Project

Project - Specifications

Project - Pictures

Type 61

Type 61 - Development

Type 61 - Program

Type 61 - Armament

Type 61 - Mobility

Type 61 - Protection

Type 61 - Specifications

Type 61 - Pictures

Type 61 tank - Program

The Type 61 tank (Rokuichishi Kisensha), classified as a postwar first-generation tank, was officially adopted in April 1961. The first domestically produced tank after the war, it was deployed in place of second-hand tanks from World War II and the Korean War provided by the US military. Over 560 cars were produced before and after the adoption of the Type 74 tank in 1974, and it was used as a front-line tank for a long time after that.

61 type tank is MBT (main battle tank) developed domestically by Japan for the first time after the war. After losing World War II, Japan was occupied by the Allied Forces and was prohibited from maintaining and producing weapons. However, with the outbreak of the Korean War in June 1950, the General Headquarters of the Supreme Commander for the Allied Forces (GHQ), which had a heightened sense of crisis, decided to rearm Japan, and in 1952, the National Police Reserve was established as a security force. When it was reorganized into a corps, it received the weapons that the U.S. military possessed.

The Type 61 tank wasthe first example of a "main force" tank developed in Japan that had a good balance of post-war mobility, defense, and firepower. when the Korean War broke out, the US military stationed in Japan was dispatched to the Korean Peninsula and the National Police Reserve was created to fill the void. The United States donated the final production M4E3A8 ( Easy M4 Sherman medium tank and the M24 Chaffee light tank. This was later joined by the M41 Walker Bulldog light tank, but these were all armed with 75mm guns and were clearly no match for the Soviet T34/85. Even when the National Police Reserve became the National Safety Force in 1953 and the Self-Defense Force in 1954, tanks continued to be insecure .

In the postwar period, the Ground Self-Defense Force and its predecessors, the National Guard and Police Reserve, used tanks supplied by the United States, such as the M4A3E8 tank (M4 Sherman Easy Eight) and the M24 light tank. After the war, the first generation of tanks began to appear in various countries, and with the San Francisco Peace Treaty in 1952 (Showa 27) coming into force, the country was freed from occupation, and with the benefits of foreign aid from the United States, the number of tanks increased. The momentum for the shift to domestic production also accelerated.

The Korean War ceased in July 1953, and just one year later, in July 1954, Japan reorganized the National Security Forces into three Self-Defense Forces, the Ground, Maritime, and Air Forces, and the Defense Agency to manage and operate them. bottom. At that time, the American side was informed that the M41 light tank and M46 tank, which were worn out in various parts of Asia, including South Korea, should be revived in Japan and used as they are for the Self-Defense Forces. Many voices of support were heard in the Ground Self-Defense Force because it could be equipped.

However, some executives of the Ground Self-Defense Force and manufacturers such as Mitsubishi Heavy Industries, which worked on tank development for the former Japanese army, opposed this, and domestically developed MBT in order to revive Japanese tank development technology, which had been discontinued after the war. While persuading the internal bureau that it should be done, he steadily accumulated basic research such as engines.

As a result, in 1955, it was officially decided to develop a domestic MBT. At the prototype stage, there were parts that were based on the former Army's Type 4 medium tank, such as the suspension and transmission. While referring to the main battle tank, it has become a vehicle that retains the vestiges of the former Japanese Army tank.

Although it was classified as a medium tank , due to the domestic political situation at the time, it was called a " special vehicle " instead of a tank , but from January 1962 (Showa 37), it came to be called a "tank". The premise was to keep the profile as low as possible to avoid detection by the enemy, and to keep the overall width of 3 meters or less so as not to exceed the vehicle limit of conventional lines required for rail transport.

