Type 74 (Nana-yon)

Form 74 (Nana-yon) Story

In 1972, a partnership between the Japan Ground Self-Defense Force (JGSDF) and Mitsubishi Heavy Industries led to the development of a main battle tank designed to replace the aging Type 61 tank from 1961. Decades after the end of World War II, the Japanese defense industry was on short-term leases to produce weapons of civil war, mostly equipped with U.S. military hardware. The Type 61 is significant because it was the first tank to come out of Japan after World War II. By 1962, however, MHI was already drawing up a new design to counter the latest generation of Soviet tanks - the T-62 series - a main battle tank that was not part of the existing Type 61 range.

The design was completed in 1964 and led to the construction of two pilot vehicles for evaluation trials by September 1969.

The prototype, designated STB-1, was a very traditional system, but comparable to its contemporaries. They feature the adjustable hydropneumatic suspension system of the ill-fated Virtue MBT-70, and the basic hull design of the German Leopard I series.

The vehicles are armed with a British 105mm L7 rifled main gun, attached to an automatic loader and mounted on a 360-degree rotating turret. The automatic loader is a product of Nippon Steel Works. The Commander's Cupola is fully traversable, allowing a 360-degree vantage point from the location.

The 12.7mm anti-aircraft machine gun system can also be remotely controlled from inside the vehicle.

These design constraints forced some modifications that culminated in the 1971 STB-3 prototype. The design was further developed into the final STB-6 pilot vehicle in 1973 and officially commissioned by the JGSDF in 1974. The basic "Type 74" designation was applied to the series. At this time, the autoloader function and the remote-controlled anti-aircraft gun were discontinued due to production costs, and a fourth crew member - a dedicated ammunition loader - was added to the then-many three-operator roster.

Serial production of the tank began a year later, with 225 delivered by early 1980. A total of about 893 prototypes were delivered to the Japan Ground Self-Defense Force in 10 major versions, with production officially ending in 1989.

The design of the Type 74 is very traditional for Cold War tank design, and actually mimics the look of several American Cold War tanks that came online during this period. The sides of the hull are spanned by a traditional five large wheel chain system, with the drive sprocket at the rear, the chain idler at the front, and no chain return rollers. The engine and turret forward midship were kept in the aft compartment. The crew consisted of four people, consisting of the driver, commander, gunner and loader.

The driver sits in the front left, and the turret houses the commander, gunner, and loader. The commander and gunner are on the right side of the turret, and the loader is on the left, operating the main gun breech as needed. Armor protection is the thickest at 120 mm. The sides of the tower are steeply sloped.

The base of the main gun is protected by a heavily armored curved cloak. There is a prominent smoke vent on the main gun and no muzzle brake. The commander's rangefinder works in tandem with the gunner's available digital fire control system for rapid response.

Antennas are noted on both sides of the rear tower area. On later models, a front-mounted dozer blade became an optional accessory.

The main gun is the proven Royal Ordnance L7 series 105mm towed main gun, mounted in a turret similar to the French AMX-30 series turret. About 55 105mm rounds were released to the crew. Secondary armament includes a heavy 12.7mm Browning M2HB machine gun for use against low-flying targets or soft-skinned vehicles. Mounted on the trunnion of the Commander's cupola, the gun holds 660 rounds of 12.7mm ammunition in the ammo box. A 7.62mm Type 74 machine gun was used as a coaxial anti-infantry weapon, with 4500 rounds of 7.62mm ammunition held by the gunner.

Six smoke grenade launchers were mounted on either side of the turret (three on each side) to cover offensive and defensive operations.

Power is provided by a 750 hp Mitsubishi 10ZF Type 21 10-cylinder diesel engine. This gives the tank a top speed of 38 mph and a range of nearly 250 miles. The suspension is hydropneumatic and promotes good off-road maneuverability. This special suspension system allows the driver to adjust the height of the tank in flight to suit the terrain being traversed - a design that dates back to the failed MBT-70 program between the Germans and Americans.

The suspension is very flexible (ground clearance is adjustable from 0.2m to 0.65m) and the driver can raise or lower the fuel tank at the front, rear or side as needed. As an added bonus, this system can also be used in conjunction with the addition of main guns to further increase the available bows.

Once the Type 74 entered service, it was subsequently upgraded to keep up with the needs of the battlefield. The most important of these updates is the installation of an infrared imager and a laser rangefinder (commander position).

A new 105mm projectile was also added to the Type 74's power, going hand in hand with the digital fire control system (gunner position).

The first production model was the Type 74 First Mod, followed by the Type 74 Mod B, Mod C, Mod D, Mod E, Mod F, and Mod G/Kai. The Mod G/Kai was a brief upgrade in 1993 that included the addition of side skirt armor protection and a passive infrared camera system to the sides of the hull. The Mod G/Kai upgrade program proved prohibitive and was discontinued.

Several variations in tank design form the basis of the Type 87 Self-Propelled Anti-Aircraft Gun (SPAAG), Type 78 Armoured Rescue Vehicle (ARV), and Type 91 Armoured Bridge Layer (AVLB) platforms - all three platforms use a complete chassis base74 type tank.

Despite progress, the Type 74 proved unsuitable for a new generation of globally available tanks, making it an unremarkable addition and in some ways obsolete even before it entered service. Thus, work began on another new main battle tank - this became the 120mm-armed Mitsubishi Type 90 in 1990 - which helped overcome the limitations of the Type 74. The Type 90 was designed to completely replace the outdated Type 74 series, but the end of the Cold War - and shrinking defense budgets - reduced this move, forcing the two tank types to operate side by side.

In any case, the domestically produced next-generation main battle tank system has emerged, taking on the roles of the Type 74 and Type 90 - this is the Type 10, which will enter service in 2012.

Specification

Basic

Roles

Dimensions

Performance

Performance

Armor

55x105mm projectile.

660x12.7mm ammo.

4,500x7.62mm ammo.

Changes