type 5 7.5 cm (75 mm) gun|
2 x Type 97 7.7 mm machine gun
|Engine|| Mitsubishi AL Type 4 air-cooled V12 diesel engine|
400 HP/1800 rpm
|Speed||45-50 km / h|
|Production quantity||2 pieces|
|Crew|| 5 men |
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