This domestically-produced MBT was given the name of "Chutokusha" (abbreviation: ST). The abbreviation of this vehicle, ST , is commonly used as an acronym for "trial production medium special vehicle", but in reality it is not an initial, but a Type 60 self-propelled 106mm recoilless gun SS ( " This is because it is the next development of "tracked armored vehicle" (or "armored combat vehicle", "armored tracked vehicle", etc.). and the abbreviations that follow are

• "SS" added in alphabetical order.
• ST: Type 61 tank "Chutokusha"
• SU: Experimental Type 56 Armored Car
• SV: Experimental Type 56 Self-propelled 81mm Mortar
• SW: Experimental Mine Clearing Vehicle
• SX: Experimental Type 56 Self-propelled 107mm Mortar
• SY: Experimental Type 56 105mm Self-propelled Gun
• SZ: Experimental Type 56 Special Transport Vehicle

The new constitution enacted in 1947 stipulated that Japan would not maintain military power, so the tanks owned by Japan were called "special vehicles" by replacing the word "sen", which reminds of military power, from the days of the National Guard. Therefore, "medium special car" is nothing but "medium tank". However, it gradually became inconsistent, and some vehicles were not named, and eventually this naming system disappeared naturally, and now the abbreviation TK-X (Tank experimental) for the next main battle tank remains.

In May 1955, the MSA Agreement, including the ``Mutual Defense Assistance Agreement between Japan and the United States,'' was promulgated, and Japan was to receive technical assistance from the United States to promote the domestic production of weapons. Based on this MSA agreement, in June, the United States loaned the M36 self-propelled anti-tank gun equipped with a 90mm tank gun to the Self-Defense Forces as a research sample.

The Type 61 tank is the first generation tank after the war, but due to delays in development, the world already has T-62 ( Soviet Union ), AMX-30 (France), M60 ( USA ), Leopard I (West Germany) with a 105mm or larger gun. After the war, the second generation tank equipped with a tank gun appeared, and the Type 61 became an obsolete tank one generation behind. This relationship will be transferred as it is at the time of the 74 type tank . The reason Japan caught up with the Type 90 was that each country stopped developing new tanks.

Production of the Type 61 tank continued for 13 years from 1962 to 1974, and a total of 560 vehicles were delivered to the Ground Self-Defense Force. After that, all vehicles were retired by the end of 2000 with the equipping of the Type 90 tank, which was developed as a substitute vehicle for this vehicle.

It was by no means a world-class tank, but for those who lamented the thinness of the armor of Japanese tanks during the war, the performance was sufficiently satisfactory. Without the Type 61 tank, the Type 74, Type 90 and Type 10 tanks would not have existed.

Although the Type 61 tank had several problems, such as the fact that the power pack of the power mechanism and the automatic transmission were not realized, and the timing of its appearance was too late for the first generation MBT after the war, it was a technological void after the war. It can be appreciated that it overcame the problems and created a tank that is comparable to other countries' post-war first-generation MBTs.

Type 61 tank - Development

The first two prototypes, the ST-A1 and ST-A2, incorporated the torsion bar suspension technology that had been researched before the war. In this way, the technology of the former Japanese army was able to be incorporated into tanks after the war because the former 4th Army Technical Research Institute, which was developing tanks, realized that it would not be possible to put it into practical use immediately. In addition to the engine and suspension, the 35t class tank with a cast turret and a large caliber gun mounted on the turret, not a riveted turret like the old army tank.

The ST was to be fitted with a new air-cooled diesel engine from Mitsubishi Heavy Industries, but as it had not yet been completed at this point, the first prototype was replaced with a liquid-cooled marine diesel from Mitsubishi Heavy Industries.·Equipped with a DL10T engine (output 550hp) modified for on-board use.

One of the first prototypes, the STA-1, has a body shape as low as the Leopard 1 tank, which is the second generation MBT of the former West Germany after the war, and the number of wheels is seven on one side, the same as the Leopard 1 tank. However, the STA-1 was forced to lower the vehicle height, so the vehicle body had to be extended by that amount, and the vehicle length was 6.60m, which was longer than the proposed request.

On the other hand, the STA-2 was manufactured in a form close to the request, and although the vehicle height is higher than the STA-1, the vehicle length is suppressed to 6.15m, and the number of wheels is 6 on each side, which is one less.

The two first prototype cars underwent break-in until April 1957, after which they were subjected to receipt inspections and various technical tests. Tests revealed that the STA-1, which has a longer hull, had worse turning performance than the STA-2, and that the rear-firing depression angle was extremely limited due to the step at the rear of the hull. For this reason, the second prototype was to be manufactured based on the body shape of the STA-2.

In December 1958, the manufacturer announced the production of two second prototypes, and the STA-4 was completed in November 1959, and the STA-3 in January 1960. The STA-3 and STA-4 had little difference in the basic structure of the hull and turret, and the same main gun and engine were installed, but the structure of the commander's cupola and the installation method of the 12.7mm heavy machine gun were different. There was a difference.

The STA-3 has a rear-opening gunner hatch on the left side of the center of the turret, and a low all-round swivel commander's cupola on the right side of the center. It was armed with a mm heavy machine gun.vOn the other hand, the commander's cupola of the STA-4 was changed to a cupola-type commander's gun turret similar to the American M48 Patton tank, and a 12.7mm heavy machine gun was equipped at the front of the turret.vThe turret can be rotated all around, and the 12.7mm heavy machine gun can be raised up and down from inside the turret. This cupola-type gun turret was originally devised by the U.S. military so that the vehicle commander could fire a 12.7mm heavy machine gun safely.

The STA-3 also had a powered semi-automatic feeder in the main gun magazine in the rear turret bustle. This is to send out the main gun ammunition in the magazine to the vicinity of the breech while rotating it with motor power, and it was designed to reduce the burden on the loader and enable quick shooting.

Using these two prototypes, various technical tests and operational tests were continued throughout 1960, and the test results were satisfactory, so in December of the same year, it was officially decided to adopt the ST as an MBT for the Ground Self-Defense Force. . Subsequently, work to determine the production type specifications of the ST and preparations for mass production proceeded, and in April 1961, it was formalized as the "61 type tank".

Type 61 tank - Design

The Type 61 tank has been handed down to future generations with a bad reputation. In the ST development goal proposal submitted by the Defense Agency Ground Staff Office at the end of January 1955, the ST was to be equipped with a combat weight of 25 tons and a 90 mm tank gun as the main gun. The American M4A3E8 medium tank that the Ground Self-Defense Force was equipped with at that time had a combat weight of 34 tons, and compared to this, the ST's combat weight of 25 tons was very light, but compared to the United States, it was mountainous and paddy fields. In Japan, where there are many regions, there was a strong opinion that it would be difficult to operate unless it was a light tank such as the M24 light tank (combat weight 18t).

The M36 anti-tank self-propelled gun was based on the chassis of the M4 medium tank, had a combat weight of 31 tons, and was equipped with an open-top turret with a 50-caliber 90mm rifled gun M3, the same as the M46 tank. From the results of shooting tests using this vehicle, it became clear that a 30t-class body weight was necessary to stably fire a 90mm tank gun. For this reason, the ST was to be developed as a 35-ton class tank, and in December 1955, the Defense Agency announced to the manufacturer that two first prototypes of the ST would be produced.

In the end, the ST was put into practical use as a 35t combat weight tank. Considering the terrain and railroad transportation in Japan, the Type 61 had a compact style. The turret was equipped with a 90mm gun, a 12.7mm machine gun, smoke discharger, and canvas fabric for the mantlet. It also uses technology from the former Japanese Army. Although the old army tanks are often said to have low performance, the technical level at that time was not necessarily low. Speaking of the former Japanese Army tanks, both in terms of firepower and armor, they were far behind the tanks of the US Army, which were their main opponents, and have received a terrible evaluation. However, the effort to catch up with the world standard while considering the operation in Japan and Asia region during the war will be utilized in the postwar Type 61 tank.

Mitsubishi Heavy Industries, which was in charge of development, developed tanks for the Japanese army before and during the war, and has improved its technology by being in charge of repairing American-made tanks after the war, and the new tank is an American-made tank provided after the war. It was developed in a way that incorporates the technology of the former army while being influenced by In particular, the engine is an air-cooled diesel engine, and in Japan, where tanks equipped with diesel engines were developed from the early days before and during the war, the technology accumulated at that time was greatly utilized.

Speaking of Japanese tanks during the war, the "Type 95 light tank" and "Type 97 medium tank" that confronted American tanks on the Pacific islands could not keep up with the rapid evolution of weapons and could not demonstrate satisfactory capabilities. is widely known. Therefore, even among the Japanese military weapons, which have many poor evaluations, tanks have a particularly low evaluation. However, although it has not fought, the "Type 3 medium tank" that can somehow fight the American "M4 tank" is being mass-produced for the mainland decisive battle, and research on the Type 4 and Type 5 tanks is also progressing. , On the design concept, there were elements that managed to catch up with the standards of each country just before the end of the war.

Such accumulation was finally demonstrated, and the "Type 61 tank" was born as a diesel engine-powered vehicle with a cast turret equipped with a 90mm gun and a steel plate welded body.

The design concept of the former army was inherited, and at first, after discussions at the Ground Staff Office and Fuji School, there was a request to create a light tank with a weight of 25 tons. However, it was impossible to mount a 90mm gun on that design, and even if the caliber of the gun was slightly reduced, it would certainly have had to shave off the armor.

In the production version of the Type 61 tank, the commander's cupola was a turret type like the STA-4, but the 12.7mm heavy machine gun was changed to be mounted externally with a mount on the top of the turret. , It was made possible to shoot remotely from within the turret. In addition, the adoption of the semi-automatic ammunition delivery device installed in the STA-3 was shelved for reasons such as cost.

After all, the weight will be 35t, and the armor will be 114mm for the turret and 55mm for the upper front of the hull. In fact, even with this, the frontal armor of the hull was thinner than that of the main battle tanks of the US and the Soviet Union at the time, but this was due to the immature tank technology in Japan at that time, so the armor of only the turret was thickened. It is said that this happened because the basic tactics of the Type 61 tank were ambush attacks that frequently used hull-downs (a tactic to protect the body by hiding everything other than the turret).

In terms of performance, compared to the tanks of the United States, Germany, the Soviet Union, and other countries in the 1960s, there are many technically immature parts, and it is said that the performance is inferior, but Japanese tanks that were thought to be discontinued. It must have played the role of inheriting technology and became the foundation of the Self-Defense Forces tank, catching up with later world standards such as the Type 74 tank.

Although the Type 61 tank had various structural weaknesses as a weapon , the development and production of the Type 61 tank established the development and production technology for the domestic main battle tank ( MBT ) , and the Ground Self-Defense Force began operating domestic tanks. It was very meaningful to be able to meet him. It seems that the design of the M36 tank destroyer provided by the US military was largely used as a reference during development.

The basics of combat for the Type 61 tank are against enemy Marines' PT76 light tanks or, at best, T55s. Still, if forced to fight the T72 class, it would have to act like the Sherman tank did to the Tiger tank in WW2. It is impossible to destroy them from the front, but it is possible to use old-style armor-piercing bullets from the sides and rear.

After the Type 74, which incorporated the lessons of the Type 61, Japan was able to develop tanks that were more or less in line with the world trend and also suited to Japan's national conditions. In that sense, the Type 61 may have been a tank filled with a warning: "It's too early to think that everything has changed after the war! The postwar isn't over yet!"

Type 61 tank - Armament

As the main gun, the Type 61 tank is equipped with a 52-caliber 90mm rifle (Type 61 90mm tank gun) developed independently by Japan Steel Works, based on the 90mm rifled gun equipped in the American Patton tank series. , Although classified as the first generation MBT after the war, the former Soviet T-62 medium tank, which is equipped with a 115mm smoothbore gun and classified as the second generation MBT after the war, began mass production in 1961. It appears one generation later.

The main gun mounted on the cast (cast) turret is a 52-caliber 90mm rifled cannon , and it can be said that it was a powerful armament for its light and compact body at the time. The official name is " M3 Kai 90mm Tank Gun ", and as the name suggests , the M3 type 90mm gun used by the M26 Pershing and the M36 tank destroyer has been made longer by the Japan Steel Works . The chamber and barrel strength have also been improved, making it compatible with post-war standard 90mm shells.

At first, armor -piercing bullets with caps were used, but they were too weak against the Soviet T-55 and T-62 , so from 1970 , Type 70 anti -tank missiles ( HEAT bullets ) were used. Deployed. In the case of an emergency one morning before that , it seems that they were planning to face the T-54/55 after receiving high-velocity armor-piercing ammunition ( HV AP ) from the US military.

In 1982 , the APFSDS for the Type 61 tank was also developed, prototyped, and successfully tested. However, it must be less powerful than the Type 70 anti-tank grenade . This was shelved as the license for the M73 5A P FS DS for the Type 74 tank took precedence. Licensed ammunition was expensive and not easy to manufacture, so APFSDS was concentrated on Type 74 105 mm.

The main gun ammunition is M318A1 APCBC (armor-piercing shell with wind cap), M431 HEAT (anti-tank high-explosive shell), and M71 HE (high-explosive shell). When using M318A1, the muzzle velocity is 910m/sec, and the range is 1,000m. It is possible to penetrate 189 mm thick RHA (homogeneously rolled armor plate). This is about the same power as the 100mm rifle mounted on the T-54/T-55 medium tanks, the first generation MBTs of the former Soviet Union after the war.

The muzzle brake ( muzzle deterrent) suppresses the recoil of the main gun by promoting the discharge of gas from the muzzle when the cannon fires the shell , reducing blurring and increasing the hit rate. In modern times, it has become obsolete because it improves the performance of parking aircraft and decreases the accuracy of AP DS and APFSDS. The Type 61 tank adopted a T- shaped muzzle brake based on the M48 , the best-selling tank " 3rd generation Patton tank ", which can be called the standard in the western world . The main gun barrel of the Type 61 tank itself is a unique improvement based on the main gun of the American tank.

The function of the muzzle brake also has the function of quickly discharging and diffusing gun smoke , so it is also a "chimney" in a sense. Thanks to this, the Type 61 had a smaller firing flame than the Type 74, and demonstrated considerable accuracy when hit by a craftsman 's gunner.

The depression and elevation angle of the main gun is -10 to +13 degrees, which is larger than the Leopard 1 and AMX-30 tanks that appeared around the same time as the Type 61 tank, which seems to support this. It was often said that it was inferior to WW2 's Tiger and Panther. However, although there are some technical deficiencies, the quality of the main gun and bulletproof steel plate has been improved, the development of new shells, the use of highly flame-retardant diesel , and the lessons learned from WW2.

In 1955, the Soviet Union, which was a hypothetical enemy, had already begun deploying T54 tanks equipped with 100mm tank guns , and the United States , while still maintaining the 90mm guns that had been formalized at the end of World War II, had the latest M48 tanks. -Deployment, in 1956, development of the M60 equipped with a 105mm tank gun has begun. Nonetheless, the T-54 first appeared in public during the Hungarian uprising of 1956, so at that time, it was right to think that it was a "tank that could fully compete with the T-34/85".

By the time the 61 tank was adopted, Western tanks were already in the process of transitioning to 105mm tank guns, and at the time of its appearance, it was already given the title of 2nd class. However, due to the minimal body design of the 90mm tank gun, it is impossible to replace it with a 105mm tank gun, and the development of the next tank (Type 74 tank) has begun, and the maintenance of the next tank was prioritized. The tank received almost no modifications.

There was an improvement to install Vickers L7 on the Type 61, but it was abandoned due to the fact that the balance of the car body would deteriorate significantly and it would be difficult to operate.

Armament other than the main gun is M2 heavy machine gun , M1 919 coaxial machine gun . Both are old machine guns from WW2 , but it is said that the latter in particular was much more reliable than the domestically produced Type 74 7.62 mm machine gun and was well received.

Type 61 tank - Protection

Initially, domestic tanks were required to be small and light due to Japan's geographical factors, and the weight was considered to be 25 tons. In Japan , which was still in the process of post - war reconstruction , there was no infrastructure or technology to build a larger tank.

The idea of ``the lighter the tank, the better'' since the old army was inherited until after the war. Rather than primary factors such as firepower and defense power, secondary factors such as railroad transportation and road conditions were emphasized. However, in order to mount a 90mm gun, it is impossible to make it 25t, and the required weight is 30t, and finally the Type 61 tank will be completed at 35t.

The armor thickness of the Type 61 tank is said to be 55mm on the upper front, 46mm on the lower front, 36mm on the sides, 16mm on the top/bottom, and 114-102mm on the front, 100-40mm on the sides, and 40mm on the top/rear of the turret.

It is natural to thicken the armor of the turret, which has a high probability of being hit, but since the armor of the turret is much thicker than the body, the Type 61 tank is dug into the tank trench. It is presumed that the operation was assumed to ambush enemy tanks.

As a result of primarily considering rail transport, it was lighter than the M47 by more than 10 tons, but at the expense of armor (the armor thickness of the Type 61 has not been announced, but it is certain that it is thinner than the M47. ). Its weak point is that it has a high vehicle height and an opening on the front of the vehicle that is more likely to be hit. The Type 61's firepower is equal to or greater than that of the M47, but it is clearly at a disadvantage in terms of defense.

The development of the prototype tank " STA ", which later became the Type 61, was decided in the 1950s , and at that time the main force of the Soviet tanks landing in Hokkaido and other places was the T-34. The T34/85 was used for a long time in the Soviet bloc countries even after the war and was put into many actual battles. The T34's D-5 type 85mm tank gun could penetrate about 100mm of armor at 1000m. The armor thickness of the Type 61 is undisclosed, but the gun shield is 90mm, and the front of the hull is about 70mm.

In order to be transported by Japanese railways , which have narrow rails and narrow tunnels , the car body is small and light, with a 570 -horsepower V12 direct- injection air- cooled turbocharged diesel engine with good fuel efficiency and fire resistance, inheriting the tradition from the days of the former Imperial Japanese Army, was installed at the rear.

It is a drive layout that can be called RF ( rear engine front drive ) , unlike the FF , FR , and MR of general cars , where the driving force of the rear - mounted engine is transmitted to the front derailleur via the drive shaft to move the front wheels . This suggests that the remnants of the old military tank design still remained strong at that time. Also, due to this body structure, it was a weak point in terms of protection that the armor on the front of the body had to be detachable with bolts for maintenance .

For this reason, the armor on the hull and front of the turret is resistant to the T-34 /85's 85mm armor-piercing bullets . Despite that purpose , durability tests on the hull have been limited to the Bofors 40mm cannon . The front of the turret is said to be cast armor with a maximum thickness of 102 mm. Aside from the armor, the weak point was the hydraulic turret rotation , which was a fire hazard when hit.

Type 61 tank - Mobility

The interior layout of the Type 61 tank is the cockpit on the right side of the front of the vehicle, the storage room for the transmission and steering gear on the left side of the front, the battle room with the all-around turret in the center of the vehicle, and the engine and cooling system on the rear of the vehicle.

The propeller shaft is extended forward from the engine placed at the rear of the vehicle body, and the front driving wheel is driven through the transmission and steering gear placed at the front of the vehicle body, but this is the old Japan during the war. It is similar to the power transmission mechanism of military tanks.

In May 1955, the Ground Staff Office presented the ST's first required performance plan, and the ST was like the American M46 tank. It was planned to put it in the rear and drive the driving wheel placed at the rear, but it was difficult to make a power pack of the power mechanism with the technology of Japan at that time, so this was eventually abandoned, and the old Japanese army tank A mechanism was used.

The power pack of this power mechanism was later realized in the Type 74 tank, which was developed as a successor to the Type 61 tank. Since the Type 61 tank houses the transmission and steering gear on the left side of the front part of the body, the front body armor plate is removed during inspection and maintenance. It is a screwed panel so that it can be removed.

The engine of the Type 61 tank adopts a domestic air-cooled diesel engine with good fuel efficiency and low risk of fire, whereas the first generation MBT of the United States and the United Kingdom after the war adopted a gasoline engine. Since before the war, Japan has developed an air-cooled diesel engine domestically ahead of other countries and installed it in tanks, and was very advanced in this respect.

The diesel engine for the Type 61 tank was developed by Mitsubishi Heavy Industries. This engine, called 12HM20WT, was a 4-stroke, 90-degree V-type 12-cylinder direct-injection, air-cooled diesel engine, supercharged by two turbochargers, with a displacement of 29.6 liters and a maximum output of 604 hp.

This 12HM20WT diesel engine was also installed in the second prototype vehicles STA-3 and STA-4, and the 12HM21WT diesel engine that improved the defects found in the test was installed in the production type 61 tank. The 12HM21WT diesel engine has a maximum output of 570hp/2,100rpm and a maximum shaft torque of 200kgm.

* Gasoline is extracted at a distillation temperature of 30 to 230 degrees Celsius, and diesel oil is extracted at a distillation temperature of 140 to 380 degrees Celsius. Diesel oil has a higher volatilization temperature . Gasoline is more volatile and flammable than light oil , and is a dangerous substance. Therefore, diesel engines that use light oil are more suitable for tanks that are at risk of being hit and burned . It is for the same reason that Israel upgraded the Magach by replacing the gasoline engine of the M60 tank purchased from the United States with a diesel engine.

Fuel efficient direct injection engine and diesel engineSince it is technically easier, Mitsubishi 's specialty direct injection engine was commercialized from the diesel engine . In addition, diesel engines are suitable for turbo boosting, which uses exhaust gas to turn the turbine, and which can perform high exhaust pressure and quick boosting even at low speeds.

The transmission/steering mechanism of the Type 61 tank is a double differential manual transmission/steering mechanism with 5 forward speeds and 1 reverse speed. The mechanism was outdated and difficult to operate compared to the Kouki. The first prototype of the ST was equipped with a newly developed automatic transmission/steering gear with a torque converter called the 'ST type', but this had a large power loss and was prone to failure.

At the time, it was difficult for Japan to make fundamental improvements, so in the end, the automatic transmission was abandoned and replaced with a mechanical steering gear with a manual transmission. The first mechanical steering gear that was manufactured was a clutch/brake type with a planetary reduction gear, the same as that used in the former Japanese Army's Type 4 medium tank (Chito car), hence the name 'Chito type'. had been given.

In August 1957, the Chito-type transmission/steering gear was installed on the STA-2 and tested, but the power transmission did not go smoothly and it was prone to failure, so a differential gear was added. I tried to improve it. This double differential steering gear was installed in the second prototype vehicle, and because the test results were good, it was also adopted in the production version of the Type 61 tank.

The prototype of the Type 61 was a front-wheel drive system with the transmission and starting wheels in front of the vehicle body, and the mass-produced model was the same. This has been a tradition since the old military, but it had the drawback of increasing the vehicle height. In addition, it was not preferable that the opening for maintenance of the transmission was located in the front part of the vehicle body, where the probability of being hit by bullets was high.

These were problems that were difficult to solve with the technological capabilities of Japan at the time (in terms of operation, it seems that there were voices pushing for a front-wheel drive that could prevent the caterpillar from coming off). The Type 74 tank, which is the successor to the Type 61, adopts a rear-wheel drive system.

It is said that the type 61 was difficult to operate the clutch and could not be operated well unless it was an expert. However, the mobility itself was not bad, and the acceleration figures up to 200m were comparable to post-war third-generation tanks , making it suitable for hit-and-away. In addition, due to the layout of the drive shaft and transmission , the temperature in the cockpit in particular was extremely high, reaching nearly 60°C, making it a very harsh environment .

Crew	4 people
weight	35 tons
full length	8.19m
body length	6.30m
Width	2.95m
Height	2.49m ( 3.16m with M2 machine gun on turret )
main gun	Type 61 52 caliber 90mm rifle
muzzle muzzle velocity approx. 910m/s (when using M318AP-T)
secondary armament	7.62mm machine gun M1919A4 ( main gun coaxial )
	12.7mm heavy machine gun M2 (upper turret, length observation tower)
armor *	Turret 114mm Body 55mm Front: 55-46mm, angle unknown (around 45°) Side: 36mm, angle unknown (almost upright) Rear: 16mm Turret front: 114-102mm, R-shaped turret side: 100-40mm , R shape) Turret rear surface: 40mm * Official figures are unknown, but it is said to be about this.
engine	Mitsubishi 12HM21WT air-cooled 4 -stroke V12 direct injection turbocharged diesel engine 570hp/2,100rpm
Displacement	29,600cc
Suspension method	Torsion bar type
speed	45km/h
acceleration	25 seconds acceleration time for 200m section (0-200m section)
range	200km
Hill-climbing power	31°
Fuel consumption	0.3km/L
Minimum turning radius	10m